[Title 30 CFR ]
[Code of Federal Regulations (annual edition) - July 1, 2017 Edition]
[From the U.S. Government Publishing Office]
[[Page i]]
Title 30
Mineral Resources
________________________
Parts 1 to 199
Revised as of July 1, 2017
Containing a codification of documents of general
applicability and future effect
As of July 1, 2017
Published by the Office of the Federal Register
National Archives and Records Administration as a
Special Edition of the Federal Register
[[Page ii]]
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[[Page iii]]
Table of Contents
Page
Explanation................................................. v
Title 30:
Chapter I--Mine Safety and Health Administration,
Department of Labor 3
Finding Aids:
Table of CFR Titles and Chapters........................ 765
Alphabetical List of Agencies Appearing in the CFR...... 785
List of CFR Sections Affected........................... 795
[[Page iv]]
----------------------------
Cite this Code: CFR
To cite the regulations in
this volume use title,
part and section number.
Thus, 30 CFR 1.1 refers to
title 30, part 1, section
1.
----------------------------
[[Page v]]
EXPLANATION
The Code of Federal Regulations is a codification of the general and
permanent rules published in the Federal Register by the Executive
departments and agencies of the Federal Government. The Code is divided
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name of the issuing agency. Each chapter is further subdivided into
parts covering specific regulatory areas.
Each volume of the Code is revised at least once each calendar year
and issued on a quarterly basis approximately as follows:
Title 1 through Title 16.................................as of January 1
Title 17 through Title 27..................................as of April 1
Title 28 through Title 41...................................as of July 1
Title 42 through Title 50................................as of October 1
The appropriate revision date is printed on the cover of each
volume.
LEGAL STATUS
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HOW TO USE THE CODE OF FEDERAL REGULATIONS
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OMB CONTROL NUMBERS
The Paperwork Reduction Act of 1980 (Pub. L. 96-511) requires
Federal agencies to display an OMB control number with their information
collection request.
[[Page vi]]
Many agencies have begun publishing numerous OMB control numbers as
amendments to existing regulations in the CFR. These OMB numbers are
placed as close as possible to the applicable recordkeeping or reporting
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PAST PROVISIONS OF THE CODE
Provisions of the Code that are no longer in force and effect as of
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for 1949-1963, 1964-1972, 1973-1985, and 1986-2000.
``[RESERVED]'' TERMINOLOGY
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INCORPORATION BY REFERENCE
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This material, like any other properly issued regulation, has the force
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What is a proper incorporation by reference? The Director of the
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the requirements of 1 CFR part 51 are met. Some of the elements on which
approval is based are:
(a) The incorporation will substantially reduce the volume of
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(b) The matter incorporated is in fact available to the extent
necessary to afford fairness and uniformity in the administrative
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(c) The incorporating document is drafted and submitted for
publication in accordance with 1 CFR part 51.
What if the material incorporated by reference cannot be found? If
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this volume.
[[Page vii]]
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Oliver A. Potts,
Director,
Office of the Federal Register.
July 1, 2017.
[[Page ix]]
THIS TITLE
Title 30--Mineral Resources is composed of three volumes. The parts
in these volumes are arranged in the following order: parts 1--199,
parts 200--699, and part 700 to end. The contents of these volumes
represent all current regulations codified under this title of the CFR
as of July 1, 2017.
For this volume, Gabrielle E. Burns was Chief Editor. The Code of
Federal Regulations publication program is under the direction of John
Hyrum Martinez, assisted by Stephen J. Frattini.
[[Page 1]]
TITLE 30--MINERAL RESOURCES
(This book contains parts 1 to 199)
--------------------------------------------------------------------
Part
chapter i--Mine Safety and Health Administration, Department
of Labor.................................................. 1
[[Page 3]]
CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
--------------------------------------------------------------------
Editorial Note: Nomenclature changes to chapter I appear at 69 FR
18803, Apr. 9, 2004.
SUBCHAPTER A--OFFICIAL EMBLEM AND OMB CONTROL NUMBERS FOR RECORDKEEPING
AND REPORTING
Part Page
1 Mine Safety and Health Administration;
establishment and use of official emblem 7
3 OMB Control Numbers under the Paperwork
Reduction Act........................... 7
SUBCHAPTER B--TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS
5 Fees for testing, evaluation, and approval
of mining products...................... 11
6 Testing and evaluation by independent
laboratories and non-MSHA product safety
standards............................... 12
7 Testing by applicant or third party......... 14
14 Requirements for the approval of flame-
resistant conveyor belts................ 90
15 Requirements for approval of explosives and
sheathed explosive units................ 94
18 Electric motor-driven mine equipment and
accessories............................. 101
19 Electric cap lamps.......................... 143
20 Electric mine lamps other than standard cap
lamps................................... 148
22 Portable methane detectors.................. 153
23 Telephones and signaling devices............ 157
27 Methane-monitoring systems.................. 162
28 Fuses for use with direct current in
providing short-circuit protection for
trailing cables in coal mines........... 170
33 Dust collectors for use in connection with
rock drilling in coal mines............. 175
35 Fire-resistant hydraulic fluids............. 182
[[Page 4]]
36 Approval requirements for permissible mobile
diesel-powered transportation equipment. 189
SUBCHAPTERS C-F [RESERVED]
SUBCHAPTER G--FILING AND OTHER ADMINISTRATIVE REQUIREMENTS
40 Representative of miners.................... 203
41 Notification of legal identity.............. 204
42 National Mine Health and Safety Academy..... 206
43 Procedures for processing hazardous
conditions complaints................... 207
44 Rules of practice for petitions for
modification of mandatory safety
standards............................... 210
45 Independent contractors..................... 222
SUBCHAPTER H--EDUCATION AND TRAINING
46 Training and retraining of miners engaged in
shell dredging or employed at sand,
gravel, surface stone, surface clay,
colloidal phosphate, or surface
limestone mines......................... 224
47 Hazard Communication (HazCom)............... 232
48 Training and retraining of miners........... 240
49 Mine rescue teams........................... 260
SUBCHAPTER I--ACCIDENTS, INJURIES, ILLNESSES, EMPLOYMENT, AND PRODUCTION
IN MINES
50 Notification, investigation, reports and
records of accidents, injuries,
illnesses, employment, and coal
production in mines..................... 274
SUBCHAPTER J [RESERVED]
SUBCHAPTER K--METAL AND NONMETAL MINE SAFETY AND HEALTH
56 Safety and health standards--surface metal
and nonmetal mines...................... 285
57 Safety and health standards--underground
metal and nonmetal mines................ 341
[[Page 5]]
58 Health standards for metal and nonmetal
mines................................... 443
SUBCHAPTER L [RESERVED]
SUBCHAPTER M--UNIFORM MINE HEALTH REGULATIONS
62 Occupational noise exposure................. 444
SUBCHAPTER N [RESERVED]
SUBCHAPTER O--COAL MINE SAFETY AND HEALTH
70 Mandatory health standards--underground coal
mines................................... 452
71 Mandatory health standards--surface coal
mines and surface work areas of
underground coal mines.................. 466
72 Health standards for coal mines............. 480
74 Coal mine dust sampling devices............. 485
75 Mandatory safety standards--underground coal
mines................................... 496
77 Mandatory safety standards, surface coal
mines and surface work areas of
underground coal mines.................. 679
90 Mandatory health standards--coal miners who
have evidence of the development of
pneumoconiosis.......................... 735
SUBCHAPTER P--CIVIL PENALTIES FOR VIOLATIONS OF THE FEDERAL MINE SAFETY
AND HEALTH ACT OF 1977
100 Criteria and procedures for proposed
assessment of civil penalties........... 747
101-103 [Reserved]
SUBCHAPTER Q--PATTERN OF VIOLATIONS
104 Pattern of violations....................... 760
105-199 [Reserved]
[[Page 7]]
SUBCHAPTER A_OFFICIAL EMBLEM AND OMB CONTROL NUMBERS FOR RECORDKEEPING
AND REPORTING
PART 1_MINE SAFETY AND HEALTH ADMINISTRATION; ESTABLISHMENT AND USE
OF OFFICIAL EMBLEM--Table of Contents
Sec.
1.1 Official emblem.
1.2 Description.
1.3 Use of letters and acronym MSHA.
Authority: Sec. 508, Federal Coal Mine Health and Safety Act of
1969; sec. 301 of Title 5, United States Code; secs. 301(a) and 302(a),
Federal Mine Safety and Health Amendments Act of 1977, Pub. L. 95-164,
30 U.S.C. 961 and 951 and 29 U.S.C. 577a, 91 Stat. 1317 and 91 Stat.
1319; sec. 508, Federal Mine Safety and Health Act of 1977, Pub. L. 91-
173 as amended by Pub. L. 95-164, 30 U.S.C. 957, 83 Stat. 803.
Source: 39 FR 23997, June 28, 1974, unless otherwise noted.
Sec. 1.1 Official emblem.
The following emblem is established and shall be used as the
official emblem of the Mine Safety and Health Administration, except
where use of the Departmental Seal is required:
[GRAPHIC] [TIFF OMITTED] TC22OC91.000
[39 FR 23997, June 28, 1974, as amended at 43 FR 12312, Mar. 24, 1978]
Sec. 1.2 Description.
The emblem of the Mine Safety and Health Administration is of
contemporary design with the letters and acronym of the Administration
delineated as MSHA appearing in large letters in the middle of the
emblem. Above the letters and acronym appear the words ``United States
Department of Labor'' and below the letters and acronym appear the words
``Mine Safety and Health Administration.''
[39 FR 23997, June 28, 1974, as amended at 43 FR 12312, Mar. 24, 1978]
Sec. 1.3 Use of letters and acronym MSHA.
The letters and acronym MSHA may be used and substituted for the
words ``Mine Safety and Health Administration'' in correspondence,
rules, regulations, and in certificates of approval, approval plates,
labels, and markings prescribed by the Mine Safety and Health
Administration to designate and denote equipment, devices, and apparatus
approved as ``permissible'' and suitable for use in mines under the
applicable parts of Chapter I of this title, and in such other
documents, publications, and pamphlets, and on signs, clothing and
uniforms, and offices of the Administration and at such times and
locations as may be deemed appropriate by the Assistant Secretary of
Labor for Mine Safety and Health.
[39 FR 23997, June 28, 1974, as amended at 43 FR 12312, Mar. 24, 1978]
PART 3_OMB CONTROL NUMBERS UNDER THE PAPERWORK REDUCTION ACT--
Table of Contents
Authority: 30 U.S.C. 957; 44 U.S.C. 3501-3520.
Sec. 3.1 OMB control numbers.
The collection of information requirements in MSHA regulation
sections in this chapter have been approved and assigned control numbers
by the Office of Management and Budget (OMB) under the Paperwork
Reduction Act. Regulation sections in this chapter containing paperwork
requirements and their respective OMB control numbers are displayed in
the following table:
Table 1--OMB Control Numbers
------------------------------------------------------------------------
30 CFR Citation OMB Control No.
------------------------------------------------------------------------
Subchapter B--Testing, Evaluation, and Approval of Mining Products
------------------------------------------------------------------------
6.10................................................. 1219-0066
7.3.................................................. 1219-0066
7.4.................................................. 1219-0066
7.6.................................................. 1219-0066
7.7.................................................. 1219-0066
[[Page 8]]
7.23................................................. 1219-0066
7.27................................................. 1219-0066
7.28................................................. 1219-0066
7.29................................................. 1219-0066
7.30................................................. 1219-0066
7.43................................................. 1219-0066
7.46................................................. 1219-0066
7.47................................................. 1219-0066
7.48................................................. 1219-0066
7.49................................................. 1219-0066
7.51................................................. 1219-0066
7.63................................................. 1219-0066
7.69................................................. 1219-0066
7.71................................................. 1219-0066
7.83................................................. 1219-0066
7.90................................................. 1219-0066
7.97................................................. 1219-0066
7.105................................................ 1219-0066
7.108................................................ 1219-0066
7.303................................................ 1219-0066
7.306................................................ 1219-0066
7.309................................................ 1219-0066
7.311................................................ 1219-0066
7.403................................................ 1219-0066
7.407................................................ 1219-0066
7.408................................................ 1219-0066
7.409................................................ 1219-0066
7.411................................................ 1219-0066
15.4................................................. 1219-0066
15.8................................................. 1219-0066
18.6................................................. 1219-0066
18.15................................................ 1219-0066
18.53................................................ 1219-0066, -0116
18.81................................................ 1219-0066
18.82................................................ 1219-0066
18.93................................................ 1219-0066
18.94................................................ 1219-0066
19.3................................................. 1219-0066
19.13................................................ 1219-0066
20.3................................................. 1219-0066
20.14................................................ 1219-0066
22.4................................................. 1219-0066
22.8................................................. 1219-0066
22.11................................................ 1219-0066
23.3................................................. 1219-0066
23.7................................................. 1219-0066
23.10................................................ 1219-0066
23.12................................................ 1219-0066
23.14................................................ 1219-0066
27.4................................................. 1219-0066
27.6................................................. 1219-0066
27.11................................................ 1219-0066
28.10................................................ 1219-0066
28.23................................................ 1219-0066
28.25................................................ 1219-0066
28.30................................................ 1219-0066
28.31................................................ 1219-0066
33.6................................................. 1219-0066
33.12................................................ 1219-0066
35.6................................................. 1219-0066
35.10................................................ 1219-0066
35.12................................................ 1219-0066
36.6................................................. 1219-0066
36.12................................................ 1219-0066
------------------------------------------------------------------------
Subchapter G--Filing and Other Administrative Requirements
------------------------------------------------------------------------
40.3................................................. 1219-0042
40.4................................................. 1219-0042
40.5................................................. 1219-0042
41.20................................................ 1219-0042
43.4................................................. 1219-0014
43.7................................................. 1219-0014
44.9................................................. 1219-0065
44.10................................................ 1219-0065
44.11................................................ 1219-0065
45.3................................................. 1219-0040
45.4................................................. 1219-0040
------------------------------------------------------------------------
Subchapter H--Education and Training
------------------------------------------------------------------------
46.3................................................. 1219-0131
46.5................................................. 1219-0131
46.6................................................. 1219-0131
46.7................................................. 1219-0131
46.8................................................. 1219-0131
46.9................................................. 1219-0131
46.11................................................ 1219-0131
47.31................................................ 1219-0133
47.32................................................ 1219-0133
47.32(a)(4).......................................... 1219-0133
47.41................................................ 1219-0133
47.51................................................ 1219-0133
47.71................................................ 1219-0133
47.73................................................ 1219-0133
48.3................................................. 1219-0009, -0141
48.9................................................. 1219-0009
48.23................................................ 1219-0009
48.29................................................ 1219-0009
49.2................................................. 1219-0078
49.3................................................. 1219-0078
49.4................................................. 1219-0078
49.6................................................. 1219-0078
49.7................................................. 1219-0078
49.8................................................. 1219-0078
49.9................................................. 1219-0078
49.12................................................ 1219-0144
49.16................................................ 1219-0144
49.18................................................ 1219-0144
49.50................................................ 1219-0144
------------------------------------------------------------------------
Subchapter I--Accidents, Injuries, Illnesses, Employment, and Production
in Mines
------------------------------------------------------------------------
50.10................................................ 1219-0007, -0141
50.11................................................ 1219-0007, -0141
50.20................................................ 1219-0007
50.30................................................ 1219-0007
------------------------------------------------------------------------
Subchapter K--Metal and Nonmetal Mine Safety and Health
------------------------------------------------------------------------
56.1000.............................................. 1219-0042
56.3203(a)........................................... 1219-0121
56.5005.............................................. 1219-0048
56.13015............................................. 1219-0089
56.13030............................................. 1219-0089
56.14100............................................. 1219-0089
56.18002............................................. 1219-0089
56.19022............................................. 1219-0034
56.19023............................................. 1219-0034
56.19057............................................. 1219-0049
56.19121............................................. 1219-0034
57.1000.............................................. 1219-0042
57.3203(a)........................................... 1219-0121
57.3461.............................................. 1219-0097
57.5005.............................................. 1219-0048
57.5037.............................................. 1219-0003
57.5040.............................................. 1219-0003
57.5047.............................................. 1219-0039
57.5060.............................................. 1219-0135
[[Page 9]]
57.5065.............................................. 1219-0135
57.5066.............................................. 1219-0135
57.5067.............................................. 1219-0135
57.5070.............................................. 1219-0135
57.5071.............................................. 1219-0135
57.5075.............................................. 1219-0135
57.8520.............................................. 1219-0016
57.8525.............................................. 1219-0016
57.11053............................................. 1219-0046
57.13015............................................. 1219-0089
57.13030............................................. 1219-0089
57.14100............................................. 1219-0089
57.18002............................................. 1219-0089
57.19022............................................. 1219-0034
57.19023............................................. 1219-0034
57.19057............................................. 1219-0049
57.19121............................................. 1219-0034
57.22004(c).......................................... 1219-0103
57.22204............................................. 1219-0030
57.22229............................................. 1219-0103
57.22230............................................. 1219-0103
57.22231............................................. 1219-0103
57.22239............................................. 1219-0103
57.22401............................................. 1219-0096
57.22606............................................. 1219-0095
------------------------------------------------------------------------
Subchapter M--Uniform Mine Health Regulations
------------------------------------------------------------------------
62.110............................................... 1219-0120
62.130............................................... 1219-0120
62.170............................................... 1219-0120
62.171............................................... 1219-0120
62.172............................................... 1219-0120
62.173............................................... 1219-0120
62.174............................................... 1219-0120
62.175............................................... 1219-0120
62.180............................................... 1219-0120
62.190............................................... 1219-0120
------------------------------------------------------------------------
Subchapter O--Coal Mine Safety and Health
------------------------------------------------------------------------
70.201(c)............................................ 1219-0011
70.202(b)............................................ 1219-0011
70.204............................................... 1219-0011
70.209............................................... 1219-0011
70.210............................................... 1219-0011
70.220............................................... 1219-0011
70.220(a)............................................ 1219-0011
71.201(c)............................................ 1219-0011
71.202(b)............................................ 1219-0011
71.204............................................... 1219-0011
71.209............................................... 1219-0011
71.210............................................... 1219-0011
71.220............................................... 1219-0011
71.220(a)............................................ 1219-0011
71.300............................................... 1219-0011
71.301............................................... 1219-0011
71.301(d)............................................ 1219-0011
71.403............................................... 1219-0024
71.404............................................... 1219-0024
72.500............................................... 1219-0124
72.503............................................... 1219-0124
72.510............................................... 1219-0124
72.520............................................... 1219-0124
75.100............................................... 1219-0127
75.153(a)(2)......................................... 1219-0001
75.155............................................... 1219-0127
75.159............................................... 1219-0127
75.160............................................... 1219-0127
75.161............................................... 1219-0127
75.204(a)............................................ 1219-0121
75.215............................................... 1219-0004
75.220............................................... 1219-0004
75.221............................................... 1219-0004
75.222............................................... 1219-0004
75.223............................................... 1219-0004
75.310............................................... 1219-0088
75.312............................................... 1219-0088
75.335............................................... 1219-0142
75.336............................................... 1219-0142
75.337............................................... 1219-0142
75.338............................................... 1219-0142
75.342............................................... 1219-0088
75.350............................................... 1219-0138
75.351............................................... 1219-0088, -0116,
-0138
75.352............................................... 1219-0138
75.360............................................... 1219-0088
75.361............................................... 1219-0088
75.362............................................... 1219-0088
75.363............................................... 1219-0088
75.364............................................... 1219-0088
75.370............................................... 1219-0088
75.371............................................... 1219-0088, -0138
75.372............................................... 1219-0073
75.373............................................... 1219-0073
75.382............................................... 1219-0088
75.512............................................... 1219-0116
75.703............................................... 1219-0116
75.703-3............................................. 1219-0116
75.800............................................... 1219-0116
75.800-4............................................. 1219-0116
75.820............................................... 1210-0116
75.821............................................... 1219-0116
75.900............................................... 1219-0116
75.900-4............................................. 1219-0116
75.1001-1............................................ 1219-0116
75.1100-3............................................ 1219-0054
75.1103-8............................................ 1219-0054
75.1103-11........................................... 1219-0054
75.1200.............................................. 1219-0073
75.1200-1............................................ 1219-0073
75.1201.............................................. 1219-0073
75.1202.............................................. 1219-0073
75.1202-1............................................ 1219-0073
75.1203.............................................. 1219-0073
75.1204.............................................. 1219-0073
75.1204-1............................................ 1219-0073
75.1321.............................................. 1219-0025
75.1327.............................................. 1219-0025
75.1400-2............................................ 1219-0034
75.1400-4............................................ 1219-0034
75.1432.............................................. 1219-0034
75.1433.............................................. 1219-0034
75.1501.............................................. 1219-0054
75.1502.............................................. 1219-0054, -0141
75.1504.............................................. 1219-0141
75.1505.............................................. 1219-0141
75.1702.............................................. 1219-0041
75.1712-4............................................ 1219-0024
75.1712-5............................................ 1219-0024
75.1713-1............................................ 1219-0078
75.1714-3............................................ 1219-0141
75.1714-3(e)......................................... 1219-0044
75.1714-4............................................ 1219-0044
75.1714-5............................................ 1219-0141
75.1714-8............................................ 1219-0141
75.1716.............................................. 1219-0020
75.1716-1............................................ 1219-0020
75.1716-3............................................ 1219-0020
75.1721.............................................. 1219-0073
75.1901.............................................. 1219-0119
[[Page 10]]
75.1904.............................................. 1219-0119
75.1911.............................................. 1219-0119
75.1912.............................................. 1219-0119
75.1914.............................................. 1219-0119
75.1915.............................................. 1219-0119, -0124
77.100............................................... 1219-0127
77.103(a)(2)......................................... 1219-0001
77.105............................................... 1219-0127
77.106............................................... 1219-0127
77.107............................................... 1219-0127
77.107-1............................................. 1219-0127
77.215............................................... 1219-0015
77.215-2............................................. 1219-0015
77.215-3............................................. 1219-0015
77.215-4............................................. 1219-0015
77.216-2............................................. 1219-0015
77.216-3............................................. 1219-0015
77.216-4............................................. 1219-0015
77.216-5............................................. 1219-0015
77.502............................................... 1219-0116
77.800............................................... 1219-0116
77.800-2............................................. 1219-0116
77.900............................................... 1219-0116
77.900-2............................................. 1219-0116
77.1000.............................................. 1219-0026
77.1000-1............................................ 1219-0026
77.1101.............................................. 1219-0051
77.1200.............................................. 1219-0073
77.1201.............................................. 1219-0073
77.1202.............................................. 1219-0073
77.1404.............................................. 1219-0034
77.1432.............................................. 1219-0034
77.1433.............................................. 1219-0034
77.1702.............................................. 1219-0078
77.1713.............................................. 1219-0083
77.1900.............................................. 1219-0019
77.1901.............................................. 1219-0082
77.1906.............................................. 1219-0034
77.1909-1............................................ 1219-0025
90.201(c)............................................ 1219-0011
90.202(b)............................................ 1219-0011
90.204............................................... 1219-0011
90.209............................................... 1219-0011
90.220............................................... 1219-0011
90.300............................................... 1219-0011
90.301............................................... 1219-0011
90.301(d)............................................ 1219-0011
------------------------------------------------------------------------
[73 FR 36790, June 30, 2008]
[[Page 11]]
SUBCHAPTER B_TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS
PART 5_FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS
--Table of Contents
Sec.
5.10 Purpose and scope.
5.30 Fee calculation.
5.40 Fee administration.
5.50 Fee revisions.
Authority: 30 U.S.C. 957.
Source: 80 FR 45056, July 29, 2015, unless otherwise noted.
Sec. 5.10 Purpose and scope.
This part establishes a system under which MSHA charges a fee for
services provided. This part includes the management and calculation of
fees for the approval program, which includes: Application processing,
testing and evaluation, approval decisions, post-approval activities,
and termination of approvals.
Sec. 5.30 Fee calculation.
(a) Fee calculation. MSHA charges a fee based on an hourly rate for
Approval and Certification Center (A&CC) approval program activities and
other associated costs, such as travel expenses and part 15 fees. Part
15 fees for services provided to MSHA by other organizations may be set
by those organizations.
(b) Hourly rate calculation. The hourly rate consists of direct and
indirect costs of the A&CC's approval program divided by the number of
direct hours worked on all approval program activities.
(1) Direct costs are compensation and benefit costs for hours worked
on approval program activities.
(2) Indirect costs are a proportionate share of the following A&CC
costs:
(i) Compensation and benefit hours worked in support of all A&CC
activities;
(ii) A&CC building and equipment depreciation costs;
(iii) A&CC utilities, facility and equipment maintenance, and
supplies and materials; and
(iv) Information Technology and other services the Department of
Labor provides to the A&CC.
(c) Fees are charged for--
(1) Application processing (e.g., administrative and technical
review of applications, computer tracking, and status reporting);
(2) Testing and evaluation (e.g., analysis of drawings, technical
evaluation, testing, test set up and test tear down, and internal
quality control activities);
(3) Approval decisions (e.g., consultation on applications, records
control and security, document preparation); and
(4) Two post-approval activities: changes to approvals and post-
approval product audits.
(d) Fees are not charged for--
(1) Technical assistance not related to processing an approval
application;
(2) Technical programs, including development of new technology
programs;
(3) Participation in research conducted by other government agencies
or private organizations; and
(4) Regulatory review activities, including participation in the
development of health and safety standards, regulations, and
legislation.
(e) Fee estimate. Except as provided in paragraphs (e)(1) and (2) of
this section, on completion of an initial administrative review of the
application, the A&CC will prepare a maximum fee estimate for each
application. A&CC will begin the technical evaluation after the
applicant authorizes the fee estimate.
(1) The applicant may pre-authorize an expenditure for services, and
may further choose to pre-authorize either a maximum dollar amount or an
expenditure without a specified maximum amount.
(i) All applications containing a pre-authorization statement will
be put in the queue for the technical evaluation on completion of an
initial administrative review.
[[Page 12]]
(ii) MSHA will concurrently prepare a maximum fee estimate for
applications containing a statement pre-authorizing a maximum dollar
amount, and will provide the applicant with this estimate.
(2) Where MSHA's estimated maximum fee exceeds the pre-authorized
maximum dollar amount, the applicant has the choice of cancelling the
action and paying for all work done up to the time of the cancellation,
or authorizing MSHA's estimate.
(3) Under the Revised Acceptance Modification Program (RAMP), MSHA
expedites applications for acceptance of minor changes to previously
approved, certified, accepted, or evaluated products. The applicant must
pre-authorize a fixed dollar amount, set by MSHA, for processing the
application.
(f) If unforeseen circumstances are discovered during the
evaluation, and MSHA determines that these circumstances would result in
the actual costs exceeding either the pre-authorized expenditure or the
authorized maximum fee estimate, as appropriate, MSHA will prepare a
revised maximum fee estimate for completing the evaluation. The
applicant will have the option of either cancelling the action and
paying for services rendered or authorizing MSHA's revised estimate, in
which case MSHA will continue to test and evaluate the product.
(g) If the actual cost of processing the application is less than
MSHA's maximum fee estimate, MSHA will charge the actual cost.
Sec. 5.40 Fee administration.
Applicants and approval holders will be billed for all fees,
including actual travel expenses, if any, when approval program
activities are completed. Invoices will contain specific payment
instruction, including the address to mail payments and authorized
methods of payment.
Sec. 5.50 Fee revisions.
The hourly rate will remain in effect for at least one year and be
subject to revision at least once every three years.
PART 6_TESTING AND EVALUATION BY INDEPENDENT LABORATORIES AND NON-MSHA
PRODUCT SAFETY STANDARDS--Table of Contents
Sec.
6.1 Purpose and effective date.
6.2 Definitions.
6.10 Use of independent laboratories.
6.20 MSHA acceptance of equivalent non-MSHA product safety standards.
6.30 MSHA listing of equivalent non-MSHA product safety standards.
Authority: 30 U.S.C. 957.
Source: 68 FR 36417, June 17, 2003, unless otherwise noted.
Sec. 6.1 Purpose and effective date.
This part sets out alternate requirements for testing and evaluation
of products MSHA approves for use in gassy underground mines. It permits
manufacturers of certain products who seek MSHA approval to use an
independent laboratory to perform, in whole or part, the necessary
testing and evaluation for approval. It also permits manufacturers to
have their products approved based on non-MSHA product safety standards
once MSHA has determined that the non-MSHA standards are equivalent to
MSHA's applicable product approval requirements or can be modified to
provide at least the same degree of protection as those MSHA
requirements. The provisions of this part may be used by applicants for
product approval under parts 18, 19, 20, 22, 23, 27, 33, 35, and 36.
This rule is effective August 18, 2003.
Sec. 6.2 Definitions.
The following definitions apply in this part.
Applicant. An individual or organization that manufactures or
controls the assembly of a product and applies to MSHA for approval of
that product.
Approval. A written document issued by MSHA which states that a
product has met the applicable requirements of part 18, 19, 20, 22, 23,
27, 33, 35, or 36. The definition is based on the existing definitions
of ``approval'' in the parts specified above. It is expanded to include
``certification'' and ``acceptance'' because these terms also are used
to denote MSHA approval.
[[Page 13]]
Approval holder. An applicant whose application for approval of a
product under part 18, 19, 20, 22, 23, 27, 33, 35 or 36 of this chapter
has been approved by MSHA.
Equivalent non-MSHA product safety standards. A non-MSHA product
safety standard, or group of standards, determined by MSHA to provide at
least the same degree of protection as the applicable MSHA product
approval requirements in parts 14, 18, 19, 20, 22, 23, 27, 33, 35, and
36, or which in modified form provide at least the same degree of
protection.
Independent laboratory. A laboratory that:
(1) has been recognized by a laboratory accrediting organization to
test and evaluate products to a product safety standard, and
(2) is free from commercial, financial, and other pressures that may
influence the results of the testing and evaluation process.
Post-approval product audit. The examination, testing, or both, by
MSHA of approved products selected by MSHA to determine whether those
products meet the applicable product approval requirements and have been
manufactured as approved.
Product safety standard. A document, or group of documents, that
specifies the requirements for the testing and evaluation of a product
for use in explosive gas and dust atmospheres, and, when appropriate,
includes documents addressing the flammability properties of products.
[68 FR 36417, June 17, 2003, as amended at 73 FR 80609, Dec. 31, 2008]
Sec. 6.10 Use of independent laboratories.
(a) MSHA will accept testing and evaluation performed by an
independent laboratory for purposes of MSHA product approval provided
that MSHA receives as part of the application:
(1) Written evidence of the laboratory's independence and current
recognition by a laboratory accrediting organization;
(2) Complete technical explanation of how the product complies with
each requirement in the applicable MSHA product approval requirements;
(3) Identification of components or features of the product that are
critical to the safety of the product; and
(4) All documentation, including drawings and specifications, as
submitted to the independent laboratory by the applicant and as required
by the applicable part under this chapter.
(b) Product testing and evaluation performed by independent
laboratories for purposes of MSHA approval must comply with the
applicable MSHA product approval requirements.
(c) Product testing and evaluation must be conducted or witnessed by
the laboratory's personnel.
(d) After review of the information required under paragraphs (a)(1)
through (a)(4) of this section, MSHA will notify the applicant if
additional information or testing is required. The applicant must
provide this information, arrange any additional or repeat tests and
notify MSHA of the location, date, and time of the test(s). MSHA may
observe any additional testing conducted by an independent laboratory.
Further, MSHA may decide to conduct the additional or repeated tests at
the applicant's expense. The applicant must supply any additional
components necessary for testing and evaluation.
(e) Upon request by MSHA, but not more than once a year, except for
cause, approval holders of products approved based on independent
laboratory testing and evaluation must make such products available for
post-approval audit at a mutually agreeable site at no cost to MSHA.
(f) Once the product is approved, the approval holder must notify
MSHA of all product defects of which they become aware.
Sec. 6.20 MSHA acceptance of equivalent non-MSHA product safety
standards.
(a) MSHA will accept non-MSHA product safety standards, or groups of
standards, as equivalent after determining that they:
(1) Provide at least the same degree of protection as MSHA's product
approval requirements in parts 14, 18, 19, 20, 33, 35 and 36 of this
chapter; or
[[Page 14]]
(2) Can be modified to provide at least the same degree of
protection as those MSHA requirements.
(b) MSHA will publish its intent to review any non-MSHA product
safety standard for equivalency in the Federal Register for the purpose
of soliciting public input.
(c) A listing of all equivalency determinations will be published in
this part 6 and the applicable approval parts. The listing will state
whether MSHA accepts the non-MSHA product safety standards in their
original form, or whether MSHA will require modifications to demonstrate
equivalency. If modifications are required, they will be provided in the
listing. MSHA will notify the public of each equivalency determination
and will publish a summary of the basis for its determination. MSHA will
provide equivalency determination reports to the public upon request to
the Approval and Certification Center.
(d) After MSHA has determined that non-MSHA product safety standards
are equivalent and has notified the public of such determinations,
applicants may seek MSHA product approval based on such non-MSHA product
safety standards.
[68 FR 36417, June 17, 2003, as amended at 73 FR 80609, Dec. 31, 2008]
Sec. 6.30 MSHA listing of equivalent non-MSHA product safety
standards.
MSHA evaluated the following non-MSHA product safety standards and
determined that they provide at least the same degree of protection as
current MSHA requirements with or without modifications as indicated:
(a) The International Electrotechnical Commission's (IEC) standards
for Electrical Apparatus for Explosive Gas Atmospheres, Part 0, General
Requirements (IEC 60079-0, Fourth Edition, 2004-01) and Part 1,
Electrical Apparatus for Explosive Gas Atmospheres, Flameproof
Enclosures ``d'' (IEC 60079-1, Fifth Edition, 2003-11) must be modified
in order to provide at least the same degree of protection as MSHA
explosion-proof enclosure requirements included in parts 7 and 18 of
this chapter. Refer to Secs. 7.10(c)(1) and 18.6(a)(3)(i) for a list of
the required modifications. The IEC standards may be inspected at the
U.S. Department of Labor, Mine Safety and Health Administration,
Electrical Safety Division, Approval and Certification Center, 765
Technology Drive, Triadelphia, WV 26059, and may be purchased from
International Electrical Commission, Central Office 3, rue de Varembe,
P.O. Box 131, CH-1211 GENEVA 20, Switzerland.
(b) [Reserved]
[71 FR 28583, May 17, 2006, as amended at 73 FR 52210, Sept. 9, 2008]
PART 7_TESTING BY APPLICANT OR THIRD PARTY--Table of Contents
Subpart A_General
Sec.
7.1 Purpose and scope.
7.2 Definitions.
7.3 Application procedures and requirements.
7.4 Product testing.
7.5 Issuance of approval.
7.6 Approval marking and distribution record.
7.7 Quality assurance.
7.8 Post-approval product audit.
7.9 Revocation.
7.10 MSHA acceptance of equivalent non--MSHA product safety standards.
Subpart B_Brattice Cloth and Ventilation Tubing
7.21 Purpose and effective date.
7.22 Definitions.
7.23 Application requirements.
7.24 Technical requirements.
7.25 Critical characteristics.
7.26 Flame test apparatus.
7.27 Test for flame resistance of brattice cloth.
7.28 Test for flame resistance of rigid ventilation tubing.
7.29 Approval marking.
7.30 Post-approval product audit.
7.31 New technology.
Subpart C_Battery Assemblies
7.41 Purpose and effective date.
7.42 Definitions.
7.43 Application requirements.
7.44 Technical requirements.
7.45 Critical characteristics.
7.46 Impact test.
7.47 Deflection temperature test.
7.48 Acid resistance test.
7.49 Approval marking.
7.50 Post-approval product audit.
7.51 Approval checklist.
[[Page 15]]
7.52 New technology.
Subpart D_Multiple-Shot Blasting Units
7.61 Purpose and effective date.
7.62 Definitions.
7.63 Application requirements.
7.64 Technical requirements.
7.65 Critical characteristics.
7.66 Output energy test.
7.67 Construction test.
7.68 Firing line terminals test.
7.69 Approval marking.
7.70 Post-approval product audit.
7.71 Approval checklist.
7.72 New technology.
Subpart E_Diesel Engines Intended for Use in Underground Coal Mines
7.81 Purpose and effective date.
7.82 Definitions.
7.83 Application requirements.
7.84 Technical requirements.
7.85 Critical characteristics.
7.86 Test equipment and specifications.
7.87 Test to determine the maximum fuel-air ratio.
7.88 Test to determine the gaseous ventilation rate.
7.89 Test to determine the particulate index.
7.90 Approval marking.
7.91 Post-approval product audit.
7.92 New technology.
Subpart F_Diesel Power Packages Intended for Use in Areas of Underground
Coal Mines Where Permissible Electric Equipment Is Required
7.95 Purpose and effective date.
7.96 Definitions.
7.97 Application requirements.
7.98 Technical requirements.
7.99 Critical characteristics.
7.100 Explosion tests.
7.101 Surface temperature tests.
7.102 Exhaust gas cooling efficiency test.
7.103 Safety system control test.
7.104 Internal static pressure test.
7.105 Approval marking.
7.106 Post-approval product audit.
7.107 New technology.
7.108 Power package checklist.
Subpart J_Electric Motor Assemblies
7.301 Purpose and effective date.
7.302 Definitions.
7.303 Application requirements.
7.304 Technical requirements.
7.305 Critical characteristics.
7.306 Explosion tests.
7.307 Static pressure test.
7.308 Lockwasher equivalency test.
7.309 Approval marking.
7.310 Post-approval product audit.
7.311 Approval checklist.
Appendix I to Subpart J of Part 7
Subpart K_Electric Cables, Signaling Cables, and Cable Splice Kits
7.401 Purpose and effective date.
7.402 Definitions.
7.403 Application requirements.
7.404 Technical requirements.
7.405 Critical characteristics.
7.406 Flame test apparatus.
7.407 Test for flame resistance of electric cables and cable splices.
7.408 Test for flame resistance of signaling cables.
7.409 Approval markings.
7.410 Post-approval product audit.
7.411 New technology.
Subpart L_Refuge Alternatives
7.501 Purpose and scope.
7.502 Definitions.
7.503 Application requirements.
7.504 Refuge alternatives and components; general requirements.
7.505 Structural components.
7.506 Breathable air components.
7.507 Air-monitoring components.
7.508 Harmful gas removal components.
7.509 Approval markings.
7.510 New technology.
Authority: 30 U.S.C. 957.
Source: 53 FR 23500, June 22, 1988, unless otherwise noted.
Subpart A_General
Sec. 7.1 Purpose and scope.
This part sets out requirements for MSHA approval of certain
equipment and materials for use in underground mines whose product
testing and evaluation does not involve subjective analysis. These
requirements apply to products listed in the subparts following this
Subpart A. After the dates specified in the following subparts, requests
for approval of products shall be made in accordance with this Subpart A
and the applicable subpart.
Sec. 7.2 Definitions.
The following definitions apply in this part.
Applicant. An individual or organization that manufactures or
controls the assembly of a product and that applies to MSHA for approval
of that product.
[[Page 16]]
Approval. A document issued by MSHA which states that a product has
met the requirements of this part and which authorizes an approval
marking identifying the product as approved.
Authorized company official. An individual designated by applicant
who has the authority to bind the company.
Critical characteristic. A feature of a product that, if not
manufactured as approved, could have a direct adverse effect on safety
and for which testing or inspection is required prior to shipment to
ensure conformity with the technical requirements under which the
approval was issued.
Equivalent non-MSHA product safety standards. A non-MSHA product
safety standard, or group of standards, that is determined by MSHA to
provide at least the same degree of protection as the applicable MSHA
product technical requirements in the subparts of this part, or can be
modified to provide at least the same degree of protection as those MSHA
requirements.
Extention of approval. A document issued by MSHA which states that
the change to a product previously approved by MSHA under this part
meets the requirements of this part and which authorizes the continued
use of the approval marking after the appropriate extension number has
been added.
Post-approval product audit. Examination, testing, or both, by MSHA
of approved products selected by MSHA to determine whether those
products meet the applicable technical requirements and have been
manufactured as approved.
Technical requirements. The design and performance requirements for
a product, as specified in a subpart of this part.
Test procedures. The methods specified in a subpart of this part
used to determine whether a product meet the performance portion of the
technical requirements.
[53 FR 23500, June 22, 1988; 53 FR 25569, July 7, 1988, as amended at 68
FR 36418, June 17, 2003]
Sec. 7.3 Application procedures and requirements.
(a) Application. Requests for an approval or extension of approval
shall be sent to: U.S. Department of Labor, Mine Safety and Health
Administration, Approval and Certification Center, 765 Technology Drive,
Triadelphia, WV 26059.
(b) Fees. Fees calculated in accordance with part 5 of this title
shall be submitted in accordance with Sec. 5.40.
(c) Original approval. Each application for approval of a product
shall include--
(1) A brief description of the product;
(2) The documentation specified in the appropriate subpart of this
part;
(3) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application;
(4) If appropriate, a statement indicating whether, in the
applicant's opinion, testing is required. If testing is not proposed,
the applicant shall explain the reasons for not testing; and
(5) If appropriate, the place and date for product testing.
(d) Subsequent approval of a similar product. Each application for a
product similar to one for which the applicant already holds an approval
shall include--
(1) The approval number for the product which most closely resembles
the new one;
(2) The information specified in paragraph (c) of this section for
the new product, except that any document which is the same as one
listed by MSHA in prior approvals need not be submitted, but shall be
noted in the application;
(3) An explanation of any change from the existing approval; and
(4) A statement as to whether, in the applicant's opinion, the
change requires product testing. If testing is not proposed, the
applicant shall explain the reasons for not testing.
(e) Extension of an approval. Any change in the approved product
from the documentation on file at MSHA that affects the technical
requirements of this part shall be submitted to MSHA for approval prior
to implementing the change. Each application for an extension of
approval shall include--
(1) The MSHA-assigned approval number for the product for which the
extension is sought;
[[Page 17]]
(2) A brief description of the proposed change to the previously
approved product;
(3) Drawings and specifications which show the change in detail;
(4) A statement as to whether, in the applicant's opinion, the
change requires product testing. If testing is not proposed, the
applicant shall explain the reasons for not testing;
(5) The place and date for product testing, if testing will be
conducted; and
(6) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(f) Certification statement. (1) Each application for original
approval, subsequent approval, or extension of approval of a product
shall include a certification by the applicant that the product meets
the design portion of the technical requirements, as specified in the
appropriate subpart, and that the applicant will perform the quality
assurance functions specified in Sec. 7.7. For a subsequent approval or
extension of approval, the applicant shall also certify that the
proposed change cited in the application is the only change that affects
the technical requirements.
(2) After completion of the required product testing, the applicant
shall certify that the product has been tested and meets the performance
portion of the technical requirements, as specified in the appropriate
subpart.
(3) All certification statements shall be signed by an authorized
company official.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33722, June 29, 1995;
73 FR 52210, Sept. 9, 2008]
Sec. 7.4 Product testing.
(a) All products submitted for approval under this part shall be
tested using the test procedures specified in the appropriate subpart
unless MSHA determines, upon review of the documentation submitted, that
testing is not required. Applicants shall maintain records of test
results and procedures for three years.
(b) Unless otherwise specified in the subpart, test instruments
shall be calibrated at least as frequently as, and according to, the
instrument manufacturer's specifications, using calibration standards
traceable to those set by the National Bureau of Standards, U.S.
Department of Commerce or other nationally recoginzed standards and
accurate to at least one significant figure beyond the desired accuracy.
(c) When MSHA elects to observe product testing, the applicant shall
permit an MSHA official to be present at a mutually agreeable date,
time, and place.
(d) MSHA will accept product testing conducted outside the United
States where such acceptance is specifically required by international
agreement.
[53 FR 23500, June 22, 1988; 53 FR 25569, July 7, 1988; 60 FR 33722,
June 29, 1995]
Sec. 7.5 Issuance of approval.
(a) An applicant shall not advertise or otherwise represent a
product as approved until MSHA has issued the applicant an approval.
(b) MSHA will issue an approval or a notice of the reasons for
denying approval after reviewing the application, and the results of
product testing, when applicable. An approval will identify the
documents upon which the approval is based.
Sec. 7.6 Approval marking and distribution record.
(a) Each approved product shall have an approval marking, as
specified in the appropriate subpart of this part.
(b) For an extension of approval, the extension number shall be
added to the original approval number on the approval marking.
(c) Applicants shall maintain records of the initial sale of each
unit having an approval marking. The record retention period shall be at
least the expected shelf life and service life of the product.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33722, June 29, 1995]
Sec. 7.7 Quality assurance.
Applicants granted an approval or an extension of approval under
this part shall--
(a) Inspect or test, or both, the critical characteristics in
accordance with the appropriate subpart of this part;
[[Page 18]]
(b) Unless otherwise specified in the subparts, calibrate
instruments used for the inspection and testing of critical
characteristics at least as frequently as, and according to, the
instrument manufacturer's specifications, using calibration standards
traceable to those set by the National Bureau of Standards, U.S.
Department of Commerce or other nationally recognized standards and use
instruments accurate to at least one significant figure beyond the
desired accuracy.
(c) Control production documentation so that the product is
manufactured as approved;
(d) Immediately report to the MSHA Approval and Certification
Center, any knowledge of a product distributed with critical
characteristics not in accordance with the approval specifications.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33722, June 29, 1995]
Sec. 7.8 Post-approval product audit.
(a) Approved products shall be subject to periodic audits by MSHA
for the purpose of determining conformity with the technical
requirements upon which the approval was based. Any approved product
which is to be audited shall be selected by MSHA and be representative
of those distributed for use in mines. The approval-holder may obtain
any final report resulting from such audit.
(b) No more than once a year except for cause, the approval-holder,
at MSHA's request, shall make an approved product available at no cost
to MSHA for an audit to be conducted at a mutually agreeable site and
time. The approval-holder may observe any tests conducted during this
audit.
(c) An approved product shall be subject to audit for cause at any
time MSHA believes that it is not in compliance with the technical
requirements upon which the approval was based.
Sec. 7.9 Revocation.
(a) MSHA may revoke for cause an approval issued under this part if
the product:
(1) Fails to meet the applicable technical requirements; or
(2) Creates a hazard when used in a mine.
(b) Prior to revoking an approval, the approval-holder shall be
informed in writing of MSHA's intention to revoke approval. The notice
shall:
(1) Explain the specific reasons for the proposed revocation; and
(2) Provide the approval-holder an opportunity to demonstrate or
achieve compliance with the product approval requirements.
(c) Upon request, the approval-holder shall be afforded an
opportunity for a hearing.
(d) If a product poses an imminent hazard to the safety or health of
miners, the approval may be immediately suspended without a written
notice of the agency's intention to revoke. The suspension may continue
until the revocation proceedings are completed.
Sec. 7.10 MSHA acceptance of equivalent non-MSHA product safety
standards.
(a) MSHA will accept non-MSHA product safety standards, or groups of
standards, as equivalent after determining that they:
(1) Provide at least the same degree of protection as MSHA's
applicable technical requirements for a product in the subparts of this
part; or
(2) Can be modified to provide at least the same degree of
protection as those MSHA requirements.
(b) MSHA will publish its intent to review any non-MSHA product
safety standard for equivalency in the Federal Register for the purpose
of soliciting public input.
(c) A listing of all equivalency determinations will be published in
this part 7. The listing will state whether MSHA accepts the non-MSHA
product safety standards in their original form, or whether MSHA will
require modifications to demonstrate equivalency. If modifications are
required, they will be provided in the listing. MSHA will notify the
public of each equivalency determination and will publish a summary of
the basis for its determination. MSHA will provide equivalency
determination reports to the public upon request to the Approval and
Certification Center. MSHA has made the following equivalency
determinations applicable to this part 7.
[[Page 19]]
(1) MSHA will accept applications for motors under Subpart J
designed and tested to the International Electrotechnical Commission's
(IEC) standards for Electrical Apparatus for Explosive Gas Atmospheres,
Part 0, General Requirements (IEC 60079-0, Fourth Edition, 2004-01) and
Part 1, Electrical Apparatus for Explosive Gas Atmospheres, Flameproof
Enclosures ``d'' (IEC 60079-1, Fifth Edition, 2003-11) (which are hereby
incorporated by reference and made a part hereof) provided the
modifications to the IEC standards specified in Sec. 7.10(c)(1)(i)
through (ix) are met. The Director of the Federal Register approves this
incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. The IEC standards may be inspected at the U.S. Department of
Labor, Mine Safety and Health Administration, Electrical Safety
Division, Approval and Certification Center, 765 Technology Drive,
Triadelphia, WV 26059, or at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/
federal_register/code_of_federal_regulations/ibr_locations.html. These
IEC standards may be obtained from International Electrical Commission,
Central Office 3, rue de Varembe, P.O. Box 131, CH-1211 GENEVA 20,
Switzerland.
(i) Enclosures associated with an electric motor assembly shall be
made of metal and not have a compartment exceeding ten (10) feet in
length. External surfaces of enclosures shall not exceed 150 C (302 F)
in normal operation.
(ii) Enclosures shall be rugged in construction and should meet
existing requirements for minimum bolt size and spacing and for minimum
wall, cover, and flange thicknesses specified in paragraph (g)(19) of
Sec. 7.304 Technical requirements. Enclosure fasteners should be uniform
in size and length, be provided at all corners, and be secured from
loosening by lockwashers or equivalent. An engineering analysis shall be
provided for enclosure designs that deviate from the existing
requirements. The analysis shall show that the proposed enclosure design
meets or exceeds the mechanical strength of a comparable enclosure
designed to 150 psig according to existing requirements, and that
flamepath clearances in excess of existing requirements will not be
produced at an internal pressure of 150 psig. This shall be verified by
explosion testing the enclosure at a minimum of 150 psig.
(iii) Enclosures shall be designed to withstand a minimum pressure
of at least 150 psig without leakage through any welds or castings,
rupture of any part that affects explosion-proof integrity, clearances
exceeding those permitted under existing requirements along flame-
arresting paths, or permanent distortion exceeding 0.040-inch per linear
foot.
(iv) Flamepath clearances, including clearances between fasteners
and the holes through which they pass, shall not exceed those specified
in existing requirements. No intentional gaps in flamepaths are
permitted.
(v) The minimum lengths of the flame arresting paths, based on
enclosure volume, shall conform to those specified in existing
requirements to the nearest metric equivalent value (e.g., 12.5 mm, 19
mm, and 25 mm are considered equivalent to \1/2\ inch, \3/4\ inch and 1
inch respectively for plane and cylindrical joints). The widths of any
grooves for o-rings shall be deducted in measuring the widths of flame-
arresting paths.
(vi) Gaskets shall not be used to form any part of a flame-arresting
path. If o-rings are installed within a flamepath, the location of the
o-rings shall meet existing requirements.
(vii) Cable entries into enclosures shall be of a type that utilizes
either flame-resistant rope packing material or sealing rings
(grommets). If plugs and mating receptacles are mounted to an enclosure
wall, they shall be of explosion-proof construction. Insulated bushings
or studs shall not be installed in the outside walls of enclosures. Lead
entrances utilizing sealing compounds and flexible or rigid metallic
conduit are not permitted.
(viii) Unused lead entrances shall be closed with a metal plug that
is secured by spot welding, brazing, or equivalent.
(ix) Special explosion tests are required for electric motor
assemblies
[[Page 20]]
that share leads (electric conductors) through a common wall with
another explosion-proof enclosure, such as a motor winding compartment
and a conduit box. These tests are required to determine the presence of
any pressure piling conditions in either enclosure when one or more of
the insulating barriers, sectionalizing terminals, or other isolating
parts are sequentially removed from the common wall between the
enclosures. Enclosures that exhibit pressures during these tests that
exceed those specified in existing requirements must be provided with a
warning tag. The durable warning tag must indicate that the insulating
barriers, sectionalizing terminals, or other isolating parts be
maintained in order to insure the explosion-proof integrity for either
enclosure sharing a common wall. A warning tag is not required if the
enclosures withstand a static pressure of twice the maximum value
observed in the explosion tests.
(2) [Reserved]
(d) After MSHA has determined that non-MSHA product safety standards
are equivalent and has notified the public of such determinations,
applicants may seek MSHA product approval based on such non-MSHA product
safety standards.
[68 FR 36418, June 17, 2003, as amended at 71 FR 28583, May 17, 2006; 73
FR 52210, Sept. 9, 2008]
Subpart B_Brattice Cloth and Ventilation Tubing
Sec. 7.21 Purpose and effective date.
This subpart establishes the specific requirements for approval of
brattice cloth and ventilation tubing. It is effective August 22, 1988.
Applications for approval or extension of approval submitted after
August 22, 1989, shall meet the requirements of this part.
Sec. 7.22 Definitions.
The following definitions apply in this subpart:
Brattice cloth. A curtain of jute, plastic, or similar material used
to control or direct ventilating air.
Denier. A unit of yarn size indicating the fineness of fiber of
material based on the number of grams in a length of 9,000 meters.
Film. A sheet of flexible material applied to a scrim by pressure,
temperature, adhesion, or other method.
Scrim. A substrate material of plastic or fabric laminated between
or coated with a film.
Ventilation tubing. Rigid or flexible tubing used to convey
ventilating air.
Sec. 7.23 Application requirements.
(a) Brattice cloth. A single application may address two or more
products if the products differ only in: weight of the finished product;
weight or weave of the same fabric or scrim; or thickness or layers of
the same film. Applications shall include the following information:
(1) Trade name.
(2) Product designations (for example, style and code number).
(3) Color.
(4) Type of brattice (for example, plastic or jute).
(5) Weight of finished product.
(6) Film: type, weight, thickness, supplier, supplier's stock number
or designation, and percent of finished product by weight.
(7) Scrim: Type, denier, weight, weave, the supplier, supplier's
stock number or designation, and percent of finished product by weight.
(8) Adhesive: type, supplier, supplier's stock number or
designation, and percent of finished product by weight.
(b) Flexible ventilation tubing. Applications shall include the
product description information in paragraph (a) of this section and
list the type of supporting structure, if applicable; inside diameters;
and configurations.
(c) Rigid ventilation tubing. A single application may address two
or more products if the products differ only in diameters, lengths,
configuration, or average wall thickness. Applications shall include the
following information:
(1) Trade name.
(2) Product designations (for example, style and code numbers).
(3) Color.
(4) Type of ventilation tubing (for example, fiberglass, plastic, or
polyethylene).
[[Page 21]]
(5) Inside diameter, configuration, and average wall thickness.
(6) Suspension system (for example, metal hooks).
(7) Base material: type, supplier, the supplier's stock number, and
percent of finished product by weight.
(8) Resin: type, supplier, the supplier's stock number, and percent
of finished product by weight.
(9) Flame retardant, if added during manufacturing: type, supplier,
the supplier's stock number, and percent of finished product by weight.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33722, June 29, 1995]
Sec. 7.24 Technical requirements.
(a) Brattice cloth shall be flame resistant when tested in
accordance with the flame resistance test in Sec. 7.27.
(b) Flexible ventilation tubing shall be manufactured using an MSHA-
approved brattice cloth. If a supporting structure is used, it shall be
metal or other noncombustible material which will not ignite, burn,
support combustion or release flammable vapors when subjected to fire or
heat.
(c) Rigid ventilation tubing shall be flame resistant when tested in
accordance with the flame resistance test in Sec. 7.28.
Sec. 7.25 Critical characteristics.
A sample of each batch or lot of brattice cloth and ventilation
tubing shall be flame tested or a sample of each batch or lot of the
materials that contribute to the flame-resistance characteristic shall
be inspected or tested to ensure that the finished product will meet the
flame-resistance test.
Sec. 7.26 Flame test apparatus.
The principal parts of the apparatus used to test for flame-
resistance of brattice cloth and ventilation tubing shall be constructed
as follows:
(a) A 16-gauge stainless steel gallery lined on the top, bottom and
both sides with \1/2\ inch thick Marinite or equivalent insulating
material yielding inside dimensions approximately 58 inches long, 41
inches high, and 30 inches wide;
(b) Two \3/8\-inch diameter steel J hooks and a \9/16\-inch diameter
steel rod to support the sample located approximately 2\3/16\-inches
from the front and back ends of the test gallery, 1\1/2\-inches from the
ceiling insulation and centrally located in the gallery along its
length. Samples shall be suspended to preclude folds or wrinkles;
(c) A tapered 16-gauge stainless steel duct section tapering from a
cross sectional area measuring 2 feet 7 inches wide by 3 feet 6 inches
high at the test gallery to a cross-sectional area 1 foot 6 inches
square over a length of 3 feet. The tapered duct section must be tightly
connected to the test gallery;
(d) A 16-gauge stainless steel fan housing, consisting of a 1 foot 6
inches square section 6 inches long followed by a 10 inch long section
which tapers from 1 foot 16 inches square to 12 inches diameter round
and concluding with a 12 inch diameter round collar 3 inches long. A
variable speed fan capable of producing an air velocity of 125 ft./min.
in the test gallery must be secured in the fan housing. The fan housing
must be tightly connected to the tapered duct section;
(e) A methane-fueled impinged jet burner igniting source, measuring
12 inches long from the threaded ends of the first and last jets and 4
inches wide with 12 impinged jets, approximately 1\3/8\-inches long and
spaced alternately along the length of the burner tube. The burner jets
must be canted so that they point toward each other in pairs and the
flame from these pairs impinge upon each other.
Sec. 7.27 Test for flame resistance of brattice cloth.
(a) Test procedures. (1) Prepare 6 samples of brattice cloth 40
inches wide by 48 inches long.
(2) Prior to testing, condition each sample for a minimum of 24
hours at a temperature of 70 10 F (21 5.5 C) and a relative humidity
of 55 10%.
(3) For each test, suspend the sample in the gallery by wrapping the
brattice cloth around the rod and clamping each end and the center. The
brattice cloth must hang 4 inches from the gallery floor.
(4) Use a front exhaust system to remove smoke escaping from the
gallery. The exhaust system must remain on during all testing, but not
affect the air flow in the gallery.
[[Page 22]]
(5) Set the methane-fueled impinged jet burner to yield a flame
height of 12 inches as measured at the outermost tip of the flame.
(6) Apply the burner to the front lower edge of the brattice cloth
and keep it in contact with the material for 25 seconds or until 1 foot
of material, measured horizontally, is consumed, whichever occurs first.
If the material shrinks during application of the burner flame, move the
burner flame to maintain contact with 1 foot of the material. If melting
material might clog the burner orifices, rotate the burner slightly
during application of the flame.
(7) Test 3 samples in still air and 3 samples with an average of 125
ft./min. of air flowing past the sample.
(8) Record the propagation length and duration of burning for each
of the 6 samples. The duration of burning is the total burning time of
the specimen during the flame test. This includes the burn time of any
material that falls on the floor of the test gallery during the igniting
period. However, the suspended specimen is considered burning only after
the burner is removed. Should the burning time of a suspended specimen
and a specimen on the floor coincide, count the coinciding burning time
only once.
(9) Calculate the average duration of burning for the first 3
samples (still air) and the second 3 samples (125 ft./min. air flow).
(b) Acceptable performance. The brattice cloth shall meet each of
the following criteria:
(1) Flame propagation of less than 4 feet in each of the six tests.
(2) An average duration of burning of less than 1 minute in both
groups of three tests.
(3) A duration of burning not exceeding two minutes in each of the
six tests.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.28 Test for flame resistance of rigid ventilation tubing.
(a) Test procedures. (1) Prepare 6 samples of ventilation tubing 48
inches in length with all flared or thickened ends removed. Any sample
with a cross-sectional dimension greater than 24 inches must be tested
in a 24-inch size.
(2) For each test, suspend the sample in the center of the gallery
by running a wire through the 48-inch length of tubing.
(3) Use a front exhaust system to remove smoke escaping from the
gallery. The exhaust system must remain on during all testing but not
affect the air flow in the gallery.
(4) Set the methane-fueled impinged jet burner to yield a flame
height of 12 inches as measured at the outermost tip of the flame.
(5) Apply the burner to the front lower edge of the tubing so that
two-thirds of the burner is under the tubing and the remaining third is
exposed to allow the flames to curl onto the inside of the tubing. Keep
the burner in contact with the material for 60 seconds. If melting
material might clog the burner orifices, rotate the burner slightly
during application of the flame.
(6) Test 3 samples in still air and 3 samples with an average of 125
ft./min. of air flowing past the sample.
(7) Record the propagation length and duration of burning for each
of the 6 samples. The duration of burn is the total burning time of the
specimen during the flame test. This includes the burning time of any
material that falls on the floor of the test gallery during the igniting
period. However, the suspended specimen is considered burning only after
the burner is removed. Should the burning time of a suspended specimen
and a specimen on the floor coincide, count the coinciding burn time
only once.
(8) Calculate the average duration of burning for the first 3
samples (still air) and the second 3 samples (125 ft./min. air flow).
(b) Acceptable performance. The ventilation tubing shall meet each
of the following criteria:
(1) Flame propagation of less than 4 feet in each of the 6 tests.
(2) An average duration of burning of less than 1 minute in both
groups of 3 tests.
(3) A duration of burning not exceeding 2 minutes in each of the 6
tests.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
[[Page 23]]
Sec. 7.29 Approval marking.
(a) Approved brattice cloth shall be legibly and permanently marked
with the assigned MSHA approval number at intervals not exceeding ten
feet. If the nature of the material or method of processing makes such
marking impractical, permanent paint or ink may be used to mark the edge
with an MSHA-assigned color code.
(b) Approved ventilation tubing shall be legibly and permanently
marked on each section with the assigned MSHA approval number.
(c) An approved product shall be marketed only under a brand or
trade name that has been furnished to MSHA.
Sec. 7.30 Post-approval product audit.
Upon request by MSHA but no more than once a year except for cause,
the approval-holder shall supply to MSHA at no cost up to fifty feet of
each approved design of brattice cloth and ventilation tubing for audit.
Sec. 7.31 New technology.
MSHA may approve brattice cloth and ventilation tubing that
incorporates technology for which the requirements of this subpart are
not applicable, if the Agency determines that the product is as safe as
those which meet the requirements of this subpart.
Subpart C_Battery Assemblies
Sec. 7.41 Purpose and effective date.
This subpart establishes the specific requirements for MSHA approval
of battery assemblies intended for incorporation in approved equipment
in underground mines. It is effective August 22, 1988. Applications for
approval or extensions of approval submitted after August 22, 1989,
shall meet the requirements of this part.
Sec. 7.42 Definitions.
The following definitions apply in this subpart:
Battery assembly. A unit or units consisting of cells and their
electrical connections, assembled in a battery box or boxes with covers.
Battery box. The exterior sides, bottom, and connector receptacle
compartment, if any, of a battery assembly, excluding internal
partitions.
Sec. 7.43 Application requirements.
(a) An application for approval of a battery assembly shall contain
sufficient information to document compliance with the technical
requirements of this subpart and include a composite drawing with the
following information:
(1) Overall dimensions of the battery assembly, including the
minimum distance from the underside of the cover to the top of the
terminals and caps.
(2) Composition and thicknesses of the battery box and cover.
(3) Provision for securing covers.
(4) Documentation of flame-resistance of insulating materials and
cables.
(5) Number, type, and rating of the battery cells.
(6) Diagram of battery connections between cells and between battery
boxes, except when connections between battery boxes are a part of the
machine's electrical system.
(7) Total weight of the battery, charged and ready for service.
(8) Documentation of materials and configurations for battery cells,
intercell connectors, filler caps, and battery top:
(i) If nonmetallic cover designs are used with cover support blocks;
or
(ii) If the cover comes into contact with any portion of the cells,
caps, filler material, battery top, or intercell connectors during the
impact test specified by Sec. 7.46.
(b) All drawings shall be titled, dated, numbered, and include the
latest revision number.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.44 Technical requirements.
(a)(1) Battery boxes and covers constructed of AISI 1010 hot rolled
steel shall have the following minimum thicknesses based on the total
weight of a unit of the battery assembly charged and ready for service:
------------------------------------------------------------------------
Weight of battery unit Minimum required thickness
------------------------------------------------------------------------
1,000 lbs. maximum........................ 10 gauge or \1/8\" nominal
1,001 to 2,000 lbs........................ 7 gauge or \3/16\" nominal
2,001 to 4,500 lbs........................ 3 gauge or \1/4\" nominal
[[Page 24]]
Over 4,500 lbs............................ 0 gauge or \5/16\" nominal
------------------------------------------------------------------------
(2) Battery boxes not constructed of AISI 1010 hot rolled steel
shall have at least the tensile strength and impact resistance of
battery boxes for the same weight class, as listed in paragraph (a)(1)
of this section.
(3) Battery box covers constructed of materials with less than the
tensile strength and impact resistance of AISI 1010 hot rolled steel or
constructed of nonmetallic materials shall meet the acceptable
performance criteria for the impact test in Sec. 7.46. Nonmetallic
covers shall be used only in the battery assembly configuration in which
they pass the impact test.
(4) Nonmetallic materials for boxes and covers shall--
(i) Be accepted by MSHA as flame-resistant material under part 18 of
this chapter; and
(ii) Meet the acceptable performance criteria for the deflection
temperature test in Sec. 7.47.
(b) All insulating material shall have a minimum resistance of 100
megohms at 500 volts d.c. and be accepted by MSHA as flame resistant
under part 18 of this chapter.
(c) Battery box and cover insulating material shall meet the
acceptable performance criteria for the acid resistance test in
Sec. 7.48.
(d) Covers shall be lined with insulating material permanently
attached to the underside of the cover, unless the cover is constructed
of insulating material.
(e) Covers, including those used over connector receptacle housings,
shall be provided with a means of securing them in a closed position.
(f) Battery boxes shall be provided with vent openings to prevent
the accumulation of flammable or toxic gases or vapors within the
battery assembly. The size and location of openings shall prevent direct
access to cell terminals and other uninsulated current carrying parts.
The total minimum unobstructed cross-sectional area of the ventilation
openings shall be no less than the value determined by the following
formula:
[GRAPHIC] [TIFF OMITTED] TC15NO91.011
N = Number of cells in battery box.
R = Rated 6 hour battery capacity in ampere hours.
M = Total minimum ventilation area in square inches per battery box.
(g) Battery boxes shall have drainage holes to prevent accumulation
of water or electrolyte.
(h) Battery cells shall be insulated from the battery box walls,
partitions and bottom by insulating material, unless such part of the
battery box is constructed of insulating material. Battery box wall
insulating material shall extend to the top of the wall.
(i) Cell terminals shall be burned on, except that bolted connectors
using two or more bolts may be used on end terminals.
(j) Battery connections shall be designed so that total battery
potential is not available between adjacent cells.
(k) Cables within a battery box shall be accepted by MSHA as flame
resistant under part 18 of this chapter or approved under subpart K of
this part. The cables shall be protected against abrasion by insulation,
location, clamping, or other effective means.
(l) When the battery plug and receptacle are not located on or
within the battery box, strain on the battery terminals shall be
prevented by a strain-relief device on the cable. Insulating material
shall be placed between the strain-relief device and cable, unless the
device is constructed of insulating material.
(m) At least a \1/2\-inch air space shall be provided between the
underside of the battery cover and the top of the battery, including the
terminals and connectors.
[53 FR 23500, June 22, 1988, as amended at 57 FR 61220, Dec. 23, 1992]
Sec. 7.45 Critical characteristics
The following critical characteristics shall be inspected or tested
on each battery assembly to which an approval marking is affixed:
(a) Thickness of covers and boxes.
(b) Application and resistance of insulating material.
(c) Size and location of ventilation openings.
[[Page 25]]
(d) Method of cell terminations.
(e) Strain relief devices for cables leaving boxes.
(f) Type, location, and physical protection of cables.
Sec. 7.46 Impact test.
(a) Test procedures. (1) Prepare four covers for testing by
conditioning two covers at ^13 F (^25 C) and two covers at 122 F (50
C) for a period of 48 hours.
(2) Mount the covers on a battery box of the same design with which
the covers are to be approved, including any support blocks, with the
battery cells completely assembled. If used, support blocks must contact
only the filler material or partitions between the individual cells. At
the test temperature range of 65 F-80 F (18.3 C-26.7 C), apply a
dynamic force of 200 ft. lbs. to the following areas using a
hemispherical weight with a 6" maximum radius:
(i) The center of the two largest unsupported areas;
(ii) The areas above at least two support blocks, if used;
(iii) The areas above at least two intercell connectors, one cell,
and one filler cap; and
(iv) Areas on at least two corners. If the design consists of both
inside and outside corners, test one of each.
(3) Record the condition of the covers, supports, intercell
connectors, filler caps, cell covers, and filler material.
(b) Acceptable performance. Impact tests of any of the four covers
shall not result in any of the following:
(1) Bent intercell connectors.
(2) Cracked or broken filler caps, except plastic tabs which extend
from the body of the filler caps.
(3) Cracks in the cell cover, cells, or filler material.
(4) Cracked or bent supports.
(5) Cracked or splintered battery covers.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.47 Deflection temperature test.
(a) Test procedures. (1) Prepare two samples for testing that
measure 5 inches by \1/2\ inch, by the thickness of the material as it
will be used. Prior to testing, condition the samples at 73.4 3.6 F
(23 2 C) and 50 5% relative humidity for at least 40 hours.
(2) Place a sample on supports which are 4 inches apart and immersed
in a heat transfer medium at a test temperature range of 65 F^80 F
(18.3 C^26.7 C). The heat transfer medium must be a liquid which will
not chemically affect the sample. The testing apparatus must be
constructed so that expansion of any components during heating of the
medium does not result in deflection of the sample.
(3) Place a temperature measuring device with an accuracy of 1% into
the heat transfer medium within \1/8\ inch of, but not touching, the
sample.
(4) Apply a total load, in pounds, numerically equivalent to 11
times the thickness of the sample, in inches, to the sample midway
between the supports using a \1/8\ inch radius, rounded contact. The
total load includes that weight used to apply the load and any force
exerted by the deflection measurement device.
(5) Use a deflection measuring device with an accuracy of .001
inches to measure the deflection of the sample at the point of loading
as the temperature of the medium is increased at a uniform rate of 3.6
.36 F/min. (2 0.2 C/min.). Apply the load to the sample for 5
minutes prior to heating, to allow compensation for creep in the sample
due to the loading.
(6) Record the deflection of the sample due to heating at 180 F (82
C).
(7) Repeat steps 2 through 6 for the other sample.
(b) Acceptable performance. Neither sample shall have a deflection
greater than .010 inch at 180 F (82 C).
[53 FR 23500, June 22, 1988; 53 FR 25569, July 7, 1988; 60 FR 33723,
June 29, 1995]
Sec. 7.48 Acid resistance test.
(a) Test procedures. (1) Prepare one sample each of the insulated
surfaces of the battery box and of the cover that measure at least 4
inches by 8 inches, by the thickness of the sample which includes the
insulation plus the battery cover or box material. The insulation
thickness shall be representative of that used on the battery box and
cover. If the insulation material and thickness of material are
identical for
[[Page 26]]
the battery box and cover, only one sample need be prepared and tested.
(2) Prepare a 30 percent solution of sulfuric acid (H2
SO4) by mixing 853 ml of water with 199 ml of sulfuric acid
(H2 SO4) with a specific gravity of 1.84.
Completely cover the samples with the acid solution at the test
temperature range of 65 F^80 F (18.3 C^26.7 C) and maintain these
conditions for 7 days.
(3) After 7 days, record the condition of the samples.
(b) Acceptable performance. At the end of the test, the insulation
shall not exhibit any blistering, discoloration, cracking, swelling,
tackiness, rubberiness, or loss of bond.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.49 Approval marking.
Each approved battery assembly shall be identified by a legible and
permanent approval plate inscribed with the assigned MSHA approval
number and securely attached to the battery box.
Sec. 7.50 Post-approval product audit.
Upon request by MSHA, but no more than once a year except for cause,
the approval-holder shall make an approved battery assembly available
for audit at no cost to MSHA.
Sec. 7.51 Approval checklist.
Each battery assembly bearing an MSHA approval plate shall be
accompanied by a description of what is necessary to maintain the
battery assembly as approved.
[53 FR 23500, June 22, 1988, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.52 New technology.
MSHA may approve a battery assembly that incorporates technology for
which the requirements of this subpart are not applicable, if the Agency
determines that the battery assembly is as safe as those which meet the
requirements of this subpart.
Subpart D_Multiple-Shot Blasting Units
Source: 54 FR 48210, Nov. 21, 1989, unless otherwise noted.
Sec. 7.61 Purpose and effective date.
This subpart establishes the specific requirements for MSHA approval
of multiple-shot blasting units. It is effective January 22, 1990.
Applications for approval or extensions of approval submitted after
January 22, 1991 shall meet the requirements of this subpart.
Sec. 7.62 Definitions.
The following definitions apply in this subpart:
Blasting circuit. A circuit that includes one or more electric
detonators connected in a single series and the firing cable used to
connect the detonators to the blasting unit.
Blasting unit. An electric device used to initiate electric
detonators.
Normal operation. Operation of the unit according to the
manufacturer's instructions with fully-charged batteries, with electric
components at any value within their specified tolerances, and with
adjustable electric components set to any value within their range.
Sec. 7.63 Application requirements.
(a) Each application for approval of a blasting unit shall include
the following:
(1) An overall assembly drawing showing the physical construction of
the blasting unit.
(2) A schematic diagram of the electric circuit.
(3) A parts list specifying each electric component and its
electrical ratings, including tolerances.
(4) A layout drawing showing the location of each component and
wiring.
(5) The model number or other manufacturer's designation of the
blasting unit.
(b) All drawings shall be titled, numbered, dated, and include the
latest revision number. The drawings may be combined into one or more
composite drawings.
[[Page 27]]
(c) The application shall contain a list of all the drawings
submitted, including drawing titles, numbers, and revisions.
(d) A detailed technical description of the operation and use of the
blasting unit shall be submitted with the application.
[54 FR 48210, Nov. 21, 1989, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.64 Technical requirements.
(a) Energy output. Blasting units shall meet the acceptable
performance criteria of the output energy test in Sec. 7.66.
(b) Maximum blasting circuit resistance. The maximum value of the
resistance of the blasting circuit that can be connected to the firing
line terminals of the blasting unit, without exceeding its capacity,
shall be specified by the applicant. The specified maximum blasting
circuit resistance shall be at least 150 ohms.
(c) Visual indicator. The blasting unit shall provide a visual
indication to the user prior to the operation of the firing switch when
the voltage necessary to produce the required firing current is
attained.
(d) Firing switch. The switch used to initiate the application of
energy to the blasting circuit shall--
(1) Require deliberate action for its operation to prevent
accidental firing; and
(2) Operate only when the voltage necessary to produce the required
firing current is available to the blasting circuit.
(e) Firing line terminals. The terminals used to connect the
blasting circuit to the blasting unit shall--
(1) Provide a secure, low-resistance connection to the blasting
circuit as demonstrated by the firing line terminals test in Sec. 7.68;
(2) Be corrosion-resistant;
(3) Be insulated to protect the user from electrical shock; and
(4) Be separated from each other by an insulated barrier.
(f) Ratings of electric components. No electric component of the
blasting unit, other than batteries, shall be operated at more than 90
percent of any of its electrical ratings in the normal operation of the
blasting unit.
(g) Non-incendive electric contacts. In the normal operation of a
blasting unit, the electric energy discharged by making and breaking
electric contacts shall not be capable of igniting a methane-air
atmosphere, as determined by the following:
(1) The electric current through an electric contact shall not be
greater than that determined from Figure D-1.
(2) The maximum voltage that can be applied across an electric
contact that discharges a capacitor shall not be greater than that
determined from Figure D-2.
(3) The electric current through an electric contact that interrupts
a circuit containing inductive components shall not be greater than that
determined from Figure D-3. Inductive components include inductors,
chokes, relay coils, motors, transformers, and similar electric
components that have an inductance greater than 100 microhenries. No
inductive component in a circuit with making and breaking electric
contacts shall have an inductance value greater than 100 millihenries.
[[Page 28]]
[GRAPHIC] [TIFF OMITTED] TC22OC91.001
[[Page 29]]
[GRAPHIC] [TIFF OMITTED] TC22OC91.002
[[Page 30]]
[GRAPHIC] [TIFF OMITTED] TC22OC91.003
(h) Maximum temperature. In the normal operation of the blasting
unit, the maximum temperature of any electric component shall not exceed
302 F (150 C).
(i) Capacitor discharge. The blasting unit shall include an
automatic means
[[Page 31]]
to dissipate any electric charge remaining in any capacitor after the
blasting unit is deenergized and not in use.
(j) Construction. Blasting units shall meet the acceptable
performance criteria of the construction test of Sec. 7.67.
(k) Locking device. The blasting unit shall be equipped with a
locking device to prevent unauthorized use.
(l) Enclosure. The blasting unit enclosure shall be protected
against tampering by--
(1) Sealing the enclosure, except the battery compartment, using
continuous welding, brazing, soldering, or equivalent methods; or
(2) Sealing the electric components, other than batteries, in a
solidified insulating material and assembling the enclosure with tamper-
resistant hardware.
(m) Battery charging. Blasting units that contain rechargeable
batteries shall have the following:
(1) A blocking diode, or equivalent device, in series with the
battery to prevent electric energy in the battery from being available
at the charging connector.
(2) The charging connector recessed into the enclosure.
Sec. 7.65 Critical characteristics.
The following critical characteristics shall be inspected or tested
on each blasting unit to which an approval marking is affixed:
(a) The output current.
(b) The voltage cut-off time.
(c) The components that control voltage and current through each
making and breaking electric contact.
(d) Operation of the visual indicator and the firing switch.
Sec. 7.66 Output energy test.
(a) Test procedures. The blasting unit shall be tested by firing
into each of the following resistive loads, within a tolerance of 1%:
(1) The maximum blasting circuit resistance.
(2) Any resistive load between 3 ohms and the maximum blasting
circuit resistance.
(3) One ohm.
(b) Acceptable performance. (1) The voltage shall be zero at the
firing line terminals 10 milliseconds after operation of the firing
switch.
(2) The electric current from the blasting unit shall be:
(i) Less than 50 milliamperes except during firing of the blasting
unit.
(ii) Available only through the firing line terminals.
(iii) At least an average of 2 amperes during the first 5
milliseconds following operation of the firing switch.
(iv) Not exceed an average of 100 amperes during the first 10
milliseconds following operation of the firing switch.
Sec. 7.67 Construction test.
The constuction test is to be performed on the blasting unit
subsequent to the output energy test of Sec. 7.66.
(a) Test procedures. (1) The blasting unit shall be dropped 20 times
from a height of 3 feet onto a horizontal concrete floor. When dropped,
the orientation of the blasting unit shall be varied each time in an
attempt to have a different surface, corner, or edge strike the floor
first for each drop.
(2) After the blasting unit has been drop tested in accordance with
paragraph (a)(1) above, it shall be submerged in 1 foot of water for 1
hour in each of 3 tests. The water temperature shall be maintained
within 5 F (2.8 C) of 40 F (4.4 C), 70 F (21.1 C) and 100 F
(37.8 C) during the tests.
(3) Immediately after removing the blasting unit from the water at
each temperature, the unit shall be operated first with the firing line
terminals open circuited, then operated again with the firing line
terminals short circuited, and last, the output energy tested in
accordance with the output energy test of Sec. 7.66.
(b) Acceptable performance. (1) The blasting unit shall meet the
acceptable performance criteria of the output energy test in Sec. 7.66
each time it is performed.
(2) There shall be no damage to the firing line terminals that
exposes an electric conductor.
(3) The visual indicator shall be operational.
(4) The batteries shall not be separated from the blasting unit.
[[Page 32]]
(5) There shall be no water inside the blasting unit enclosure,
except for the battery compartment.
Sec. 7.68 Firing line terminals test.
(a) Test procedures. (1) The contact resistance through each firing
line terminal shall be determined.
(2) A 10-pound pull shall be applied to a No. 18 gauge wire that has
been connected to each firing line terminal according to the
manufacturer's instructions.
(b) Acceptable performance. (1) The contact resistance shall not be
greater than 1 ohm.
(2) The No. 18 gauge wire shall not become disconnected from either
firing line terminal.
Sec. 7.69 Approval marking.
Each approved blasting unit shall be identified as permissible by a
legible and permanent marking securely attached, stamped, or molded to
the outside of the unit. This marking shall include the following:
(a) The assigned MSHA approval number.
(b) The maximum blasting circuit resistance.
(c) A warning that the unit's components must not be disassembled or
removed.
(d) The replacement battery types if the unit has replaceable
batteries.
(e) A warning placed next to the charging connector that the battery
only be charged in a fresh air location if rechargeable batteries are
used.
(f) A warning that the unit is compatible only with detonators that
will--
(1) Fire when an average of 1.5 amperes is applied for 5
milliseconds;
(2) Not misfire when up to an average 100 amperes is applied for 10
milliseconds; and
(3) Not fire when a current of 250 milliamperes or less is applied.
Sec. 7.70 Post-approval product audit.
Upon request by MSHA, but not more than once a year except for
cause, the approval holder shall make an approved blasting unit
available for audit at no cost to MSHA.
Sec. 7.71 Approval checklist.
Each blasting unit bearing an MSHA approval marking shall be
accompanied by a description of what is necessary to maintain the
blasting unit as approved.
[54 FR 48210, Nov. 21, 1989, as amended at 60 FR 33723, June 29, 1995]
Sec. 7.72 New technology.
MSHA may approve a blasting unit that incorporates technology for
which the requirements of this subpart are not applicable if the Agency
determines that the blasting unit is as safe as those which meet the
requirements of this subpart.
Subpart E_Diesel Engines Intended for Use in Underground Coal Mines
Source: 61 FR 55504, Oct. 25, 1996, unless otherwise noted.
Sec. 7.81 Purpose and effective date.
Subpart A general provisions of this part apply to this subpart E.
Subpart E establishes the specific engine performance and exhaust
emission requirements for MSHA approval of diesel engines for use in
areas of underground coal mines where permissible electric equipment is
required and areas where non-permissible electric equipment is allowed.
It is effective November 25, 1996.
Sec. 7.82 Definitions.
In addition to subpart A definitions of this part, the following
definitions apply in this subpart.
Brake Power. The observed power measured at the crankshaft or its
equivalent when the engine is equipped only with standard auxiliaries
necessary for its operation on the test bed.
Category A engines. Diesel engines intended for use in areas of
underground coal mines where permissible electric equipment is required.
Category B engines. Diesel engines intended for use in areas of
underground coal mines where nonpermissible electric equipment is
allowed.
[[Page 33]]
Corrosion-resistant material. Material that has at least the
corrosion-resistant properties of type 304 stainless steel.
Diesel engine. Any compression ignition internal combustion engine
using the basic diesel cycle where combustion results from the spraying
of fuel into air heated by compression.
Exhaust emission. Any substance emitted to the atmosphere from the
exhaust port of the combustion chamber of a diesel engine.
Intermediate speed. Maximum torque speed if it occurs between 60
percent and 75 percent of rated speed. If the maximum torque speed is
less than 60 percent of rated speed, then the intermediate speed shall
be 60 percent of the rated speed. If the maximum torque speed is greater
than 75 percent of the rated speed, then the intermediate speed shall be
75 percent of rated speed.
Low idle speed. The minimum no load speed as specified by the engine
manufacturer.
Maximum torque speed. The speed at which an engine develops maximum
torque.
Operational range. All speed and load (including percent loads)
combinations from the rated speed to the minimum permitted engine speed
at full load as specified by the engine manufacturer.
Particulates. Any material collected on a specified filter medium
after diluting exhaust gases with clean, filtered air at a temperature
of less than or equal to 125 F (52 C), as measured at a point
immediately upstream of the primary filter. This is primarily carbon,
condensed hydrocarbons, sulfates, and associated water.
Percent load. The fraction of the maximum available torque at an
engine speed.
Rated horsepower. The nominal brake power output of a diesel engine
as specified by the engine manufacturer with a specified production
tolerance. For laboratory test purposes, the fuel pump calibration for
the rated horsepower must be set between the nominal and the maximum
fuel tolerance specification.
Rated speed. Speed at which the rated power is delivered, as
specified by the engine manufacturer.
Steady-state condition. Diesel engine operating condition which is
at a constant speed and load and at stabilized temperatures and
pressures.
Total oxides of nitrogen. The sum total of the measured parts per
millions (ppm) of nitric oxide (NO) plus the measured ppm of nitrogen
dioxide (NO2).
Sec. 7.83 Application requirements.
(a) An application for approval of a diesel engine shall contain
sufficient information to document compliance with the technical
requirements of this subpart and specify whether the application is for
a category A engine or category B engine.
(b) The application shall include the following engine
specifications--
(1) Model number;
(2) Number of cylinders, cylinder bore diameter, piston stroke,
engine displacement;
(3) Maximum recommended air inlet restriction and exhaust
backpressure;
(4) Rated speed(s), rated horsepower(s) at rated speed(s), maximum
torque speed, maximum rated torque, high idle, minimum permitted engine
speed at full load, low idle;
(5) Fuel consumption at rated horsepower(s) and at the maximum rated
torque;
(6) Fuel injection timing; and
(7) Performance specifications of turbocharger, if applicable.
(c) The application shall include dimensional drawings (including
tolerances) of the following components specifying all details affecting
the technical requirements of this subpart. Composite drawings
specifying the required construction details may be submitted instead of
individual drawings of the following components--
(1) Cylinder head;
(2) Piston;
(3) Inlet valve;
(4) Exhaust valve;
(5) Cam shaft--profile;
(6) Fuel cam shaft, if applicable;
(7) Injector body;
(8) Injector nozzle;
(9) Injection fuel pump;
(10) Governor;
(11) Turbocharger, if applicable;
(12) Aftercooler, if applicable;
(13) Valve guide;
[[Page 34]]
(14) Cylinder head gasket; and
(15) Precombustion chamber, if applicable.
(d) The application shall include a drawing showing the general
arrangement of the engine.
(e) All drawings shall be titled, dated, numbered, and include the
latest revision number.
(f) When all necessary testing has been completed, the following
information shall be submitted:
(1) The gaseous ventilation rate for the rated speed and horsepower.
(2) The particulate index for the rated speed and horsepower.
(3) A fuel deration chart for altitudes for each rated speed and
horsepower.
Sec. 7.84 Technical requirements.
(a) Fuel injection adjustment. The fuel injection system of the
engine shall be constructed so that the quantity of fuel injected can be
controlled at a desired maximum value. This adjustment shall be
changeable only after breaking a seal or by altering the design.
(b) Maximum fuel-air ratio. At the maximum fuel-air ratio determined
by Sec. 7.87 of this part, the concentrations (by volume, dry basis) of
carbon monoxide (CO) and oxides of nitrogen (NOX) in the
undiluted exhaust gas shall not exceed the following:
(1) There shall be no more than 0.30 percent CO and no more than
0.20 percent NOX for category A engines.
(2) There shall be no more than 0.25 percent CO and no more than
0.20 percent NOX for category B engines.
(c) Gaseous emissions ventilation rate. Ventilation rates necessary
to dilute gaseous exhaust emissions to the following values shall be
determined under Sec. 7.88 of this part:
Carbon dioxide......................... ^5000 ppm
Carbon monoxide........................ ^50 ppm
Nitric oxide........................... ^25 ppm
Nitrogen dioxide....................... ^5 ppm
A gaseous ventilation rate shall be determined for each requested speed
and horsepower rating as described in Sec. 7.88(b) of this part.
(d) Fuel deration. The fuel rates specified in the fuel deration
chart shall be based on the tests conducted under paragraphs (b) and (c)
of this section and shall ensure that the maximum fuel:air (f/a) ratio
determined under paragraph (b) of this section is not exceeded at the
altitudes specified in the fuel deration chart.
(e) Particulate index. For each rated speed and horsepower
requested, the particulate index necessary to dilute the exhaust
particulate emissions to 1 mg/m\3\ shall be determined under Sec. 7.89
of this part.
Sec. 7.85 Critical characteristics.
The following critical characteristics shall be inspected or tested
on each diesel engine to which an approval marking is affixed--
(a) Fuel rate is set properly; and
(b) Fuel injection pump adjustment is sealed, if applicable.
Sec. 7.86 Test equipment and specifications.
(a) Dynamometer test cell shall be used in determining the maximum
f/a ratio, gaseous ventilation rates, and the particulate index.
(1) The following testing devices shall be provided:
(i) An apparatus for measuring torque that provides an accuracy of
2.0 percent based on the engine's maximum value;
(ii) An apparatus for measuring revolutions per minute (rpm) that
provides an accuracy of 2.0 percent based on the engine's maximum
value;
(iii) An apparatus for measuring temperature that provides an
accuracy of 4 F (2 C) of the absolute value except for the exhaust
gas temperature device that provides an accuracy of 27 F (15 C);
(iv) An apparatus for measuring intake and exhaust restriction
pressures that provides an accuracy of 5 percent of maximum;
(v) An apparatus for measuring atmospheric pressure that provides an
accuracy of 0.5 percent of reading;
(vi) An apparatus for measuring fuel flow that provides an accuracy
of 2 percent based on the engine's maximum value;
(vii) An apparatus for measuring the inlet air flow rate of the
diesel engine that provides an accuracy of 2 percent based on the
engine's maximum value; and
(viii) For testing category A engines, an apparatus for metering in
1.0 0.1
[[Page 35]]
percent, by volume, of methane (CH4) into the intake air
system shall be provided.
(2) The test fuel specified in Table E-1 shall be a low volatile
hydrocarbon fuel commercially designated as ``Type 2-D'' grade diesel
fuel. The fuel may contain nonmetallic additives as follows: Cetane
improver, metal deactivator, antioxidant, dehazer, antirust, pour
depressant, dye, dispersant, and biocide.
Table E-1--Diesel Test Fuel Specifications
------------------------------------------------------------------------
Item ASTM Type 2-D
------------------------------------------------------------------------
Cetane number.......................... D613 40-48
Cetane index........................... D976 40-48
Distillation range:
IBP F.............................. D86 340-400
(C)............................ .............. (171.1-204.4)
10 pct. point, F................... D86 400-460
(C)............................ .............. (204.4-237.8)
50 pct. point, F................... D86 470.540
(C)............................ .............. (243.3-282.2)
90 pct. point, F................... D86 560-630
(C)............................ .............. (293.3-332.2)
EP, F.............................. D86 610-690
(C)............................ .............. (321.1-365.6)
Gravity,API............................ D287 32-37
Total sulfur, pct...................... D2622 0.03-0.05
Hydrocarbon composition:
Aromatics, pct..................... D1319 27 minimum
Paraffins, naphthenes, olefins..... D1319 Remainder
Flashpoint, minimum, F................. 93 130
(C)................................ .............. (54.4)
Viscosity, centistokes................. 445 2.0-3.2
------------------------------------------------------------------------
(3) The test fuel temperature at the inlet to the diesel engine's
fuel injection pump shall be controlled to the engine manufacturer's
specification.
(4) The engine coolant temperature (if applicable) shall be
maintained at normal operating temperatures as specified by the engine
manufacturer.
(5) The charge air temperature and cooler pressure drop (if
applicable) shall be set to within 7 F(4 C) and 0.59 inches Hg
(2kPa) respectively, of the manufacturer's specification.
(b) Gaseous emission sampling system shall be used in determining
the gaseous ventilation rates.
(1) The schematic of the gaseous sampling system shown in Figure E-1
shall be used for testing category A engines. Various configurations of
Figure E-1 may produce equivalent results. The components in Figure E-1
are designated as follows--
(i) Filters--F1, F2, F3, and F4;
(ii) Flowmeters--FL1, FL2, FL3, FL4, FL5, FL6, and FL7;
(iii) Upstream Gauges--G1, G2, and G5;
(iv) Downstream Gauges--G3, G4, and G6;
(v) Pressure Gauges--P1, P2, P3, P4, P5, and P6;
(vi) Regulators--R1, R2, R3, R4, R5, R6, and R7;
(vii) Selector Valves--V1, V2, V3, V4, V6, V7, V8, V15, and V19;
(viii) Heated Selector Valves--V5, V13, V16, and V17;
(ix) Flow Control Valves--V9, V10, V11 and V12;
(x) Heated Flow Control Valves--V14 and V18;
(xi) Pump--Sample Transfer Pump;
(xii) Temperature Sensor--(T1);
(xiii) Dryer--D1 and D2; and
(xiv) Water traps--WT1 and WT2.
(A) Water removal from the sample shall be done by condensation.
(B) The sample gas temperature or dew point shall be monitored
either within the water trap or downstream of the water trap and shall
not exceed 45 F (7 C).
(C) Chemical dryers are not permitted.
[[Page 36]]
[GRAPHIC] [TIFF OMITTED] TR25OC96.000
(2) The schematic of the gaseous sampling system shown in Figure E-2
shall be used for testing category B engines. Various configurations of
Figure E-2 may produce equivalent results. The components are designated
as follows--
(i) Filters--F1, F2, F3, and F4;
[[Page 37]]
(ii) Flowmeters--FL1, FL2, FL3, and FL4;
(iii) Upstream Gauges--G1, and G2;
(iv) Downstream Gauges--G3, and G4;
(v) Pressure Gauges--P1, P2, P3, and P4;
(vi) Regulators--R1, R2, R3, and R4;
(vii) Selector Valves--V1, V2, V3, V4, V6, and V7;
(viii) Heated Selector Valves--V5, V8, and V12;
(ix) Flow Control Valves--V9, V10, V11;
(x) Heated Flow Control Valves--V13;
(xi) Pump--Sample Transfer Pump;
(xii) Temperature Sensor--(T1); and
(xiii) Water traps--WT1 and WT2.
(A) Water removal from the sample shall be done by condensation.
(B) The sample gas temperature or dew point shall be monitored
either within the water trap or downstream of the water trap and shall
not exceed 45 F (7 C).
(C) Chemical dryers are not permitted.
(3) All components or parts of components that are in contact with
the sample gas or corrosive calibration gases shall be corrosion-
resistant material.
[[Page 38]]
[GRAPHIC] [TIFF OMITTED] TR25OC96.001
(4) All analyzers shall obtain the sample to be analyzed from the
same sample probe.
(5) CO and CO2 measurements shall be made on a dry basis.
[[Page 39]]
(6) Calibration or span gases for the NOX measurement
system shall pass through the NO2 to NO converter.
(7) A stainless steel sample probe shall be straight, closed-end,
multi-holed, and shall be placed inside the exhaust pipe.
(i) The probe length shall be at least 80 percent of the diameter of
the exhaust pipe.
(ii) The inside diameter of the sample probe shall not be greater
than the inside diameter of the sample line.
(iii) The heated sample line shall have a 0.197 inch (5 mm) minimum
and a 0.53 inch (13.5 mm) maximum inside diameter.
(iv) The wall thickness of the probe shall not be greater than 0.040
inch (1 mm).
(v) There shall be a minimum of 3 holes in 3 different radial planes
sized to sample approximately the same flow.
(8) The sample probe shall be located in the exhaust pipe at a
minimum distance of 1.6 feet (0.5 meters) or 3 times the diameter of the
exhaust pipe, whichever is the larger, from the exhaust manifold outlet
flange or the outlet of the turbocharger. The exhaust gas temperature at
the sample probe shall be a minimum of 158 F (70 C).
(9) The maximum allowable leakage rate on the vacuum side of the
analyzer pump shall be 0.5 percent of the in-use flow rate for the
portion of the system being checked.
(10) General analyzer specifications. (i) The total measurement
error, including the cross sensitivity to other gases, (paragraphs
(b)(11)(ii), (b)(12)(iii), (b)(13)(iii), and (b)(13)(iv) of this
section), shall not exceed 5 percent of the reading or 3.5 percent of
full scale, whichever is smaller. For concentrations of less than 100
ppm the measurement error shall not exceed 4 ppm.
(ii) The repeatability, defined as 2.5 times the standard deviation
of 10 repetitive responses to a given calibration or span gas, must be
no greater than 1 percent of full scale concentration for each range
used above 155 parts per million (ppm) or parts per million equivalent
carbon (ppmC) or 2 percent of each range used below 155 ppm (or ppmC).
(iii) The analyzer peak to peak response to zero and calibration or
span gases over any 10 second period shall not exceed 2 percent of full
scale on all ranges used.
(iv) The analyzer zero drift during a 1-hour period shall be less
than 2 percent of full scale on the lowest range used. The zero-response
is the mean response, including noise, to a zero gas during a 30-second
time interval.
(v) The analyzer span drift during a 1-hour period shall be less
than 2 percent of full scale on the lowest range used. The analyzer span
is defined as the difference between the span response and the zero
response. The span response is the mean response, including noise, to a
span gas during a 30-second time interval.
(11) CO and CO2 analyzer specifications. (i) Measurements
shall be made with nondispersive infrared (NDIR) analyzers.
(ii) For the CO analyzer, the water and CO2 interference
shall be less than 1 percent of full scale for ranges equal to or
greater than 300 ppm (3 ppm for ranges below 300 ppm) when a
CO2 span gas concentration of 80 percent to 100 percent of
full scale of the maximum operating range used during testing is bubbled
through water at room temperature.
(12) For NOX analysis using a chemiluminescence (CL)
analyzer the following parameters shall apply:
(i) From the sample point to the NO2 to NO converter, the
NOX sample shall be maintained between 131 F (55 C) and 392
F (200 C).
(ii) The NO2 to NO converter efficiency shall be at least
90 percent.
(iii) The quench interference from CO2 and water vapor
must be less than 3.0 percent.
(13) For NOX analysis using an NDIR analyzer system the
following parameters shall apply:
(i) The system shall include a NO2 to NO converter, a
water trap, and a NDIR analyzer.
(ii) From the sample point to the NO2 to NO converter,
the NOX sample shall be maintained between 131 F (55 C) and
392 F (200 C).
(iii) The minimum water rejection ratio (maximum water interference)
[[Page 40]]
for the NOX NDIR analyzer shall be 5,000:1.
(iv) The minimum CO2 rejection ratio (maximum
CO2 interference) for the NOX NDIR analyzer shall
be 30,000:1.
(14) When CH4 is measured using a heated flame ionization
detector (HFID) the following shall apply:
(i) The analyzer shall be equipped with a constant temperature oven
that houses the detector and sample-handling components.
(ii) The detector, oven, and sample-handling components shall be
suitable for continuous operation at temperatures of 374 F (190 C) 18
F (10 C).
(iii) The analyzer fuel shall contain 40 2 percent hydrogen. The
balance shall be helium. The mixture shall contain 1 part per million
equivalent carbon (ppmC), and 400 ppm CO.
(iv) The burner air shall contain <2 ppmC hydrocarbon.
(v) The percent of oxygen interference shall be less than 5 percent.
(15) An NDIR analyzer for measuring CH4 may be used in
place of the HFID specified in paragraph (b)(14) of this section and
shall conform to the requirements of paragraph (b)(10) of this section.
Methane measurements shall be made on a dry basis.
(16) Calibration gas values shall be traceable to the National
Institute for Standards and Testing (NIST), ``Standard Reference
Materials'' (SRM's). The analytical accuracy of the calibration gas
values shall be within 2.0 percent of NIST gas standards.
(17) Span gas values shall be traceable to NIST SRM's. The
analytical accuracy of the span gas values shall be within 2.0 percent
of NIST gas standards.
(18) Calibration or span gases for the CO and CO2
analyzers shall have purified nitrogen as a diluent. Calibration or span
gases for the CH4 analyzer shall be CH4 with
purified synthetic air or purified nitrogen as diluent.
(19) Calibration or span gases for the NOX analyzer shall
be NO with a maximum NO2 concentration of 5 percent of the NO
content. Purified nitrogen shall be the diluent.
(20) Zero-grade gases for the CO, CO2, CH4 ,
and NOX analyzers shall be either purified synthetic air or
purified nitrogen.
(21) The allowable zero-grade gas (purified synthetic air or
purified nitrogen) impurity concentrations shall not exceed 1ppm C, 1
ppm CO, 400 ppm CO2, and 0.1 ppm NO.
(22) The calibration and span gases may also be obtained by means of
a gas divider. The accuracy of the mixing device must be such that the
concentration of the diluted calibration gases are within 2 percent.
(c) Particulate sampling system shall be used in determining the
particulate index. A schematic of a full flow (single dilution)
particulate sampling system for testing under this subpart is shown in
Figures E-3 and E-4.
(1) The dilution system shall meet the following parameters:
(i) Either a positive displacement pump (PDP) or a critical flow
venturi (CFV) shall be used as the pump/mass measurement device shown in
Figure E-3.
(ii) The total volume of the mixture of exhaust and dilution air
shall be measured.
(iii) All parts of the system from the exhaust pipe up to the filter
holder, which are in contact with raw and diluted exhaust gas, shall be
designed to minimize deposition or alteration of the particulate.
(iv) All parts shall be made of electrically conductive materials
that do not react with exhaust gas components.
(v) All parts shall be electrically grounded to prevent
electrostatic effects.
(vi) Systems other than full flow systems may also be used provided
they yield equivalent results where:
(A) A seven sample pair (or larger) correlation study between the
system under consideration and a full flow dilution system shall be run
concurrently.
(B) Correlation testing is to be performed at the same laboratory,
test cell, and on the same engine.
(C) The equivalency criterion is defined as a 5 percent agreement
of the sample pair averages.
(2) The mass of particulate in the exhaust shall be collected by
filtration. The exhaust temperature immediately
[[Page 41]]
before the primary particulate filter shall not exceed 125 F (52.0 C).
(3) Exhaust system backpressure shall not be artificially lowered by
the PDP, CFV systems or dilution air inlet system. Static exhaust
backpressure measured with the PDP or CFV system operating shall remain
within 0.44 inches Hg (1.5 kPa) of the static pressure measured without
being connected to the PDP or CFV at identical engine speed and load.
(4) The gas mixture temperature shall be measured at a point
immediately ahead of the pump or mass measurement device.
(i) Using PDP, the gas mixture temperature shall be maintained
within 10 F (6.0 C) of the average operating temperature observed
during the test, when no flow compensation is used.
(ii) Flow compensation can be used provided that the temperature at
the inlet to the PDP does not exceed 122 F (50 C).
(iii) Using CFV, the gas mixture temperature shall be maintained
within 20 F (11 C) of the average operating temperature observed
during the test, when no flow compensation is used.
(5) The heat exchanger shall be of sufficient capacity to maintain
the temperature within the limits required above and is optional if
electronic flow compensation is used.
(6) When the temperature at the inlet of either the PDP or CFV
exceeds the limits stated in either paragraphs (c)(4)(i) or (c)(4)(iii)
of this section, an electronic flow compensation system shall be
required for continuous measurement of the flow rate and control of the
proportional sampling in the particulate sampling system.
(7) The flow capacity of the system shall be large enough to
eliminate water condensation.
[[Page 42]]
[GRAPHIC] [TIFF OMITTED] TR25OC96.002
[[Page 43]]
[GRAPHIC] [TIFF OMITTED] TR25OC96.003
(8) The flow capacity of the PDP or CFV system using single dilution
shall maintain the diluted exhaust at 125 F (52.0 C) or less
immediately before the primary particulate filter.
(9) The flow capacity of the PDP or CFV system using a double
dilution
[[Page 44]]
system shall be sufficient to maintain the diluted exhaust in the
dilution tunnel at 375 F (191 C) or less at the sampling zone.
(10) The secondary dilution system shall provide sufficient
secondary dilution air to maintain the double-diluted exhaust stream at
125 F (52.0 C) or less immediately before the primary particulate
filter.
(11) The gas flow meters or the mass flow measurement
instrumentation shall have a maximum error of the measured value within
2 percent of reading.
(12) The dilution air shall have a temperature of 77 F 9 F (25 C
5 C), and be--
(i) Filtered at the air inlet; or
(ii) Sampled to determine background particulate levels, which can
then be subtracted from the values measured in the exhaust stream.
(13) The dilution tunnel shall have the following specifications:
(i) Be small enough in diameter to cause turbulent flow (Reynolds
number greater than 4,000) and of sufficient length to cause complete
mixing of the exhaust and dilution air;
(ii) Be at least 3 inches (75 mm) in diameter; and
(iii) Be configured to direct the engine exhaust downstream at the
point where it is introduced into the dilution tunnel for thorough
mixing.
(14) The exhaust pipe length from the exit of the engine exhaust
manifold or turbocharger outlet to the dilution tunnel shall not exceed
a total length of 32 feet (10 m).
(i) When the exhaust pipe exceeds 12 feet (4 m), then all pipe in
excess of 12 feet (4 m) shall be insulated with a radial thickness of at
least 1.0 inch (25 mm) and the thermal conductivity of the insulating
material shall be no greater than 0.1 W/mK measured at 752 F (400 C).
(ii) To reduce the thermal inertia of the exhaust pipe, the
thickness to diameter ratio shall be 0.015 or less.
(iii) The use of flexible sections shall be limited to the length to
diameter ratio of 12 or less.
(15) The particulate sample probe shall--
(i) Be installed in the dilution tunnel facing upstream, on the
dilution tunnel centerline, and approximately 10 dilution tunnel
diameters downstream of the point where the engine's exhaust enters the
dilution tunnel; and
(ii) Have 0.5 inches (12 mm) minimum inside diameter.
(16) The inlet gas temperature to the particulate sample pump or
mass measurement device shall remain a constant temperature of 5 F
(3.0 C) if flow compensation is not used.
(17) The secondary dilution portion of the double dilution system
shall have:
(i) A particulate transfer tube shall have a 0.5 inch (12 mm)
minimum inside diameter not to exceed 40 inches (1020 mm) in length
measured from the probe tip to the secondary dilution tunnel has:
(A) An inlet with the transfer tube facing upstream in the primary
dilution tunnel, centerline, and approximately 10 dilution tunnel
diameters downstream of the point where the engine's exhaust enters the
dilution tunnel.
(B) An outlet where the transfer tube exits on the centerline of the
secondary tunnel and points downstream.
(ii) A secondary tunnel that has a minimum diameter of 3.0 inches
(75 mm), and of sufficient length to provide a residence time of at
least 0.25 seconds for the double-diluted sample.
(iii) Secondary dilution air supplied at a temperature of 77 F 9
F (25 C 5 C).
(iv) A primary filter holder located within 12.0 inches (300 mm) of
the exit of the secondary tunnel.
(18) The particulate sampling filters shall--
(i) Be fluorocarbon-coated glass fiber filters or fluorocarbon-based
(membrane) filters and have a 0.3 mm di-octylphthalate (DOP) collection
efficiency of at least 95 percent at a gas face velocity between 35 and
80 cm/s.;
(ii) Have a minimum diameter of 1.85 inches (47 mm), 1.46 inches (37
mm) stain diameter;
(iii) Have a minimum filter loading ratio of 0.5mg/1075 mm \2\ stain
area for the single filter method.
(iv) Have minimum filter loading such that the sum of all eight (8)
multiple filters is equal to the minimum loading value (mg) for a single
filter
[[Page 45]]
multiplied by the square root of eight (8).
(v) Be sampled at the same time by a pair of filters in series (one
primary and one backup filter) so that:
(A) The backup filter holder shall be located no more than 4 inches
(100 mm) downstream of the primary filter holder.
(B) The primary and backup filters shall not be in contact with each
other.
(C) The filters may be weighed separately or as a pair with the
filters placed stain side to stain side.
(D) The single filter method incorporates a bypass system for
passing the sample through the filters at the desired time.
(vi) Have a pressure drop increase between the beginning and end of
the test of no more than 7.4 in Hg (25kPa).
(vii) Filters of identical quality shall be used when performing
correlation tests specified in paragraph (c)(1)(vi) of this section.
(19) Weighing chamber specifications. (i) The temperature of the
chamber (room) in which the particulate filters are conditioned and
weighed shall be maintained to within 72 F 5 F (22 C 3 C) during
all filter conditioning and weighing.
(ii) The humidity of the chamber (room) in which the particulate
filters are conditioned and weighed shall be maintained to a dewpoint of
49 F 5 F (9.5 C 3 C) and a relative humidity of 45 percent 8
percent during all filter conditioning and weighing.
(iii) The chamber (room) environment shall be free of any ambient
contaminants (such as dust) that would settle on the particulate filters
during their stabilization. This shall be determined as follows:
(A) At least two unused reference filters or reference filter pairs
shall be weighed within four (4) hours of, but preferably at the same
time as the sample filter (pair) weighings.
(B) The reference filters are to be the same size and material as
the sample filters.
(C) If the average weight of reference filters (reference filter
pairs) changes between sample filter weighings by more than 5.0 percent
(7.5 percent for the filter pair respectively) of the recommended
minimum filter loading in paragraphs (c)(18)(iii) or (c)(18)(iv) of this
section, then all sample filters shall be discarded and the tests
repeated.
(20) The analytical balance used to determine the weights of all
filters shall have a precision (standard deviation) of 20 mg and
resolution of 10 mg. For filters less than 70 mm diameter, the precision
and resolution shall be 2 mg and 1 mg, respectively.
(21) All filters shall be neutralized to eliminate the effects of
static electricity prior to weighing.
Sec. 7.87 Test to determine the maximum fuel-air ratio.
(a) Test procedure. (1) Couple the diesel engine to the dynamometer
and connect the sampling and measurement devices specified in Sec. 7.86.
(2) Prior to testing, zero and span the CO and NOX
analyzers to the lowest analyzer range that will be used during this
test.
(3) While running the engine, the following shall apply:
(i) The parameter for the laboratory atmospheric factor,
fa, shall be: 0.98fa1.02;
(A) The equation is fa = ( 99/Ps) *
((Ta + 273)/298)\0.7\ for a naturally aspirated and
mechanically supercharged engines; or
(B) The equation is fa = (99/Ps)\0.7\*
((Ta + 273)/298)\1.5\ for a turbocharged engine with or
without cooling of the intake air.
Where:
Ps = dry atmospheric pressure (kPa)
Ta = intake air temperature (C)
(ii) The air inlet restriction shall be set within 10 percent of
the recommended maximum air inlet restriction as specified by the engine
manufacturer at the engine operating condition giving maximum air flow
to determine the concentration of CO as specified in paragraph (a)(6) of
this section.
(iii) The exhaust backpressure restriction shall be set within 10
percent of the maximum exhaust backpressure as specified by the engine
manufacturer at the engine operating condition giving maximum rated
horsepower to determine the concentrations of CO and NOX as
specified in paragraph (a)(6)of this section.
[[Page 46]]
(iv) The air inlet restriction shall be set within 10 percent of a
recommended clean air filter at the engine operating condition giving
maximum air flow as specified by the engine manufacturer to determine
the concentration of NOX as specified in paragraph (a)(6) of
this section.
(4) The engine shall be at a steady-state condition when the exhaust
gas samples are collected and other test data is measured.
(5) In a category A engine, 1.0 0.1 percent CH4 shall be
injected into the engine's intake air.
(6) Operate the engine at several speed/torque conditions to
determine the concentrations of CO and NOX, dry basis, in the
raw exhaust.
(b) Acceptable performance. The CO and NOX concentrations
in the raw exhaust shall not exceed the limits specified in Sec. 7.84(b)
throughout the specified operational range of the engine.
Sec. 7.88 Test to determine the gaseous ventilation rate.
The test shall be performed in the order listed in Table E-2. The
test for determination of the particulate index described in Sec. 7.89
may be done simultaneously with this test.
(a) Test procedure. (1) Couple the diesel engine to the dynamometer
and attach the sampling and measurement devices specified in Sec. 7.86.
(2) A minimum time of 10 minutes is required for each test mode.
(3) CO, CO2, NOX, and CH4 analyzers
shall be zeroed and spanned at the analyzer range to be used prior to
testing.
(4) Run the engine.
(i) The parameter for fa shall be calculated in
accordance with Sec. 7.87(a)(3).
(ii) The air inlet and exhaust backpressure restrictions on the
engine shall be set as specified in Secs. 7.87(a)(3) (iii) and (iv).
(5) The engine shall be at a steady-state condition before starting
the test modes.
(i) The output from the gas analyzers shall be measured and recorded
with exhaust gas flowing through the analyzers a minimum of the last
three (3) minutes of each mode.
(ii) To evaluate the gaseous emissions, the last 60 seconds of each
mode shall be averaged.
(iii) A 1.0 0.1 percent CH4, by volume, shall be
injected into the engine's intake air for category A engines.
(iv) The engine speed and torque shall be measured and recorded at
each test mode.
(v) The data required for use in the gaseous ventilation
calculations specified in paragraph (a)(9) of this section shall be
measured and recorded at each test mode.
(6) Operate the engine at each rated speed and horsepower rating
requested by the applicant according to Table E-2 in order to measure
the raw exhaust gas concentration, dry basis, of CO, CO2, NO,
and NO2, and CH4- exhaust (category A engines
only).
(i) Test speeds shall be maintained within 1 percent of rated speed
or 3 RPM, which ever is greater, except for low idle which shall be
within the tolerances established by the manufacturer.
(ii) The specified torque shall be held so that the average over the
period during which the measurements are taken is within 2 percent of
the maximum torque at the test speed.
(7) The concentration of CH4 in the intake air shall be
measured for category A engines.
Table E-2--Gaseous Test Modes
----------------------------------------------------------------------------------------------------------------
Speed Rated speed Intermediate speed Low-idle speed
----------------------------------------------------------------------------------------------------------------
% Torque 100 75 50 10 100 75 50 0
----------------------------------------------------------------------------------------------------------------
(8) After completion of the test modes, the following shall be done:
(i) Zero and span the analyzers at the ranges used during the test.
(ii) The gaseous emission test shall be acceptable if the difference
in the zero and span results taken before the test and after the test
are less than 2 percent.
[[Page 47]]
(9) The gaseous ventilation rate for each exhaust gas contaminant
shall be calculated as follows--
(i) The following abbreviations shall apply to both category A and
category B engine calculations as appropriate:
cfm--Cubic feet per min (ft\3\/min)
Exh--Exhaust
A--Air (lbs/hr)
H--Grains of water per lb. of dry intake air
J--Conversion factor
m--Mass flow rate (mass/hr)
TI--Intake air temperature (F)
PCAir--Percent Air
PCCH4--Percent CH4 (intake air)
UCH4--Unburned CH4
PCECH4--Percent Exhaust CH4
(ii) Exhaust gas flow calculation for category B engines shall be (m
Exh) = (A) + (m fuel).
(iii) Fuel/air ratio for category B engines shall be (f/a) = (m
fuel) / (A).
(iv) Methane flow through category A engines shall be determined by
the following:
PCAir = 100^PCCH4
Y = (PCAir)(0.289) + (PCCH4)(0.16)
Z = (0.16)(PCCH4) Y
mCH4 = (A)(Z) (1^Z)
(v) Exhaust gas flow calculation for category A engines shall be (m
Exh) = (A) + (m fuel) + (m CH4)
(vi) Unburned CH4 (lbs/hr) calculation for category A
engines shall be mUCH4 = (m Exh)(0.0052)(PCECH4)
(vii) Fuel/air ratio for category A engines shall be (f/a) = ((m
fuel) + (m CH4)^(m UCH4)) (A)
(viii) Conversion from dry to wet basis for both category A and
category B engines shall be:
(NO wet basis) = (NO dry basis)(J)
(NO2 wet basis) = (NO2 dry basis)(J)
(CO2 wet basis) = (CO2 dry basis)(J)
(CO wet basis) = (CO dry basis)(10^4)(J)
Where:
J = (f/a)(^1.87) + (1 ^ (0.00022)(H))
(ix) NO and NO2 correction for humidity and temperature
for category A and category B engines shall be:
(NO corr) = (NO wet basis) (E)
(NO2 corr) = (NO2 wet basis) (E)
Where:
E = 1.0 + (R)(H ^ 75) + (G)(TI ^ 77)
R = (f/a)(0.044) ^ (0.0038)
G = (f/a)(^0.116) + (0.0053)
(x) The calculations to determine the m of each exhaust gas
contaminant in grams per hour at each test point shall be as follows for
category A and category B engines:
(m NO) = (NO corr)(0.000470)(m Exh)
(m NO2) = (NO2 corr)(0.000720)(m Exh)
(m CO2) = (CO2 wet basis)(6.89)(m Exh)
(m CO) = (CO wet basis)(4.38)(m Exh)
(xi) The calculations to determine the ventilation rate for each
exhaust gas contaminant at each test point shall be as follows for
category A and category B engines:
(cfm NO) = (m NO)(K)
(cfm NO2) = (m NO2)(K)
(cfm CO2) = (m CO2)(K)
(cfm CO) = (m CO)(K)
Where:
K = 13,913.4/ (pollutant grams/mole) (pollutant dilution value specified
in Sec. 7.84(c)).
(b) The gaseous ventilation rate for each requested rated speed and
horsepower shall be the highest ventilation rate calculated in paragraph
(a)(9)(xi) of this section.
(1) Ventilation rates less than 20,000 cfm shall be rounded up to
the next 500 cfm.
Example: 10,432 cfm shall be listed 10,500 cfm.
(2) Ventilation rates greater than 20,000 cfm shall be rounded up to
the next 1,000 cfm.
Example: 26,382 cfm shall be listed 27,000 cfm.
[61 FR 55504, Oct. 25, 1996; 62 FR 34640, June 27, 1997]
Sec. 7.89 Test to determine the particulate index.
The test shall be performed in the order listed in Table E-3.
(a) Test procedure. (1) Couple the diesel engine to the dynamometer
and connect the sampling and measurement devices specified in Sec. 7.86.
(2) A minimum time of 10 minutes is required for each measuring
point.
(3) Prior to testing, condition and weigh the particulate filters as
follows:
(i) At least 1 hour before the test, each filter (pair) shall be
placed in a closed, but unsealed, petri dish and placed in a weighing
chamber (room) for stabilization.
[[Page 48]]
(ii) At the end of the stabilization period, each filter (pair)
shall be weighed. The reading is the tare weight.
(iii) The filter (pair) shall then be stored in a closed petri dish
or a filter holder, both of which shall remain in the weighing chamber
(room) until needed for testing.
(iv) The filter (pair) must be re-weighed if not used within 8 hours
of its removal from the weighing chamber (room).
(4) Run the engine.
(i) The parameter for fa shall be calculated in
accordance with Sec. 7.87(a)(3).
(ii) The air inlet and exhaust backpressure restrictions on the
engine shall be set as specified in Secs. 7.87(a)(3) (iii) and (iv).
(iii) The dilution air shall be set to obtain a maximum filter face
temperature of 125 F (52 C) or less at each test mode.
(iv) The total dilution ratio shall not be less than 4.
(5) The engine shall be at a steady state condition before starting
the test modes.
(i) The engine speed and torque shall be measured and recorded at
each test mode.
(ii) The data required for use in the particulate index calculation
specified in paragraph (a)(9) of this section shall be measured and
recorded at each test mode.
(6) A 1.0 0.1 percent CH4, by volume shall be injected
into the engine's intake air for category A engines.
(7) Operate the engine at each rated speed and horsepower rating
requested by the applicant according to Table E-3 to collect particulate
on the primary filter.
(i) One pair of single filters shall be collected or eight multiple
filter pairs shall be collected.
(ii) Particulate sampling shall be started after the engine has
reached a steady-state condition.
(iii) The sampling time required per mode shall be either a minimum
of 20 seconds for the single filter method or a minimum of 60 seconds
for the multiple filter method.
(iv) The minimum particulate loading specified in Secs. 7.86(c)(18)
(iii) or (iv) shall be done.
Table E-3--Particulate Test Modes
----------------------------------------------------------------------------------------------------------------
Speed Rated speed Intermediate speed Low-idle speed
----------------------------------------------------------------------------------------------------------------
% Torque 100 75 50 10 100 75 50 0
----------------------------------------------------------------------------------------------------------------
Weighting factor..................... 0.15 0.15 0.15 0.1 0.1 0.1 0.1 0.15
----------------------------------------------------------------------------------------------------------------
(v) Test speeds shall be maintained within percent of rated speed
or 3 RPM, which ever is greater, except for low idle which shall be
within the tolerances set by the manufacturer.
(vi) The specified torque shall be held so that the average over the
period during which the measurements are being taken is within 2
percent of the maximum torque at the test speed.
(vii) The modal weighting factors (WF) given in Table E-3 shall be
applied to the multiple filter method during the calculations as shown
in paragraph (a)(9)(iii)(B) of this section.
(viii) For the single filter method, the modal WF shall be taken
into account during sampling by taking a sample proportional to the
exhaust mass flow for each mode of the cycle.
(8) After completion of the test, condition and weigh the
particulate filters in the weighing chamber (room) as follows:
(i) Condition the filters for at least 1 hour, but not more than 80
hours.
(ii) At the end of the stabilization period, weigh each filter. The
reading is the gross weight.
(iii) The particulate mass of each filter is its gross weight minus
its tare weight.
(iv) The particulate mass (PF for the single filter
method; PF,i for the multiple filter method) is
the sum of the particulate masses collected on the primary and back-up
filters.
(v) The test is void and must be rerun if the sample on the filter
contacts the petri dish or any other surface.
[[Page 49]]
(9) The particulate index for the mass particulate shall be
calculated from the equations listed below--
(i) The following abbreviations shall be:
cfm--Cubic feet per min (ft\3\ min)
PT--Particulate (gr/hr)
m mix--Diluted exhaust gas mass flow rate on wet basis (kg/hr)
m sample--Mass of the diluted exhaust sample passed through the
particulate sampling filters (kg)
Pf--Particulate sample mass collected on a filter (mg) at
each test mode as determined in Table E-3.
Kp--Humidity correction factor for particulate
WF--Weighting factor
i-Subscript denoting an individual mode, i = 1, . . . n
PI--Particulate Index (cfm)
(ii) When calculating ambient humidity correction for the
particulate concentration (Pf part), the equation shall be:
Pfcorr = (Pf)(Kp)
Kp = 1 / (1 + 0.0133 * (H ^ 10.71))
Where:
Ha = humidity of the intake air, g water per kg dry air
Ha = (6.220 * Ra * pa) /
(pB^pa ^ Ra *
10^2)
Ra = relative humidity of the intake air, %
pa = saturation vapor pressure of the intake air, kPa
pB = total barometric pressure, kPa
(iii) When the multiple filter method is used, the following
equations shall be used.
(A) Mass of particulate emitted is calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR25OC96.004
(B) Determination of weighted particulate average is calculated as
follows:
[GRAPHIC] [TIFF OMITTED] TR25OC96.005
(C) Determination of particulate index for the mass particulate from
the average of the test modes shall be calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR25OC96.006
(iv) When the single filter method is used, the following equations
shall be used.
(A) Mass of particulate emitted:
[GRAPHIC] [TIFF OMITTED] TR25OC96.007
[[Page 50]]
Where:
[GRAPHIC] [TIFF OMITTED] TR25OC96.008
[GRAPHIC] [TIFF OMITTED] TR25OC96.009
(B) Determination of particulate index for the mass particulate from
the average of the test modes shall be as follows:
[GRAPHIC] [TIFF OMITTED] TR25OC96.010
(v) When the effective weighting factor,
WFE,i, for each mode is calculated for the single
filter method, the following shall apply.
[GRAPHIC] [TIFF OMITTED] TR25OC96.011
(B) The value of the effective weighting factors shall be within
0.005 (absolute value) of the weighting factors listed in Table E-3.
(b) A particulate index for each requested rated speed and
horsepower shall be the value determined in paragraph (a)(9)(iii)(C) of
this section for the multiple filter method or paragraph (a)(9)(iv)(B)
of this section for the single filter method.
(1) Particulate indices less than 20,000 cfm shall be rounded up to
the next 500 cfm. Example: 10,432 cfm shall be listed 10,500 cfm.
(2) Particulate indices greater than 20,000 cfm shall be rounded up
to the nearest thousand 1,000 cfm. Example: 26,382 cfm shall be listed
27,000 cfm.
[61 FR 55504, Oct. 25, 1996; 62 FR 34640, June 27, 1997]
Sec. 7.90 Approval marking.
Each approved diesel engine shall be identified by a legible and
permanent approval marking inscribed with the assigned MSHA approval
number and securely attached to the diesel engine. The marking shall
also contain the following information:
(a) Ventilation rate.
(b) Rated power.
(c) Rated speed.
(d) High idle.
(e) Maximum altitude before deration.
(f) Engine model number.
Sec. 7.91 Post-approval product audit.
Upon request by MSHA, but no more than once a year except for cause,
the approval holder shall make a diesel engine available for audit at no
cost to MSHA.
[[Page 51]]
Sec. 7.92 New technology.
MSHA may approve a diesel engine that incorporates technology for
which the requirements of this subpart are not applicable if MSHA
determines that the diesel engine is as safe as those which meet the
requirements of this subpart.
Subpart F_Diesel Power Packages Intended for Use in Areas of Underground
Coal Mines Where Permissible Electric Equipment is Required
Source: 61 FR 55518, Oct. 25, 1996, unless otherwise noted.
Sec. 7.95 Purpose and effective date.
Part 7, subpart A general provisions apply to subpart F. Subpart F
establishes the specific requirements for MSHA approval of diesel power
packages intended for use in approved equipment in areas of underground
coal mines where electric equipment is required to be permissible. It is
effective November 25, 1996.
Sec. 7.96 Definitions.
In addition to the definitions in subparts A and E of this part, the
following definitions apply in this subpart.
Cylindrical joint. A joint comprised of two contiguous, concentric,
cylindrical surfaces.
Diesel power package. A diesel engine with an intake system, exhaust
system, and a safety shutdown system installed.
Dry exhaust conditioner. An exhaust conditioner that cools the
exhaust gas without direct contact with water.
Exhaust conditioner. An enclosure, containing a cooling system,
through which the exhaust gases pass.
Exhaust system. A system connected to the outlet of the diesel
engine which includes, but is not limited to, the exhaust manifold, the
exhaust pipe, the exhaust conditioner, the exhaust flame arrester, and
any adapters between the exhaust manifold and exhaust flame arrester.
Fastening. A bolt, screw, or stud used to secure adjoining parts to
prevent the escape of flame from the diesel power package.
Flame arrester. A device so constructed that flame or sparks from
the diesel engine cannot propagate an explosion of a flammable mixture
through it.
Flame arresting path (explosion-proof joint). Two or more adjoining
or adjacent surfaces between which the escape of flame is prevented.
Flammable mixture. A mixture of methane or natural gas with normal
air, that will propagate flame or explode when ignited.
Grade. The slope of an incline expressed as a percent.
High idle speed. The maximum no load speed specified by the engine
manufacturer.
Intake system. A system connected to the inlet of the diesel engine
which includes, but is not limited to, the intake manifold, the intake
flame arrester, the emergency intake air shutoff device, the air
cleaner, and all piping and adapters between the intake manifold and air
cleaner.
Plane joint. A joint comprised of two adjoining surfaces in parallel
planes.
Safety shutdown system. A system which, in response to signals from
various safety sensors, recognizes the existence of a potential
hazardous condition and automatically shuts off the fuel supply to the
engine.
Step (rabbet) joint. A joint comprised of two adjoining surfaces
with a change or changes in direction between its inner and outer edges.
A step joint may be composed of a cylindrical portion and a plane
portion or of two or more plane portions.
Threaded joint. A joint consisting of a male- and female-threaded
member, both of which are the same type and gauge.
Wet exhaust conditioner. An exhaust conditioner that cools the
exhaust gas through direct contact with water, commonly called a water
scrubber.
Sec. 7.97 Application requirements.
(a) An application for approval of a diesel power package shall
contain sufficient information to document compliance with the technical
requirements of this subpart and include:
[[Page 52]]
drawings, specifications, and descriptions with dimensions (including
tolerances) demonstrating compliance with the technical requirements of
Sec. 7.98. The specifications and descriptions shall include the
materials of construction and quantity. These shall include the
following--
(1) A general arrangement drawing showing the diesel power package
and the location and identification of the intake system, exhaust
system, safety shutdown system sensors, flame arresters, exhaust
conditioner, emergency intake air shutoff device, automatic fuel shutoff
device and the engine.
(2) Diesel engine specifications including the MSHA approval number,
the engine manufacturer, the engine model number, and the rated speed,
rated horsepower, and fuel rate.
(3) A drawing(s) which includes the fan blade material
specifications, the location and identification of all water-cooled
components, coolant lines, radiator, surge tank, temperature sensors,
and orifices; arrows indicating proper flow direction; the height
relationship of water-cooled components to the surge tank; and the
proper procedure for filling the cooling system.
(4) A drawing(s) showing the relative location, identification of
components, and design of the safety shutdown system.
(5) Specific component identification, or specific information
including detail drawings that identify the characteristics of the
cooling system and safety shutdown system that ensures compliance with
the technical requirements.
(6) Detail drawings of gaskets used to form flame-arresting paths.
(7) An assembly drawing showing the location and identification of
all intake system components from the air cleaner to the engine head.
(8) An assembly drawing showing the location and identification of
all exhaust system components from the engine head to the exhaust
outlet.
(9) Detail drawings of those intake and exhaust system components
identified in paragraphs (a)(7) and (a)(8) of this section that ensure
compliance with the technical requirements. An exhaust conditioner
assembly drawing shall be provided showing the location, dimensions, and
identification of all internal parts, exhaust inlet and outlet, sensors,
and the exhaust gas path through the exhaust conditioner. If a wet
exhaust conditioner is used, the exhaust conditioner assembly drawing
must also show the location, dimensions, and identification of the fill
port, drain port, low water check port; high or normal operating water
level; minimum allowable low water level; and the maximum allowable
grade that maintains explosion-proof operations.
(10) A power package checklist which shall consist of a list of
specific features that must be checked and tests that must be performed
to determine if a previously approved diesel power package is in
approved condition. Test procedures shall be specified in sufficient
detail to allow the evaluation to be made without reference to other
documents. Illustrations shall be used to fully identify the approved
configuration of the diesel power package.
(11) Information showing that the electrical systems and components
meet the requirements of Sec. 7.98.
(12) A drawing list consisting of a complete list of those drawings
and specifications which show the details of the construction and design
of the diesel power package.
(b) Composite drawings specifying the required construction details
may be submitted instead of the individual drawings in paragraph (a) of
this section.
(c) All documents shall be titled, dated, numbered, and include the
latest revision.
(d) When all testing has been completed, the following information
shall be submitted and become part of the approval documentation:
(1) The settings of any adjustable devices used to meet the
performance requirements of this subpart.
(2) The coolant temperature sensor setting and exhaust gas
temperature sensor setting used to meet the performance requirements of
this subpart.
(3) The minimum allowable low water level and the low water sensor
setting used to meet the performance requirements of this subpart for
systems using a wet exhaust conditioner as the exhaust flame arrester.
[[Page 53]]
(4) The maximum grade on which the wet exhaust conditioner can be
operated retaining the flame arresting characteristics.
(5) A finalized version of the power package checklist.
Sec. 7.98 Technical requirements.
(a) The diesel power package shall use a category A diesel engine
approved under subpart E of this part with the following additional
requirements:
(1) A hydraulic, pneumatic, or other mechanically actuated starting
mechanism. Other means of starting shall be evaluated in accordance with
the provisions of Sec. 7.107.
(2) If an air compressor is provided, the intake air line shall be
connected to the engine intake system between the air cleaner and the
flame arrester. If the air compressor's inlet air line is not connected
to the engine's intake system, it shall have an integral air filter.
(b) The temperature of any external surface of the diesel power
package shall not exceed 302 F (150 C).
(1) Diesel power package designs using water jacketing to meet this
requirement shall be tested in accordance with Sec. 7.101.
(2) Diesel power packages using other techniques will be evaluated
under the provisions of Sec. 7.107.
(3) When using water-jacketed components, provisions shall be made
for positive circulation of coolant, venting of the system to prevent
the accumulation of air pockets, and effective activation of the safety
shutdown system before the temperature of the coolant in the jackets
exceeds the manufacturer's specifications or 212 F (100 C), whichever
is lower.
(c) External rotating parts shall not be constructed of aluminum
alloys containing more than 0.6 percent magnesium.
(d) If nonmetallic rotating parts are used, they shall be provided
with a means to prevent an accumulation of static electricity. Static
conducting materials shall have a total resistance of 1 megohm or less,
measured with an applied potential of 500 volts or more. Static
conducting materials having a total resistance greater than 1 megohm
will be evaluated under the provisions of Sec. 7.107.
(e) All V-belts shall be static conducting and have a resistance not
exceeding 6 megohms, when measured with a direct current potential of
500 volts or more.
(f) The engine crankcase breather shall not be connected to the air
intake system of the engine. The discharge from the breather shall be
directed away from hot surfaces of the engine and exhaust system.
(g) Electrical components on diesel power packages shall be
certified or approved by MSHA under parts 7, 18, 20, and 27 of this
chapter.
(h) Electrical systems on diesel power packages consisting of
electrical components, interconnecting wiring, and mechanical and
electrical protection shall meet the requirements of parts 7, 18, and 27
of this chapter, as applicable.
(i) The diesel power package shall be equipped with a safety
shutdown system which will automatically shut off the fuel supply and
stop the engine in response to signals from sensors indicating--
(1) The coolant temperature limit specified in paragraph (b) of this
section;
(2) The exhaust gas temperature limit specified in paragraph (s)(4)
of this section;
(3) The minimum allowable low water level, for a wet exhaust
conditioner, as established by tests in Sec. 7.100. Restarting of the
engine shall be prevented until the water level in the wet exhaust
conditioner has been replenished above the minimum allowable low water
level; and
(4) The presence of other safety hazards such as high methane
concentration, actuation of the fire suppression system, etc., if such
sensors are included in the safety shutdown system.
(j) The safety shutdown system shall have the following features:
(1) A means to automatically disable the starting circuit and
prevent engagement of the starting mechanism while the engine is
running, or a starting mechanism constructed of nonsparking materials.
(2) If the design of the safety shutdown system requires that the
lack of
[[Page 54]]
engine oil pressure must be overridden to start the engine, the override
shall not be capable of overriding any of the safety shutdown sensors
specified in paragraph (i) of this section.
(k) The diesel power package shall be explosion-proof as determined
by the tests set out in Sec. 7.100.
(l) Engine joints that directly or indirectly connect the combustion
chamber to the surrounding atmosphere shall be explosion-proof in
accordance with paragraphs (m) through (q) of this section and
Sec. 7.100. This paragraph does not apply to the following:
(1) Pistons to piston rings;
(2) Pistons to cylinder walls;
(3) Piston rings to cylinder walls;
(4) Cylinder head to cylinder block;
(5) Valve stem to valve guide; or
(6) Injector body to cylinder head.
(m) Each segment of the intake system and exhaust system required to
provide explosion-proof features shall be constructed of metal and
designed to withstand a minimum internal pressure equal to four times
the maximum pressure observed in that segment in tests under Sec. 7.100
or a pressure of 150 psig, whichever is less. Castings shall be free
from blowholes.
(n) Welded joints forming the explosion-proof intake and exhaust
systems shall be continuous and gas-tight. At a minimum, they shall be
made in accordance with American Welding Society Standard D14.4-77 or
meet the test requirements of Sec. 7.104 with the internal pressure
equal to four times the maximum pressure observed in tests under
Sec. 7.100 or a pressure of 150 psig, whichever is less.
(o) Flexible connections shall be permitted in segments of the
intake and exhaust systems required to provide explosion-proof features,
provided that failure of the connection activates the safety shutdown
system before the explosion-proof characteristics are lost.
(p) Flame-arresting paths in the intake and exhaust systems shall be
formed either by--
(1) Flanged metal to metal joints meeting the requirements of
paragraph (q) of this section; or
(2) Metal flanges fitted with metal gaskets and meeting the
following requirements:
(i) Flat surfaces between bolt holes that form any part of a flame-
arresting path shall be planed to within a maximum deviation of one-half
the maximum clearance specified in paragraph (q)(7) of this section. All
metal surfaces forming a flame-arresting path shall be finished during
the manufacturing process to not more than 250 microinches.
(ii) A means shall be provided to ensure that fastenings maintain
the tightness of joints. The means provided shall not lose its
effectiveness through repeated assembly and disassembly.
(iii) Fastenings shall be as uniform in size as practicable to
preclude improper assembly.
(iv) Holes for fastenings shall not penetrate to the interior of an
intake or exhaust system and shall be threaded to ensure that all
specified bolts or screws will not bottom even if the washers are
omitted.
(v) Fastenings used for joints of flame-arresting paths on intake or
exhaust systems shall be used only for attaching parts that are
essential in maintaining the explosion-proof integrity. They shall not
be used for attaching brackets or other parts.
(vi) The minimum thickness of material for flanges shall be \1/2\-
inch, except that a final thickness of \7/16\-inch is allowed after
machining rolled plate.
(vii) The maximum fastening spacing shall be 6 inches.
(viii) The minimum diameter of fastenings shall be \3/8\-inch,
except smaller diameter fastenings may be used if the joint first meets
the requirements of the static pressure test in Sec. 7.104, and the
explosion test in Sec. 7.100.
(ix) The minimum thread engagement of fastenings shall be equal to
or greater than the nominal diameter of the fastenings specified, or the
intake or exhaust system must meet the test requirements of the
explosion tests in Sec. 7.100 and the static pressure test in
Sec. 7.104.
(x) The minimum contact surface of gaskets forming flame-arresting
paths shall be \3/8\-inch, and the thickness of the gaskets shall be no
greater than \1/16\-inch. The minimum distance from the interior edge of
a gasket to the edge of a fastening hole shall be \3/8\-inch. The
gaskets shall be positively
[[Page 55]]
positioned, and a means shall be provided to preclude improper
installation. When the joint is completely assembled, it shall be
impossible to insert a 0.0015-inch thickness gauge to a depth exceeding
\1/8\-inch between the gasket and mating flanges. Other gasket designs
shall be evaluated in accordance with Sec. 7.107.
(q) The following construction requirements shall apply to flame-
arresting paths formed without gaskets:
(1) Flat surfaces between fastening holes that form any part of a
flame-arresting path shall be planed to within a maximum deviation of
one-half the maximum clearance specified in paragraph (q)(7) of this
section. All metal surfaces forming a flame-arresting path shall be
finished during the manufacturing process to not more than 250
microinches. A thin film of nonhardening preparation to inhibit rusting
may be applied to these finished metal surfaces, as long as the final
surface can be readily wiped free of any foreign materials.
(2) A means shall be provided to ensure that fastenings maintain the
tightness of joints. The means provided shall not lose its effectiveness
through repeated assembly and disassembly.
(3) Fastenings shall be as uniform in size as practicable to
preclude improper assembly.
(4) Holes for fastenings shall not penetrate to the interior of an
intake or exhaust system and shall be threaded to ensure that all
specified bolts or screws will not bottom even if the washers are
omitted.
(5) Fastenings used for joints of flame-arresting paths on intake or
exhaust systems shall be used only for attaching parts that are
essential in maintaining the explosion-proof integrity. They shall not
be used for attaching brackets or other parts.
(6) The flame-arresting path of threaded joints shall conform to the
requirements of paragraph (q)(7) of this section.
(7) Intake and exhaust systems joints shall meet the specifications
set out in Table F-1.
Table F-1--Dimensional Requirements for Explosion-Proof Intake and
Exhaust System Joints
------------------------------------------------------------------------
------------------------------------------------------------------------
Minimum thickness of material for flanges........ \1/2\"\1\
Minimum width of joint; all in one plane......... 1"
Maximum clearance; joint all in one plane........ 0.004"
Minimum width of joint, portions of which are \3/4\"\2\
different planes; cylinders or equivalent.
Maximum clearances; joint in two or more planes,
cylinders or equivalent:
Portion perpendicular to plane............... 0.008"\3\
Plane portion................................ 0.006"
Maximum fastening \4\ spacing; joints all in one 6"
plane \5\.
Maximum fastening spacing; joints, portions of 8"
which are in different planes.
Minimum diameter of fastening (without regard to \3/8\"
type of joint) \6\.
Minimum thread engagement of fastening \7\....... \3/8\"
Maximum diametrical clearance between fastening \1/16\"
body and unthreaded holes through which it
passes \8 9 10\.
Minimum distance from interior of the intake or
exhaust system to the edge of a fastening hole:
\11\
Joint-minimum width 1"....................... \7/16\"\8 12\
Shafts centered by ball or roller bearings:
Minimum length of flame-arresting path....... 1"
Maximum diametrical clearance................ 0.030"
Other cylindrical joints:
Minimum length of flame-arresting path....... 1"
Maximum diametrical clearance................ 0.010"
------------------------------------------------------------------------
\1\ \1/16\-inch less is allowable for machining rolled plate.
\2\ If only two planes are involved, neither portion of a joint shall be
less than \1/8\-inch wide, unless the wider portion conforms to the
same requirements as those for a joint that is all in one plane. If
more than two planes are involved (as in labyrinths or tongue-in-
groove joints), the combined lengths of those portions having
prescribed clearances are considered.
\3\ The allowable diametrical clearance is 0.008-inch when the portion
perpendicular to the plane portion is \1/4\-inch or greater in length.
If the perpendicular portion is more than \1/8\-inch but less than \1/
4\-inch wide, the diametrical clearance shall not exceed 0.006-inch.
\4\ Studs, when provided, shall bottom in blind holes, be completely
welded in place, or have the bottom of the hole closed with a plug
secured by weld or braze. Fastenings shall be provided at all corners.
[[Page 56]]
\5\ The requirements as to diametrical clearance around the fastening
and minimum distance from the fastening hole to the inside of the
intake or exhaust system apply to steel dowel pins. In addition, when
such pins are used, the spacing between centers of the fastenings on
either side of the pin shall not exceed 5 inches.
\6\ Fastening diameters smaller than specified may be used if the joint
or assembly meets the test requirements of Sec. 7.104.
\7\ Minimum thread engagement shall be equal to or greater than the
nominal diameter of the fastening specified, or the intake or exhaust
system must meet the test requirements of Sec. 7.104.
\8\ The requirements as to diametrical clearance around the fastening
and minimum distance from the fastening hole to the inside of the
intake or exhaust system apply to steel dowel pins. In addition, when
such pins are used, the spacing between centers of the fastenings on
either side of the pin shall not exceed 5 inches.
\9\ This maximum clearance only applies when the fastening is located
within the flame-arresting path.
\10\ Threaded holes for fastenings shall be machined to remove burrs or
projections that affect planarity of a surface forming a flame-
arresting path.
\11\ Edge of the fastening hole shall include any edge of any machining
done to the fastening hole, such as chamfering.
\12\ If the diametrical clearance for fastenings does not exceed \1/32\-
inch, then the minimum distance shall be \1/4\-inch.
(r) Intake system. (1) The intake system shall include a device
between the air cleaner and intake flame arrester, operable from the
equipment operator's compartment, to shut off the air supply to the
engine for emergency purposes. Upon activation, the device must operate
immediately and the engine shall stop within 15 seconds.
(2) The intake system shall include a flame arrester that will
prevent an explosion within the system from propagating to a surrounding
flammable mixture when tested in accordance with the explosion tests in
Sec. 7.100. The flame arrester shall be located between the air cleaner
and the intake manifold and shall be attached so that it can be removed
for inspection or cleaning. The flame arrester shall be constructed of
corrosion-resistant metal and meet the following requirements:
(i) Two intake flame arrester designs, the spaced-plate type and the
crimped ribbon type, will be tested in accordance with the requirements
of Sec. 7.100. Variations to these designs or other intake flame
arrester designs will be evaluated under the provisions of Sec. 7.107.
(ii) In flame arresters of the spaced-plate type, the thickness of
the plates shall be at least 0.125-inch; spacing between the plates
shall not exceed 0.018-inch; and the flame-arresting path formed by the
plates shall be at least 1 inch wide. The unsupported length of the
plates shall be short enough that permanent deformation resulting from
explosion tests shall not exceed 0.002-inch. The plates and flame
arrester housing shall be an integral unit which cannot be disassembled.
(iii) In flame arresters of the crimped ribbon type, the dimensions
of the core openings shall be such that a plug gauge 0.018-inch in
diameter shall not pass through, and the flame-arresting path core
thickness shall be at least 1 inch. The core and flame arrester housing
shall be an integral unit which cannot be disassembled.
(3) The intake system shall be designed so that improper
installation of the flame arrester is impossible.
(4) The intake system shall include an air cleaner service
indicator. The air cleaner shall be installed so that only filtered air
will enter the flame arrester. The air cleaner shall be sized and the
service indicator set in accordance with the engine manufacturer's
recommendations. Unless the service indicator is explosion-proof, it
shall be located between the air cleaner and flame arrester, and the
service indicator setting shall be reduced to account for the additional
restriction imposed by the flame arrester.
(5) The intake system shall include a connection between the intake
flame arrester and the engine head for temporary attachment of a device
to indicate the total vacuum in the system. This opening shall be closed
by a plug or other suitable device that is sealed or locked in place
except when in use.
(s) Exhaust system. (1) The exhaust system shall include a flame
arrester that will prevent propagation of flame or discharge of glowing
particles to a surrounding flammable mixture. The flame arrester shall
be constructed of corrosion-resistant metal.
(i) If a mechanical flame arrester is used, it shall be positioned
so that only cooled exhaust gas at a maximum temperature of 302 F (150
C) will be discharged through it.
(ii) If a mechanical flame arrester of the spaced-plate type is
used, it must meet the requirements of paragraph (r)(2)(ii) of this
section and the test requirements of Sec. 7.100. Variations to the
spaced-plate flame arrester design and
[[Page 57]]
other mechanical flame arrester designs shall be evaluated under the
provisions of Sec. 7.107. The flame arrester shall be designed and
attached so that it can be removed for inspection and cleaning.
(2) The exhaust system shall allow a wet exhaust conditioner to be
used as the exhaust flame arrester provided that the explosion tests of
Sec. 7.100 demonstrate that the wet exhaust conditioner will arrest
flame. When used as a flame arrester, the wet exhaust conditioner shall
be equipped with a sensor to automatically activate the safety shutdown
system at or above the minimum allowable low water level established by
Sec. 7.100. Restarting of the engine shall be prevented until the water
supply in the wet exhaust conditioner has been replenished above the
minimum allowable low water level. All parts of the wet exhaust
conditioner and associated components that come in contact with
contaminated exhaust conditioner water shall be constructed of
corrosion-resistant material. The wet exhaust conditioner shall include
a means for verifying that the safety shutdown system operates at the
proper water level. A means shall be provided for draining and cleaning
the wet exhaust conditioner. The final exhaust gas temperature at
discharge from the wet exhaust conditioner shall not exceed 170 F (76
C) under test conditions specified in Sec. 7.102. A sensor shall be
provided that activates the safety shutdown system before the exhaust
gas temperature at discharge from the wet exhaust conditioner exceeds
185 F (85 C) under test conditions specified in Sec. 7.103(a)(4).
(3) The exhaust system shall be designed so that improper
installation of the flame arrester is impossible.
(4) The exhaust system shall provide a means to cool the exhaust gas
and prevent discharge of glowing particles.
(i) When a wet exhaust conditioner is used to cool the exhaust gas
and prevent the discharge of glowing particles, the temperature of the
exhaust gas at the discharge from the exhaust conditioner shall not
exceed 170 F (76 C) when tested in accordance with the exhaust gas
cooling efficiency test in Sec. 7.102. A sensor shall be provided that
activates the safety shutdown system before the exhaust gas temperature
at discharge from the wet exhaust conditioner exceeds 185 F (85 C)
when tested in accordance with the safety system controls test in
Sec. 7.103. All parts of the wet exhaust conditioner and associated
components that come in contact with contaminated exhaust conditioner
water shall be constructed of corrosion-resistant material.
(ii) When a dry exhaust conditioner is used to cool the exhaust gas,
the temperature of the exhaust gas at discharge from the diesel power
package shall not exceed 302 F (150 C) when tested in accordance with
the exhaust gas cooling efficiency test of Sec. 7.102. A sensor shall be
provided that activates the safety shutdown system before the exhaust
gas exceeds 302 F (150 C) when tested in accordance with the safety
system control test in Sec. 7.103. A means shall be provided to prevent
the discharge of glowing particles, and it shall be evaluated under the
provisions of Sec. 7.107.
(5) Other means for cooling the exhaust gas and preventing the
propagation of flame or discharge of glowing particles shall be
evaluated under the provisions of Sec. 7.107.
(6) There shall be a connection in the exhaust system for temporary
attachment of a device to indicate the total backpressure in the system
and collection of exhaust gas samples. This opening shall be closed by a
plug or other suitable device that is sealed or locked in place except
when in use.
[61 FR 55518, Oct. 25, 1996, 62 FR 34640, 34641, June 27, 1997]
Sec. 7.99 Critical characteristics.
The following critical characteristics shall be inspected or tested
on each diesel power package to which an approval marking is affixed:
(a) Finish, width, planarity, and clearances of surfaces that form
any part of a flame-arresting path.
(b) Thickness of walls and flanges that are essential in maintaining
the explosion-proof integrity of the diesel power package.
(c) Size, spacing, and tightness of fastenings.
(d) The means provided to maintain tightness of fastenings.
[[Page 58]]
(e) Length of thread engagement on fastenings and threaded parts
that ensure the explosion-proof integrity of the diesel power package.
(f) Diesel engine approval marking.
(g) Fuel rate setting to ensure that it is appropriate for the
intended application, or a warning tag shall be affixed to the fuel
system notifying the purchaser of the need to make proper adjustments.
(h) Material and dimensions of gaskets that are essential in
maintaining the explosion-proof integrity of the diesel power package.
(i) Dimensions and assembly of flame arresters.
(j) Materials of construction to ensure that the intake system,
exhaust system, cooling fans, and belts have been fabricated from the
required material.
(k) Proper interconnection of the coolant system components and use
of specified components.
(l) Proper interconnection of the safety shutdown system components
and use of specified components.
(m) All plugs and covers to ensure that they are tightly installed.
(n) The inspections and tests described in the diesel power package
checklist shall be performed and all requirements shall be met.
Sec. 7.100 Explosion tests.
(a) Test procedures. (1) Prepare to test the diesel power package as
follows:
(i) Perform a detailed check of parts against the drawings and
specifications submitted under Sec. 7.97 to determine that the parts and
drawings agree.
(ii) Remove all parts that do not contribute to the operation or
ensure the explosion-proof integrity of the diesel power package such as
the air cleaner and exhaust gas dilution system.
(iii) Fill coolant system fluid and engine oil to the engine
manufacturer's recommended levels.
(iv) Interrupt fuel supply to the injector pump.
(v) Establish a preliminary low water level for systems using the
wet exhaust conditioner as a flame arrester.
(2) Perform static and dynamic tests of the intake system as
follows:
(i) Install the diesel power package in an explosion test chamber
which is large enough to contain the complete diesel power package. The
chamber must be sufficiently darkened and provide viewing capabilities
of the flame-arresting paths to allow observation during testing of any
discharge of flame or ignition of the flammable mixture surrounding the
diesel power package. Couple the diesel power package to an auxiliary
drive mechanism. Attach a pressure measuring device, a temperature
measuring device, and an ignition source to the intake system. The
pressure measuring device shall be capable of indicating the peak
pressure accurate to 1 pound-per-square inch gauge (psig) at 100 psig
static pressure and shall have a frequency response of 40 Hertz or
greater. The ignition source shall be an electric spark with a minimum
energy of 100 millijoules. The ignition source shall be located
immediately adjacent to the intake manifold and the pressure and
temperature devices shall be located immediately adjacent to the flame
arrester.
(ii) For systems using the wet exhaust conditioner as an exhaust
flame arrester, fill the exhaust conditioner to the specified high or
normal operating water level.
(iii) Fill the test chamber with a mixture of natural gas and air or
methane and air. If natural gas is used, the content of combustible
hydrocarbons shall total at least 98.0 percent, by volume, with the
remainder being inert. At least 80.0 percent, by volume, of the gas
shall be methane. For all tests, the methane or natural gas
concentration shall be 8.5 1.8 percent, by volume, and the oxygen
concentration shall be no less than 18 percent, by volume.
(iv) Using the auxiliary drive mechanism, motor the engine to fill
the intake and exhaust systems with the flammable mixture. The intake
system, exhaust system, and test chamber gas concentration shall not
differ by more than 0.3 percent, by volume, at the time of ignition.
(v) For static tests, stop the engine, actuate the ignition source,
and observe the peak pressure. The peak pressure shall not exceed 110
psig. If the peak pressure exceeds 110 psig, construction changes shall
be made that result in a reduction of pressure to 110
[[Page 59]]
psig or less, or the system shall be tested in accordance with the
static pressure test of Sec. 7.104 with the pressure parameter replaced
with a static pressure of twice the highest value recorded.
(vi) If the peak pressure does not exceed 110 psig or if the system
meets the static pressure test requirements of this section and there is
no discharge of visible flames or glowing particles or ignition of the
flammable mixture in the chamber, a total of 20 tests shall be conducted
in accordance with the explosion test specified above.
(vii) For dynamic tests, follow the same procedures for static
tests, except actuate the ignition source while motoring the engine.
Forty dynamic tests shall be conducted at two speeds, twenty at 1800
200 RPM and twenty at 1000 200 RPM. Under some circumstances, during
dynamic testing the flammable mixture may continue to burn within the
diesel power package after ignition. This condition can be recognized by
the presence of a rumbling noise and a rapid increase in temperature.
This can cause the flame-arrester to reach temperatures which can ignite
the surrounding flammable mixture. Ignition of the flammable mixture in
the test chamber under these circumstances does not constitute failure
of the flame arrester. However; if this condition is observed, the test
operator should immediately stop the engine and allow components to cool
to prevent damage to the components.
(3) Perform static and dynamic tests of the exhaust system as
follows:
(i) Prepare the diesel power package for explosion tests according
to Sec. 7.100(a)(2)(i) as follows:
(A) Install the ignition source immediately adjacent to the exhaust
manifold.
(B) Install pressure measuring devices in each segment as follows:
immediately adjacent to the exhaust conditioner inlet; in the exhaust
conditioner; and immediately adjacent to the flame arrester, if
applicable.
(C) Install a temperature device immediately adjacent to the exhaust
conditioner inlet.
(ii) If the exhaust system is provided with a spaced-plate flame
arrester in addition to an exhaust conditioner, explosion tests of the
exhaust system shall be performed as described for the intake system in
accordance with this section. Water shall not be present in a wet
exhaust conditioner for the tests.
(iii) If the wet exhaust conditioner is used as the exhaust flame
arrester, explosion testing of this type of system shall be performed as
described for the intake system in accordance with this section with the
following modifications:
(A) Twenty static tests, twenty dynamic tests at 1800 200 RPM, and
twenty dynamic tests at 1000 200 RPM shall be conducted at 2 inches
below the minimum allowable low water level. All entrances in the wet
exhaust conditioner which do not form explosion-proof joints shall be
opened. These openings may include lines which connect the reserve water
supply to the wet exhaust conditioner, insert flanges, float flanges,
and cover plates. These entrances are opened during this test to verify
that they are not flame paths.
(B) Twenty static tests, twenty dynamic tests at 1800 200 RPM, and
twenty dynamic tests at 1000 200 RPM shall be conducted at 2 inches
below the minimum allowable low water level. All entrances in the wet
exhaust conditioner (except the exhaust conditioner outlet) which do not
form explosion-proof joints shall be closed. These openings are closed
to simulate normal operation.
(C) Twenty static tests, twenty dynamic tests at 1800 200 RPM, and
twenty dynamic tests at 1000 200 RPM shall be conducted at the
specified high or normal operating water level. All entrances in the wet
exhaust conditioner which do not form explosion-proof joints shall be
opened.
(D) Twenty static tests, twenty dynamic tests at 1800 200 RPM, and
twenty dynamic tests at 1000 200 RPM shall be conducted at the
specified high or normal operating water level. All entrances in the wet
exhaust conditioner (except the exhaust conditioner outlet) which do not
form explosion-proof joints shall be closed.
(iv) After successful completion of the explosion tests of the
exhaust system, the minimum allowable low water level, for a wet exhaust
conditioner used as the exhaust flame arrester, shall be determined by
adding two
[[Page 60]]
inches to the lowest water level that passed the explosion tests.
(v) A determination shall be made of the maximum grade on which the
wet exhaust conditioner can be operated retaining the flame-arresting
characteristics.
(b) Acceptable performance. The explosion tests shall not result in
any of the following--
(1) Discharge of flame or glowing particles.
(2) Visible discharge of gas through gasketed joints.
(3) Ignition of the flammable mixture in the test chamber.
(4) Rupture of any part that affects the explosion-proof integrity.
(5) Clearances, in excess of those specified in this subpart, along
accessible flame-arresting paths, following any necessary retightening
of fastenings.
(6) Pressure exceeding 110 psig, unless the intake system or exhaust
system has withstood a static pressure of twice the highest value
recorded in the explosion tests of this section following the static
pressure test procedures of Sec. 7.104.
(7) Permanent distortion of any planar surface of the diesel power
package exceeding 0.04-inches/linear foot.
(8) Permanent deformation exceeding 0.002-inch between the plates of
spaced-plate flame arrester designs.
[61 FR 55518, Oct. 25, 1996; 62 FR 34641, June 27, 1997]
Sec. 7.101 Surface temperature tests.
The test for determination of exhaust gas cooling efficiency
described in Sec. 7.102 may be done simultaneously with this test.
(a) Test procedures. (1) Prepare to test the diesel power package as
follows:
(i) Perform a detailed check of parts against the drawings and
specifications submitted to MSHA under compliance with Sec. 7.97 to
determine that the parts and drawings agree.
(ii) Fill the coolant system with a mixture of equal parts of
antifreeze and water, following the procedures specified in the
application, Sec. 7.97(a)(3).
(iii) If a wet exhaust conditioner is used to cool the exhaust gas,
fill the exhaust conditioner to the high or normal operating water level
and have a reserve water supply available, if applicable.
(2) Tests shall be conducted as follows:
(i) The engine shall be set to the rated horsepower specified in
Sec. 7.97(a)(2).
(ii) Install sufficient temperature measuring devices to determine
the location of the highest coolant temperature. The temperature
measuring devices shall be accurate to 4 F (2 C).
(iii) Operate the engine at rated horsepower and with 0.5 0.1
percent, by volume, of methane in the intake air mixture until all parts
of the engine, exhaust coolant system, and other components reach their
respective equilibrium temperatures. The liquid fuel temperature into
the engine shall be maintained at 100 F (38 C) 10 F (6 C) and the
intake air temperature shall be maintained at 70 F (21 C) 5 F (3
C).
(iv) Increase the coolant system temperatures until the highest
coolant temperature is 205 F to 212 F (96 C to 100 C), or to the
maximum temperature specified by the applicant, if lower.
(v) After all coolant system temperatures stabilize, operate the
engine for 1 hour.
(vi) The ambient temperature shall be between 50 F (10 C) and 104
F (40 C) throughout the tests.
(b) Acceptable performance. The surface temperature of any external
surface of the diesel power package shall not exceed 302 F (150 C)
during the test.
Sec. 7.102 Exhaust gas cooling efficiency test.
(a) Test procedures. (1) Follow the procedures specified in
Sec. 7.101(a).
(2) Install a temperature measuring device to measure the exhaust
gas temperature at discharge from the exhaust conditioner. The
temperature measuring device shall be accurate to 4 F (2 C).
(3) Determine the exhaust gas temperature at discharge from the
exhaust conditioner before the exhaust gas is diluted with air.
(b) Acceptable performance. (1) The exhaust gas temperature at
discharge
[[Page 61]]
from a wet exhaust conditioner before the exhaust gas is diluted with
air shall not exceed 170 F (76 C).
(2) The exhaust gas temperature at discharge from a dry exhaust
conditioner before the gas is diluted with air shall not exceed 302 F
(150 C).
Sec. 7.103 Safety system control test.
(a) Test procedures. (1) Prior to testing, perform the tasks
specified in Sec. 7.101(a)(1) and install sufficient temperature
measuring devices to measure the highest coolant temperature and exhaust
gas temperature at discharge from the exhaust conditioner. The
temperature measuring devices shall be accurate to 4 F (2 C).
(2) Determine the effectiveness of the coolant system temperature
shutdown sensors which will automatically activate the safety shutdown
system and stop the engine before the coolant temperature in the cooling
jackets exceeds manufacturer's specifications or 212 F (100 C),
whichever is lower, by operating the engine and causing the coolant in
the cooling jackets to exceed the specified temperature.
(3) For systems using a dry exhaust gas conditioner, determine the
effectiveness of the temperature sensor in the exhaust gas stream which
will automatically activate the safety shutdown system and stop the
engine before the cooled exhaust gas temperature exceeds 302 F (150
C), by operating the engine and causing the cooled exhaust gas to
exceed the specified temperature.
(4) For systems using a wet exhaust conditioner, determine the
effectiveness of the temperature sensor in the exhaust gas stream which
will automatically activate the safety shutdown system and stop the
engine before the cooled exhaust gas temperature exceeds 185 F (85 C),
with the engine operating at a high idle speed condition. Temporarily
disable the reserve water supply, if applicable, and any safety shutdown
system control that might interfere with the evaluation of the operation
of the exhaust gas temperature sensor. Prior to testing, set the water
level in the wet exhaust conditioner to a level just above the minimum
allowable low water level. Run the engine until the exhaust gas
temperature sensor activates the safety shutdown system and stops the
engine.
(5) For systems using a wet exhaust conditioner as an exhaust flame
arrester, determine the effectiveness of the low water sensor which will
automatically activate the safety shutdown system and stop the engine at
or above the minimum allowable low water level established from results
of the explosion tests in Sec. 7.100 with the engine operating at a high
idle speed condition. Temporarily disable the reserve water supply, if
applicable, and any safety shutdown system control that might interfere
with the evaluation of the operation of the low water sensor. Prior to
testing, set the water level in the wet exhaust conditioner to a level
just above the minimum allowable low water level. Run the engine until
the low water sensor activates the safety shutdown system and stops the
engine. Measure the low water level. Attempt to restart the engine.
(6) Determine the effectiveness of the device in the intake system
which is designed to shut off the air supply and stop the engine for
emergency purposes with the engine operating at both a high idle speed
condition and a low idle speed condition. Run the engine and activate
the emergency intake air shutoff device.
(7) Determine the total air inlet restriction of the complete intake
system, including the air cleaner, as measured between the intake flame
arrester and the engine head with the engine operating at maximum air
flow.
(8) Determine the total exhaust backpressure with the engine
operating at rated horsepower as specified in Sec. 7.103(a)(7). If a wet
exhaust conditioner is used, it must be filled to the high or normal
operating water level during this test.
(9) The starting mechanism shall be tested to ensure that engagement
is not possible while the engine is running. Operate the engine and
attempt to engage the starting mechanism.
(10) Where the lack of engine oil pressure must be overridden in
order to start the engine, test the override to ensure that it does not
override any of the safety shutdown sensors specified in Sec. 7.98(i).
After each safety shutdown sensor test specified in paragraphs
[[Page 62]]
(a)(2) through (a)(5) of this section, immediately override the engine
oil pressure and attempt to restart the engine.
(b) Acceptable performance. Tests of the safety system controls
shall result in the following:
(1) The coolant system temperature shutdown sensor shall
automatically activate the safety shutdown system and stop the engine
before the water temperature in the cooling jackets exceeds
manufacturer's specifications or 212 F (100 C), whichever is lower.
(2) The temperature sensor in the exhaust gas stream of a system
using a dry exhaust conditioner shall automatically activate the safety
shutdown system and stop the engine before the cooled exhaust gas
exceeds 302 F (150 C).
(3) The temperature sensor in the exhaust gas stream of a system
using a wet exhaust conditioner shall automatically activate the safety
shutdown system and stop the engine before the cooled exhaust gas
exceeds 185 F (85 C).
(4) The low water sensor for systems using a wet exhaust conditioner
shall automatically activate the safety shutdown system and stop the
engine at or above the minimum allowable low water level and prevent
restarting of the engine.
(5) The emergency intake air shutoff device shall operate
immediately when activated and stop the engine within 15 seconds.
(6) The total intake air inlet restriction and the total exhaust
backpressure shall not exceed the engine manufacturer's specifications.
(7) It shall not be possible to engage the starting mechanism while
the engine is running, unless the starting mechanism is constructed of
nonsparking material.
(8) The engine oil pressure override shall not override any of the
shutdown sensors.
Sec. 7.104 Internal static pressure test.
(a) Test procedures. (1) Isolate and seal each segment of the intake
system or exhaust system to allow pressurization.
(2) Internally pressurize each segment of the intake system or
exhaust system to four times the maximum pressure observed in each
segment during the tests of Sec. 7.100, or 150 psig 5 psig, whichever
is less. Maintain the pressure for a minimum of 10 seconds.
(3) Following the pressure hold, the pressure shall be removed and
the pressurizing agent removed from the intake system or exhaust system.
(b) Acceptable performance. (1) The intake system or exhaust system,
during pressurization, shall not exhibit--
(i) Leakage through welds and gasketed joints; or
(ii) Leakage other than along joints meeting the explosion-proof
requirements of Sec. 7.98(q).
(2) Following removal of the pressurizing agent, the intake system
or exhaust system shall not exhibit any--
(i) Changes in fastening torque;
(ii) Visible cracks in welds;
(iii) Permanent deformation affecting the length or gap of any
flame-arresting paths;
(iv) Stretched or bent fastenings;
(v) Damaged threads of parts affecting the explosion-proof integrity
of the intake system or exhaust system; or
(vi) Permanent distortion of any planar surface of the diesel power
package exceeding 0.04-inches/linear foot.
Sec. 7.105 Approval marking.
Each approved diesel power package shall be identified by a legible
and permanent approval plate inscribed with the assigned MSHA approval
number and securely attached to the diesel power package in a manner
that does not impair any explosion-proof characteristics. The grade
limitation of a wet exhaust conditioner used as an exhaust flame
arrester shall be included on the approval marking.
Sec. 7.106 Post-approval product audit.
Upon request by MSHA, but not more than once a year except for
cause, the approval-holder shall make an approved diesel power package
available for audit at no cost to MSHA.
Sec. 7.107 New technology.
MSHA may approve a diesel power package that incorporates technology
for which the requirements of this subpart are not applicable if MSHA
determines that the diesel power package is
[[Page 63]]
as safe as those which meet the requirements of this subpart.
Sec. 7.108 Power package checklist.
Each diesel power package bearing an MSHA approval plate shall be
accompanied by a power package checklist. The power package checklist
shall consist of a list of specific features that must be checked and
tests that must be performed to determine if a previously approved
diesel power package is in approved condition. Test procedures shall be
specified in sufficient detail to allow evaluation to be made without
reference to other documents. Illustrations shall be used to fully
identify the approved configuration of the diesel power package.
Subpart J_Electric Motor Assemblies
Source: 57 FR 61193, Dec. 23, 1992, unless otherwise noted.
Sec. 7.301 Purpose and effective date.
This subpart establishes the specific requirements for MSHA approval
of certain explosion-proof electric motor assemblies intended for use in
approved equipment in underground mines. Applications for approval or
extensions of approval submitted after February 22, 1996 shall meet the
requirements of this part. Those motors that incorporate features not
specifically addressed in this subpart will continue to be evaluated
under part 18 of this chapter.
Sec. 7.302 Definitions.
The following definitions apply in this subpart:
Afterburning. The combustion of any flammable mixture that is drawn
into an enclosure after an internal explosion in the enclosure. This
condition is determined through detection of secondary pressure peaks
occurring subsequent to the initial explosion.
Cylindrical joint. A joint comprised of two contiguous, concentric,
cylindrical surfaces.
Explosion-proof enclosure. A metallic enclosure used as a winding
compartment, conduit box, or a combination of both that complies with
the applicable requirements of Sec. 7.304 of this part and is
constructed so that it will withstand the explosion tests of Sec. 7.306
of this part.
Fastening. A bolt, screw, or stud used to secure adjoining parts to
prevent the escape of flame from an explosion-proof enclosure.
Flame-arresting path. Two or more adjoining or adjacent surfaces
between which the escape of flame is prevented.
Internal free volume (of an empty enclosure). The volume remaining
after deducting the volume of any part that is essential in maintaining
the explosion-proof integrity of the enclosure or necessary for
operation of the motor. Essential parts include the parts that
constitute the flame-arresting path and those necessary to secure parts
that constitute a flame-arresting path.
Motor assembly. The winding compartment including a conduit box when
specified. A motor assembly is comprised of one or more explosion-proof
enclosures.
Plane joint. A joint comprised of two adjoining surfaces in parallel
planes.
Step (rabbet) joint. A joint comprised of two adjoining surfaces
with a change or changes in direction between its inner and outer edges.
A step joint may be composed of a cylindrical portion and a plane
portion or of two or more plane portions.
Stuffing box. An entrance with a recess filled with packing material
for cables extending through a wall of an explosion-proof enclosure.
Threaded joint. A joint consisting of a male- and a female-threaded
member, both of which are the same type and gauge.
Sec. 7.303 Application requirements.
(a) An application for approval of a motor assembly shall include a
composite drawing or drawings with the following information:
(1) Model (type), frame size, and rating of the motor assembly.
(2) Overall dimensions of the motor assembly, including conduit box
if applicable, and internal free volume.
(3) Material and quantity for each of the component parts that form
the explosion-proof enclosure or enclosures.
(4) All dimensions (including tolerances) and specifications
required to
[[Page 64]]
ascertain compliance with the requirements of Sec. 7.304 of this part.
(b) All drawings shall be titled, dated, numbered, and include the
latest revision.
Sec. 7.304 Technical requirements.
(a) Voltage rating of the motor shall not exceed 4160 volts.
(b) The temperature of the external surfaces of the motor assembly
shall not exceed 150 C (302 F) when operated at the manufacturers'
specified ratings.
(c) Minimum clearances between uninsulated electrical conductor
surfaces, or between uninsulated conductor surfaces and grounded metal
surfaces, within the enclosure shall meet the requirements of table J-1
of this section.
Table J-1--Minimum Clearances Between Uninsulated Surfaces
------------------------------------------------------------------------
Clearances (inches)
-----------------------
Phase-to-
Phase-to-phase voltage (rms) Phase-to- ground or
phase control
circuit
------------------------------------------------------------------------
0 to 250........................................ 0.25 0.25
251 to 600...................................... 0.28 0.25
601 to 1000..................................... 0.61 0.25
1001 to 2400.................................... 1.4 0.6
2401 to 4160.................................... 3.0 1.4
------------------------------------------------------------------------
(d) Parts whose dimensions can change with the motor operation, such
as ball and roller bearings and oil seals, shall not be used as flame-
arresting paths.
(e) The widths of any grooves, such as grooves for holding oil seals
or o-rings, shall be deducted in measuring the widths of flame-arresting
paths.
(f) An outer bearing cap shall not be considered as forming any part
of a flame-arresting path unless the cap is used as a bearing cartridge.
(g) Requirements for explosion-proof enclosures of motor assemblies.
(1) Enclosures shall be--
(i) Constructed of metal;
(ii) Designed to withstand a minimum internal pressure of 150 pounds
per square inch (gauge);
(iii) Free from blowholes when cast; and
(iv) Explosion proof as determined by the tests set out in
Sec. 7.306 of this part.
(2) Welded joints forming an enclosure shall be--
(i) Continuous and gas-tight; and
(ii) Made in accordance with or exceed the American Welding Society
Standard AWS D14.4-77, ``Classification and Application of Welded Joints
for Machinery and Equipment,'' or meet the test requirements set out in
Sec. 7.307 of this part. AWS D14.4-77 is incorporated by reference and
has been approved by the Director of the Federal Register in accordance
with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the
American Welding Society, Inc., 2501 NW 7th Street, Miami, FL 33125.
Copies may be inspected at the U.S. Department of Labor, Mine Safety and
Health Administration, Approval and Certification Center, 765 Technology
Drive, Triadelphia, WV 26059, or at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/
federal_register/code_of_federal_regulations/ibr_locations.html.
(3) External rotating parts shall not be constructed of aluminum
alloys containing more than 0.6 percent magnesium. Non-metallic rotating
parts shall be provided with a means to prevent an accumulation of
static electricity.
(4) Threaded covers and mating parts shall be designed with Class 1A
and 1B (coarse, loose fitting) threads. The covers shall be secured
against loosening.
(5) Flat surfaces between fastening holes that form any part of a
flame-arresting path shall be plane to within a maximum deviation of
one-half the maximum clearance specified in paragraph (g)(19) of this
section. All surfaces forming a flame-arresting path shall be finished
during the manufacturing process to not more than 250 microinches. A
thin film of nonhardening preparation to inhibit rusting may be applied
to these finished metal surfaces as long as the final surface can be
readily wiped free of any foreign materials.
(6) For a laminated stator frame, it shall be impossible to insert a
0.0015 inch thickness gauge to a depth exceeding \1/8\ inch between
adjacent laminations or between end rings and laminations.
[[Page 65]]
(7) Lockwashers, or equivalent, shall be provided for all
fastenings. Devices other than lockwashers shall meet the requirements
of Sec. 7.308 of this part. Equivalent devices shall only be used in the
configuration in which they were tested.
(8) Fastenings shall be as uniform in size as practicable to
preclude improper installation.
(9) Holes for fastenings in an explosion-proof enclosure shall be
threaded to ensure that all specified bolts or screws will not bottom
even if the washers are omitted.
(10) Holes for fastenings shall not penetrate to the interior of an
explosion-proof enclosure, except holes made through motor casings for
bolts, studs, or screws to hold essential parts, such as pole pieces,
brush rigging, and bearing cartridges. The attachments of such parts
shall be secured against loosening. The threaded holes in these parts
shall be blind unless the fastenings are inserted from the inside, in
which case the fastenings shall not be accessible with the rotor in
place.
(11) For direct current motor assemblies with narrow interpoles, the
distance from the edge of the pole piece to any bolt hole in the frame
shall be at least \1/8\ inch. If the distance is \1/8\ to \1/4\ inch,
the diametrical clearance for the pole bolt shall not exceed \1/64\ inch
for not less than \1/2\ inch through the frame. Furthermore, the pole
piece shall have the same radius as the inner surface of the frame. Pole
pieces may be shimmed as necessary. If used, the total resulting
thickness of the shims shall be specified. The shim assembly shall meet
the same requirements as the pole piece.
(12) Coil-thread inserts, if used in holes for fastenings, shall
meet the following:
(i) The inserts shall have internal screw threads.
(ii) The holes for the inserts shall be drilled and tapped
consistent with the insert manufacturer's specifications.
(iii) The inserts shall be installed consistent with the insert
manufacturer's specifications.
(iv) The insert shall be of sufficient length to ensure the minimum
thread engagement of fastening specified in paragraph (g)(19) of this
section.
(13) A minimum of \1/8\ inch of stock shall be left at the center of
the bottom of each blind hole that could penetrate into the interior of
an explosion-proof enclosure.
(14) Fastenings shall be used only for attaching parts that are
essential in maintaining the explosion-proof integrity of the enclosure,
or necessary for the operation of the motor. They shall not be used for
making electrical connections.
(15) Through holes not in use shall be closed with a metal plug.
Plugs, including eyebolts, in through holes where future access is
desired shall meet the flame-arresting paths, lengths, and clearances of
paragraph (g)(19) of this section and be secured by spot welding or
brazing. The spot weld or braze may be on a plug, clamp, or fastening
(for example see figure J-1). Plugs for holes where future access is not
desired shall be secured all around by a continuous gas-tight weld.
(16) O-rings, if used in a flame-arresting path, shall meet the
following:
(i) When the flame-arresting path is in one plane, the o-ring shall
be located at least one-half the acceptable flame-arresting path length
specified in paragraph (g)(19) of this section from within the outside
edge of the path (see figure J-2).
(ii) When the flame-arresting path is one of the plane-cylindrical
type (step joint), the o-ring shall be located at least \1/2\ inch from
within the outer edge of the plane portion (see figure J-3), or at the
junction of the plane and cylindrical portion of the joint (see figure
J-4), or in the cylindrical portion (see figure J-5).
(17) Mating parts comprising a pressed fit shall result in a minimum
interference of 0.001 inch between the parts. The minimum length of the
pressed fit shall be equal to the minimum thickness requirement of
paragraph (g)(19) of this section for the material in which the fit is
made.
(18) The flame-arresting path of threaded joints shall conform to
the requirements of paragraph (g)(19) of this section.
(19) Explosion-proof enclosures shall meet the requirements set out
in table
[[Page 66]]
J-2 of this section, based on the internal free volume of the empty
enclosure.
Table J-2--Explosion-Proof Requirements Based on Volume
----------------------------------------------------------------------------------------------------------------
Volume of empty enclosure
-----------------------------------------------
Less than 45 45 to 124 cu. More than 124
cu. ins. ins. inclusive cu. ins.
----------------------------------------------------------------------------------------------------------------
Minimum thickness of material for walls \1\..................... \1/8\" \3/16\" \1/4\"
Minimum thickness of material for flanges and covers............ \2\ \1/4\" \3\ \3/8\" \3\ \1/2\"
Minimum width of joint; all in one plane........................ \1/2\" \3/4\" 1"
Maximum clearance; joint all in one plane....................... 0.002" 0.003" 0.004"
Minimum width of joint, portions of which are in different \4\ \3/8\" \4\ \5/8\" \4\ \3/4\"
planes; cylinders or equivalent................................
Maximum clearances; joint in two or more planes, cylinders or
equivalent: \5\
(a) Portion perpendicular to plane \6\...................... 0.008" 0.008" 0.008"
(b) Plane portion........................................... 0.006" 0.006" 0.006"
Maximum fastening \7 8\ spacing; joints all in one plane........ (\16\) (\16\) (\16\)
Maximum fastening spacing; joints, portions of which are in (\17\) (\17\) (\17\)
different planes...............................................
Minimum diameter of fastening \9\ (without regard to type of \1/4\" \1/4\" \3/8\"
joint).........................................................
Minimum thread engagement of fastening \10\..................... \1/4\" \1/4\" \3/8\"
Maximum diametrical clearance between fastening body and \1/64\" \1/32\" \1/16\"
unthreaded holes through which it passes \8 11 12\.............
Minimum distance from interior of enclosure to the edge of a
fastening hole: \8 13\
Joint--minimum width 1"..................................... .............. .............. \14\ \7/16\"
Joint--less than 1" wide.................................... \1/8\" \3/16\"
----------------------------------------------------------------------------------------------------------------
Cylindrical Joints
----------------------------------------------------------------------------------------------------------------
Shaft centered by ball or roller bearings:
Minimum length of flame-arresting path........................ \1/2\" \3/4\" 1"
Maximum diametrical clearance................................. 0.020" 0.025" 0.030"
Other cylindrical joints: \15\
Minimum length of flame-arresting path...................... \1/2\" \3/4\" 1"
Maximum diametrical clearance............................... 0.006" 0.008" 0.010"
----------------------------------------------------------------------------------------------------------------
\1\ This is the minimal nominal dimension when applied to standard steel plate.
\2\ \1/32\ inch less is allowable for machining rolled plate.
\3\ \1/16\ inch less is allowable for machining rolled plate.
\4\ If only two planes are involved, neither portion of a joint shall be less than \1/8\ inch wide, unless the
wider portion conforms to the same requirements as those for a joint that is all in one plane. If more than
two planes are involved (as in labyrinths or tongue-and-groove joints) the combined lengths of those portions
having prescribed clearances are considered.
\5\ For winding compartments having internal free volume not exceeding 350 cubic inches and joints not exceeding
32 inches in outer circumference and provided with step joints between the stator frame and the end bracket
the following dimensions shall apply:
Dimensions of Rabbet (Step) Joints-Inches
[See figure J-6 in appendix]
----------------------------------------------------------------------------------------------------------------
Maximum
Minimum width Maximum diametrical
Minimum total width of clamped clearance of clearance at
radial portion radial portion axial portion
----------------------------------------------------------------------------------------------------------------
\3/8\........................................................... \3/64\ 0.0015 0.003
\1/2\........................................................... \3/64\ 0.002 0.003
\1/2\........................................................... \3/32\ 0.002 0.004
----------------------------------------------------------------------------------------------------------------
\6\ The allowable diametrical clearance is 0.008 inch when the portion perpendicular to the plane portion is \1/
4\ inch or greater in length. If the perpendicular portion is more than \1/8\ inch but less than \1/4\ inch
wide, the diametrical clearance shall not exceed 0.006 inch.
\7\ Studs, when provided, shall bottom in blind holes, be completely welded in place, or have the bottom of the
hole closed with a plug secured by weld or braze. Fastenings shall be provided at all corners.
\8\ The requirements as to diametrical clearance around the fastening and minimum distance from the fastening
hole to the inside of the explosion-proof enclosure apply to steel dowel pins. In addition, when such pins are
used, the spacing between centers of the fastenings on either side of the pin shall not exceed 5 inches.
\9\ Fastening diameters smaller than specified may be used if the enclosure meets the test requirements of 30
CFR 7.307 and then 7.306 in that order.
\10\ Minimum thread engagement shall be equal to or greater than the diameter of the fastening specified, or the
enclosure must meet the test requirements of 30 CFR 7.307 and then 7.306 in that order.
\11\ This maximum clearance applies only when the fastening is located within the flame-arresting path.
\12\ Threaded holes for fastening bolts shall be machined to remove burrs or projections that affect planarity
of a surface forming a flame-arresting path.
\13\ Edge of the fastening hole shall include the edge of any machining done to the fastening hole, such as
chamfering.
\14\ If the diametrical clearance for fastenings does not exceed \1/32\ inch, then the minimum distance shall be
\1/4\ inch.
[[Page 67]]
\15\ Shafts or operating rods through journal bearings shall be at least \1/4\" in diameter. The length of the
flame-arresting path shall not be reduced when a pushbutton is depressed. Operating rods shall have a shoulder
or head on the portion inside the enclosure. Essential parts riveted or bolted to the inside portion are
acceptable in lieu of a head or shoulder, but cotter pins and similar devices shall not be used.
\16\ 6" with a minimum of 4 fastenings.
\17\ 8" with a minimum of 4 fastenings.
(h) Lead entrances. (1) Each cable, which extends through an outside
wall of the motor assembly, shall pass through a stuffing-box lead
entrance (see figure J-7). All sharp edges shall be removed from
stuffing boxes, packing nuts, and other lead entrance (gland) parts, so
that the cable jacket is not damaged.
(2) When the packing is properly compressed, the gland nut shall
have--
(i) A clearance distance of \1/8\ inch or more, with no maximum, to
travel without interference by parts other than packing; and
(ii) A minimum of three effective threads engaged (see figures J-8,
J-9, and J-10).
(3) Packing nuts (see figure J-7) and stuffing boxes shall be
secured against loosening (see figure J-11).
(4) Compressed packing material shall be in contact with the cable
jacket for a length of not less than \1/2\ inch.
(5) Requirements for lead entrances in which MSHA accepted rope
packing material is specified, are:
(i) Rope packing material shall be acceptable under Sec. 18.37(e) of
this chapter.
(ii) The width of the space for packing material shall not exceed by
more than 50 percent the diameter or width of the uncompressed packing
material (see figure J-12).
(iii) The maximum diametrical clearance, using the specified
tolerances, between the cable and the through holes in the gland parts
adjacent to the packing (stuffing box, packing nut, hose tube, or
bushings) shall not exceed 75 percent of the nominal diameter or width
of the packing material (see figure J-13).
(6) Requirements for lead entrances in which grommet packing made of
compressible material is specified, are:
(i) The grommet packing material shall be accepted by MSHA as flame-
resistant material under Sec. 18.37(f)(1) of this chapter.
(ii) The diametrical clearance between the cable jacket and the
nominal inside diameter of the grommet shall not exceed \1/16\ inch,
based on the nominal specified diameter of the cable (see figure J-14).
(iii) The diametrical clearance between the nominal outside diameter
of the grommet and the inside wall of the stuffing box shall not exceed
\1/16\ inch (see figure J-14).
(i) Combustible gases from insulating material. (1) Insulating
materials that give off flammable or explosive gases when decomposed
electrically shall not be used within explosion-proof enclosures where
the materials are subjected to destructive electrical action.
(2) Parts coated or impregnated with insulating materials shall be
treated to remove any combustible solvent before assembly in an
explosion-proof enclosure.
[57 FR 61193, Dec. 23, 1992, as amended at 73 FR 52210, Sept. 9, 2008]
Sec. 7.305 Critical characteristics.
The following critical characteristics shall be inspected on each
motor assembly to which an approval marking is affixed:
(a) Finish, width, and planarity of surfaces that form any part of a
flame-arresting path.
(b) Clearances between mating parts that form flame-arresting paths.
(c) Thickness of walls, flanges, and covers that are essential in
maintaining the explosion-proof integrity of the enclosure.
(d) Spacing of fastenings.
(e) Length of thread engagement on fastenings and threaded parts
that assure the explosion-proof integrity of the enclosure.
(f) Use of lockwasher or equivalent with all fastenings.
(g) Dimensions which affect compliance with the requirements for
packing gland parts in Sec. 7.304 of this part.
Sec. 7.306 Explosion tests.
(a) The following shall be used for conducting an explosion test:
(1) An explosion test chamber designed and constructed to contain an
[[Page 68]]
explosive gas mixture to surround and fill the motor assembly being
tested. The chamber must be sufficiently darkened and provide viewing
capabilities of the flame-arresting paths to allow observation during
testing of any discharge of flame or ignition of the explosive mixture
surrounding the motor assembly.
(2) A methane gas supply with at least 98 by volume per centum of
combustible hydrocarbons, with the remainder being inert. At least 80
percent by volume of the gas shall be methane.
(3) Coal dust having a minimum of 22 percent dry volatile matter and
a minimum heat constant of 11,000 moist BTU (coal containing natural bed
moisture but not visible surface water) ground to a fineness of minus
200 mesh U.S. Standard sieve series.
(4) An electric spark ignition source with a minimum of 100
millijoules of energy.
(5) A pressure recording system that will indicate the pressure
peaks resulting from the ignition and combustion of explosive gas
mixtures within the enclosure being tested.
(b) General test procedures. (1) Motor assemblies being tested
shall--
(i) Be equipped with unshielded bearings regardless of the type of
bearings specified; and
(ii) Have all parts that do not contribute to the operation or
assure the explosion-proof integrity of the enclosure, such as oil
seals, grease fittings, hose conduit, cable clamps, and outer bearing
caps (which do not house the bearings) removed from the motor assembly.
(2) Each motor assembly shall be placed in the explosion test
chamber and tested as follows:
(i) The motor assembly shall be filled with and surrounded by an
explosive mixture of the natural gas supply and air. The chamber gas
concentrations shall be between 6.0 by volume per centum and the motor
assembly natural gas concentration just before ignition of each test.
Each externally visible flame-arresting path fit shall be observed for
discharge of flames for at least two of the tests, including one with
coal dust added.
(ii) A single spark source is used for all testing. Pressure shall
be measured at each end of the winding compartment simultaneously during
all tests. Quantity and location of test holes shall permit ignition on
each end of the winding compartment and recording of pressure on the
same and opposite ends as the ignition.
(iii) Motor assemblies incorporating a conduit box shall have the
pressure in the conduit box recorded simultaneously with the other
measured pressures during all tests. Quantity and location of test holes
in the conduit box shall permit ignition and recording of pressure as
required in paragraphs (c)(1) and (c)(4)(i) of this section.
(iv) The motor assembly shall be completely purged and recharged
with a fresh explosive gas mixture from the chamber or by injection
after each test. The chamber shall be completely purged and recharged
with a fresh explosive gas mixture as necessary. The oxygen level of the
chamber gas mixture shall be no less than 18 percent by volume for
testing. In the absence of oxygen monitoring equipment, the maximum
number of tests conducted before purging shall be less than or equal to
the chamber volume divided by forty times the volume occupied by the
motor assembly.
(c) Test procedures. (1) Eight tests at 9.4 0.4 percent methane by
volume within the winding compartment shall be conducted, with the rotor
stationary during four tests and rotating at rated speed (rpm) during
four tests. The ignition shall be at one end of the winding compartment
for two stationary and two rotating tests, and then switched to the
opposite end for the remaining four tests. If a nonisolated conduit box
is used, then two additional tests, one stationary and one rotating,
shall be conducted with ignition in the conduit box at a point furthest
away from the opening between the conduit box and the winding
compartment.
(2) Four tests at 7.0 0.3 percent methane by volume within the
winding compartment shall be conducted with the rotor stationary, 2
ignitions at each end.
(3) Four tests at 9.4 0.4 percent methane by volume plus coal dust
shall be conducted. A quantity of coal dust
[[Page 69]]
equal to 0.05 ounces per cubic foot of internal free volume of the
winding compartment plus the nonisolated conduit box shall be introduced
into each end of the winding compartment and nonisolated conduit box to
coat the interior surface before conducting the first of the four tests.
The coal dust introduced into the conduit box shall be proportional to
its volume. The remaining coal dust shall be equally divided between the
winding compartment ends. For two tests, one stationary and one
rotating, the ignition shall be either in the conduit box or one end of
the connected winding compartment, whichever produced the highest
pressure in the previous tests. The two remaining tests, one stationary
and one rotating, shall be conducted with the ignition in the winding
compartment end furthest away from the conduit box.
(4) For motor assemblies incorporating a conduit box which is
isolated from the winding compartment by an isolating barrier the
following additional tests shall be conducted--
(i) For conduit boxes with an internal free volume greater than 150
cubic inches, two ignition points shall be used, one as close to the
geometric center of the conduit box as practical and the other at the
furthest point away from the isolating barrier between the conduit box
and the winding compartment. Recording of pressure shall be on the same
and opposite sides as the ignition point furthest from the isolating
barrier between the conduit box and the winding compartment. Conduit
boxes with an internal free volume of 150 cubic inches or less shall
have one test hole for ignition located as close to the geometric center
of the conduit box as practical and one for recording of pressure
located on a side of the conduit box.
(ii) The conduit box shall be tested separately. Six tests at 9.4
0.4 percent methane by volume within the conduit box shall be conducted
followed by two tests at 7.0 0.3 percent methane by volume. Then two
tests at 9.4 0.4 percent methane by volume with a quantity of coal dust
equal to 0.05 ounces per cubic foot of internal free volume of the
conduit box and meeting the specifications in paragraph (c)(3) of this
section shall be conducted. For conduit boxes with an internal free
volume of more than 150 cubic inches, the number of tests shall be
evenly divided between each ignition point.
(iii) The motor assembly shall be tested following removal of the
isolating barrier or one sectionalizing terminal (as applicable). Six
tests at 9.4 0.4 percent methane by volume in the winding compartment
and conduit box shall be conducted using three ignition locations. The
ignition shall be at one end of the winding compartment for one
stationary and one rotating test; the opposite end for one stationary
and one rotating test; and at the ignition point that produced the
highest pressure on the previous test in paragraph (c)(4)(ii) of this
section in the conduit box for one stationary and one rotating test.
Motor assemblies that use multiple sectionalizing terminals shall have
one test conducted as each additional terminal is removed. Each of these
tests shall use the rotor state and ignition location that produced the
highest pressure in the previous tests.
(d) A motor assembly incorporating a conduit box that is isolated
from the winding compartment that exhibits pressures exceeding 110 psig,
while testing during removal of any or all isolating barriers as
specified in paragraph (c)(4) of this section, shall have a warning
statement on the approval plate. This statement shall warn that the
isolating barrier must be maintained to ensure the explosion-proof
integrity of the motor assembly. A statement is not required when the
motor assembly has withstood a static pressure of twice the maximum
pressure recorded in the explosion tests of paragraph (c)(4) of this
section. The static pressure test shall be conducted on the motor
assembly with all isolating barriers removed, and in accordance with
Sec. 7.307 of this part.
(e) Acceptable performance. Explosion tests of a motor assembly
shall not result in--
(1) Discharge of flames.
(2) Ignition of the explosive mixture surrounding the motor assembly
in the chamber.
(3) Development of afterburning.
[[Page 70]]
(4) Rupture of any part of the motor assembly or any panel or
divider within the motor assembly.
(5) Clearances, in excess of those specified in this subpart, along
accessible flame-arresting paths, following any necessary retightening
of fastenings.
(6) Pressure exceeding 110 psig, except as provided in paragraph (d)
of this section unless the motor assembly has withstood a static
pressure of twice the maximum pressure recorded in the explosion tests
of this section following the static pressure test procedures of
Sec. 7.307 of this part.
(7) Permanent deformation greater than 0.040 inches per linear foot.
Sec. 7.307 Static pressure test.
(a) Test procedure. (1) The enclosure shall be internally
pressurized to a minimum of 150 psig and the pressure maintained for a
minimum of 10 seconds.
(2) Following the pressure hold, the pressure shall be removed and
the pressurizing agent removed from the enclosure.
(b) Acceptable performance. (1) The enclosure during pressurization
shall not exhibit--
(i) Leakage through welds or casting; or
(ii) Rupture of any part that affects the explosion-proof integrity
of the enclosure.
(2) The enclosure following removal of the pressurizing agent shall
not exhibit--
(i) Visible cracks in welds;
(ii) Permanent deformation exceeding 0.040 inches per linear foot;
or
(iii) Clearances, in excess of those specified in this subpart,
along accessible flame-arresting paths, following any necessary
retightening of fastenings.
Sec. 7.308 Lockwasher equivalency test.
(a) Test procedure. (1) Each test sample shall be an assembly
consisting of a fastening with a locking device. Each standard sample
shall be an assembly consisting of a fastening with a lockwasher.
(2) Five standard samples and five test samples shall be tested.
(3) Each standard and test sample shall use a new fastening of the
same specifications as being used on the motor assembly.
(4) A new tapped hole shall be used for each standard and test
sample. The hole shall be of the same specifications as used on the
motor assembly.
(5) Each standard and test sample shall be inserted in the tapped
hole and continuously and uniformly tightened at a speed not to exceed
30 rpm until the fastening's proof load is achieved. The torquing device
shall not contact the locking device or the threaded portion of the
fastening.
(6) Each standard and test sample shall be engaged and disengaged
for 15 full cycles.
(b) Acceptable performance. The minimum torque value required to
start removal of the fastening from the installed position (minimum
breakway torque) for any cycle of any test sample shall be greater than
or equal to the average breakway torque of each removal cycle of every
standard sample.
Sec. 7.309 Approval marking.
Each approved motor assembly shall be identified by a legible and
permanent approval plate inscribed with the assigned MSHA approval
number and a warning statement as specified in Sec. 7.306(d) of this
part. The plate shall be securely attached to the motor assembly in a
manner that does not impair any explosion-proof characteristics.
Sec. 7.310 Post-approval product audit.
Upon request by MSHA but not more than once a year, except for
cause, the approval holder shall make a motor assembly available for
audit at no cost.
Sec. 7.311 Approval checklist.
Each motor assembly bearing an MSHA approval marking shall be
accompanied by a list of items necessary for maintenance of the motor
assembly as approved.
[[Page 71]]
Sec. Appendix I to Subpart J of Part 7
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Subpart K_Electric Cables, Signaling Cables, and Cable Splice Kits
Source: 57 FR 61220, Dec. 23, 1992, unless otherwise noted.
Sec. 7.401 Purpose and effective date.
This subpart establishes the flame-resistant requirements for
approval of electric cables, signaling cables and cable splice kit
designs. Applications for approval or extension of approval submitted
after February 22, 1994 shall meet the requirements of this subpart.
Sec. 7.402 Definitions.
The following definitions apply in this subpart.
Component. Any material in a cable splice kit which becomes part of
a splice.
Conductor. A bare or insulated wire or combination of wires not
insulated from one another, suitable for carrying an electric current.
Electric Cable. An assembly of one or more insulated conductors of
electric current under a common or integral jacket. A cable may also
contain one or more uninsulated conductors.
Jacket. A nonmetallic abrasion-resistant outer covering of a cable
or splice.
Power Conductor. An insulated conductor of a cable assembly through
which the primary electric current or power is transmitted.
Signaling Cable. A fiber optic cable, or a cable containing electric
conductors of a cross-sectional area less than #14 AWG used where the
circuit cannot deliver currents which would increase conductor
temperatures beyond that established for the current-carrying capacity
of the conductors.
[[Page 81]]
Splice. The mechanical joining of one or more severed conductors in
a single length of a cable including the replacement of insulation and
jacket.
Splice Kit. A group of materials and related instructions which
clearly identify all components and detail procedures used in safely
making a flame-resistant splice in an electric cable.
Sec. 7.403 Application requirements.
(a) Electric cables and signaling cables. A single application may
address two or more sizes, types, and constructions if the products do
not differ in composition of materials or basic design. Applications
shall include the following information for each product:
(1) Product information:
(i) Cable type (for example, G or G-GC).
(ii) Construction (for example, round or flat).
(iii) Number and size (gauge) of each conductor.
(iv) Voltage rating for all cables containing electric conductors.
(v) For electric cables, current-carrying capacity of each
conductor, with corresponding ambient temperature upon which the current
rating (ampacity) is based, of each power conductor.
(2) Design standard. Specify any published consensus standard used
and fully describe any deviations from it, or fully describe any
nonstandard design used.
(3) Materials. Type and identifying numbers for each material
comprising the finished assembly.
(b) Splice kit. A single application may address two or more sizes,
types, and constructions if the products do not differ in composition of
materials or basic design. Applications shall include the following
information for each product:
(1) Product information:
(i) Trade name or designation (for example, style or code number).
(ii) Type or kit (for example, shielded or nonshielded).
(iii) Voltage rating.
(2) Design standard. Specify any published design standard used and
fully describe any deviations from it, or provide complete final
assembly dimensions for all components for each cable that the splice
kit is designed to repair.
(3) Materials. Type of materials, supplier, supplier's stock number
or designation for each component.
(4) Complete splice assembly instructions which clearly identify all
components and detail procedures used in making the splice.
Sec. 7.404 Technical requirements.
(a) Electric cables and splices shall be flame resistant when tested
in accordance with Sec. 7.407.
(b) Signaling cables shall be flame resistant when tested in
accordance with Sec. 7.408.
Sec. 7.405 Critical characteristics.
(a) A sample from each production run, batch, or lot of manufactured
electric cable, signaling cable, or splice made from a splice kit shall
be flame tested, or
(b) A sample of the materials that contribute to the flame-resistant
characteristic of the cable or splice and a sample of the cable or
splice kit assembly shall be visually inspected or tested through other
means for each production run, batch, or lot to ensure that the finished
product meets the flame-resistance test.
Sec. 7.406 Flame test apparatus.
The principal parts of the apparatus used to test for flame
resistance of electric cables, signaling cables and splices shall
include#:
(a) Test chamber. A rectangular enclosure measuring 17 inches deep
by 14\1/2\ inches high by 39 inches wide and completely open at the top
and front. The floor or base of the chamber shall be fabricated or lined
with a noncombustible material that will not extinguish burning matter
which may fall from the test specimen during testing. The chamber shall
have permanent connections mounted to the back wall, sides, or floor of
the chamber which extend to the sample end location. These are used to
energize the electric cable and splice specimens. They are not used, but
may stay in place, when testing signaling cables.
(b) Specimen holder (support). A specimen holder (support)
consisting of
[[Page 82]]
three separate metal rods each measuring approximately \3/16\ inch in
diameter (nominal) to support the specimen. The horizontal portion of
the rod which contacts the test specimen shall be approximately 12
inches in length.
(c) Gas ignition source. A standard natural gas type Tirrill burner,
with a nominal inside diameter of \3/8\ inch, to apply the flame to the
test specimen. The fuel for the burner shall be natural gas composed of
at least 96 percent combustible hydrocarbons, with at least 80 percent
being methane.
(d) Current source. (For electric cables and splices only). A source
of electric current (either alternating current or direct current) for
heating the power conductors of the test specimen. The current source
shall have a means to regulate current flow through the test specimen
and have an open circuit voltage not exceeding the voltage rating of the
test specimen.
(e) Current measuring device. (For electric cables and splices
only). An instrument to monitor the effective value of heating current
flow through the power conductors of the specimen within an accuracy of
1 percent.
(f) Temperature measuring device. (For electric cables and splices
only). An instrument to measure conductor temperature within an accuracy
of 2 percent without the necessity of removing material from the test
specimen in order to measure the temperature.
Sec. 7.407 Test for flame resistance of electric cables and cable
splices.
(a) Test procedure. (1) For electric cables, prepare 3 specimens of
cable, each 3 feet in length, by removing 5 inches of jacket material
and 2\1/2\ inches of conductor insulation from both ends of each test
specimen. For splices, prepare a splice specimen in each of 3 sections
of MSHA-approved flame-resistant cable. The cable shall be of the type
that the splice kit is designed to repair. The finished splice shall not
exceed 18 inches or be less than 6 inches in length for test purposes.
The spliced cables shall be 3 feet in length with the midpoint of the
splice located 14 inches from one end. Both ends of each of the spliced
cables shall be prepared by removing 5 inches of jacket material and
2\1/2\ inches of conductor insulation. The type, amperage, voltage
rating, and construction of the cable shall be compatible with the
splice kit design. Each splice shall be made in accordance with the
instructions provided with the splice kit.
(2) Prior to testing, condition each test specimen for a minimum of
24 hours at a temperature of 70 10 F (21.1 5.5 C) and a relative
humidity of 55 10 percent. These environmental conditions shall be
maintained during testing.
(3) For electric cables, locate the sensing element of the
temperature measuring device 26 inches from one end of each test
specimen. For splices, locate the sensing element 12 inches from the
midpoint of the splice and 10 inches from the end of the cable. The
sensing element must be secured so that it remains in direct contact
with the metallic portion of the power conductor for the duration of the
flame-resistant test. If a thermocouple-type temperature measuring
instrument is used, connect the sensing element through the cable jacket
and power conductor insulation. Other means for monitoring conductor
temperature may be used, provided the temperature measurement is made at
the same location. If the jacket and conductor insulation must be
disturbed to insert the temperature measuring device, each must be
restored as closely as possible to its original location and maintained
there for the duration of the testing.
(4) Center the test specimen horizontally in the test chamber on the
three rods. The three rods shall be positioned perpendicular to the
longitudinal axis of the test specimen and at the same height, which
permits the tip of the inner cone from the flame of the gas burner, when
adjusted in accordance with the test procedure, to touch the jacket of
the test specimen. The specimen shall be maintained at this level for
the duration of the flame test. The two outermost rods shall be placed
so that 1 inch of cable jacket extends beyond each rod. For electric
cables, the third rod shall be placed 14 inches from the end of the test
specimen nearer the temperature monitoring location on the specimen. For
splices, the third rod shall be placed between the splice and the
temperature monitoring
[[Page 83]]
location at a distance 8 inches from the midpoint of the splice. The
specimen shall be free from external air currents during testing.
(5) Adjust the gas burner to give an overall blue flame 5 inches
high with a 3-inch inner cone. There shall be no persistence of yellow
coloration.
(6) Connect all power conductors of the test specimen to the current
source. The connections shall be secure and compatible with the size of
the cable's power conductors in order to reduce contact resistance.
(7) Energize all power conductors of the test specimen with an
effective heating current value of 5 times the power conductor ampacity
rating (to the nearest whole ampere) at an ambient temperature of 104 F
(40 C).
(8) Monitor the electric current through the power conductors of the
test specimen with the current measuring device. Adjust the amount of
heating current, as required, to maintain the proper effective heating
current value within 5 percent until the power conductors reach a
temperature of 400 F (204.4 C).
(9) For electric cables, apply the tip of the inner cone from the
flame of the gas burner directly beneath the test specimen for 60
seconds at a location 14 inches from one end of the cable and between
the supports separated by a 16-inch distance. For splices, apply the tip
of the inner cone from the flame of a gas burner for 60 seconds beneath
the midpoint of the splice jacket.
(10) After subjecting the test specimen to external flame for the
specified time, fully remove the flame of the gas from beneath the
specimen without disturbing air currents within the test chamber.
Simultaneously turn off the heating current.
(11) Record the amount of time the test specimen continues to burn
after the flame from the gas burner has been removed. The duration of
burning includes the burn time of any material that falls from the test
specimen after the flame from the gas has been removed.
(12) Record the length of burned (charred) area of each test
specimen measured longitudinally along the cable axis.
(13) Repeat the procedure for the remaining two specimens.
(b) Acceptable performance. Each of the three test specimens shall
meet the following criteria:
(1) The duration of burning shall not exceed 240 seconds.
(2) The length of the burned (charred) area shall not exceed 6
inches.
Sec. 7.408 Test for flame resistance of signaling cables.
(a) Test procedure. (1) Prepare 3 samples of cable each 2 feet long.
(2) Prior to testing, condition each test specimen for a minimum of
24 hours at a temperature of 70 10 F (21.1 5.5 C) and relative
humidity of 55 10 percent. These environmental conditions shall be
maintained during testing.
(3) Center the test specimen horizontally in the test chamber on the
three rods. The three rods shall be positioned perpendicular to the
longitudinal axis of the test specimen and at the same height, which
permits the tip of the inner cone from the flame of the gas burner, when
adjusted in accordance with the test procedure, to touch the test
specimen. The specimen shall be maintained at this height for the
duration of the flame test. The two outermost rods shall be placed so
that 1 inch of cable extends beyond each rod. The third rod shall be
placed at the midpoint of the cable. The specimen shall be free from
external air currents during testing.
(4) Adjust the gas burner to give an overall blue flame 5 inches
high with a 3-inch inner cone. There shall be no persistence of yellow
coloration.
(5) Apply the tip of the inner cone from the flame of the gas burner
for 30 seconds directly beneath the specimen centered between either and
support and the center support.
(6) After subjecting the test specimen to external flame for the
specified time, fully remove the flame of the gas from beneath the
specimen without disturbing air currents within the test chamber.
(7) Record the amount of time the test specimen continues to burn
after the flame from the gas burner has been removed. The duration of
burning includes the burn time of any material
[[Page 84]]
that falls from the test specimen after the flame from the gas has been
removed.
(8) Record the length of burned (charred) area of each test specimen
measured longitudinally along the cable axis.
(9) Repeat the procedure for the remaining two specimens.
(b) Acceptable performance. Each of the three test specimens shall
meet the following criteria:
(1) The duration of burning shall not exceed 60 seconds.
(2) The length of the burned (charred) area shall not exceed 6
inches.
Sec. 7.409 Approval marking.
Approved electric cables, signaling cables, and splices shall be
legibly and permanently marked with the MSHA-assigned approval marking.
For electric cables and signaling cables, the marking shall appear at
intervals not exceeding 3 feet and shall include the MSHA-assigned
approval number in addition to the number and size (gauge) of conductors
and cable type. For cables containing electric conductors, the marking
shall also include the voltage rating. For splices, the marking shall be
placed on the jacket so that it will appear at least once on the
assembled splice.
Sec. 7.410 Post-approval product audit.
Upon request by MSHA, but no more than once a year except for cause,
the approval holder shall supply to MSHA for audit at no cost--
(a) 12 feet of an approved electric cable or approved signaling
cable; or
(b) 3 splice kits of one approved splice kit design and 12 feet of
MSHA-assigned cable that the splice kit is designed to repair.
Sec. 7.411 New technology.
MSHA may approve cable products or splice kits that incorporate
technology for which the requirements of this subpart are not applicable
if the Agency determines that they are as safe as those which meet the
requirements of this subpart.
Subpart L_Refuge Alternatives
Source: 74 FR 80694, Dec. 31, 2008, unless otherwise noted.
Sec. 7.501 Purpose and scope.
This subpart L establishes requirements for MSHA approval of refuge
alternatives and components for use in underground coal mines. Refuge
alternatives are intended to provide a life-sustaining environment for
persons trapped underground when escape is impossible.
Sec. 7.502 Definitions.
The following definitions apply in this subpart:
Apparent temperature. A measure of relative discomfort due to the
combined effects of air movement, heat, and humidity on the human body.
Breathable oxygen. Oxygen that is at least 99 percent pure with no
harmful contaminants.
Flash fire. A fire that rapidly spreads through a diffuse fuel, such
as airborne coal dust or methane, without producing damaging pressure.
Noncombustible material. Material, such as concrete or steel, that
will not ignite, burn, support combustion, or release flammable vapors
when subjected to fire or heat.
Overpressure. The highest pressure over the background atmospheric
pressure that could result from an explosion, which includes the impact
of the pressure wave on an object.
Refuge alternative. A protected, secure space with an isolated
atmosphere and integrated components that create a life-sustaining
environment for persons trapped in an underground coal mine.
Sec. 7.503 Application requirements.
(a) An application for approval of a refuge alternative or component
shall include:
(1) The refuge alternative's or component's make and model number,
if applicable.
(2) A list of the refuge alternative's or component's parts that
includes--
(i) The MSHA approval number for electric-powered equipment;
(ii) Each component's or part's in-mine shelf life, service life,
and recommended replacement schedule;
[[Page 85]]
(iii) Materials that have a potential to ignite used in each
component or part with their MSHA approval number; and
(iv) A statement that the component or part is compatible with other
components and, upon replacement, is equivalent to the original
component or part.
(3) The capacity and duration (the number of persons it is designed
to maintain and for how long) of the refuge alternative or component on
a per-person per-hour basis.
(4) The length, width, and height of the space required for storage
of each component.
(b) The application for approval of the refuge alternative shall
include the following:
(1) A description of the breathable air component, including
drawings, air-supply sources, piping, regulators, and controls.
(2) The maximum volume, excluding the airlock; the dimensions of
floor space and volume provided for each person using the refuge
alternative; and the floor space and volume of the airlock.
(3) The maximum positive pressures in the interior space and the
airlock and a description of the means used to limit or control the
positive pressure.
(4) The maximum allowable apparent temperature of the interior space
and the airlock and the means to control the apparent temperature.
(5) The maximum mine air temperature under which the refuge
alternative is designed to operate when the unit is fully occupied.
(6) Drawings that show the features of each component and contain
sufficient information to document compliance with the technical
requirements.
(7) A manual that contains sufficient detail for each refuge
alternative or component addressing in-mine transportation, operation,
and maintenance of the unit.
(8) A summary of the procedures for deploying refuge alternatives.
(9) A summary of the procedures for using the refuge alternative.
(10) The results of inspections, evaluations, calculations, and
tests conducted under this subpart.
(c) The application for approval of the air-monitoring component
shall specify the following:
(1) The operating range, type of sensor, gas or gases measured, and
environmental limitations, including the cross-sensitivity to other
gases, of each detector or device in the air-monitoring component.
(2) The procedure for operation of the individual devices so that
they function as necessary to test gas concentrations over a 96-hour
period.
(3) The procedures for monitoring and maintaining breathable air in
the airlock, before and after purging.
(4) The instructions for determining the quality of the atmosphere
in the airlock and refuge alternative interior and a means to maintain
breathable air in the airlock.
(d) The application for approval of the harmful gas removal
component shall specify the following:
(1) The volume of breathable air available for removing harmful gas
both at start-up and while persons enter through the airlock.
(2) The maximum volume of each gas that the component is designed to
remove on a per-person per-hour basis.
Sec. 7.504 Refuge alternatives and components; general requirements.
(a) Refuge alternatives and components: (1) Electrical components
that are exposed to the mine atmosphere shall be approved as
intrinsically safe for use. Electrical components located inside the
refuge alternative shall be either approved as intrinsically safe or
approved as permissible.
(2) Shall not produce continuous noise levels in excess of 85 dBA in
the structure's interior.
(3) Shall not liberate harmful or irritating gases or particulates
into the structure's interior or airlock.
(4) Shall be designed so that the refuge alternative can be safely
moved with the use of appropriate devices such as tow bars.
(5) Shall be designed to withstand forces from collision of the
refuge alternative structure during transport or handling.
(b) The apparent temperature in the structure shall be controlled as
follows:
[[Page 86]]
(1) When used in accordance with the manufacturer's instructions and
defined limitations, the apparent temperature in the fully occupied
refuge alternative shall not exceed 95 degrees Fahrenheit (F).
(2) Tests shall be conducted to determine the maximum apparent
temperature in the refuge alternative when used at maximum occupancy and
in conjunction with required components. Test results including
calculations shall be reported in the application.
(c) The refuge alternative shall include:
(1) A two-way communication facility that is a part of the mine
communication system, which can be used from inside the refuge
alternative; and accommodations for an additional communication system
and other requirements as defined in the communications portion of the
operator's approved Emergency Response Plan.
(2) Lighting sufficient for persons to perform tasks.
(3) A means to contain human waste effectively and minimize
objectionable odors.
(4) First aid supplies.
(5) Materials, parts, and tools for repair of components.
(6) A fire extinguisher that--
(i) Meets the requirements for portable fire extinguishers used in
underground coal mines under part 75;
(ii) Is appropriate for extinguishing fires involving the chemicals
used for harmful gas removal; and
(iii) Uses a low-toxicity extinguishing agent that does not produce
a hazardous by-product when deployed.
(d) Containers used for storage of refuge alternative components or
provisions shall be--
(1) Airtight, waterproof, and rodent-proof;
(2) Easy to open and close without the use of tools; and
(3) Conspicuously marked with an expiration date and instructions
for use.
Sec. 7.505 Structural components.
(a) The structure shall--
(1) Provide at least 15 square feet of floor space per person and 30
to 60 cubic feet of volume per person according to the following chart.
The airlock can be included in the space and volume if waste is disposed
outside the refuge alternative.
------------------------------------------------------------------------
Unrestricted
volume (cubic
Mining height (inches) feet) per
person *
------------------------------------------------------------------------
36 or less............................................... 30
>36-42................................................... 37.5
>42-48................................................... 45
>48-54................................................... 52.5
>54...................................................... 60
------------------------------------------------------------------------
* Includes an adjustment of 12 inches for clearances.
(2) Include storage space that secures and protects the components
during transportation and that permits ready access to components for
maintenance examinations.
(3) Include an airlock that creates a barrier and isolates the
interior space from the mine atmosphere, except for a refuge alternative
capable of maintaining adequate positive pressure.
(i) The airlock shall be designed for multiple uses to accommodate
the structure's maximum occupancy.
(ii) The airlock shall be configured to accommodate a stretcher
without compromising its function.
(4) Be designed and made to withstand 15 pounds per square inch
(psi) overpressure for 0.2 seconds prior to deployment.
(5) Be designed and made to withstand exposure to a flash fire of
300 F for 3 seconds prior to deployment.
(6) Be made with materials that do not have a potential to ignite or
are MSHA-approved.
(7) Be made from reinforced material that has sufficient durability
to withstand routine handling and resist puncture and tearing during
deployment and use.
(8) Be guarded or reinforced to prevent damage to the structure that
would hinder deployment, entry, or use.
(9) Permit measurement of outside gas concentrations without exiting
the structure or allowing entry of the outside atmosphere.
(b) Inspections or tests shall be conducted as follows:
(1) A test shall be conducted to demonstrate that trained persons
can fully deploy the structure, without the use of tools, within 10
minutes of reaching the refuge alternative.
[[Page 87]]
(2) A test shall be conducted to demonstrate that an overpressure of
15 psi applied to the pre-deployed refuge alternative structure for 0.2
seconds does not allow gases to pass through the structure separating
the interior and exterior atmospheres.
(3) A test shall be conducted to demonstrate that a flash fire of
300 F for 3 seconds does not allow gases to pass from the outside to
the inside of the structure.
(4) An inspection shall be conducted to determine that the
overpressure forces of 15 psi applied to the pre-deployed refuge
alternative structure for 0.2 seconds does not prevent the stored
components from operating.
(5) An inspection shall be conducted to determine that a flash fire
of 300 F for 3 seconds does not prevent the stored components from
operating.
(6) A test shall be conducted to demonstrate that each structure
resists puncture and tearing when tested in accordance with ASTM D2582-
07 ``Standard Test Method for Puncture-Propagation Tear Resistance of
Plastic Film and Thin Sheeting.'' This publication is incorporated by
reference. The Director of the Federal Register approves this
incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. A copy may be obtained from the American Society for Testing
and Materials (ASTM), 100 Barr Harbor Drive, P.O. Box C700, West
Conshohocken, PA 19428-2959; 610-832-9500; http://www.astm.org. A copy
may be inspected at any MSHA Coal Mine Safety and Health District
Office; or at MSHA's Office of Standards, Regulations, and Variances,
201 12th Street South, Arlington, VA 22202-5452; 202-693-9440; or at the
National Archives and Records Administration (NARA). For information on
the availability of this material at NARA, call 202-741-6030, or go to:
http://www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.
(7) A test shall be conducted to demonstrate that each reasonably
anticipated repair can be completed within 10 minutes of opening the
storage space for repair materials and tools.
(8) A test shall be conducted to demonstrate that no harmful gases
or noticeable odors are released from nonmetallic materials before or
after the flash fire test. The test shall identify the gases released
and determine their concentrations.
(c) If pressurized air is used to deploy the structure or maintain
its shape, the structure shall--
(1) Include a pressure regulator or other means to prevent over
pressurization of the structure, and
(2) Provide a means to repair and re-pressurize the structure in
case of failure of the structure or loss of air pressure.
(d) The refuge alternative structure shall provide a means--
(1) To conduct a preshift examination, without entering the
structure, of components critical for deployment; and
(2) To indicate unauthorized entry or tampering.
[73 FR 80694, Dec. 31, 2008, as amended at 80 FR 52985, Sept. 2, 2015]
Sec. 7.506 Breathable air components.
(a) Breathable air shall be supplied by compressed air cylinders,
compressed breathable-oxygen cylinders, or boreholes with fans installed
on the surface or compressors installed on the surface. Only
uncontaminated breathable air shall be supplied to the refuge
alternative.
(b) Mechanisms shall be provided and procedures shall be included so
that, within the refuge alternative,--
(1) The breathable air sustains each person for 96 hours,
(2) The oxygen concentration is maintained at levels between 18.5
and 23 percent, and
(3) The average carbon dioxide concentration is 1.0 percent or less
and excursions do not exceed 2.5 percent.
(c) Breathable air supplied by compressed air from cylinders, fans,
or compressors shall provide a minimum flow rate of 12.5 cubic feet per
minute of breathable air for each person.
(1) Fans or compressors shall meet the following:
(i) Be equipped with a carbon monoxide detector located at the
surface that automatically provides a visual and audible alarm if carbon
monoxide in supplied air exceeds 10 parts per million (ppm).
[[Page 88]]
(ii) Provide in-line air-purifying sorbent beds and filters or other
equivalent means to assure the breathing air quality and prevent
condensation, and include maintenance instructions that provide
specifications for periodic replacement or refurbishment.
(iii) Provide positive pressure and an automatic means to assure
that the pressure is relieved at 0.18 psi, or as specified by the
manufacturer, above mine atmospheric pressure in the refuge alternative.
(iv) Include warnings to assure that only uncontaminated breathable
air is supplied to the refuge alternative.
(v) Include air lines to supply breathable air from the fan or
compressor to the refuge alternative.
(A) Air lines shall be capable of preventing or removing water
accumulation.
(B) Air lines shall be designed and protected to prevent damage
during normal mining operations, a flash fire of 300 F for 3 seconds, a
pressure wave of 15 psi overpressure for 0.2 seconds, and ground
failure.
(vi) Assure that harmful or explosive gases, water, and other
materials cannot enter the breathable air.
(2) Redundant fans or compressors and power sources shall be
provided to permit prompt re-activation of equipment in the event of
failure.
(d) Compressed breathable oxygen shall--
(1) Include instructions for deployment and operation;
(2) Provide oxygen at a minimum flow rate of 1.32 cubic feet per
hour per person;
(3) Include a means to readily regulate the pressure and volume of
the compressed oxygen;
(4) Include an independent regulator as a backup in case of failure;
and
(5) Be used only with regulators, piping, and other equipment that
is certified and maintained to prevent ignition or combustion.
(e) The applicant shall prepare and submit an analysis or study
demonstrating that the breathable air component will not cause an
ignition.
(1) The analysis or study shall specifically address oxygen fire
hazards and fire hazards from chemicals used for removal of carbon
dioxide.
(2) The analysis or study shall identify the means used to prevent
any ignition source.
Sec. 7.507 Air-monitoring components.
(a) Each refuge alternative shall have an air-monitoring component
that provides persons inside with the ability to determine the
concentrations of carbon dioxide, carbon monoxide, oxygen, and methane,
inside and outside the structure, including the airlock.
(b) Refuge alternatives designed for use in mines with a history of
harmful gases, other than carbon monoxide, carbon dioxide, and methane,
shall be equipped to measure the harmful gases' concentrations.
(c) The air-monitoring component shall be inspected or tested and
the test results shall be included in the application.
(d) The air-monitoring component shall meet the following:
(1) The total measurement error, including the cross-sensitivity to
other gases, shall not exceed 10 percent of the reading, except as
specified in the approval.
(2) The measurement error limits shall not be exceeded after start-
up, after 8 hours of continuous operation, after 96 hours of storage,
and after exposure to atmospheres with a carbon monoxide concentration
of 999 ppm (full-scale), a carbon dioxide concentration of 3 percent,
and full-scale concentrations of other gases.
(3) Calibration gas values shall be traceable to the National
Institute for Standards and Technology (NIST) ``Standard Reference
Materials'' (SRMs).
(4) The analytical accuracy of the calibration gas and span gas
values shall be within 2.0 percent of NIST gas standards.
(5) The detectors shall be capable of being kept fully charged and
ready for immediate use.
Sec. 7.508 Harmful gas removal components.
(a) Each refuge alternative shall include means for removing harmful
gases.
(1) Purging or other effective procedures shall be provided for the
airlock
[[Page 89]]
to dilute the carbon monoxide concentration to 25 ppm or less and the
methane concentration to 1.0 percent or less as persons enter, within 20
minutes of persons deploying the refuge alternative.
(2) Chemical scrubbing or other effective procedures shall be
provided so that the average carbon dioxide concentration in the
occupied structure shall not exceed 1.0 percent over the rated duration,
and excursions shall not exceed 2.5 percent.
(i) Carbon dioxide removal components shall be used with breathable
air cylinders or oxygen cylinders.
(ii) Carbon dioxide removal components shall remove carbon dioxide
at a rate of 1.08 cubic feet per hour per person.
(3) Instructions shall be provided for deployment and operation of
the harmful gas removal component.
(b) The harmful gas removal component shall meet the following
requirements: Each chemical used for removal of harmful gas shall be--
(1) Contained such that when stored or used it cannot come in
contact with persons, and it cannot release airborne particles.
(2) Provided with all materials; parts, such as hangers, racks, and
clips; equipment; and instructions necessary for deployment and use.
(3) Stored in an approved container that is conspicuously marked
with the manufacturer's instructions for disposal of used chemical.
(c) Each harmful gas removal component shall be tested to determine
its ability to remove harmful gases.
(1) The component shall be tested in a refuge alternative structure
that is representative of the configuration and maximum volume for which
the component is designed.
(i) The test shall include three sampling points located vertically
along the centerlines of the length and width of the structure and
equally spaced over the horizontal centerline of the height of the
structure.
(ii) The structure shall be sealed airtight.
(iii) The operating gas sampling instruments shall be placed inside
the structure and continuously exposed to the test atmosphere.
(iv) Sampling instruments shall simultaneously measure the gas
concentrations at the three sampling points.
(2) For testing the component's ability to remove carbon monoxide,
the structure shall be filled with a test gas of either purified
synthetic air or purified nitrogen that contains 400 ppm carbon
monoxide, 5 percent.
(i) After a stable concentration of 400 ppm, 5 percent, carbon
monoxide has been obtained for 5 minutes at all three sampling points, a
timer shall be started and the structure shall be purged or carbon
monoxide otherwise removed.
(ii) Carbon monoxide concentration readings from each of the three
sampling instruments shall be recorded every 2 minutes.
(iii) The time shall be recorded from the start of harmful gas
removal until the readings of the three sampling instruments all
indicate a carbon monoxide concentration of 25 ppm or less.
(3) For testing the component's ability to remove carbon dioxide,
the carbon dioxide concentration shall not exceed 1.0 percent over the
rated duration and excursions shall not exceed 2.5 percent under the
following conditions:
(i) At 55 F (4 F), 1 atmosphere (1 percent), and 50 percent (5
percent) relative humidity.
(ii) At 55 F (4 F), 1 atmosphere (1 percent), and 100 percent
(5 percent) relative humidity.
(iii) At 90 F (4 F), 1 atmosphere (1 percent), and 50 percent
(5 percent) relative humidity.
(iv) At 82 F (4 F), 1 atmosphere (1 percent), and 100 percent
(5 percent) relative humidity.
(4) Testing shall demonstrate the component's continued ability to
remove harmful gases effectively throughout its designated shelf-life,
specifically addressing the effects of storage and transportation.
(d) Alternate performance tests may be conducted if the tests
provide the same level of assurance of the harmful gas removal
component's capability as the tests specified in paragraph (c) of this
section. Alternate tests shall be specified in the approval application.
[[Page 90]]
Sec. 7.509 Approval markings.
(a) Each approved refuge alternative or component shall be
identified by a legible, permanent approval marking that is securely and
conspicuously attached to the component or its container.
(b) The approval marking shall be inscribed with the component's
MSHA approval number and any additional markings required by the
approval.
(c) The refuge alternative structure shall provide a conspicuous
means for indicating an out-of-service status, including the reason it
is out of service.
(d) The airlock shall be conspicuously marked with the recommended
maximum number of persons that can use it at one time.
Sec. 7.510 New technology.
MSHA may approve a refuge alternative or a component that
incorporates new knowledge or technology, if the applicant demonstrates
that the refuge alternative or component provides no less protection
than those meeting the requirements of this subpart.
PART 14_REQUIREMENTS FOR THE APPROVAL OF FLAME-RESISTANT CONVEYOR BELTS
--Table of Contents
Subpart A_General Provisions
Sec.
14.1 Purpose, effective date for approval holders.
14.2 Definitions.
14.3 Observers at tests and evaluations.
14.4 Application procedures and requirements.
14.5 Test samples.
14.6 Issuance of approval.
14.7 Approval marking and distribution records.
14.8 Quality assurance.
14.9 Disclosure of information.
14.10 Post-approval product audit.
14.11 Revocation.
Subpart B_Technical Requirements
14.20 Flame resistance.
14.21 Laboratory-scale flame test apparatus.
14.22 Test for flame resistance of conveyor belts.
14.23 New technology.
Authority: 30 U.S.C. 957.
Source: 73 FR 80609, Dec. 31, 2008, unless otherwise noted.
Subpart A_General Provisions
Sec. 14.1 Purpose, effective date for approval holders.
This Part establishes the flame resistance requirements for MSHA
approval of conveyor belts for use in underground coal mines.
Applications for approval or extensions of approval submitted after
December 31, 2008, must meet the requirements of this Part.
Sec. 14.2 Definitions.
The following definitions apply in this part:
Applicant. An individual or organization that manufactures or
controls the production of a conveyor belt and applies to MSHA for
approval of conveyor belt for use in underground coal mines.
Approval. A document issued by MSHA, which states that a conveyor
belt has met the requirements of this Part and which authorizes an
approval marking identifying the conveyor belt as approved.
Extension of approval. A document issued by MSHA, which states that
a change to a product previously approved by MSHA meets the requirements
of this Part and which authorizes the continued use of the approval
marking after the appropriate extension number has been added.
Flame-retardant ingredient. A material that inhibits ignition or
flame propagation.
Flammable ingredient. A material that is capable of combustion.
Inert ingredient. A material that does not contribute to combustion.
Post-approval product audit. An examination, testing, or both, by
MSHA of an approved conveyor belt selected by MSHA to determine if it
meets the technical requirements and has been manufactured as approved.
Similar conveyor belt. A conveyor belt that shares the same cover
compound, general carcass construction, and fabric type as another
approved conveyor belt.
[[Page 91]]
Sec. 14.3 Observers at tests and evaluations.
Representatives of the applicant and other persons agreed upon by
MSHA and the applicant may be present during tests and evaluations
conducted under this Part. However, if MSHA receives a request from
others to observe tests, the Agency will consider it.
Sec. 14.4 Application procedures and requirements.
(a) Application address. Applications for approvals or extensions of
approval under this Part may be sent to: U.S. Department of Labor, Mine
Safety and Health Administration, Chief, Approval and Certification
Center, 765 Technology Drive, Triadelphia, West Virginia 26059.
Alternatively, applications for approval or extensions of approval may
be filed online at http://www.msha.gov or faxed to: Chief, Mine Safety
and Health Administration Approval and Certification Center at 304-547-
2044.
(b) Approval application. Each application for approval of a
conveyor belt for use in underground coal mines must include the
information below, except any information submitted in a prior approval
application need not be re-submitted, but must be noted in the
application.
(1) A technical description of the conveyor belt, which includes:
(i) Trade name or identification number;
(ii) Cover compound type and designation number;
(iii) Belt thickness and thickness of top and bottom covers;
(iv) Presence and type of skim coat;
(v) Presence and type of friction coat;
(vi) Carcass construction (number of plies, solid woven);
(vii) Carcass fabric by textile type and weight (ounces per square
yard);
(viii) Presence and type of breaker or floated ply; and
(ix) The number, type, and size of cords and fabric for metal cord
belts.
(2) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(c) Similar belts and extensions of approval may be evaluated for
approval without testing using the BELT method if the following
information is provided in the application:
(1) Formulation information on the compounds in the conveyor belt
indicated by either:
(i) Specifying each ingredient by its chemical name along with its
percentage (weight) and tolerance or percentage range; or
(ii) Specifying each flame-retardant ingredient by its chemical or
generic name with its percentage and tolerance or percentage range or
its minimum percent. List each flammable ingredient and inert ingredient
by chemical, generic, or trade name along with the total percentage of
all flammable and inert ingredients.
(2) Identification of any similar approved conveyor belt for which
the applicant already holds an approval, and the formulation
specifications for that belt if it has not previously been submitted to
the Agency.
(i) The MSHA assigned approval number of the conveyor belt that most
closely resembles the new one; and
(ii) An explanation of any changes from the existing approval.
(d) Extension of approval. Any change in an approved conveyor belt
from the documentation on file at MSHA that affects the technical
requirements of this Part must be submitted for approval prior to
implementing the change. Each application for an extension of approval
must include:
(1) The MSHA-assigned approval number for the conveyor belt for
which the extension is sought;
(2) A description of the proposed change to the conveyor belt; and
(3) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(e) MSHA will determine if testing, additional information, samples,
or material is required to evaluate an application. If the applicant
believes that flame testing is not required, a statement explaining the
rationale must be included in the application.
(f) Equivalent non-MSHA product safety standard. An applicant may
request an equivalency determination to this part under Sec. 6.20 of
this chapter, for a non-MSHA product safety standard.
[[Page 92]]
(g) Fees. Fees calculated in accordance with Part 5 of this chapter
must be submitted in accordance with Sec. 5.40.
Sec. 14.5 Test samples.
Upon request by MSHA, the applicant must submit 3 precut, unrolled,
flat conveyor belt samples for flame testing. Each sample must be 60
\1/4\ inches long (152.4 0.6 cm) by 9 \1/8\ inches (22.9 0.3 cm)
wide.
Sec. 14.6 Issuance of approval.
(a) MSHA will issue an approval or notice of the reasons for denying
approval after completing the evaluation and testing provided in this
part.
(b) An applicant must not advertise or otherwise represent a
conveyor belt as approved until MSHA has issued an approval.
Sec. 14.7 Approval marking and distribution records.
(a) An approved conveyor belt must be marketed only under the name
specified in the approval.
(b) Approved conveyor belt must be legibly and permanently marked
with the assigned MSHA approval number for the service life of the
product. The approval marking must be at least \1/2\ inch (1.27 cm)
high, placed at intervals not to exceed 60 feet (18.3 m) and repeated at
least once every foot (0.3 m) across the width of the belt.
(c) Where the construction of a conveyor belt does not permit
marking as prescribed above, other permanent marking may be accepted by
MSHA.
(d) Applicants granted approval must maintain records of the initial
sale of each belt having an approval marking. The records must be
retained for at least 5 years following the initial sale.
Sec. 14.8 Quality assurance.
Applicants granted an approval or an extension of approval under
this Part must:
(a) In order to assure that the finished conveyor belt will meet the
flame-resistance test--
(1) Flame test a sample of each batch, lot, or slab of conveyor
belts; or
(2) Flame test or inspect a sample of each batch or lot of the
materials that contribute to the flame-resistance characteristic.
(b) Calibrate instruments used for the inspection and testing in
paragraph (a) of this section according to the instrument manufacturer's
specifications. Instruments must be calibrated using standards set by
the National Institute of Standards and Technology, U.S. Department of
Commerce or other nationally or internationally recognized standards.
The instruments used must be accurate to at least one significant figure
beyond the desired accuracy.
(c) Control production so that the conveyor belt is manufactured in
accordance with the approval document. If a third party is assembling or
manufacturing all or part of an approved belt, the approval holder shall
assure that the product is manufactured as approved.
(d) Immediately notify the MSHA Approval and Certification Center of
any information that a conveyor belt has been distributed that does not
meet the specifications of the approval. This notification must include
a description of the nature and extent of the problem, the locations
where the conveyor belt has been distributed, and the approval holder's
plans for corrective action.
Sec. 14.9 Disclosure of information.
(a) All proprietary information concerning product specifications
and performance submitted to MSHA by the applicant will be protected.
(b) MSHA will notify the applicant or approval holder of requests
for disclosure of information concerning its conveyor belts, and provide
an opportunity to present its position prior to any decision on
disclosure.
Sec. 14.10 Post-approval product audit.
(a) Approved conveyor belts will be subject to periodic audits by
MSHA to determine conformity with the technical requirements upon which
the approval was based. MSHA will select an approved conveyor belt to be
audited; the selected belt will be representative of that distributed
for use in mines. Upon request to MSHA, the approval holder may obtain
any final report resulting from the audit.
(b) No more than once a year, except for cause, the approval holder,
at
[[Page 93]]
MSHA's request, must make 3 samples of an approved conveyor belt of the
size specified in Sec. 14.5 available at no cost to MSHA for an audit.
If a product is not available because it is not currently in production,
the manufacturer will notify MSHA when it is available. Representatives
of the applicant and other persons agreed upon by MSHA and the applicant
may be present during audit tests and evaluations. MSHA will also
consider requests by others to observe tests.
(c) A conveyor belt will be subject to audit for cause at any time
MSHA believes the approval holder product is not in compliance with the
technical requirements of the approval.
Sec. 14.11 Revocation.
(a) MSHA may revoke for cause an approval issued under this Part if
the conveyor belt--
(1) Fails to meet the technical requirements; or
(2) Creates a danger or hazard when used in a mine.
(b) Prior to revoking an approval, the approval holder will be
informed in writing of MSHA's intention to revoke. The notice will--
(1) Explain the reasons for the proposed revocation; and
(2) Provide the approval holder an opportunity to demonstrate or
achieve compliance with the product approval requirements.
(c) Upon request to MSHA, the approval holder will be given the
opportunity for a hearing.
(d) If a conveyor belt poses an imminent danger to the safety or
health of miners, an approval may be immediately suspended without
written notice of the Agency's intention to revoke.
Subpart B_Technical Requirements
Sec. 14.20 Flame resistance.
Conveyor belts for use in underground coal mines must be flame-
resistant and:
(a) Tested in accordance with Sec. 14.22 of this part; or
(b) Tested in accordance with an alternate test determined by MSHA
to be equivalent under 30 CFR Secs. 6.20 and 14.4(e).
Sec. 14.21 Laboratory-scale flame test apparatus.
The principal parts of the apparatus used to test for flame
resistance of conveyor belts are as follows--
(a) A horizontal test chamber 66 inches (167.6 cm) long by 18 inches
(45.7 cm) square (inside dimensions) constructed from 1 inch (2.5 cm)
thick Marinite I , or equivalent insulating material.
(b) A 16-gauge (0.16 cm) stainless steel duct section which tapers
over a length of at least 24 inches (61 cm) from a 20 inch (51 cm)
square cross-sectional area at the test chamber connection to a 12 inch
(30.5 cm) diameter exhaust duct, or equivalent. The interior surface of
the tapered duct section must be lined with \1/2\ inch (1.27 cm) thick
ceramic blanket insulation, or equivalent insulating material. The
tapered duct must be tightly connected to the test chamber.
(c) A U-shaped gas-fueled impinged jet burner ignition source,
measuring 12 inches (30.5 cm) long and 4 inches (10.2 cm) wide, with two
parallel rows of 6 jets each. Each jet is spaced alternately along the
U-shaped burner tube. The 2 rows of jets are slanted so that they point
toward each other and the flame from each jet impinges upon each other
in pairs. The burner fuel must be at least 98 percent methane (technical
grade) or natural gas containing at least 96 percent combustible gases,
which includes not less than 93 percent methane.
(d) A removable steel rack, consisting of 2 parallel rails and
supports that form a 7 \1/8\ inches (17.8 0.3 cm) wide by 60 \1/8\
inches (152.4 0.3 cm) long assembly to hold a belt sample.
(1) The 2 parallel rails, with a 5 \1/8\ inches (12.7 0.3 cm)
space between them, comprise the top of the rack. The rails and supports
must be constructed of slotted angle iron with holes along the top
surface.
(2) The top surface of the rack must be 8 \1/8\ inches (20.3 0.3
cm) from the inside roof of the test chamber.
[[Page 94]]
Sec. 14.22 Test for flame resistance of conveyor belts.
(a) Test procedures. The test must be conducted in the following
sequence using a flame test apparatus meeting the specifications of
Sec. 14.21:
(1) Lay three samples of the belt, 60 \1/4\ inches (152.4 0.6 cm)
long by 9 \1/8\ inches (22.9 0.3 cm) wide, flat at a temperature of 70
10 Fahrenheit (21 5 Centigrade) for at least 24 hours prior to the
test;
(2) For each of three tests, place one belt sample with the load-
carrying surface facing up on the rails of the rack so that the sample
extends 1 \1/8\ inch (2.5 0.3 cm) beyond the front of the rails and 1
\1/8\ inch (2.5 0.3 cm) from the outer lengthwise edge of each rail;
(3) Fasten the sample to the rails of the rack with steel washers
and cotter pins. The cotter pins shall extend at least \3/4\ inch (1.9
cm) below the rails. Equivalent fasteners may be used. Make a series of
5 holes approximately \9/32\ inch (0.7 cm) in diameter along both edges
of the belt sample, starting at the first rail hole within 2 inches (5.1
cm) from the front edge of the sample. Make the next hole 5 \1/4\
inches (12.7 0.6 cm) from the first, the third hole 5 \1/4\ inches
(12.7 0.6 cm) from the second, the fourth hole approximately midway
along the length of the sample, and the fifth hole near the end of the
sample. After placing a washer over each sample hole, insert a cotter
pin through the hole and spread it apart to secure the sample to the
rail;
(4) Center the rack and sample in the test chamber with the front
end of the sample 6 \1/2\ inches (15.2 1.27 cm) from the entrance;
(5) Measure the airflow with a 4-inch (10.2 cm) diameter vane
anemometer, or an equivalent device, placed on the centerline of the
belt sample 12 \1/2\ inches (30.5 1.27 cm) from the chamber entrance.
Adjust the airflow passing through the chamber to 200 20 ft/min (61 6
m/min);
(6) Before starting the test on each sample, the inner surface
temperature of the chamber roof measured at points 6 \1/2\, 30 \1/2\,
and 60 \1/2\ inches (15.2 1.27, 76.2 1.27, and 152.4 1.27 cm) from
the front entrance of the chamber must not exceed 95 Fahrenheit (35
Centigrade) at any of these points with the specified airflow passing
through the chamber. The temperature of the air entering the chamber
during the test on each sample must not be less than 50 Fahrenheit (10
Centigrade);
(7) Center the burner in front of the sample's leading edge with the
plane, defined by the tips of the burner jets, \3/4\ \1/8\ inch (1.9
0.3 cm) from the front edge of the belt;
(8) With the burner lowered away from the sample, set the gas flow
at 1.2 0.1 standard cubic feet per minute (SCFM) (34 2.8 liters per
minute) and then ignite the gas burner. Maintain the gas flow to the
burner throughout the 5 to 5.1 minute ignition period;
(9) After applying the burner flame to the front edge of the sample
for a 5 to 5.1 minute ignition period, lower the burner away from the
sample and extinguish the burner flame;
(10) After completion of each test, determine the undamaged portion
across the entire width of the sample. Blistering without charring does
not constitute damage.
(b) Acceptable performance. Each tested sample must exhibit an
undamaged portion across its entire width.
(c) MSHA may modify the procedures of the flammability test for
belts constructed of thicknesses more than \3/4\ inch (1.9 cm).
Sec. 14.23 New technology.
MSHA may approve a conveyor belt that incorporates technology for
which the requirements of this part are not applicable if the Agency
determines that the conveyor belt is as safe as those which meet the
requirements of this part.
PART 15_REQUIREMENTS FOR APPROVAL OF EXPLOSIVES AND SHEATHED EXPLOSIVE
UNITS--Table of Contents
Subpart A_General Provisions
Sec.
15.1 Purpose and effective dates.
15.2 Definitions.
15.3 Observers at tests and evaluation.
15.4 Application procedures and requirements.
15.5 Test samples.
15.6 Issuance of approval.
15.7 Approval marking.
[[Page 95]]
15.8 Quality assurance.
15.9 Disclosure of information.
15.10 Post-approval product audit.
15.11 Revocation.
Subpart B_Requirements for Approval of Explosives
15.20 Technical requirements.
15.21 Tolerances for ingredients.
15.22 Tolerances for performance, wrapper, and specific gravity.
Subpart C_Requirements for Approval of Sheathed Explosive Units or Other
Explosive Units Designed to be Fired Outside the Confines of a Borehole
15.30 Technical requirements.
15.31 Tolerances for ingredients.
15.32 Tolerances for weight of explosive, sheath, wrapper, and specific
gravity.
Authority: 30 U.S.C. 957.
Source: 53 FR 46761, Nov. 18, 1988, unless otherwise noted.
Subpart A_General Provisions
Sec. 15.1 Purpose and effective dates.
This part sets forth the requirements for approval of explosives and
sheathed explosive units to be used in underground coal mines and
certain underground metal and nonmetal gassy mines and is effective
January 17, 1989. Those manufacturers proceeding under the provisions of
the previous regulation may file requests for approval or extension of
approval of explosives under that regulation until January 17, 1990.
After January 17, 1990, all requests for approval or extension of
approval of explosives or sheathed explosive units shall be made in
accordance with Subpart A and the applicable subpart of this part.
Explosives issued an approval under regulations in place prior to
January 17, 1989, and in compliance with those regulations, may continue
to be manufactured and marked as approved as long as no change to the
explosive is made.
[53 FR 46761, Nov. 18, 1988; 54 FR 351, Jan. 5, 1989]
Sec. 15.2 Definitions.
The following definitions apply in this part.
Applicant. An individual or organization that manufactures or
controls the production of an explosive or an explosive unit and that
applies to MSHA for approval of that explosive or explosive unit.
Approval. A document issued by MSHA which states that an explosive
or explosive unit has met the requirements of this part and which
authorizes an approval marking identifying the explosive or explosive
unit as approved as permissible.
Explosive. A substance, compound, or mixture, the primary purpose of
which is to function by explosion.
Extension of approval. A document issued by MSHA which states that
the change to an explosive or explosive unit previously approved by MSHA
under this part meets the requirements of this part and which authorizes
the continued use of the approval marking after the appropriate
extension number has been added.
Minimum product firing temperature. The lowest product temperature
at which the explosive or explosive unit is approved for use under this
part.
Post-approval product audit. Examination, testing, or both, by MSHA
of approved explosives or explosive units selected by MSHA to determine
whether they meet the technical requirements and have been manufactured
as approved.
Sheath. A chemical compound or mixture incorporated in a sheathed
explosive unit and which forms a flame inhibiting cloud on detonation of
the explosive.
Sheathed explosive unit. A device consisting of an approved or
permissible explosive covered by a sheath encased in a sealed covering
and designed to be fired outside the confines of a borehole.
Test detonator. An instantaneous detonator that has a strength
equivalent to that of a detonator with a base charge of 0.40-0.45 grams
PETN.
[53 FR 46761, Nov. 18, 1988; 54 FR 351, Jan. 5, 1989]
Sec. 15.3 Observers at tests and evaluation.
Only personnel of MSHA, designees of MSHA, representatives of the
applicant, and such other persons as agreed upon by MSHA and the
applicant shall
[[Page 96]]
be present during tests and evaluations conducted under this part.
[70 FR 46342, Aug. 9, 2005]
Sec. 15.4 Application procedures and requirements.
(a) Application. Requests for an approval or an extension of
approval under this part shall be sent to: U.S. Department of Labor,
Mine Safety and Health Administration, Approval and Certification
Center, 765 Technology Drive, Triadelphia, WV 26059.
(b) Fees. Fees calculated in accordance with Part 5 of this Title
shall be submitted in accordance with Sec. 5.40.
(c) Original approval for explosives. Each application for approval
of an explosive shall include--
(1) A technical description of the explosive, including the chemical
composition of the explosive with tolerances for each ingredient;
(2) A laboratory number or other suitable designation identifying
the explosive. The applicant shall provide the brand or trade name under
which the explosive will be marketed prior to issuance of the approval;
(3) The lengths and diameters of explosive cartridges for which
approval is requested;
(4) The proposed minimum product firing temperature of the
explosive; and
(5) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(d) Original approval for sheathed explosive units. Each application
for approval of a sheathed explosive unit shall include--
(1) A technical description of the sheathed explosive unit which
includes the chemical composition of the sheath, with tolerances for
each ingredient, and the types of material used for the outer covering;
(2) The minimum thickness weight, and specific gravity of the sheath
and outer covering;
(3) The brand or trade name, weight, specific gravity, and minimum
product firing temperature of the approved explosive to be used in the
unit;
(4) The ratio of the weight of the sheath to the weight of the
explosive; and
(5) The name, address and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(e) Subsequent approval of a similar explosive or sheathed explosive
unit. Each application for approval of an explosive or sheathed
explosive unit similar to one for which the applicant already holds an
approval shall include--
(1) The approval number of the explosive or sheathed explosive unit
which most closely resembles the new one;
(2) The information specified in paragraphs (c) and (d) of this
section for an original approval, as applicable, except that any
document which is the same as the one listed by MSHA in the prior
approval need not be submitted but shall be noted in the application;
and
(3) An explanation of all changes from the existing approval.
(f) Extension of the approval. Any change in an approved explosive
or sheathed explosive unit from the documentation on file at MSHA that
affects the technical requirements of this Part shall be submitted for
approval prior to implementing the change.
(1) Each application for an extension of approval shall include--
(i) The MSHA-assigned approval number for the explosive or sheathed
explosive unit for which the extension is sought;
(ii) A description of the proposed change to the approved explosive
or sheathed explosive unit; and
(iii) The name, address, and telephone number of the applicant's
representative responsible for answering any questions regarding the
application.
(2) MSHA will determine what tests, additional information, samples,
or material, if any, are required to evaluate the proposed change.
(3) When a change involves the chemical composition of an approved
explosive or sheathed explosive unit which affects the firing
characteristics, MSHA may require the explosive or sheathed explosive
unit to be distinguished from those associated with the former
composition.
[53 FR 46761, Nov. 18, 1988; 54 FR 351, Jan. 5, 1989; 60 FR 33723, June
29, 1995; 73 FR 52211, Sept. 9, 2008]
[[Page 97]]
Sec. 15.5 Test samples.
(a) Submission of test samples. (1) The applicant shall not submit
explosives or sheathed explosive units to be tested until requested to
do so by MSHA.
(2) The applicant shall submit 70 pounds of 1\1/4\-inch diameter
explosives and additional cartridges in the amount of 3200 divided by
the length in inches, except for cartridges 12, 20 and greater than 36
inches long. The applicant shall submit 70 pounds and additional
cartridges in the amount of 3800 divided by the length in inches for
cartridges 12, 20 and greater than 36 inches long.
(3) If approval is requested for cartridges in diameters less than
1-\1/4\ inches, the applicant shall submit a number of cartridges equal
to 1800 divided by the length in inches, except for cartridges 12, 20
and greater than 36 inches long. The applicant shall submit cartridges
in the amount of 2200 divided by the length in inches for cartridges 12,
20 and greater than 36 inches long.
(4) If approval is requested for cartridges in diameters larger than
1-\1/4\ inches, the applicant shall submit an additional 10 cartridges
of each larger diameter.
(5) If approval is requested for cartridges in more than one length,
the applicant shall submit an additional 10 cartridges for each
additional length and diameter combination.
(6) Each applicant seeking approval of sheathed explosive units
shall submit 140 units.
(b) Condition and composition. Explosives and sheathed explosive
units will not be tested that--
(1) Contain chlorites, chlorates, or substances that will react over
an extended time and cause degradation of the explosive or sheathed
explosive unit;
(2) Are chemically unstable;
(3) Show leakage;
(4) Use aluminum clips to seal the cartridge;
(5) Contain any combination of perchlorate and aluminum;
(6) Contain more than 5 percent perchlorate; or
(7) Contain any perchlorate and less than 5 percent water.
(c) Storage. Explosives and sheathed explosive units shall be stored
in a magazine for at least 30 days before gallery tests are conducted.
Sec. 15.6 Issuance of approval.
(a) MSHA will issue an approval or a notice of the reasons for
denying approval after completing the evaluation and testing provided
for by this part.
(b) An applicant shall not advertise or otherwise represent an
explosive or sheathed explosive unit as approved until MSHA has issued
an approval.
Sec. 15.7 Approval marking.
(a) An approved explosive or sheathed explosive unit shall be
marketed only under the brand or trade name specified in the approval.
(b) The wrapper of each cartridge and each case of approved
explosives shall be legibly labeled with the following: the brand or
trade name, ``MSHA Approved Explosive'', the test detonator strength,
and the minimum product firing temperature.
(c) The outer covering of each sheathed explosive unit and each case
of approved sheathed explosive units shall be legibly labeled with the
following: the brand or trade name, ``MSHA Approved Sheathed Explosive
Unit'', the test detonator strength, and the minimum product firing
temperature.
[53 FR 46761, Nov. 18, 1988; 54 FR 351, Jan. 5, 1989; 54 FR 27641, June
30, 1989; 60 FR 33723, June 29, 1995]
Sec. 15.8 Quality assurance.
(a) Applicants granted an approval or an extension of approval under
this part shall manufacture the explosive or sheathed explosive unit as
approved.
(b) Applicants shall immediately report to the MSHA Approval and
Certification Center, any knowledge of explosives or sheathed explosive
units that have been distributed that do not meet the specifications of
the approval.
[53 53 FR 46761, Nov. 18, 1988, as amended at 60 FR 33723, June 29,
1995]
Sec. 15.9 Disclosure of information.
(a) All information concerning product specifications and
performance submitted to MSHA by the applicant
[[Page 98]]
shall be considered proprietary information.
(b) MSHA will notify the applicants of requests for disclosure of
information concerning its explosives or sheathed explosive units and
shall give the applicant an opportunity to provide MSHA with a statement
of its position prior to any disclosure.
Sec. 15.10 Post-approval product audit.
(a) Approved explosives and sheathed explosive units shall be
subject to periodic audits by MSHA for the purpose of determining
conformity with the technical requirements upon which the approval was
based. Any approved explosive or sheathed explosive unit which is to be
audited shall be selected by MSHA and be representative of those
distributed for use in mines. The approval-holder may obtain any final
report resulting from such audit.
(b) No more than once a year, except for cause, the approval-holder,
at MSHA's request, shall make one case of explosives or 25 sheathed
explosive units available at no cost to MSHA for an audit. The approval-
holder may observe any tests conducted during this audit.
(c) An approved explosive or sheathed explosive unit shall be
subject to audit for cause at any time MSHA believes that it is not in
compliance with the technical requirements upon which the approval was
based.
(d) Explosives approved under regulations in effect prior to January
17, 1989, shall conform to the provisions on field samples set out in
those regulations (See 30 CFR part 15, 1987 edition).
Sec. 15.11 Revocation.
(a) MSHA may revoke for cause an approval issued under this part if
the explosive or sheathed explosive unit--
(1) Fails to meet the applicable technical requirements; or
(2) Creates a hazard when used in a mine.
(b) Prior to revoking an approval, the approval-holder shall be
informed in writing of MSHA's intention to revoke. The notice shall--
(1) Explain the specific reasons for the proposed revocation; and
(2) Provide the approval-holder an opportunity to demonstrate or
achieve compliance with the product approval requirements.
(c) Upon request, the approval-holder shall be afforded an
opportunity for a hearing.
(d) If an explosive or sheathed explosive unit poses an imminent
hazard to the safety or health of miners, the approval may be
immediately suspended without a written notice of the agency's intention
to revoke. The suspension may continue until the revocation proceedings
are completed.
Subpart B_Requirements for Approval of Explosives
Sec. 15.20 Technical requirements.
(a) Chemical composition. The chemical composition of the explosive
shall be within the tolerances furnished by the applicant.
(b) Rate-of-detonation test. The explosive shall propagate
completely in the rate-of-detonation tesst. The test is conducted at an
ambient temperature between 68 and 86 F. Nongelatinous explosives are
initiated with a test detonator only, while gelatinous explosives are
initiated with a test detonator and a 60-gram tetryl pellet booster. The
test is conducted on--
(1) A 50-inch column of 1\1/4\ inch diameter cartridges; and
(2) A 50-inch column of the smallest diameter cartridges less than
1\1/4\ inches submitted for testing.
(c) Air-gap sensitivity. The air-gap sensitivity of the explosive
shall be at least 2 inches at the minimum product firing temperature and
3 inches at a temperature between 68 and 86 F, and the explosive shall
propagate completely.
(1) Air-gap sensitivity of the explosive is determined in the
explosion-by-influence test using the 7-inch cartridge method. The air-
gap sensitivity is determined for 1\1/4\ inch diameter cartridges and
each cartridge diameter smaller than 1\1/4\ inches. Explosives are
initiated with a test detonator.
(2) The 7-inch cartridge method is conducted with two 8-inch
cartridges. One inch is cut off the end of each cartridge. The
cartridges are placed in a paper tube, the cut ends facing each other,
with the appropriate 2-inch or 3-inch air gap between them. The test is
[[Page 99]]
conducted at a temperature between 68 and 86 F and at the minimum
product firing temperature proposed by the applicant, or 41 F,
whichever is lower. The test temperature at which the explosive
propagates completely will be specified in the approval as the minimum
product firing temperature at which the explosive is approved for use.
(d) Gallery Test 7. The explosive shall yield a value of at least
450 grams for the lower 95 percent confidence limit (L95) on
the weight for 50 percent probability of ignition (W50) in
gallery test 7 and shall propagate completely. The L95 and
W50 values for the explosive are determined by using the
Bruceton up-and-down method. A minimum of 20 trials are made with
explosive charges of varying weights, including wrapper and seals. Each
charge is primed with a test detonator, then tamped and stemmed with one
pound of dry-milled fire clay into the borehole of a steel cannon. The
cannon is fired into air containing 7.7 to 8.3 percent of natural gas.
The air temperature is between 68 and 86 F.
(e) Gallery Test 8. The explosive shall yield a value of at least
350 grams for the weight for 50 percent probability of ignition
(WCDG) in gallery test 8 and shall propagate completely. The
(WCDG) value for the explosive is determined using the
Bruceton up-and-down method. A minimum of 10 tests are made with
explosive charges of varying weights, including wrapper and seals. Each
charge is primed with a test detonator, then tamped into the borehole of
a steel cannon. The cannon is fired into a mixture of 8 pounds of
bituminous coal dust predispersed into 640 cubic feet of air containing
3.8 to 4.2 percent of natural gas. The air temperature is between 68 and
86 F.
(f) Pendulum-friction test. The explosive shall show no perceptible
reaction in the pendulum-friction test with the hard fiber-faced shoe.
Ten trials of the test are conducted by releasing the steel shoe from a
height of 59 inches. If there is evidence of sensitivity, the test is
repeated with the hard fiber-faced shoe.
(g) Toxic gases. The total volume equivalent to carbon monoxide (CO)
of toxic gases produced by detonation of the explosive shall not exceed
2.5 cubic feet per pound of explosive as determined in the large chamber
test. The explosive shall propagate completely.
(1) The large chamber test is conducted with a one-pound explosive
charge, including wrapper and seal, primed with a test detonator. The
explosive charge is loaded into the borehole of a steel cannon, then
tamped and stemmed with one pound of dry-milled fire clay. The cannon is
fired into the large chamber and the gaseous products resulting from
detonation of the explosive are collected and analyzed for toxic gases.
At least two trials are conducted.
(2) The equivalent volume of each toxic gas produced, relative to
CO, is determined by multiplying the measured volume of the gas by a
conversion factor. The conversion factor is equal to the threshold limit
value, time weighted average (TLV-TWA) in parts-per-million for CO
divided by the TLV-TWA for the toxic gas. The TLV-TWA conversion factor
for each gas for which MSHA shall test is specified in Table I of this
subpart. The total volume equivalent to CO of the toxic gases produced
by detonation of the explosive is the sum of the equivalent volumes of
the individual toxic gases.
Table I--Conversion Factors for Toxic Gases
[For Equivalent Volume Relative to Carbon Monoxide]
------------------------------------------------------------------------
Toxic Gas
----------------------
Conversion TLV-TWA
Factor (PPM)
------------------------------------------------------------------------
Ammonia.......................................... 2 25
Carbon Dioxide................................... 0.01 5000
Carbon Monoxide.................................. 1 50
Hydrogen Sulfide................................. 5 10
Nitric Oxide..................................... 2 25
Nitrogen Dioxide................................. 17 3
Sulfur Dioxide................................... 25 2
------------------------------------------------------------------------
(h) Cartridge diameter and length changes. (1) For proposed changes
to an approved explosive involving only cartridge diameter or length,
MSHA will determine what tests, if any, will be required.
(2) When a proposed change to an approved explosive involves a
smaller diameter than that specified in the approval, the rate-of-
detonation and air-gap sensitivity tests will be conducted.
[[Page 100]]
(3) No test will be conducted on cartridges with diameters the same
as or smaller than those that previously failed to detonate in the rate-
of-detonation test.
(i) New technology. MSHA may approve an explosive that incorporates
technology for which the requirements of this subpart are not applicable
if MSHA determines that the explosive is as safe as those which meet the
requirements of this subpart.
Sec. 15.21 Tolerances for ingredients.
Tolerances for each ingredient in an explosive, which are expressed
as a percentage of the total explosive, shall not exceed the following:
(a) Physical sensitizers: The tolerances established by the
applicant;
(b) Aluminum: 0.7 percent;
(c) Carbonaceous materials: 3 percent; and
(d) Moisture and ingredients other than specified in paragraphs (a),
(b), and (c) of this section: The tolerances specified in Table II.
Table II--Tolerances for Moisture and Other Ingredients
------------------------------------------------------------------------
Quantity of ingredients (as percent of total explosive or Tolerance
sheath) percent
------------------------------------------------------------------------
0 to 5.0................................................... 1.2
5.1 to 10.0................................................ 1.5
10.1 to 20.0............................................... 1.7
20.1 to 30.0............................................... 2.0
30.1 to 40.0............................................... 2.3
40.1 to 50.0............................................... 2.5
50.1 to 55.0............................................... 2.8
55.1 to 100.0.............................................. 3.0
------------------------------------------------------------------------
Sec. 15.22 Tolerances for performance, wrapper, and specific gravity.
(a) The rate of detonation of the explosive shall be within 15
percent of that specified in the approval.
(b) The weight of wrapper per 100 grams of explosive shall be within
2 grams of that specified in the approval.
(c) The apparent specific gravity of the explosive shall be within
7.5 percent of that specified in the approval.
Subpart C_Requirements for Approval of Sheathed Explosive Units or Other
Explosive Units Designed to be Fired Outside the Confines of a Borehole
Sec. 15.30 Technical requirements.
(a) Quantity of explosive. The sheathed explosive unit shall contain
not more than 1\1/2\ pounds of an approved or permissible explosive.
(b) Chemical composition. The chemical composition of the sheath
shall be within the tolerances furnished by the applicant.
(c) Detonator well. The sheathed explosive unit shall have a
detonator well that--
(1) Is protected by a sealed covering;
(2) Permits an instantaneous detonator to be inserted in the unit
with the detonator completely embedded in the well;
(3) Is provided with a means of securing the detonator in the well;
and
(4) Is clearly marked.
(d) Drop test. The outer covering of the sheathed explosive unit
shall not tear or rupture and the internal components shall not shift
position or be damaged in the drop test.
(1) The drop test is conducted on at least 10 sheathed explosive
units. Each unit is dropped on its top, bottom, and edge from a height
of 6 feet onto a concrete surface. For units with explosives approved
with a minimum product firing temperature, the drop test is performed
with the unit at the minimum product firing temperature established for
the explosive in the unit. For units with explosives approved under
regulations in effect prior to January 17, 1989, the drop test is
performed with the unit at 41 F.
(2) At least four units which have been drop-tested shall be cut-
open and examined.
(3) At least six units which have been drop-tested shall be
subjected to gallery tests 9 and 10 as provided in paragraphs (e)(1) and
(e)(2) of this section.
(e) Gallery tests. No sheathed explosive unit shall cause an
ignition in gallery tests 9, 10, 11, or 12. Ten trials in each gallery
test shall be conducted and each sheathed explosive unit shall propagate
completely in all tests.
[[Page 101]]
(1) Gallery test 9 is conducted in each trial with three sheathed
explosive units placed in a row 2 feet apart. One of the trials is
conducted with sheathed explosive units which have been subjected to the
drop test as provided in paragraph (d)(3) of this section. The units are
placed on a concrete slab, primed with test detonators and fired in air
containing 7.7 to 8.3 percent natural gas or 8.7 to 9.3 percent methane.
The air temperature is between 41 and 86 F.
(2) Gallery test 10 is conducted in each trial with three sheathed
explosive units placed in a row 2 feet apart. One of the trials is
conducted with sheathed explosive units which have been subjected to the
drop test as provided in paragraph (d)(3) of this section. The units are
placed on a concrete slab, primed with test detonators and fired in air
containing 3.8 to 4.2 percent natural gas, or 4.3 to 4.7 percent
methane, mixed with 0.2 ounces per cubic foot of predispersed bituminous
coal dust. The air temperature is between 41 and 86 F.
(3) Gallery test 11 is conducted in each trial with three sheathed
explosive units arranged in a triangular pattern with the units in
contact with each other. The units are placed in a simulated crevice
formed between two square concrete slabs, each measuring 24 inches on a
side and 2 inches in thickness. The crevice is formed by placing one
slab on top of the other and raising the edge of the upper slab at least
4 inches. The sheathed explosive units are primed with test detonators
and fired in air containing 7.7 to 8.3 percent natural gas or 8.7 to 9.3
percent methane. The air temperature is between 41 and 86 F.
(4) Gallery test 12 is conducted in each trial with three sheathed
explosive units arranged in a triangular pattern with the units in
contact with each other. The units are placed in a corner formed by
three square steel plates, each measuring 24 inches on a side and one
inch in thickness. The sheathed explosive units are primed with test
detonators and fired in air containing 7.7 to 8.3 percent natural gas or
8.7 to 9.3 percent methane. The air temperature is between 41 and 86 F.
(f) Detonation test. Each of ten sheathed explosive units shall
propagate completely when fired at the minimum product firing
temperature for the explosive used in the unit or 41 F for units with
explosives approved under regulations in effect prior to January 17,
1989. The units are initiated with test detonators.
(g) New technology. MSHA may approve an explosive unit designed to
be fired outside the confines of a borehole that incorporates technology
for which the requirements of this subpart are not applicable if MSHA
determines that such explosive unit is as safe as those which meet the
requirements of this subpart.
[53 FR 46761, Nov. 18, 1988; 54 FR 351, Jan. 5, 1989]
Sec. 15.31 Tolerances for ingredients.
Tolerances established by the applicant for each ingredient in the
sheath shall not exceed the tolerances specified in Table II Sec. 15.21
of this part.
Sec. 15.32 Tolerances for weight of explosive, sheath, wrapper,
and specific gravity.
(a) The weight of the explosive, the sheath, and the outer covering
shall each be within 7.5 percent of that specified in the approval.
(b) The ratio of the weight of the sheath to that of the explosive
shall be within 7.5 percent of that specified in the approval.
(c) The specific gravity of the explosive and sheath shall be within
7.5 percent of that specified in the approval.
PART 18_ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES--
Table of Contents
Subpart A_General Provisions
Sec.
18.1 Purpose.
18.2 Definitions.
18.3 Consultation.
18.4 Electrical equipment for which approval is issued.
18.5 Equipment for which certification will be issued.
18.6 Applications.
18.7 [Reserved]
18.8 Date for conducting investigation and tests.
[[Page 102]]
18.9 Conduct of investigations and tests.
18.10 Notice of approval or disapproval.
18.11 Approval plate.
18.12 Letter of certification.
18.13 Certification plate.
18.14 Identification of tested noncertified explosion-proof enclosures.
18.15 Changes after approval or certification.
18.16 Withdrawal of approval, certification, or acceptance.
Subpart B_Construction and Design Requirements
18.20 Quality of material, workmanship, and design.
18.21 Machines equipped with powered dust collectors.
18.22 Boring-type machines equipped for auxiliary face ventilation.
18.23 Limitation of external surface temperatures.
18.24 Electrical clearances.
18.25 Combustible gases from insulating material.
18.26 Static electricity.
18.27 Gaskets.
18.28 Devices for pressure relief, ventilation, or drainage.
18.29 Access openings and covers, including unused lead-entrance holes.
18.30 Windows and lenses.
18.31 Enclosures--joints and fastenings.
18.32 Fastenings--additional requirements.
18.33 Finish of surface joints.
18.34 Motors.
18.35 Portable (trailing) cables and cords.
18.36 Cables between machine components.
18.37 Lead entrances.
18.38 Leads through common walls.
18.39 Hose conduit.
18.40 Cable clamps and grips.
18.41 Plug and receptacle-type connectors.
18.42 Explosion-proof distribution boxes.
18.43 Explosion-proof splice boxes.
18.44 Non-intrinsically safe battery-powered equipment.
18.45 Cable reels.
18.46 Headlights.
18.47 Voltage limitation.
18.48 Circuit-interrupting devices.
18.49 Connection boxes on machines.
18.50 Protection against external arcs and sparks.
18.51 Electrical protection of circuits and equipment.
18.52 Renewal of fuses.
18.53 High-voltage longwall mining systems.
18.54 High-voltage continuous mining machines.
Subpart C_Inspections and Tests
18.60 Detailed inspection of components.
18.61 Final inspection of complete machine.
18.62 Tests to determine explosion-proof characteristics.
18.63 [Reserved]
18.65 Flame test of hose.
18.66 Tests of windows and lenses.
18.67 Static-pressure tests.
18.68 Tests for intrinsic safety.
18.69 Adequacy tests.
Subpart D_Machines Assembled With Certified or Explosion-Proof
Components, Field Modifications of Approved Machines, and Permits To Use
Experimental Equipment
18.80 Approval of machines assembled with certified or explosion-proof
components.
18.81 Field modification of approved (permissible) equipment;
application for approval of modification; approval of plans
for modification before modification.
18.82 Permit to use experimental electric face equipment in a gassy
mine or tunnel.
Appendix I to Subpart D J of Part 18--List of Tables
Appendix II to Subpart D J of Part 18--List of Figures
Subpart E_Field Approval of Electrically Operated Mining Equipment
18.90 Purpose.
18.91 Electric equipment for which field approvals will be issued.
18.92 Quality of material and design.
18.93 Application for field approval; filing procedures.
18.94 Application for field approval; contents of application.
18.95 Approval of machines constructed of components approved, accepted
or certified under Bureau of Mines Schedule 2D, 2E, 2F, or 2G.
18.96 Preparation of machines for inspection; requirements.
18.97 Inspection of machines; minimum requirements.
18.98 Enclosures, joints, and fastenings; pressure testing.
18.99 Notice of approval or disapproval; letters of approval and
approval plates.
Authority: 30 U.S.C. 957, 961.
Source: 33 FR 4660, Mar. 19, 1968, unless otherwise noted.
Subpart A_General Provisions
Sec. 18.1 Purpose.
The regulations in this part set forth the requirements to obtain
MSHA: Approval of electrically operated machines and accessories
intended for use in gassy mines or tunnels, certification of components
intended for use on or with approved machines, permission to
[[Page 103]]
modify the design of an approved machine or certified component,
acceptance of flame-resistant hoses, sanction for use of experimental
machines and accessories in gassy mines or tunnels; also, procedures for
applying for such approval, certification, acceptance for listing.
[43 FR 12313, Mar. 24, 1978, as amended at 52 FR 17514, May 8, 1987; 57
FR 61223, Dec. 23, 1992; 73 FR 80611, Dec. 31, 2008]
Sec. 18.2 Definitions.
As used in this part--
Acceptance means written notification by MSHA that a hose has met
the applicable requirements of this part and will be listed by MSHA as
acceptable flame-resistant auxiliary equipment.
Acceptance marking means an identifying marking indicating that the
hose has been accepted by MSHA for listing as flame resistant.
Accessory means associated electrical equipment, such as a
distribution or splice box, that is not an integral part of an approved
(permissible) machine.
Afterburning means the combustion of a flammable mixture that is
drawn into a machine compartment after an internal explosion in the
compartment.
Applicant means an individual, partnership, company, corporation,
organization, or association that designs, manufactures, assembles, or
controls the assembly of an electrical machine or accessory and seeks
approval, certification, or permit, or MSHA acceptance for listing of
flame-resistant hose.
Approval means a formal document issued by MSHA which states that a
completely assembled electrical machine or accessory has met the
applicable requirements of this part and which authorizes the attachment
of an approval plate so indicating.
Approval plate means a metal plate, the design of which meets MSHA's
requirements, for attachment to an approved machine or accessory,
identifying it as permissible for use in gassy mines or tunnels.
Assistant Secretary means the Assistant Secretary of Labor for Mine
Safety and Health.
Branch circuit means an electrical circuit connected to the main
circuit, the conductors of which are of smaller size than the main
circuit.
Bureau means the U.S. Bureau of Mines.
Certification means a formal written notification, issued by MSHA,
which states that an electrical component complies with the applicable
requirements of this part and, therefore, is suitable for incorporation
in approved (permissible) equipment.
Certification label means a plate, label, or marking, the design of
which meets MSHA's requirements, for attachment to a certified component
identifying the component as having met the MSHA's requirements for
incorporation in a machine to be submitted for approval.
Component means an integral part of an electrical machine or
accessory that is essential to the functioning of the machine or
accessory.
Connection box (also known as conduit or terminal box) means an
enclosure mounted on an electrical machine or accessory to facilitate
wiring, without the use of external splices. (Such boxes may have a
joint common with an explosion-proof enclosure provided the adjoining
surfaces conform to the requirements of subpart B of this part.)
Cylindrical joint means a joint comprised of two contiguous,
concentric, cylindrical surfaces.
Distribution box means an enclosure through which one or more
portable cables may be connected to a source of electrical energy, and
which contains a short-circuit protective device for each outgoing
cable.
Experimental equipment means any electrical machine or accessory
that an applicant or MSHA may desire to operate experimentally for a
limited time in a gassy mine or tunnel. (For example, this might include
a machine constructed at a mine, an imported machine, or a machine or
device designed and developed by MSHA.)
Explosion-proof enclosure means an enclosure that complies with the
applicable design requirements in subpart B of this part and is so
constructed that it will withstand internal explosions of methane-air
mixtures: (1) Without damage to or excessive distortion of its
[[Page 104]]
walls or cover(s), and (2) without ignition of surrounding methane-air
mixtures or discharge of flame from inside to outside the enclosure.
Flame-arresting path means two or more adjoining or adjacent
surfaces between which the escape of flame is prevented.
Flame resistant as applied to cable, hose, and insultating materials
means material that will burn when held in a flame but will cease
burning when the flame is removed.
Flammable mixture means a mixture of methane or natural gas and air
that when ignited will propagate flame. Natural gas containing a high
percentage of methane is a satisfactory substitute for pure methane in
most tests.
Gassy mine means a coal mine classed as ``gassy'' by MESA or by the
State in which the mine is situated.
Incendive arc or spark means an arc or spark releasing enough
electrical or thermal energy to ignite a flammable mixture of the most
easily ignitable composition.
Intrinsically safe means incapable of releasing enough electrical or
thermal energy under normal or abnormal conditions to cause ignition of
a flammable mixture of methane or natural gas and air of the most easily
ignitable composition.
MESA means the United States Department of the Interior, Mining
Enforcement and Safety Administration. Predecessor organization to MSHA,
prior to March 9, 1978.
Mobile equipment means equipment that is self-propelled.
MSHA means the United States Department of Labor, Mine Safety and
Health Administration.
Normal operation means the regular performance of those functions
for which a machine or accessory was designed.
Permissible equipment means a completely assembled electrical
machine or accessory for which a formal approval has been issued, as
authorized by the Administrator, Mining Enforcement and Safety
Administration under the Federal Coal Mine Health and Safety Act of 1969
(Pub. L. 91-173, 30 U.S.C. 801 or, after March 9, 1978, by the Assistant
Secretary under the Federal Mine Safety and Health Act of 1977 (Pub. L.
91-173, as amended by Pub. L. 95-164, 30 U.S.C. 801).
Permit means a formal document, signed by the Assistant Secretary,
authorizing the operation of specific experimental equipment in a gassy
mine or tunnel under prescribed conditions.
Plane joint means two adjoining surfaces in parallel planes.
Portable cable, or trailing cable means a flame-resistant, flexible
cable or cord through which electrical energy is transmitted to a
permissible machine or accessory. (A portable cable is that portion of
the power-supply system between the last short-circuit protective
device, acceptable to MSHA, in the system and the machine or accessory
to which it transmits electrical energy.)
Portable equipment means equipment that may be moved frequently and
is constructed or mounted to facilitate such movement.
Potted component means a component that is entirely embedded in a
solidified insulating material within an enclosure.
Pressure piling means the development of abnormal pressure as a
result of accelerated rate of burning of a gas-air mixture. (Frequently
caused by restricted configurations within enclosures.)
Qualified representative means a person authorized by MSHA to
determine whether the applicable requirements of this part have been
complied with in the original manufacture, rebuilding, or repairing of
equipment for which approval, certification, or a permit is sought.
Splice box means a portable enclosure in which electrical conductors
may be joined.
Step (rabbet) joint means a joint comprised of two adjoining
surfaces with a change(s) in direction between its inner and outer
edges. (A step joint may be composed of a cylindrical portion and a
plane portion or of two or more plane portions.)
Threaded joint means a joint consisting of a male- and a female-
threaded member, both of which are of the same type and gage.
[33 FR 4660, Mar. 19, 1968, as amended at 39 FR 23999, June 28, 1974; 43
FR 12314, Mar. 24, 1978; 57 FR 61223, Dec. 23, 1992; 73 FR 80611, Dec.
31, 2008]
[[Page 105]]
Sec. 18.3 Consultation.
By appointment, applicants or their representatives may visit the
U.S. Department of Labor, Mine Safety and Health Administration,
Approval and Certification Center, 765 Technology Drive, Triadelphia, WV
26059, to discuss a proposed design to be submitted for approval,
certification, or acceptance for listing. No charge is made for such
consultation and no written report thereof will be made to the
applicant.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 73
FR 52211, Sept. 9, 2008]
Sec. 18.4 Electrical equipment for which approval is issued.
An approval will be issued only for a complete electrical machine or
accessory. Only components meeting the requirements of subpart B of this
part or those approved under part 7 of this chapter, unless they contain
intrinsically safe circuits, shall be included in the assemblies.
[57 FR 61209, Dec. 23, 1992]
Sec. 18.5 Equipment for which certification will be issued.
Certification will be issued for a component or subassembly suitable
to incorporate in an approved machine. Certification may be issued for
such components as explosion-proof enclosures, battery trays, and
connectors.
Sec. 18.6 Applications.
(a)(1) Investigation leading to approval, certification, extension
thereof, or acceptance of hose will be undertaken by MSHA only pursuant
to a written application. The application shall be accompanied by all
necessary drawings, specifications, descriptions, and related materials,
as set out in this part. Fees calculated in accordance with part 5 of
this title shall be submitted in accordance with Sec. 5.40.
(2) Where the applicant for approval has used an independent testing
laboratory under part 6 of this chapter to perform, in whole or in part,
the necessary testing and evaluation for approval under this part, the
applicant must provide to MSHA as part of the approval application:
(i) Written evidence of the laboratory's independence and current
recognition by a laboratory accrediting organization;
(ii) Complete technical explanation of how the product complies with
each requirement in the applicable MSHA product approval requirements;
(iii) Identification of components or features of the product that
are critical to the safety of the product; and
(iv) All documentation, including drawings and specifications, as
submitted to the independent laboratory by the applicant and as required
by this part.
(3) An applicant may request testing and evaluation to non-MSHA
product safety standards which have been determined by MSHA to be
equivalent, under Sec. 6.20 of this chapter, to MSHA's product approval
requirements under this part. A listing of all equivalency
determinations will be published in 30 CFR part 6 and the applicable
approval parts. The listing will state whether MSHA accepts the non-MSHA
product safety standards in their original form, or whether MSHA will
require modifications to demonstrate equivalency. If modifications are
required, they will be provided in the listing. MSHA will notify the
public of each equivalency determination and will publish a summary of
the basis for its determination. MSHA will provide equivalency
determination reports to the public upon request to the Approval and
Certification Center. MSHA has made the following equivalency
determinations applicable to this part 18.
(i) MSHA will accept applications for explosion-proof enclosures
under part 18 designed and tested to the International Electrotechnical
Commission's (IEC) standards for Electrical Apparatus for Explosive Gas
Atmospheres, Part 0, General Requirements (IEC 60079-0, Fourth Edition,
2004-01); and Part 1, Electrical Apparatus for Explosive Gas
Atmospheres, Flameproof Enclosures ``d'' (IEC 60079-1, Fifth Edition,
2003-11) (which are hereby incorporated by reference and made a part
hereof) provided the modifications to the IEC standards specified in
Sec. 18.6(a)(3)(i)(A) through (I) are met. The Director of the Federal
Register
[[Page 106]]
approves this incorporation by reference in accordance with 5 U.S.C.
552(a) and 1 CFR part 51. The IEC standards may be inspected at the U.S.
Department of Labor, Mine Safety and Health Administration, Electrical
Safety Division, Approval and Certification Center, 765 Technology
Drive, Triadelphia, WV 26059, or at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/
federal_register/code_of_federal_regulations/ibr_locations.html. These
IEC standards may be obtained from International Electrical Commission,
Central Office 3, rue de Varembe, P.O. Box 131, CH-1211 GENEVA 20,
Switzerland.
(A) Enclosures shall be made of metal and not have a compartment
exceeding ten (10) feet in length. Glass or polycarbonate materials
shall be the only materials utilized in the construction of windows and
lenses. External surfaces of enclosures shall not exceed 150 C (302 F)
and internal surface temperatures of enclosures with polycarbonate
windows and lenses shall not exceed 115 C (240 F), in normal
operation. Other non-metallic materials for enclosures or parts of
enclosures will be evaluated, on a case-by-case basis, under the new
technology provisions in Sec. 18.20(b) of this part.
(B) Enclosures shall be rugged in construction and should meet
existing requirements for minimum bolt size and spacing and for minimum
wall, cover, and flange thicknesses specified in paragraph (g)(19) of
Sec. 7.304 Technical requirements. Enclosure fasteners should be uniform
in size and length, be provided at all corners, and be secured from
loosening by lockwashers or equivalent. An engineering analysis shall be
provided for enclosure designs that deviate from the existing
requirements. The analysis shall show that the proposed enclosure design
meets or exceeds the mechanical strength of a comparable enclosure
designed to 150 psig according to existing requirements, and that
flamepath clearances in excess of existing requirements will not be
produced at an internal pressure of 150 psig. This shall be verified by
explosion testing the enclosure at a minimum of 150 psig.
(C) Enclosures shall be designed to withstand a minimum pressure of
at least 150 psig without leakage through any welds or castings, rupture
of any part that affects explosion-proof integrity, clearances exceeding
those permitted under existing requirements along flame-arresting paths,
or permanent distortion exceeding 0.040-inch per linear foot.
(D) Flamepath clearances, including clearances between fasteners and
the holes through which they pass, shall not exceed those specified in
existing requirements. No intentional gaps in flamepaths are permitted.
(E) The minimum lengths of the flame arresting paths, based on
enclosure volume, shall conform to those specified in existing
requirements to the nearest metric equivalent value (e.g., 12.5 mm, 19
mm, and 25 mm are considered equivalent to \1/2\ inch, \3/4\ inch and 1
inch respectively for plane and cylindrical joints). The widths of any
grooves for o-rings shall be deducted in measuring the widths of flame-
arresting paths.
(F) Gaskets shall not be used to form any part of a flame-arresting
path. If o-rings are installed within a flamepath, the location of the
o-rings shall meet existing requirements.
(G) Cable entries into enclosures shall be of a type that utilizes
either flame-resistant rope packing material or sealing rings
(grommets). If plugs and mating receptacles are mounted to an enclosure
wall, they shall be of explosion-proof construction. Insulated bushings
or studs shall not be installed in the outside walls of enclosures. Lead
entrances utilizing sealing compounds and flexible or rigid metallic
conduit are not permitted.
(H) Unused lead entrances shall be closed with a metal plug that is
secured by spot welding, brazing, or equivalent.
(I) Special explosion tests are required for explosion-proof
enclosures that share leads (electric conductors) through a common wall
with another explosion-proof enclosure. These tests are required to
determine the presence of pressure piling conditions in either
[[Page 107]]
enclosure when one or more of the insulating barriers, sectionalizing
terminals, or other isolating parts are sequentially removed from the
common wall between the enclosures. Enclosures that exhibit pressures
during these tests that exceed those specified in existing requirements
must be provided with a warning tag. The durable warning tag must
indicate that the insulating barriers, sectionalizing terminals, or
other isolating parts be maintained in order to insure the explosion-
proof integrity for either enclosure sharing a common wall. A warning
tag is not required if the enclosures withstand a static pressure of
twice the maximum value observed in the explosion tests.
(ii) [Reserved]
(4) The application, all related documents, and all correspondence
concerning it shall be addressed to the U.S. Department of Labor, Mine
Safety and Health Administration, Approval and Certification Center, 765
Technology Drive, Triadelphia, WV 26059.
(b)-(c) [Reserved]
(d) Applications for acceptance of hose as flame resistant shall
include the following information: Trade name of hose, identification of
materials used, including compound numbers, thickness of cover,
thickness of tube, and number and weight of plies. The applicant shall
provide other description or specifications as may be subsequently
required.
(e) Drawings, drawing lists, specifications, wiring diagram, and
descriptions shall be adequate in number and detail to identify fully
the complete assembly, component parts, and subassemblies. Drawings
shall be titled, numbered, dated and shall show the latest revision.
Each drawing shall include a warning statement that changes in design
must be authorized by MSHA before they are applied to approved
equipment. When intrinsically safe circuits are incorporated in a
machine or accessory, the wiring diagram shall include a warning
statement that any change(s) in the intrinsically safe circuitry or
components may result in an unsafe condition. The specifications shall
include an assembly drawing(s) (see Figure 1 in Appendix II) showing the
overall dimensions of the machine and the identity of each component
part which may be listed thereon or separately, as in a bill of material
(see Figure 2 in Appendix II). MSHA may accept photographs (minimum size
8" x 10\1/2\") in lieu of assembly drawing(s). Purchased parts shall
be identified by the manufacturer's name, catalog number(s), and
rating(s). In the case of standard hardware and miscellaneous parts,
such as insulating pieces, size and kind of material shall be specified.
All drawings of component parts submitted to MSHA shall be identical to
those used in the manufacture of the parts. Dimensions of parts designed
to prevent the passage of flame shall specify allowable tolerances. A
notation ``Do Not Drill Through'' or equivalent should appear on
drawings with the specifications for all ``blind'' holes.
(f) MSHA reserves the right to require the applicant to furnish
supplementary drawings showing sections through complex flame-arresting
paths, such as labyrinths used in conjunction with ball or roller
bearings, and also drawings containing dimensions not indicated on other
drawings submitted to MSHA.
(g) The applicant may ship his equipment to MSHA for investigation
at the time of filing his application and payment of the required fees.
Shipping charges shall be prepaid by the applicant.
(h) For a complete investigation leading to approval or
certification the applicant shall furnish MSHA with the components
necessary for inspection and testing. Expendable components shall be
supplied by the applicant to permit continuous operation of the
equipment while being tested. If special tools are necessary to assemble
or disassemble any component for inspection or test, the applicant shall
furnish them with the equipment to be tested.
(i) For investigation of a hose, the applicant shall furnish samples
as follows:
Hose--a sample having a minimum length of 2 feet
(j) The applicant shall submit a sample caution statement (see
Figure 3 in Appendix II) specifying the conditions for maintaining
permissibility of the equipment.
[[Page 108]]
(k) The applicant shall submit a factory-inspection form (see Figure
4 in Appendix II) used to maintain quality control at the place of
manufacture or assembly to insure that component parts are made and
assembled in strict accordance with the drawings and specifications
covering a design submitted to MSHA for approval or certification.
(l) MSHA will accept an application for an approval, a letter of
certification, or an acceptance for listing of a product that is
manufactured in a country other than the United States provided: (1) All
correspondence, specifications, lettering on drawings (metric-system
dimensions acceptable), instructions, and related information are in
English; and (2) all other requirements of this part are met the same as
for a domestic applicant.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 47
FR 14696, Apr. 6, 1982; 57 FR 61223, Dec. 23, 1992; 60 FR 33723, June
29, 1995; 60 FR 35693, July 11, 1995; 68 FR 36419, June 17, 2003; 70 FR
46343, Aug. 9, 2005; 71 FR 28584, May 17, 2006; 73 FR 52211, Sept. 9,
2008; 73 FR 80611, Dec. 31, 2008]
Sec. 18.7 [Reserved]
Sec. 18.8 Date for conducting investigation and tests.
The date of receipt of an application will determine the order of
precedence for investigation and testing. If an electrical machine
component or accessory fails to meet any of the requirements, it shall
lose its order of precedence. If an application is submitted to resume
investigation and testing after correction of the cause of failure, it
will be treated as a new application and the order of precedence for
investigation and testing will be so determined.
Sec. 18.9 Conduct of investigations and tests.
(a) Prior to the issuance of an approval, certification, or
acceptance of a hose, only MSHA personnel, representative(s) of the
applicant, and such other person(s) as may be mutually agreed upon may
observe any part of the investigation or tests. The MSHA will hold as
confidential and will not disclose principles or patentable features;
nor will it disclose to persons other than the applicant the results of
tests, chemical analysis of materials or any details of the applicant's
drawings, specifications, instructions, and related material.
(b) Unless notified to the contrary by MSHA, the applicant shall
provide assistance in disassembling parts for inspection, preparing
parts for testing, and preparing equipment for return shipment.
Explosion-proof enclosures shall be drilled and tapped for pipe
connections in accordance with instructions supplied by MSHA.
(c) MSHA reserves the right to inspect a complete machine, component
part, or accessory at a place other than the Bureau's premises, such as
the assembly plant or other location acceptable to MSHA, at the
applicant's expense.
(d) Applicants shall be responsible for their representatives
present during tests and for observers admitted at their request and
shall save the Government harmless in the event of damage to applicant's
property or injury to applicant's representatives or to observers
admitted at their request.
[33 FR 4660, Mar. 19, 1968; 33 FR 6345, Apr. 26, 1968, as amended at 57
FR 61223, Dec. 23, 1992; 73 FR 80612, Dec. 31, 2008]
Sec. 18.10 Notice of approval or disapproval.
(a) Upon completing investigation of a complete assembly of an
electrical machine or accessory, MSHA will issue to the applicant either
a written notice of approval or a written notice of disapproval, as the
case may require. No informal notification of approval will be issued.
If a notice of disapproval is issued, it will be accompanied by details
of the defects, with recommendations for possible correction. MSHA will
not disclose, except to the applicant, any information upon which a
notice of disapproval has been issued.
(b) A formal notice of approval will be accompanied by a list of
drawings, specifications, and related material, covering the details of
design and construction of the equipment upon which the approval is
based. Applicants shall keep exact duplicates of the drawings,
specifications, and descriptions that relate to equipment for which an
approval has been issued, and the drawings and specifications shall be
adhered
[[Page 109]]
to exactly in production of the approved equipment.
(c) An applicant shall not advertise or otherwise represent his
equipment as approved (permissible) until he has received MSHA's formal
notice of approval.
Sec. 18.11 Approval plate.
(a)(1) The notice of approval will be accompanied by a photograph of
an approval plate, bearing the emblem of Mine Safety and Health
Administration, the name of the complete assembly, the name of the
applicant, and spaces for the approval number, serial number, and the
type or model of machine.
(2) An extension of approval will not affect the original approval
number except that the extension number shall be added to the original
approval number on the approval plate. (Example: Original approval No.
2G-3000; seventh extension No. 2G-3000-7.)
(b) The applicant shall reproduce the design on a separate plate,
which shall be attached in a suitable place, on each complete assembly
to which it relates. The size, type, location, and method of attaching
an approval plate are subject to MSHA's concurrence. The method for
affixing the approval plate shall not impair any explosion-proof feature
of the equipment.
(c) The approval plate identifies as permissible the machine or
accessory to which it is attached, and use of the approval plate
obligates the applicant to whom the approval was issued to maintain in
his plant the quality of each complete assembly and guarantees that the
equipment is manufactured and assembled according to the drawings,
specifications, and descriptions upon which the approval and subsequent
extension(s) of approval were based.
(d) A completely assembled approved machine with an integral dust
collector shall bear an approval plate indicating that the requirements
of part 33 of this chapter (Bureau of Mines Schedule 25B), have been
complied with. Approval numbers will be assigned under each part of such
joint approvals.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978]
Sec. 18.12 Letter of certification.
(a) A letter of certification may be issued by MSHA for a component
intended for incorporation in a complete machine or accessory for which
an approval may be subsequently issued. A letter of certification will
be issued to an applicant when a component has met all the applicable
requirements of this part. Included in the letter of certification will
be an assigned MSHA certification number that will identify the
certified component.
(b) A letter of certification will be accompanied by a list of
drawings, specifications, and related material covering the details of
design and construction of a component upon which the letter of
certification is based. Applicants shall keep exact duplicates of the
drawings, specifications, and descriptions that relate to the component
for which a letter of certification has been issued; and the drawings
and specifications shall be adhered to exactly in production of the
certified component.
(c) A component shall not be represented as certified until the
applicant has received MSHA's letter of certification for the component.
Certified components are not to be represented as ``approved'' or
``permissible'' because such terms apply only to completely assembled
machines or accessories.
Sec. 18.13 Certification plate.
Each certified component shall be identified by a certification
plate attached to the component in a manner acceptable to MSHA. The
method of attachment shall not impair any explosion-proof
characteristics of the component. The plate shall be of serviceable
material, acceptable, to MSHA, and shall contain the following:
Certified as complying with the applicable requirements of 30 CFR part
____.
Certification No.____.
The blank spaces shall be filled with appropriate designations.
Inclusion of the information on a company name plate will be permitted
provided the plate is made of material acceptable to MSHA.
[[Page 110]]
Sec. 18.14 Identification of tested noncertified explosion-proof
enclosures.
An enclosure that meets all applicable requirements of this part,
but has not been certified by MSHA, shall be identified by a permanent
marking on it in a conspicuous location. The design of such marking
shall consist of capital letters USMSHA not less than \1/4\ inch in
height, enclosed in a circle not less than 1 inch in diameter.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978] st
Sec. 18.15 Changes after approval or certification.
If an applicant desires to change any feature of approved equipment
or a certified component, he shall first obtain MSHA's concurrence
pursuant to the following procedure:
(a)(1) Application shall be made as for an original approval or
letter of certification requesting that the existing approval or
certification be extended to cover the proposed changes and shall be
accompanied by drawings, specifications, and related information,
showing the changes in detail.
(2) Where the applicant for approval has used an independent
laboratory under part 6 of this chapter to perform, in whole or in part,
the necessary testing and evaluation for approval of changes to an
approved or certified product under this part, the applicant must
provide to MSHA as part of the approval application:
(i) Written evidence of the laboratory's independence and current
recognition by a laboratory accrediting organization;
(ii) Complete technical explanation of how the product complies with
each requirement in the applicable MSHA product approval requirements;
(iii) Identification of components or features of the product that
are critical to the safety of the product; and
(iv) All documentation, including drawings and specifications, as
submitted to the independent laboratory by the applicant and as required
by this part.
(b) The application will be examined by MSHA to determine whether
inspection or testing will be required. Testing will be required if
there is a possibility that the change(s) may adversely affect safety.
(c) If the change(s) meets the requirements of this part, a formal
extension of approval or certification will be issued, accompanied by a
list of new or revised drawings, specifications, and related information
to be added to those already on file for the original approval or
certification.
(d) Revisions in drawings or specifications that do not involve
actual change in the explosion-proof features of equipment may be
handled informally.
[43 FR 12313, Mar. 24, 1978, as amended at 52 FR 17514, May 8, 1987; 68
FR 36419, June 17, 2003]
Sec. 18.16 Withdrawal of approval, certification, or acceptance.
MSHA reserves the right to rescind, for cause, any approval,
certification, acceptance, or extension thereof, issued under this part.
Subpart B_Construction and Design Requirements
Sec. 18.20 Quality of material, workmanship, and design.
(a) Electrically operated equipment intended for use in coal mines
shall be rugged in construction and shall be designed to facilitate
inspection and maintenance.
(b) MSHA will test only electrical equipment that in the opinion of
its qualified representatives is constructed of suitable materials, is
of good quality workmanship, based on sound engineering principles, and
is safe for its intended use. Since all possible designs, circuits,
arrangements, or combinations of components and materials cannot be
foreseen, MSHA reserves the right to modify design, construction, and
test requirements to obtain the same degree of protection as provided by
the tests described in Subpart C of this part.
(c) Moving parts, such as rotating saws, gears, and chain drives,
shall be guarded to prevent personal injury.
(d) Flange joints and lead entrances shall be accessible for field
inspection, where practicable.
(e) An audible warning device shall be provided on each mobile
machine
[[Page 111]]
that travels at a speed greater than 2.5 miles per hour.
(f) Brakes shall be provided for each wheel-mounted machine, unless
design of the driving mechanism will preclude accidental movement of the
machine when parked.
(g) A headlight and red light-reflecting material shall be provided
on both front and rear of each mobile transportation unit that travels
at a speed greater than 2.5 miles per hour. Red light-reflecting
material should be provided on each end of other mobile machines.
Sec. 18.21 Machines equipped with powered dust collectors.
Powered dust collectors on machines submitted for approval shall
meet the applicable requirements of Part 33 of this chapter (Bureau of
Mines Schedule 25B), and shall bear the approval number assigned by
MSHA.
Sec. 18.22 Boring-type machines equipped for auxiliary face
ventilation.
Each boring-type continuous-mining machine that is submitted for
approval shall be constructed with an unobstructed continuous space(s)
of not less than 200 square inches total cross-sectional area on or
within the machine to which flexible tubing may be attached to
facilitate auxiliary face ventilation.
Sec. 18.23 Limitation of external surface temperatures.
The temperature of the external surfaces of mechanical or electrical
components shall not exceed 150 C. (302 F.) under normal operating
conditions.
Sec. 18.24 Electrical clearances.
Minimum clearances between uninsulated electrical conductor
surfaces, or between uninsulated conductor surfaces and grounded metal
surfaces, within the enclosure shall be as follows:
Minimum Clearances Between Uninsulated Surfaces
------------------------------------------------------------------------
Clearances (inches)
-----------------------
Phase-to-
Phase-to-Phase Voltage (rms) Phase-to- Ground or
Phase Control
Circuit
------------------------------------------------------------------------
0 to 250........................................ 0.25 0.25
251 to 600...................................... 0.28 0.25
601 to 1000..................................... 0.61 0.25
1001 to 2400.................................... 1.4 0.6
2401 to 4160.................................... 3.0 1.4
------------------------------------------------------------------------
[57 FR 61209, Dec. 23, 1992]
Sec. 18.25 Combustible gases from insulating material.
(a) Insulating materials that give off flammable or explosive gases
when decomposed electrically shall not be used within enclosures where
the materials are subjected to destructive electrical action.
(b) Parts coated or impregnated with insulating materials shall be
heat-treated to remove any combustible solvent(s) before assembly in an
explosion-proof enclosure. Air-drying insulating materials are excepted.
Sec. 18.26 Static electricity.
Nonmetallic rotating parts, such as belts and fans, shall be
provided with a means to prevent an accumulation of static electricity.
Sec. 18.27 Gaskets.
A gasket(s) shall not be used between any two surfaces forming a
flame-arresting path except as follows:
(a) A gasket of lead, elastomer, or equivalent will be acceptable
provided the gasket does not interfere with an acceptable metal-to-metal
joint.
(b) A lead gasket(s) or equivalent will be acceptable between glass
and a hard metal to form all or a part of a flame-arresting path.
Sec. 18.28 Devices for pressure relief, ventilation, or drainage.
(a) Devices for installation on explosion-proof enclosures to
relieve pressure, ventilate, or drain will be acceptable provided the
length of the flame-arresting path and the clearances or size of holes
in perforated metal will prevent discharge of flame in explosion tests.
[[Page 112]]
(b) Devices for pressure relief, ventilation, or drainage shall be
constructed of materials that resist corrosion and distortion, and be so
designed that they can be cleaned readily. Provision shall be made for
secure attachment of such devices.
(c) Devices for pressure relief, ventilation, or drainage will be
acceptable for application only on enclosures with which they are
explosion tested.
Sec. 18.29 Access openings and covers, including unused lead-entrance
holes.
(a) Access openings in explosion-proof enclosures will be permitted
only where necessary for maintenance of internal parts such as motor
brushes and fuses.
(b) Covers for access openings shall meet the same requirements as
any other part of an enclosure except that threaded covers shall be
secured against loosening, preferably with screws having heads requiring
a special tool. (See Figure 1 in Appendix II.)
(c) Holes in enclosures that are provided for lead entrances but
which are not in use shall be closed with metal plugs secured by spot
welding, brazing, or equivalent. (See Figure 10 in Appendix II.)
Sec. 18.30 Windows and lenses.
(a) MSHA may waive testing of materials for windows or lenses except
headlight lenses. When tested, material for windows or lenses shall meet
the test requirements prescribed in Sec. 18.66 and shall be sealed in
place or provided with flange joints in accordance with Sec. 18.31.
(b) Windows or lenses shall be protected from mechanical damage by
structural design, location, or guarding. Windows or lenses, other than
headlight lenses, having an exposed area greater than 8 square inches,
shall be provided with guarding or equivalent.
Sec. 18.31 Enclosures--joints and fastenings.
(a) Explosion-proof enclosures:
(1) Cast or welded enclosures shall be designed to withstand a
minimum internal pressure of 150 pounds per square inch (gage). Castings
shall be free from blowholes.
(2) Welded joints forming an enclosure shall have continuous gas-
tight welds. All welds shall be made in accordance with American Welding
Society standards.
(3) External rotating parts shall not be constructed of aluminum
alloys containing more than 0.6 percent magnesium.
(4) MSHA reserves the right to require the applicant to conduct
static-pressure tests on each enclosure when MSHA determines that the
particular design will not permit complete visual inspection or when the
joint(s) forming an enclosure is welded on one side only (see
Sec. 18.67).
(5) Threaded covers and mating parts shall be designed with Class 1A
and 1B (coarse, loose-fitting) threads. The flame-arresting path of
threaded joints shall conform to the requirements of paragraph (a)(6) of
this section.
(6) Enclosure requirements shall be based on the internal volumes of
the empty enclosure. The internal volume is the volume remaining after
deducting the volume of any part that is essential in maintaining the
explosion-proof integrity of the enclosure or necessary for the
operation. Essential parts include the parts that constitute the flame-
arresting path and those necessary to secure parts that constitute a
flame-arresting path. Enclosures shall meet the following requirements:
Explosion-Proof Requirements Based on Volume
----------------------------------------------------------------------------------------------------------------
Volume of empty enclosure
-----------------------------------------------
Less than 45 45 to 124 cu. More than 124
cu. in. in. inclusive cu. in.
----------------------------------------------------------------------------------------------------------------
Minimum thickness of material for walls \1\..................... \1/8\" \3/16\" \1/4\"
Minimum thickness of material for flanges and covers............ \2\ \1/4\" \3\ \3/8\" \3\ \1/2\"
Minimum width of joint; all in one plane \4\.................... \1/2\" \3/4\" 1"
Maximum clearance; joint all in one plane....................... 0.002" 0.003" 0.004"
Minimum width of joint, portions of which are in different \3/8\" \5/8\" \3/4\"
planes; cylinders or equivalent \4 5\..........................
[[Page 113]]
Maximum clearances; joint in two or more planes, cylinders or
equivalent:
(a) Portion perpendicular to plane \6\...................... 0.008" 0.008" 0.008"
(b) Plane portion........................................... 0.006" 0.006" 0.006"
Maximum bolt \7 8\ spacing; joints all in one plane............. (\16\) (\16\) (\16\)
Maximum bolt spacing; joints, portions of which are in different (\9\) (\9\) (\9\)
planes.........................................................
Minimum diameter of bolt (without regard to type of joint)...... \1/4\" \1/4\" \3/8\"
Minimum thread engagement \10\.................................. \1/4\" \1/4\" \3/8\"
Maximum diametrical clearance between bolt body and unthreaded \1/64\" \1/32\" \1/16\"
holes through which it passes \8 11 12\........................
Minimum distance from interior of enclosure to the edge of a
bolt hole: 8 13
Joint--minimum width 1"..................................... .............. .............. \14\ \7/16\"
Joint--less than 1" wide.................................... \1/8\" \3/16\" ..............
----------------------------------------------------------------------------------------------------------------
Cylindrical joints
----------------------------------------------------------------------------------------------------------------
Shaft centered by ball or roller bearings:
Minimum length of flame-arresting path...................... \1/2\" \3/4\" 1"
Maximum diametrical clearance............................... 0.020" 0.025" 0.030"
Other cylindrical joints: \15\
Minimum length of flame-arresting path...................... \1/2\" \3/4\" 1"
Maximum diametrical clearance............................... 0.006" 0.008" 0.010"
----------------------------------------------------------------------------------------------------------------
\1\ This is the minimal nominal dimension when applied to standard steel plate.
\2\ \1/32\ inch less is allowable for machining rolled plate.
\3\ \1/16\ inch less is allowable for machining rolled plate.
\4\ The widths of any grooves, such as grooves for holding oil seals or O-rings, shall be deducted in measuring
the widths of flame-arresting paths.
\5\ If only two planes are involved, neither portion of a joint shall be less than \1/8\ inch wide, unless the
wider portion conforms to the same requirements as those for a joint that is all in one plane. If more than
two planes are involved (as in labyrinths or tongue-and-groove joints) the combined lengths of those portions
having prescribed clearances are considered.
\6\ The allowable diametrical clearance is 0.008 inch when the portion perpendicular to the plane portion is \1/
4\ inch or greater in length. If the perpendicular portion is more than \1/8\ inch but less than \1/4\ inch
wide, the diametrical clearance shall not exceed 0.006 inch.
\7\ Where the term ``bolt'' is used, it refers to a machine bolt or a cap screw, and for either of these studs
may be substituted provided the studs, bottom in blind holes, are completely welded in place, or the bottom of
the hole is closed with a plug secured by weld or braze. Bolts shall be provided at all corners.
\8\ The requirements as to diametrical clearance around the bolt and minimum distance from the bolt hole to the
inside of the explosion-proof enclosure apply to steel dowel pins. In addition, when such pins are used, the
spacing between centers of the bolts on either side of the pin shall not exceed 5 inches.
\9\ Adequacy of bolt spacing will be judged on the basis of size and configuration of the enclosure, strength of
materials, and explosion test results.
\10\ In general, minimum thread engagement shall be equal to or greater than the diameter of the bolt specified.
\11\ Threaded holes for fastening bolts shall be machined to remove burrs or projections that affect planarity
of a surface forming a flame-arresting path.
\12\ This maximum clearance applies only when the bolt is located within the flamepath.
\13\ The edge of the bolt hole shall include the edge of any machining done to the bolt hole, such as
chamfering.
\14\ Less than \7/16\" (\1/4\" minimum) will be acceptable provided the diametrical clearance for fastening
bolts does not exceed \1/32\".
\15\ Shafts or operating rods through journal bearings shall be at least \1/4\" in diameter. The length of fit
shall not be reduced when a push button is depressed. Operating rods shall have a shoulder or head on the
portion inside the enclosure. Essential parts riveted or bolted to the inside portion are acceptable in lieu
of a head or shoulder, but cotter pins and similar devices shall not be used.
\16\ 6" with a minimum of 4 bolts.
(7) O-rings, if used in a flame-arresting path, shall meet the
following:
(i) When the flame-arresting path is in one plane, the o-ring shall
be located at least one-half the acceptable flame-arresting path length
specified in paragraph (a)(6) of this section within the outside edge of
the path (see figure J-2 in the appendix to subpart J of part 7 of this
chapter).
(ii) When the flame-arresting path is one of the plane-cylindrical
type (step joint), the o-ring shall be located at least \1/2\ inch
within the outer edge of the plane portion (see figure J-3 in the
appendix to subpart J of part 7 of this chapter), or at the junction of
the plane and cylindrical portion of the joint (see figure J-4 in the
appendix to subpart J of part 7 of this chapter); or in the cylindrical
portion (see figure J-5 in the appendix to subpart J of part 7 of this
chapter).
(8) Mating parts comprising a pressed fit shall result in a minimum
interference of 0.001 inch between the parts. The minimum length of the
pressed fit
[[Page 114]]
shall be equal to the minimum thickness requirement of paragraph (a)(6)
of this section for the material in which the fit is made.
(b) Enclosures for potted components: Enclosures shall be rugged and
constructed with materials having 75 percent, or greater, of the
thickness and flange width specified in paragraph (a) of this section.
These enclosures shall be provided with means for attaching hose
conduit, unless energy carried by the cable is intrinsically safe.
(c) No assembly will be approved that requires the opening of an
explosion-proof enclosure to operate a switch, rheostat, or other device
during normal operation of a machine.
[33 FR 4660, Mar. 19, 1968, as amended at 57 FR 61209, Dec. 23, 1992]
Sec. 18.32 Fastenings--additional requirements.
(a) Bolts, screws, or studs shall be used for fastening adjoining
parts to prevent the escape of flame from an enclosure. Hinge pins or
clamps will be acceptable for this purpose provided MSHA determines them
to be equally effective.
(b) Lockwashers shall be provided for all bolts, screws, and studs
that secure parts of explosion-proof enclosures. Special fastenings
designed to prevent loosening will be acceptable in lieu of lockwashers,
provided MSHA determines them to be equally effective.
(c) Fastenings shall be as uniform in size as practicable to
preclude improper assembly.
(d) Holes for fastenings shall not penetrate to the interior of an
explosion-proof enclosure, except as provided in paragraph (a)(9) of
Sec. 18.34, and shall be threaded to insure that a specified bolt or
screw will not bottom even if its lockwasher is omitted.
(e) A minimum of \1/8\-inch of stock shall be left at the center of
the bottom of each hole drilled for fastenings.
(f) Fastenings used for joints on explosion-proof enclosures shall
not be used for attaching nonessential parts or for making electrical
connections.
(g) The acceptable sizes for and spacings of fastenings shall be
determined by the size of the enclosure, as indicated in Sec. 18.31.
(h) MSHA reserves the right to conduct explosion tests with standard
bolts, nuts, cap screws, or studs substituted for any special high-
tensile strength fastening(s) specified by the applicant.
(i) Coil-thread inserts, if used in holes for fastenings, shall meet
the following:
(1) The inserts shall have internal screw threads.
(2) The holes for the inserts shall be drilled and tapped consistent
with the insert manufacturer's specifications.
(3) The inserts shall be installed consistent with the insert
manufacturer's specifications.
(4) The insert shall be of sufficient length to ensure the minimum
thread engagement of fastening specified in Sec. 18.31(a)(6) of this
part.
[33 FR 4660, Mar. 19, 1968, as amended at 57 FR 61210, Dec. 23, 1992]
Sec. 18.33 Finish of surface joints.
Flat surfaces between bolt holes that form any part of a flame-
arresting path shall be plane to within a maximum deviation of one-half
the maximum clearance specified in Sec. 18.31(a)(6). All metal surfaces
forming a flame-arresting path shall be finished during the
manufacturing process to not more than 250 microinches. A thin film of
nonhardening preparation to inhibit rusting may be applied to these
finished metal surfaces as long as the final surface can be readily
wiped free of any foreign materials.
[57 FR 61210, Dec. 23, 1992]
Sec. 18.34 Motors.
Explosion-proof electric motor assemblies intended for use in
approved equipment in underground mines that are specifically addressed
in part 7 of this chapter shall be approved under part 7 of this chapter
after February 22, 1996. Those motor assemblies not specifically
addressed under part 7 of this chapter shall be accepted or certified
under this part.
(a) General. (1) Motors shall have explosion-proof enclosures.
(2) Motors submitted to MSHA for test shall be equipped with
unshielded bearings regardless of whether that type of bearing is
specified.
[[Page 115]]
(3) MSHA reserves the right to test motors with the maximum
clearance specified between the shaft and the mating part which forms
the required flame-arresting path. Also reserved is the right to
remachine these parts, at the applicant's expense, to specified
dimensions to provide the maximum clearance.
Note: For example, a shaft with a diameter greater than 2 inches at
the flame-arresting portion might require such machining.
(4) Ball and roller bearings and oil seals will not be acceptable as
flame-arresting paths; therefore, a separate path shall be provided
between the shaft and another part, preferably inby the bearing. The
length and clearances of such flame-arresting path shall conform to the
requirements of Sec. 18.31.
(5) Labyrinths or other arrangements that provide change(s) in
direction of escaping gases will be acceptable but the use of small
detachable pieces shall not be permitted unless structurally
unavoidable. The lengths of flame-arresting path(s) and clearance(s)
shall conform to the requirements of Sec. 18.31.
(6) Oil seals shall be removed from motors prior to submission for
explosion tests.
Note: Oil seals will be removed from motors prior to explosion tests
and therefore may be omitted from motors submitted for investigation.
(7) Openings for filling and draining bearing lubricants shall be so
located as to prevent escape of flame through them.
(8) An outer bearing cap will not be considered as forming any part
of a flame-arresting path unless the cap is used as a bearing cartridge.
Note: The outer bearing cap will be omitted during explosion tests
unless it houses the bearing.
(9) If unavoidable, holes may be made through motor casings for
bolts, studs, or screws to hold essential parts such as pole pieces,
brush rigging, and bearing cartridges. Such parts shall be attached to
the casing by at least two fastenings. The threaded holes in these parts
shall be blind, unless the fastenings are inserted from the inside, in
which case the fastenings shall not be accessible with the armature of
the motor in place.
(b) Direct-current motors. For direct-current motors with narrow
interpoles, the distance from the edge of the pole piece to any bolt
hole in the frame shall be not less than \1/8\ inch. If the distance is
\1/8\ to \1/4\ inch, the diametrical clearance for the pole bolt shall
not exceed \1/64\ inch for not less than \1/2\ inch through the frame.
Furthermore, the pole piece shall have the same radius as the inner
surface of the frame. Pole pieces may be shimmed as necessary.
(c) Alternating-current motors. Stator laminations that form a part
of an explosion-proof enclosure will be acceptable provided: (1) The
laminations and their end rings are fastened together under pressure;
(2) the joint between the end rings and the laminations is not less than
\1/4\ inch, but preferably as close to 1 inch as possible; and (3) it
shall be impossible to insert a 0.0015-inch thickness gage to a depth
exceeding \1/8\ inch between adjacent laminations or between end rings
and laminations.
(d) Small motors (alternating- and direct-current). Motors having
internal free volume not exceeding 350 cubic inches and joints not
exceeding 32 inches in outer circumference will be acceptable for
investigation if provided with rabbet joints between the stator frame
and the end bracket having the following dimensions:
Dimensions of Rabbet Joints--Inches
------------------------------------------------------------------------
Max.
Min. width Max. diametrical
Minimum total width of clamped clearance clearance
radial of radial at axial
portion portion portion
------------------------------------------------------------------------
\3/8\............................... \3/64\ 0.0015 0.003
\1/2\............................... \3/64\ .002 .003
\1/2\............................... \3/32\ .002 .004
------------------------------------------------------------------------
[33 FR 4660, Mar. 19, 1968, as amended at 57 FR 61210, Dec. 23, 1992]
Sec. 18.35 Portable (trailing) cables and cords.
(a) Portable cables and cords used to conduct electrical energy to
face equipment shall conform to the following:
(1) Have each conductor of a current-carrying capacity consistent
with the Insulated Power Cable Engineers Association (IPCEA) standards.
(See Tables 1 and 2 in Appendix I.)
(2) Have current-carrying conductors not smaller than No. 14 (AWG).
Cords with sizes 14 to 10 (AWG) conductors
[[Page 116]]
shall be constructed with heavy jackets, the diameters of which are
given in Table 6 in Appendix I.
(3) Be accepted as flame resistant under this part or approved under
subpart K of part 7 of this chapter.
(4) Have short-circuit protection at the outby (circuit-connecting)
end of ungrounded conductors. (See Table 8 in Appendix I.) The fuse
rating or trip setting shall be included in the assembler's
specifications.
(5) Ordinarily the length of a portable (trailing) cable shall not
exceed 500 feet. Where the method of mining requires the length of a
portable (trailing) cable to be more than 500 feet, such length of cable
shall be permitted only under the following prescribed conditions:
(i) The lengths of portable (trailing) cables shall not exceed those
specified in Table 9, Appendix I, titled ``Specifications for Portable
Cables Longer Than 500 Feet.''
(ii) Short-circuit protection shall be provided by a protective
device with an instantaneous trip setting as near as practicable to the
maximum starting-current-inrush value, but the setting shall not exceed
the trip value specified in MSHA approval for the equipment for which
the portable (trailing) cable furnishes electric power.
(6) Have nominal outside dimensions consistent with IPCEA standards.
(See Tables 4, 5, 6, and 7 in Appendix I.)
(7) Have conductors of No. 4 (AWG) minimum for direct-current mobile
haulage units or No. 6 (AWG) minimum for alternating-current mobile
haulage units.
(8) Have not more than five well-made temporary splices in a single
length of portable cable.
(b) Sectionalized portable cables will be acceptable provided the
connectors used inby the last open crosscut in a gassy mine meet the
requirements of Sec. 18.41.
(c) A portable cable having conductors smaller than No. 6 (AWG),
when used with a trolley tap and a rail clamp, shall have well insulated
single conductors not smaller than No. 6 (AWG) spliced to the outby end
of each conductor. All splices shall be made in a workmanlike manner to
insure good electrical conductivity, insulation, and mechanical
strength.
(d) Suitable provisions shall be made to facilitate disconnection of
portable cable quickly and conveniently for replacement.
[33 FR 4660, Mar. 19, 1968; 33 FR 6343, Apr. 26, 1968, as amended at 57
FR 61223, Dec. 23, 1992]
Sec. 18.36 Cables between machine components.
(a) Cables between machine components shall have: (1) Adequate
current-carrying capacity for the loads involved, (2) short-circuit
protection, (3) insulation compatible with the impressed voltage, and
(4) flame-resistant properties unless totally enclosed within a flame-
resistant hose conduit or other flame-resistant material.
(b) Cables between machine components shall be: (1) Clamped in place
to prevent undue movement, (2) protected from mechanical damage by
position, flame-resistant hose conduit, metal tubing, or troughs
(flexible or threaded rigid metal conduit will not be acceptable), (3)
isolated from hydraulic lines, and (4) protected from abrasion by
removing all sharp edges which they might contact.
(c) Cables (cords) for remote-control circuits extending from
permissible equipment will be exempted from the requirements of conduit
enclosure provided the total electrical energy carried is intrinsically
safe or that the cables are constructed with heavy jackets, the sizes of
which are stated in Table 6 of Appendix I. Cables (cords) provided with
hose-conduit protection shall have a tensile strength not less than No.
16 (AWG) three-conductor, type SO cord. (Reference: 7.7.7 IPCEA Pub. No.
S-19-81, Fourth Edition.) Cables (cords) constructed with heavy jackets
shall consist of conductors not smaller than No. 14 (AWG) regardless of
the number of conductors.
Sec. 18.37 Lead entrances.
(a) Insulated cable(s), which must extend through an outside wall of
an explosion-proof enclosure, shall pass through a stuffing-box lead
entrance. All sharp edges that might damage insulation shall be removed
from stuffing boxes and packing nuts.
[[Page 117]]
(b) Stuffing boxes shall be so designed, and the amount of packing
used shall be such, that with the packing properly compressed, the gland
nut still has a clearance distance of \1/8\ inch or more to travel
without meeting interference by parts other than packing. In addition,
the gland nut shall have a minimum of three effective threads engaged.
(See figures 8, 9 and 10 in appendix II.)
(c) Packing nuts and stuffing boxes shall be secured against
loosening.
(d) Compressed packing material shall be in contact with the cable
jacket for a length of not less than \1/2\ inch.
(e) Special requirements for glands in which asbestos-packing
material is specified are:
(1) Asbestos-packing material shall be untreated, not less than \3/
16\-inch diameter if round, or not less than \3/16\ by \3/16\ inch if
square. The width of the space for packing material shall not exceed by
more than 50 percent the diameter or width of the uncompressed packing
material.
(2) The allowable diametrical clearance between the cable and the
holes in the stuffing box and packing nut shall not exceed 75 percent of
the nominal diameter or width of the packing material.
(f) Special requirements for glands in which a compressible material
(example--synthetic elastomers) other than asbestos is specified, are:
(1) The packing material shall be flame resistant.
(2) The radial clearance between the cable jacket and the nominal
inside diameter of the packing material shall not exceed \1/32\-inch,
based on the nominal specified diameter of the cable.
(3) The radial clearance between the nominal outside diameter of the
packing material and the inside wall of the stuffing box (that portion
into which the packing material fits) shall not exceed \1/32\-inch.
[33 FR 4660, Mar. 19, 1968, as amended at 57 FR 61210, Dec. 23, 1992]
Sec. 18.38 Leads through common walls.
(a) Insulated studs will be acceptable for use in a common wall
between two explosion-proof enclosures.
(b) When insulated wires or cables are extended through a common
wall between two explosion-proof enclosures in insulating bushings, such
bushings shall be not less than 1-inch long and the diametrical
clearance between the wire or cable insulation and the holes in the
bushings shall not exceed \1/16\-inch (based on the nominal specified
diameter of the cable). The insulating bushings shall be secured in the
metal wall.
(c) Insulated wires or cables conducted from one explosion-proof
enclosure to another through conduit, tubing, piping, or other solid-
wall passageways will be acceptable provided one end of the passageway
is plugged, thus isolating one enclosure from the other. Glands of
secured bushings with close-fitting holes through which the wires or
cables are conducted will be acceptable for plugging. The tubing or duct
specified for the passageway shall be brazed or welded into the walls of
both explosion-proof enclosures with continuous gas-tight welds.
(d) If wires and cables are taken through openings closed with
sealing compounds, the design of the opening and characteristics of the
compounds shall be such as to hold the sealing material in place without
tendency of the material to crack or flow out of its place. The material
also must withstand explosion tests without cracking or loosening.
(e) Openings through common walls between explosion-proof enclosures
not provided with bushings or sealing compound, shall be large enough to
prevent pressure piling.
Sec. 18.39 Hose conduit.
Hose conduit shall be provided for mechanical protection of all
machine cables that are exposed to damage. Hose conduit shall be flame
resistant and have a minimum wall thickness of \3/16\ inch. The flame
resistance of hose conduit will be determined in accordance with the
requirements of Sec. 18.65.
Sec. 18.40 Cable clamps and grips.
Insulated clamps shall be provided for all portable (trailing)
cables to prevent strain on the cable terminals of a machine. Also
insulated clamps shall be provided to prevent strain on both ends of
each cable or cord leading from a machine to a detached or separately
[[Page 118]]
mounted component. Cable grips anchored to the cable may be used in lieu
of insulated strain clamps. Supporting clamps for cables used for wiring
around machines shall be provided in a manner acceptable to MSHA.
Sec. 18.41 Plug and receptacle-type connectors.
(a) Plug and receptacle-type connectors for use inby the last open
crosscut in a gassy mine shall be so designed that insertion or
withdrawal of a plug cannot cause incendive arcing or sparking. Also,
connectors shall be so designed that no live terminals, except as
hereinafter provided, are exposed upon withdrawal of a plug. The
following types will be acceptable:
(1) Connectors in which the mating or separation of the male and
female electrodes is accomplished within an explosion-proof enclosure.
(2) Connectors that are mechanically or electrically interlocked
with an automatic circuit-interrupting device.
(i) Mechanically interlocked connectors. If a mechanical interlock
is provided the design shall be such that the plug cannot be withdrawn
before the circuit has been interrupted and the circuit cannot be
established with the plug partially withdrawn.
(ii) Electrically interlocked connectors. If an electrical interlock
is provided, the total load shall be removed before the plug can be
withdrawn and the electrical energy in the interlocking pilot circuit
shall be intrinsically safe, unless the pilot circuit is opened within
an explosion-proof enclosure.
(3) Single-pole connectors for individual conductors of a circuit
used at terminal points shall be so designed that all plugs must be
completely inserted before the control circuit of the machine can be
energized.
(b) Plug and receptacle-type connectors used for sectionalizing the
cables outby the last open crosscut in a gassy mine need not be
explosion-proof or electrically interlocked provided such connectors are
designed and constructed to prevent accidental separation.
(c) Conductors shall be securely attached to the electrodes in a
plug or receptacle and the connections shall be totally enclosed.
(d) Molded-elastomer connectors will be acceptable provided:
(1) Any free space within the plug or receptacle is isolated from
the exterior of the plug.
(2) Joints between the elastomer and metal parts are not less than 1
inch wide and the elastomer is either bonded to or fits tightly with
metal parts.
(e) The contacts of all line-side connectors shall be shielded or
recessed adequately.
(f) For a mobile battery-powered machine, a plug and receptacle-type
connector will be acceptable in lieu of an interlock provided:
(1) The plug is padlocked to the receptacle and is held in place by
a threaded ring or equivalent mechanical fastening in addition to a
padlock. A connector within a padlocked enclosure will be acceptable;
or,
(2) The plug is held in place by a threaded ring or equivalent
mechanical fastening, in addition to the use of a device that is captive
and requires a special tool to disengage and allow for the separation of
the connector. All connectors using this means of compliance shall have
a clearly visible warning tag that states: ``DO NOT DISENGAGE UNDER
LOAD,'' or an equivalent statement; or,
(3) The plug is held in place by a spring-loaded or other locking
device, that maintains constant pressure against a threaded ring or
equivalent mechanical fastening, to secure the plug from accidental
separation. All connectors using this means of compliance shall have a
clearly visible warning tag that states: ``DO NOT DISENGAGE UNDER
LOAD,'' or an equivalent statement.
[33 FR 4660, Mar. 19, 1968, as amended at 68 FR 37082, June 23, 2003]
Sec. 18.42 Explosion-proof distribution boxes.
(a) A cable passing through an outside wall(s) of a distribution box
shall be conducted either through a packing gland or an interlocked plug
and receptacle.
(b) Short-circuit protection shall be provided for each branch
circuit connected to a distribution box. The current-carrying capacity
of the specified
[[Page 119]]
connector shall be compatible with the automatic circuit-interrupting
device.
(c) Each branch receptacle shall be plainly and permanently marked
to indicate its current-carrying capacity and each receptacle shall be
such that it will accommodate only an appropriate plug.
(d) Provision shall be made to relieve mechanical strain on all
connectors to distribution boxes.
Sec. 18.43 Explosion-proof splice boxes.
Internal connections shall be rigidly held and adequately insulated.
Strain clamps shall be provided for all cables entering a splice box.
Sec. 18.44 Non-intrinsically safe battery-powered equipment.
(a) Battery-powered equipment shall use battery assemblies approved
under Part 7 of this chapter, or battery assemblies accepted or
certified under this part prior to August 22, 1989.
(b) Battery box covers shall be secured in a closed position.
(c) Each wire or cable leaving a battery box on storage battery-
operated equipment shall have short-circuit protection in an explosion-
proof enclosure located as close as practicable to the battery
terminals. A short-circuit protection device installed within a nearby
explosion-proof enclosure will be acceptable. In no case shall the
exposed portion of the cable from the battery box to the enclosure
exceed 36 inches in length. Each wire or cable shall be protected from
damage.
[53 FR 23500, June 22, 1988]
Sec. 18.45 Cable reels.
(a) A self-propelled machine, that receives electrical energy
through a portable cable and is designed to travel at speeds exceeding
2.5 miles per hour, shall have a mechanically, hydraulically, or
electrically driven reel upon which to wind the portable cable.
(b) The enclosure for moving contacts or slip rings of a cable reel
shall be explosion-proof.
(c) Cable-reel bearings shall not constitute an integral part of a
circuit for transmitting electrical energy.
(d) Cable reels for shuttle cars and locomotives shall maintain
positive tension on the portable cable during reeling and unreeling.
Such tension shall only be high enough to prevent a machine from running
over its own cable(s).
(e) Cable reels and spooling devices shall be insulated with flame-
resistant material.
(f) The maximum speed of travel of a machine when receiving power
through a portable (trailing) cable shall not exceed 6 miles per hour.
(g) Diameters of cable reel drums and sheaves should be large enough
to prevent undue bending strain on cables.
Sec. 18.46 Headlights.
(a) Headlights shall be constructed as explosion-proof enclosures.
(b) Headlights shall be mounted to provide illumination where it
will be most effective. They shall be protected from damage by guarding
or location.
(c) Lenses for headlights shall be glass or other suitable material
with physical characteristics equivalent to \1/2\-inch thick tempered
glass, such as ``Pyrex.'' Lenses shall meet the requirements of the
tests prescribed in Sec. 18.66.
(d) Lenses permanently fixed in a ring with lead, epoxy, or
equivalent will be acceptable provided only lens assemblies meeting the
original manufacturer's specifications are used as replacements.
(e) If a single lead gasket is used, the contact surface of the
opposite side of the lens shall be plane within a maximum deviation of
0.002 inch.
Sec. 18.47 Voltage limitation.
(a) A tool or switch held in the operator's hand or supported
against his body will not be approved with a nameplate rating exceeding
300 volts direct current or alternating current.
(b) A battery-powered machine shall not have a nameplate rating
exceeding 240 volts, nominal (120 lead-acid cells or equivalent).
(c) Other direct-current machines shall not have a nameplate rating
exceeding 550 volts.
(d) An alternating-current machine shall not have a nameplate rating
exceeding 660 volts, except that a machine may have a nameplate rating
[[Page 120]]
greater than 660 volts but not exceeding 4,160 volts when the following
conditions are complied with:
(1) Adequate clearances and insulation for the particular voltage(s)
are provided in the design and construction of the equipment, its
wiring, and accessories.
(2) A continuously monitored, failsafe grounding system is provided
that will maintain the frame of the equipment and the frames of all
accessory equipment at ground potential. Also, the equipment, including
its controls and portable (trailing) cable, will be deenergized
automatically upon the occurrence of an incipient ground fault. The
ground-fault-tripping current shall be limited by grounding resistor(s)
to that necessary for dependable relaying. The maximum ground-fault-
tripping current shall not exceed 25 amperes.
(3) All high voltage switch gear and control for equipment having a
nameplate rating exceeding 1,000 volts are located remotely and operated
by remote control at the main equipment. Potential for remote control
shall not exceed 120 volts.
(4) Portable (trailing) cable for equipment with nameplate ratings
from 661 volts through 1,000 volts shall include grounding conductors, a
ground check conductor, and grounded metallic shields around each power
conductor or a grounded metallic shield over the assembly; except that
on machines employing cable reels, cables without shields may be used if
the insulation is rated 2,000 volts or more.
(5) Portable (trailing) cable for equipment with nameplate ratings
from 1,001 volts through 4,160 volts shall include grounding conductors,
a ground check conductor, and grounded metallic shields around each
power conductor.
(6) MSHA reserves the right to require additional safeguards for
high-voltage equipment, or modify the requirements to recognize improved
technology.
Sec. 18.48 Circuit-interrupting devices.
(a) Each machine shall be equipped with a circuit-interrupting
device by means of which all power conductors can be deenergized at the
machine. A manually operated controller will not be acceptable as a
service switch.
(b) When impracticable to mount the main-circuit-interrupting device
on a machine, a remote enclosure will be acceptable. When contacts are
used as a main-circuit-interrupting device, a means for opening the
circuit shall be provided at the machine and at the remote contactors.
(c) Separate two-pole switches shall be provided to deenergize power
conductors for headlights or floodlights.
(d) Each handheld tool shall be provided with a two-pole switch of
the ``dead-man-control'' type that must be held closed by hand and will
open when hand pressure is released.
(e) A machine designed to operate from both trolley wire and
portable cable shall be provided with a transfer switch, or equivalent,
which prevents energizing one from the other. Such a switch shall be
designed to prevent electrical connection to the machine frame when the
cable is energized.
(f) Belt conveyors shall be equipped with control switches to
automatically stop the driving motor in the event the belt is stopped,
or abnormally slowed down.
Note: Short transfer-type conveyors will be exempted from this
requirement when attended.
Sec. 18.49 Connection boxes on machines.
Connection boxes used to facilitate replacement of cables or machine
components shall be explosion-proof. Portable-cable terminals on cable
reels need not be in explosion-proof enclosures provided that
connections are well made, adequately insulated, protected from damage
by location, and securely clamped to prevent mechanical strain on the
connections.
Sec. 18.50 Protection against external arcs and sparks.
Provision shall be made for maintaining the frames of all off-track
machines and the enclosures of related detached components at safe
voltages by using one or a combination of the following:
(a) A separate conductor(s) in the portable cable in addition to the
power conductors by which the machine
[[Page 121]]
frame can be connected to an acceptable grounding medium, and a separate
conductor in all cables connecting related components not on a common
chassis. The cross-sectional area of the additional conductor(s) shall
not be less than 50 percent of that of one power conductor unless a
ground-fault tripping relay is used, in which case the minimum size may
be No. 8 (AWG). Cables smaller than No. 6 (AWG) shall have an additional
conductor(s) of the same size as one power conductor.
(b) A means of actuating a circuit-interrupting device, preferably
at the outby end of the portable cable.
Note: The frame to ground potential shall not exceed 40 volts.
(c) A device(s) such as a diode(s) of adequate peak inverse voltage
rating and current-carrying capacity to conduct possible fault current
through the grounded power conductor. Diode installations shall include:
(1) An overcurrent device in series with the diode, the contacts of
which are in the machine's control circuit; and (2) a blocking diode in
the control circuit to prevent operation of the machine with the
polarity reversed.
Sec. 18.51 Electrical protection of circuits and equipment.
(a) An automatic circuit-interrupting device(s) shall be used to
protect each ungrounded conductor of a branch circuit at the junction
with the main circuit when the branch-circuit conductor(s) has a current
carrying capacity less than 50 percent of the main circuit conductor(s),
unless the protective device(s) in the main circuit will also provide
adequate protection for the branch circuit. The setting of each device
shall be specified. For headlight and control circuits, each conductor
shall be protected by a fuse or equivalent. Any circuit that is entirely
contained in an explosion-proof enclosure shall be exempt from these
requirements.
(b) Each motor shall be protected by an automatic overcurrent
device. One protective device will be acceptable when two motors of the
same rating operate simultaneously and perform virtually the same duty.
(1) If the overcurrent-protective device in a direct-current circuit
does not open both lines, particular attention shall be given to marking
the polarity at the terminals or otherwise preventing the possibility of
reversing connections which would result in changing the circuit
interrupter to the grounded line.
(2) Three-phase alternating-current motors shall have an
overcurrent-protective device in at least two phases such that actuation
of a device in one phase will cause the opening of all three phases.
(c) Circuit-interrupting devices shall be so designed that they can
be reset without opening the compartment in which they are enclosed.
(d) All magnetic circuit-interrupting devices shall be mounted in a
manner to preclude the possibility of their closing by gravity.
Sec. 18.52 Renewal of fuses.
Enclosure covers that provide access to fuses, other than headlight,
control-circuit, and handheld-tool fuses, shall be interlocked with a
circuit-interrupting device. Fuses shall be inserted on the load side of
the circuit interrupter.
Sec. 18.53 High-voltage longwall mining systems.
(a) In each high-voltage motor-starter enclosure, with the exception
of a controller on a high-voltage shearer, the disconnect device
compartment, control/communications compartment, and motor contactor
compartment must be separated by barriers or partitions to prevent
exposure of personnel to energized high-voltage conductors or parts. In
each motor-starter enclosure on a high-voltage shearer, the high-voltage
components must be separated from lower voltage components by barriers
or partitions to prevent exposure of personnel to energized high-voltage
conductors or parts. Barriers or partitions must be constructed of
grounded metal or nonconductive insulating board.
(b) Each cover of a compartment in the high-voltage motor-starter
enclosure containing high-voltage components must be equipped with at
least two interlock switches arranged to automatically deenergize the
high-
[[Page 122]]
voltage components within that compartment when the cover is removed.
(c) Circuit-interrupting devices must be designed and installed to
prevent automatic reclosure.
(d) Transformers with high-voltage primary windings that supply
control voltages must incorporate grounded electrostatic (Faraday)
shielding between the primary and secondary windings. The shielding must
be connected to equipment ground by a minimum No. 12 AWG grounding
conductor. The secondary nominal voltage must not exceed 120 volts, line
to line.
(e) Test circuits must be provided for checking the condition of
ground-wire monitors and ground-fault protection without exposing
personnel to energized circuits. Each ground-test circuit must inject a
primary current of 50 percent or less of the current rating of the
grounding resistor through the current transformer and cause each
corresponding circuit-interrupting device to open.
(f) Each motor-starter enclosure, with the exception of a controller
on a high-voltage shearer, must be equipped with a disconnect device
installed to deenergize all high-voltage power conductors extending from
the enclosure when the device is in the ``open'' position.
(1) When multiple disconnect devices located in the same enclosure
are used to satisfy the above requirement they must be mechanically
connected to provide simultaneous operation by one handle.
(2) The disconnect device must be rated for the maximum phase-to-
phase voltage and the full-load current of the circuit in which it is
located, and installed so that--
(i) Visual observation determines that the contacts are open without
removing any cover;
(ii) The load-side power conductors are grounded when the device is
in the ``open'' position;
(iii) The device can be locked in the ``open'' position;
(iv) When located in an explosion-proof enclosure, the device must
be designed and installed to cause the current to be interrupted
automatically prior to the opening of the contacts; and
(v) When located in a non-explosion-proof enclosure, the device must
be designed and installed to cause the current to be interrupted
automatically prior to the opening of the contacts, or the device must
be capable of interrupting the full-load current of the circuit.
(g) Control circuits for the high-voltage motor starters must be
interlocked with the disconnect device so that--
(1) The control circuit can be operated with an auxiliary switch in
the ``test'' position only when the disconnect device is in the open and
grounded position; and
(2) The control circuit can be operated with the auxiliary switch in
the ``normal'' position only when the disconnect switch is in the closed
position.
(h) A study to determine the minimum available fault current must be
submitted to MSHA to ensure adequate protection for the length and
conductor size of the longwall motor, shearer and trailing cables.
(i) Longwall motor and shearer cables with nominal voltages greater
than 660 volts must be made of a shielded construction with a grounded
metallic shield around each power conductor.
(j) High-voltage motor and shearer circuits must be provided with
instantaneous ground-fault protection of not more than 0.125-amperes.
Current transformers used for this protection must be of the single-
window type and must be installed to encircle all three phase
conductors.
(k) Safeguards against corona must be provided on all 4,160 voltage
circuits in explosion-proof enclosures.
(l) The maximum pressure rise within an explosion-proof enclosure
containing high-voltage switchgear must be limited to 0.83 times the
design pressure.
(m) High-voltage electrical components located in high-voltage
explosion-proof enclosures must not be coplanar with a single plane
flame-arresting path.
(n) Rigid insulation between high-voltage terminals (Phase-to-Phase
or Phase-to-Ground) must be designed with creepage distances in
accordance with the following table:
[[Page 123]]
Minimum Creepage Distances
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minimum creepage distances (inches) for comparative tracking index (CTI) range \1\
Phase to phase voltage Points of measure ---------------------------------------------------------------------------------------
CTI$500 380CTI<500 175CTI<380 CTI<175
--------------------------------------------------------------------------------------------------------------------------------------------------------
2,400.................................. 0-0 1.50 1.95 2.40 2.90
0-G 1.00 1.25 1.55 1.85
4,160.................................. 0-0 2.40 3.15 3.90 4.65
0-G 1.50 1.95 2.40 2.90
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Assumes that all insulation is rated for the applied voltage or higher.
(o) Explosion-proof motor-starter enclosures must be designed to
establish the minimum free distance (MFD) between the wall or cover of
the enclosure and uninsulated electrical conductors inside the enclosure
in accordance with the following table:
High-Voltage Minimum Free Distances (MFD)
----------------------------------------------------------------------------------------------------------------
Steel MFD (in) Aluminum MFD (in)
Wall/cover thickness (in) -----------------------------------------------------------------------------
A \1\ B \2\ C \3\ A B C
----------------------------------------------------------------------------------------------------------------
\1/4\............................. 2.8 4.3 5.8 \4\ NA \4\ NA \4\ NA
\3/8\............................. 1.8 2.3 3.9 8.6 12.8 18.1
\1/2\............................. * 1.2 2.0 2.7 6.5 9.8 13.0
\5/8\............................. * 0.9 1.5 2.1 5.1 7.7 10.4
\3/4\............................. * 0.6 * 1.1 1.6 4.1 6.3 8.6
1................................. (*) * 0.6 * 1.0 2.9 4.5 6.2
----------------------------------------------------------------------------------------------------------------
Note: * The minimum electrical clearances must still be maintained.
\1\ Column A specifies the MFD for enclosures that have available 3-phase bolted short-circuit currents of
10,000 amperes rms or less.
\2\ Column B specifies the MFD for enclosures that have a maximum available 3-phase bolted short-circuit
currents greater than 10,000 and less than or equal to 15,000 amperes rms.
\3\ Column C specifies the MFD for enclosures that have a maximum available 3-phase bolted short-circuit
currents greater than 15,000 and less than or equal to 20,000 amperes rms.
\4\ Not Applicable--MSHA doesn't allow aluminum wall or covers to be \1/4\ inch or less in thickness (Section
18.31).
(1) For values not included in the table, the following formulas on
which the table is based may be used to determine the minimum free
distance.
(i) Steel Wall/Cover:
[GRAPHIC] [TIFF OMITTED] TR23NO04.000
(ii) Aluminum Wall/Cover:
[GRAPHIC] [TIFF OMITTED] TR23NO04.001
Where C is 1.4 for 2,400 volt systems or 3.0 for 4,160 volt systems,
Isc is the 3-phase short circuit current in amperes of the
system, t is the clearing time in seconds of the outby circuit-
interrupting device and d is the thickness in inches of the metal wall/
cover adjacent to an area of potential arcing.
(2) The minimum free distance must be increased by 1.5 inches for
4,160 volt systems and 0.7 inches for 2,400 volt systems when the
adjacent wall area is the top of the enclosure. If a steel shield is
mounted in conjunction with
[[Page 124]]
an aluminum wall or cover, the thickness of the steel shield is used to
determine the minimum free distances.
(p) The following static pressure test must be performed on each
prototype design of explosion-proof enclosures containing high-voltage
switchgear prior to the explosion tests. The static pressure test must
also be performed on every explosion-proof enclosure containing high-
voltage switchgear, at the time of manufacture, unless the manufacturer
uses an MSHA accepted quality assurance procedure covering inspection of
the enclosure. Procedures must include a detailed check of parts against
the drawings to determine that the parts and the drawings coincide and
that the minimum requirements stated in part 18 have been followed with
respect to materials, dimensions, configuration and workmanship.
(1) Test procedure. (i) The enclosure must be internally pressurized
to at least the design pressure, maintaining the pressure for a minimum
of 10 seconds.
(ii) Following the pressure hold, the pressure must be removed and
the pressurizing agent removed from the enclosure.
(2) Acceptable performance. (i) The enclosure during pressurization
must not exhibit--
(A) Leakage through welds or casting; or
(B) Rupture of any part that affects the explosion-proof integrity
of the enclosure.
(ii) The enclosure following removal of the pressurizing agents must
not exhibit--
(A) Visible cracks in welds;
(B) Permanent deformation exceeding 0.040 inches per linear foot; or
(C) Excessive clearances along flame-arresting paths following
retightening of fastenings, as necessary.
[67 FR 10999, Mar. 11, 2002; 69 FR 68078, Nov. 23, 2004; 69 FR 70752,
Dec. 7, 2004]
Sec. 18.54 High-voltage continuous mining machines.
(a) Separation of high-voltage components from lower voltage
components. In each motor-starter enclosure, barriers, partitions, and
covers must be provided and arranged so that personnel can test and
troubleshoot low- and medium-voltage circuits without being exposed to
energized high-voltage circuits. Barriers or partitions must be
constructed of grounded metal or nonconductive insulating board.
(b) Interlock switches. Each removable cover, barrier, or partition
of a compartment in the motor-starter enclosure providing direct access
to high-voltage components must be equipped with at least two interlock
switches arranged to automatically de-energize the high-voltage
components within that compartment when the cover, barrier, or partition
is removed.
(c) Circuit-interrupting devices. Circuit-interrupting devices must
be designed and installed to prevent automatic re-closure.
(d) Transformers supplying control voltages. (1) Transformers
supplying control voltages must not exceed 120 volts line to line.
(2) Transformers with high-voltage primary windings that supply
control voltages must incorporate a grounded electrostatic (Faraday)
shield between the primary and secondary windings. Grounding of the
shield must be as follows:
(i) Transformers with an external grounding terminal must have the
shield grounded by a minimum of No. 12 A.W.G. grounding conductor
extending from the grounding terminal to the equipment ground.
(ii) Transformers with no external grounding terminal must have the
shield grounded internally through the transformer frame to the
equipment ground.
(e) Onboard ungrounded, three-phase power circuit. A continuous
mining machine designed with an onboard ungrounded, three-phase power
circuit must:
(1) Be equipped with a light that will indicate a grounded-phase
condition;
(2) Have the indicator light installed so that it can be observed by
the operator from any location where the continuous mining machine is
normally operated; and
(3) Have a test circuit for the grounded-phase indicator light
circuit to assure that the circuit is operating properly. The test
circuit must be designed
[[Page 125]]
so that, when activated, it does not require removal of any electrical
enclosure cover or create a double-phase-to-ground fault.
(f) High-voltage trailing cable(s). High-voltage trailing cable(s)
must conform to the ampacity and outer dimensions specified in Table 10
of Appendix I to Subpart D of this part. In addition, the cable must be
constructed with:
(1) 100 percent semi-conductive tape shielding over each insulated
power conductor;
(2) A grounded metallic braid shielding over each insulated power
conductor;
(3) A ground-check conductor not smaller than a No. 10 A.W.G.; or if
a center ground-check conductor is used, not smaller than a No. 16
A.W.G. stranded conductor; and
(4) Either a double-jacketed or single-jacketed cable as follows:
(i) Double jacket. A double-jacketed cable consisting of reinforced
outer and inner protective layers. The inner layer must be a distinctive
color from the outer layer. The color black must not be used for either
protective layer. The tear strength for each layer must be more than 40
pounds per inch thickness and the tensile strength must be more than
2,400 pounds per square inch.
(ii) Single jacket. A single-jacketed cable consisting of one
protective layer. The tear strength must be more than 100 pounds per
inch thickness, and the tensile strength must be more than 4,000 pounds
per square inch. The cable jacket must not be black in color.
(g) Safeguards against corona. Safeguards against corona must be
provided on all 4,160-voltage circuits in explosion-proof enclosures.
(h) Explosion-proof enclosure design. The maximum pressure rise
within an explosion-proof enclosure containing high-voltage switchgear
must be limited to 0.83 times the design pressure.
(i) Location of high-voltage electrical components near flame paths.
High-voltage electrical components located in high-voltage explosion-
proof enclosures must not be coplanar with a single plane flame-
arresting path.
(j) Minimum creepage distances. Rigid insulation between high-
voltage terminals (Phase-to-Phase or Phase-to-Ground) must be designed
with creepage distances in accordance with the following table:
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minimum creepage distances (inches) for comparative tracking index (CTI)
range \1\
Points of ---------------------------------------------------------------------------
Phase-to-phase voltage measure 380 CTI <500 175 CTI <380
CTI $500 CTI <175
--------------------------------------------------------------------------------------------------------------------------------------------------------
2,400..................................................... 0-0 1.50 1.95 2.40 2.90
0-G 1.00 1.25 1.55 1.85
4,160..................................................... 0-0 2.40 3.15 3.90 4.65
0-G 1.50 1.95 2.40 2.90
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Assumes that all insulation is rated for the applied voltage or higher.
(k) Minimum free distances. Motor-starter enclosures must be
designed to establish the minimum free distance (MFD) between the wall
or cover of the enclosure and uninsulated electrical conductors inside
the enclosure in accordance with the following table:
----------------------------------------------------------------------------------------------------------------
Steel MFD (in) Aluminum MFD (in)
Wall/cover thickness (in) -----------------------------------------------------------------------------
A \1\ B \2\ C \3\ A \1\ B \2\ C \3\
----------------------------------------------------------------------------------------------------------------
\1/4\............................. 2.8 4.3 5.8 \4\ NA \4\ NA \4\ NA
\3/8\............................. 1.8 2.3 3.9 8.6 12.8 18.1
\1/2\............................. * 1.2 2.0 2.7 6.5 9.8 13.0
\5/8\............................. * 0.9 1.5 2.1 5.1 7.7 10.4
\3/4\............................. * 0.6 * 1.1 1.6 4.1 6.3 8.6
1................................. * * 0.6 * 1.0 2.9 4.5 6.2
----------------------------------------------------------------------------------------------------------------
* Note: The minimum electrical clearances must still be maintained in accordance with the minimum clearance
table of Sec. 18.24.
\1\ Column A specifies the MFD for enclosures that have available three-phase, bolted, short-circuit currents of
10,000 amperes root-mean-square (rms) value or less.
\2\ Column B specifies the MFD for enclosures that have maximum available three-phase, bolted, short-circuit
currents greater than 10,000 and less than or equal to 15,000 amperes rms.
\3\ Column C specifies the MFD for enclosures that have maximum available three-phase, bolted, short-circuit
currents greater than 15,000 and less than or equal to 20,000 amperes rms.
[[Page 126]]
\4\ Not Applicable--MSHA does not allow aluminum wall or covers to be \1/4\ inch or less in thickness. (See also
Sec. 18.31.)
(1) For values not included in the table, the following formulas, on
which the table is based, may be used to determine the minimum free
distance.
(i) Steel Wall/Cover:
[GRAPHIC] [TIFF OMITTED] TR06AP10.000
(ii) Aluminum Wall/Cover:
[GRAPHIC] [TIFF OMITTED] TR06AP10.001
Where ``C'' is 1.4 for 2,400 volt systems or 3.0 for 4,160 volt systems;
``Isc'' is the three-phase, short-circuit current in amperes
of the system; ``t'' is the clearing time in seconds of the outby
circuit-interrupting device; and ``d'' is the thickness in inches of the
metal wall/cover adjacent to an area of potential arcing.
(2) The minimum free distance must be increased by 1.5 inches for
4,160 volt systems and 0.7 inches for 2,400 volt systems when the
adjacent wall area is the top of the enclosure. If a steel shield is
mounted in conjunction with an aluminum wall or cover, the thickness of
the steel shield is used to determine the minimum free distances.
(l) Static pressure testing of explosion-proof enclosures containing
high-voltage switchgear--(1) Prototype enclosures. The following static
pressure test must be performed on each prototype design of an
explosion-proof enclosure containing high-voltage switchgear prior to
the explosion tests.
(i) Test procedure. (A) The enclosure must be internally pressurized
to at least the design pressure, maintaining the pressure for a minimum
of 10 seconds.
(B) Following the pressure hold, the pressure must be removed and
the pressurizing agent removed from the enclosure.
(ii) Acceptable performance. (A) During pressurization, the
enclosure must not exhibit:
(1) Leakage through welds or casting; or
(2) Rupture of any part that affects the explosion-proof integrity
of the enclosure.
(B) Following removal of the pressurizing agents, the enclosure must
not exhibit:
(1) Cracks in welds visible to the naked eye;
(2) Permanent deformation exceeding 0.040 inches per linear foot; or
(3) Excessive clearances along flame-arresting paths following
retightening of fastenings, as necessary.
(2) Enclosures for production. Every explosion-proof enclosure
containing high-voltage switchgear manufactured after the prototype was
tested must undergo one of the following tests or procedures:
(i) The static pressure test specified in paragraph (l)(1)(i) of
this section; or
(ii) An MSHA-accepted quality assurance procedure covering
inspection of the enclosure.
(A) The quality assurance procedure must include a detailed check of
parts against the drawings to determine that--
(1) The parts and the drawings coincide; and
[[Page 127]]
(2) The requirements stated in part 18 have been followed with
respect to materials, dimensions, configuration and workmanship.
(B) [Reserved]
[75 FR 17547, Apr. 6, 2010]
Subpart C_Inspections and Tests
Sec. 18.60 Detailed inspection of components.
An inspection of each electrical component shall include the
following:
(a) A detailed check of parts against the drawings submitted by the
applicant to determine that: (1) The parts and drawings coincide; and
(2) the minimum requirements stated in this part have been met with
respect to materials, dimensions, configuration, workmanship, and
adequacy of drawings and specifications.
(b) Exact measurement of joints, journal bearings, and other flame-
arresting paths.
(c) Examination for unnecessary through holes.
(d) Examination for adequacy of lead-entrance design and
construction.
(e) Examination for adequacy of electrical insulation and clearances
between live parts and between live parts and the enclosure.
(f) Examination for weaknesses in welds and flaws in castings.
(g) Examination for distortion of enclosures before tests.
(h) Examination for adequacy of fastenings, including size, spacing,
security, and possibility of bottoming.
Sec. 18.61 Final inspection of complete machine.
(a) A completely assembled new machine or a substantially modified
design of a previously approved one shall be inspected by a qualified
representative(s) of MSHA. When such inspection discloses any unsafe
condition or any feature not in strict conformance with the requirements
of this part it shall be corrected before an approval of the machine
will be issued. A final inspection will be conducted at the site of
manufacture, rebuilding, or other locations at the option of MSHA.
(b) Complete machines shall be inspected for:
(1) Compliance with the requirements of this part with respect to
joints, lead entrances, and other pertinent features.
(2) Wiring between components, adequacy of mechanical protection for
cables, adequacy of clamping of cables, positioning of cables,
particularly with respect to proximity to hydraulic components.
(3) Adequacy of protection against damage to headlights, push
buttons, and any other vulnerable component.
(4) Settings of overload- and short-circuit protective devices.
(5) Adequacy of means for connecting and protecting portable cable.
Sec. 18.62 Tests to determine explosion-proof characteristics.
(a) In testing for explosion-proof characteristics of an enclosure,
it shall be filled and surrounded with various explosive mixtures of
natural gas and air. The explosive mixture within the enclosure will be
ignited electrically and the explosion pressure developed therefrom
recorded. The point of ignition within the enclosure will be varied.
Motor armatures and/or rotors will be stationary in some tests and
revolving in others. Coal dust having a minimum of 22 percent dry
volatile matter and a minimum heat constant of 11,000 moist BTU (coal
containing natural bed moisture but not visible surface water) ground to
a fineness of minus 200 mesh U.S. Standard sieve series. At MSHA's
discretion dummies may be substituted for internal electrical components
during some of the tests. Not less than 16 explosion tests shall be
conducted; however, the nature of the enclosure and the results obtained
during the tests will determine whether additional tests shall be made.
(b) Explosion tests of an enclosure shall not result in:
(1) Discharge of flame.
(2) Ignition of an explosive mixture surrounding the enclosure.
(3) Development of afterburning.
(4) Rupture of any part of the enclosure or any panel or divider
within the enclosure.
(5) Permanent distortion of the enclosure exceeding 0.040 inch per
linear foot.
[[Page 128]]
(c) When a pressure exceeding 125 pounds per square inch (gage) is
developed during explosion tests, MSHA reserves the right to reject an
enclosure(s) unless (1) constructional changes are made that result in a
reduction of pressure to 125 pounds per square inch (gage) or less, or
(2) the enclosure withstands a dynamic pressure of twice the highest
value recorded in the initial test.
[33 FR 4660, Mar. 19, 1968, as amended at 57 FR 61210, Dec. 23, 1992]
Sec. 18.63 [Reserved]
Sec. 18.65 Flame test of hose.
(a) Size of test specimen. (1) [Reserved]
(2) Hose--four specimens each 6 inches long by \1/2\-inch wide by
thickness of the hose.
(b) Flame-test apparatus. The principal parts of the apparatus
within and/or appended to a 21-inch cubical test gallery are:
(1) A support stand with a ring clamp and wire gauze.
(2) A Pittsburgh-Universal Bunsen-type burner (inside diameter of
burner tube 11 mm.), or equivalent, mounted in a burner placement guide
in such a manner that the burner may be placed beneath the test
specimen, or pulled away from it by an external knob on the front panel
of the test gallery.
(3) A variable-speed electric fan and an ASME flow nozzle (16-8\1/2\
inches reduction) to attain constant air velocities at any speed between
50-500 feet a minute.
(4) An electric timer or stopwatch to measure the duration of the
tests.
(5) A mirror mounted inside the test gallery to permit a rear view
of the test specimen through the viewing door.
(c) Mounting of test specimen. The specimen shall be clamped in a
support with its free end centered 1 inch above the burner top. The
longitudinal axis shall be horizontal and the transverse axis inclined
at 45 to the horizontal. Under the test specimen shall be clamped a
piece of 20-mesh iron-wire gauze, 5 inches square, in a horizontal
position \1/4\-inch below the pulley cover edge of the specimen and with
about \1/2\-inch of the specimen extending beyond the edge of the gauze.
(d) Procedure for flame tests. (1) The Bunsen burner, retracted from
the test position, shall be adjusted to give a blue flame 3 inches in
height with natural gas.
(2) The observation door of the gallery shall be closed for the
entire test.
(3) The burner flame shall be applied to the free end of the
specimen for 1 minute in still air.
(4) At the end of 1 minute the burner flame shall be removed, the
ventilating fan turned on to give an air current having a velocity of
300 feet per minute, and the duration of flame measured.
(5) After the test specimen ceases to flame, it shall remain in the
air current for at least 3 minutes to determine the presence and
duration of afterglow. If a glowing specimen exhibits flame within 3
minutes the duration of flame shall be added to the duration of flame
obtained according to paragraph (d) (4) of this section.
(e) Test requirements. The tests of the four specimens cut from any
sample shall not result in either duration of flame exceeding an average
of 1 minute after removal of the applied flame or afterglow exceeding an
average of 3 minutes duration.
(f) Acceptance markings. (1) [Reserved]
(2) Hose--hose conduit accepted by MSHA as flame-resistant shall be
marked as follows: Impressed letters, raised letters on depressed
background, or printed letters with the words ``Flame-Resistant, USMSHA
No. __'' at intervals not exceeding 3 feet. This number will be assigned
to the manufacturer after the sample has passed the tests. The letters
and numbers shall be at least \1/4\-inch high.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 73
FR 80612, Dec. 31, 2008]
Sec. 18.66 Tests of windows and lenses.
(a) Impact tests. A 4-pound cylindrical weight with a 1-inch-
diameter hemispherical striking surface shall be dropped (free fall) to
strike the window or lens in its mounting, or the equivalent thereof, at
or near the center. Three of four samples shall withstand without
breakage the impact according to the following table:
[[Page 129]]
------------------------------------------------------------------------
Height of
Lens diameter, (D), inches fall,
inches
------------------------------------------------------------------------
D<4......................................................... 6
4D<5........................................................ 9
5D<6........................................................ 15
6D.......................................................... 24
------------------------------------------------------------------------
Windows or lenses of smaller diameter than 1 inch may be tested by
alternate methods at the discretion of MSHA.
(b) Thermal-shock tests. Four samples of the window or lens will be
heated in an oven for 15 minutes to a temperature of 150 C. (302 F.)
and immediately upon withdrawal of the samples from the oven they will
be immersed in water having a temperature between 15 C. (59 F) and 20
C. (68 F.). Three of the four samples shall show no defect or breakage
from this thermal-shock test.
Sec. 18.67 Static-pressure tests.
Static-pressure tests shall be conducted by the applicant on each
enclosure of a specific design when MSHA determines that visual
inspection will not reveal defects in castings or in single-seam welds.
Such test procedure shall be submitted to MSHA for approval and the
specifications on file with MSHA shall include a statement assuring that
such tests will be conducted. The static pressure to be applied shall be
150 pounds per square inch (gage) or one and one-half times the maximum
pressure recorded in MSHA's explosion tests, whichever is greater.
Sec. 18.68 Tests for intrinsic safety.
(a) General:
(1) Tests for intrinsic safety will be conducted under the general
concepts of ``intrinsically safe'' as defined in Subpart A of this part.
Further tests or requirements may be added at any time if features of
construction or use or both indicate them to be necessary. Some tests
included in these requirements may be omitted on the basis of previous
experience.
(2) Intrinsically safe circuits and/or components will be subjected
to tests consisting of making and breaking the intrinsically safe
circuit under conditions judged to simulate the most hazardous probable
faults or malfunctions. Tests will be made in the most easily ignitable
mixture of methane or natural gas and air. The method of making and
breaking the circuit may be varied to meet a particular condition.
(3) Those components which affect intrinsic safety must meet the
following requirements:
(i) Current limiting components shall consist of two equivalent
devices each of which singly will provide intrinsic safety. They shall
not be operated at more than 50 percent of their ratings.
(ii) Components of reliable construction shall be used and they
shall be so mounted as to provide protection against shock and vibration
in normal use.
(iii) Semiconductors shall be amply sized. Rectifiers and
transistors shall be operated at not more than two-thirds of their rated
current and permissible peak inverse voltage. Zener diodes shall be
operated at not more than one-half of their rated current and shall
short under abnormal conditions.
(iv) Electrolytic capacitors shall be operated at not more than two-
thirds of their rated voltage. They shall be designed to withstand a
test voltage of 1,500 volts.
(4) Intrinsically safe circuits shall be so designed that after
failure of a single component, and subsequent failures resulting from
this first failure, the circuit will remain intrinsically safe.
(5) The circuit will be considered as intrinsically safe if in the
course of testing no ignitions occur.
(b) Complete intrinsically safe equipment powered by low energy
batteries:
(1) Short-circuit tests shall be conducted on batteries at normal
operating temperature. Tests may be made on batteries at elevated
temperature if such tests are deemed necessary.
(2) Resistance devices for limiting short-circuit current shall be
an integral part of the battery, or installed as close to the battery
terminal as practicable.
(3) Transistors of battery-operated equipment may be subjected to
thermal ``run-away'' tests to determine that they will not ignite an
explosive atmosphere.
(4) A minimum of 1,000 make-break sparks will be produced in each
test for
[[Page 130]]
direct current circuits with consideration given to reversed polarity.
(5) Tests on batteries shall include series and/or parallel
combinations of twice the normal battery complement, and the effect of
capacitance and inductance, added to that normally present in the
circuit.
(6) No ignition shall occur when approximately \1/2\-inch of a
single wire strand representative of the wire used in the equipment or
device is shorted across the intrinsically safe circuit.
(7) Consideration shall be given to insure against accidental
reversal of polarity.
(c) Line-powered equipment and devices:
(1) Line-powered equipment shall meet all applicable provisions
specified for battery-powered equipment.
(2) Nonintrinsically safe components supplying power for
intrinsically safe circuits shall be housed in explosion-proof
enclosures and be provided with energy limiting components in the
enclosure.
(3) Wiring for nonintrinsically safe circuits shall not be
intermingled with wiring for intrinsically safe circuits.
(4) Transformers that supply power for intrinsically safe circuits
shall have the primary and secondary windings physically separated. They
shall be designed to withstand a test voltage of 1,500 volts when rated
125 volts or less and 2,500 volts when rated more than 125 volts.
(5) The line voltage shall be increased to 120 percent of nominal
rated voltage to cover power line voltage variations.
(6) In investigations of alternating current circuits a minimum of
5,000 make-break sparks will be produced in each test.
(d) The design of intrinsically safe circuits shall preclude
extraneous voltages caused by insufficient isolation or inductive
coupling. The investigation shall determine the effect of ground faults
where applicable.
(e) Identification markings: Circuits and components of
intrinsically safe equipment and devices shall be adequately identified
by marking or labeling. Battery-powered equipment shall be marked to
indicate the manufacturer, type designation, ratings, and size of
batteries used.
Sec. 18.69 Adequacy tests.
MSHA reserves the right to conduct appropriate test(s) to verify the
adequacy of equipment for its intended service.
Subpart D_Machines Assembled With Certified or Explosion-Proof
Components, Field Modifications of Approved Machines, and Permits To Use
Experimental Equipment
Sec. 18.80 Approval of machines assembled with certified or explosion-proof components.
(a) A machine may be a new assembly, or a machine rebuilt to perform
a service that is different from the original function, or a machine
converted from nonpermissible to permissible status, or a machine
converted from direct- to alternating-current power or vice versa.
Properly identified components that have been investigated and accepted
for application on approved machines will be accepted in lieu of
certified components.
(b) A single layout drawing (see Figure 1 in Appendix II) or
photographs will be acceptable to identify a machine that was assembled
with certified or explosion-proof components. The following information
shall be furnished:
(1) Overall dimensions.
(2) Wiring diagram.
(3) List of all components (see Figure 2 in Appendix II) identifying
each according to its certification number or the approval number of the
machine of which the component was a part.
(4) Specifications for:
(i) Overcurrent protection of motors.
(ii) All wiring between components, including mechanical protection
such as hose conduits and clamps.
(iii) Portable cable, including the type, length, outside diameter,
and number and size of conductors.
(iv) Insulated strain clamp for machine end of portable cable.
(v) Short-circuit protection to be provided at outby end of portable
cable.
(c) MSHA reserves the right to inspect and to retest any
component(s) that had been in previous service, as it deems appropriate.
[[Page 131]]
(d) When MSHA has determined that all applicable requirements of
this part have been met, the applicant will be authorized to attach an
approval plate to each machine that is built in strict accordance with
the drawings and specifications filed with MSHA and listed with MSHA's
formal approval. A design of the approval plate will accompany the
notification of approval. (Refer to Secs. 18.10 and 18.11.)
(e) Approvals are issued only by the U.S. Department of Labor, Mine
Safety and Health Administration, Approval and Certification Center, 765
Technology Drive, Triadelphia, WV 26059.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 52
FR 17514, May 8, 1987; 73 FR 52211, Sept. 9, 2008]
Sec. 18.81 Field modification of approved (permissible) equipment;
application for approval of modification; approval of plans for
modification before modification.
(a) An owner of approved (permissible) equipment who desires to make
modifications in such equipment shall apply in writing to make such
modifications. The application, together with the plans of
modifications, shall be filed with the U.S. Department of Labor, Mine
Safety and Health Administration, Approval and Certification Center, 765
Technology Drive, Triadelphia, WV 26059.
(b) Proposed modifications shall conform with the applicable
requirements of subpart B of this part, and shall not substantially
alter the basic functional design that was originally approved for the
equipment.
(c) Upon receipt of the application for modification, and after such
examination and investigation as may be deemed necessary by MSHA, MSHA
will notify the owner and the District office of the mine workers'
organization having jurisdiction at the mine where such equipment is to
be operated stating the modifications which are proposed to be made and
MSHA's action thereon.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 60
FR 35693, July 11, 1995; 73 FR 52211, Sept. 9, 2008]
Sec. 18.82 Permit to use experimental electric face equipment
in a gassy mine or tunnel.
(a) Application for permit. An application for a permit to use
experimental electric face equipment in a gassy mine or tunnel will be
considered only when submitted by the user of the equipment. The user
shall submit a written application to the Assistant Secretary of Labor
for Mine Safety and Health, 201 12th Street South, Arlington, VA 22202-
5452, and send a copy to the U.S. Department of Labor, Mine Safety and
Health Administration, Approval and Certification Center, 765 Technology
Drive, Triadelphia, WV 26059.
(b) Requirements--(1) Constructional. (i) Experimental equipment
shall be so constructed that it will not constitute a fire or explosion
hazard.
(ii) Enclosures designed as explosion-proof, unless already
certified, or components of previously approved (permissible) machines,
shall be submitted to MSHA for inspection and test and shall meet the
applicable design requirements of subpart B of this part. Components
designed as intrinsically safe also shall be submitted to MSHA for
investigation.
(iii) MSHA may, at its discretion, waive the requirements for
detailed drawings of component parts, inspections, and tests provided
satisfactory evidence is submitted that an enclosure has been certified,
or otherwise accepted by a reputable testing agency whose standards are
substantially equivalent to those set forth in subpart B of this part.
(2) Specifications. The specifications for experimental equipment
shall include a layout drawing (see Figure 1 in Appendix II) or
photograph(s) with the components, including overcurrent-protective
device(s) with setting(s) identified thereon or separately; a wiring
diagram; and descriptive material necessary to insure safe operation of
the equipment. Drawings already filed with MSHA need not be duplicated
by the applicant, but shall be properly identified.
(c) Final inspection. Unless equipment is delivered to MSHA for
investigation, the applicant shall notify the U.S. Department of Labor,
Mine Safety and Health Administration, Approval and
[[Page 132]]
Certification Center, 765 Technology Drive, Triadelphia, WV 26059, when
and where the experimental equipment will be ready for inspection by a
representative of MSHA before installing it on a trial basis. Such
inspection shall be completed before a permit will be issued.
(d) Issuance of permit. When the inspection discloses full
compliance with the applicable requirements of this subpart, the
Assistant Secretary will issue a permit sanctioning the operation of a
single unit in a gassy mine or tunnel, as designated in the application.
If the applicant is not the assembler of the equipment, a copy of the
permit also may be sent to the assembler.
(e) Duration of permit. A permit will be effective for a period of 6
months. For a valid reason, to be stated in a written application, the
Administrator of MSHA may grant an extension of a permit for an
additional period, not exceeding 6 months. Further extension will be
granted only where, after investigation, the Assistant Secretary finds
that for reasons beyond the control of the user, it has not been
possible to complete the experiment within the period covered by the
extended permit.
(f) Permit label. With the notification granting a permit, the
applicant will receive a photographic copy of a permit label bearing the
following:
(1) Emblem of the Mine Safety and Health Administration.
(2) Permit number.
(3) Expiration date of the permit.
(4) Name of machine.
(5) Name of the user and mine or tunnel.
The applicant shall attach the photographic copy of the permit label, or
replica thereof, to the experimental equipment. If a photograph is used,
a clear plastic covering shall be provided for it.
(g) Withdrawal of permit. The Assistant Secretary may rescind, for
cause, any permit granted under this subpart.
[33 FR 4660, Mar. 19, 1968, as amended at 43 FR 12314, Mar. 24, 1978; 52
FR 17514, May 8, 1987; 60 FR 35693, July 11, 1995; 67 FR 38384, June 4,
2002; 73 FR 52211, Sept. 9, 2008; 80 FR 52985, Sept. 2, 2015]
Sec. Appendix I to Subpart D of Part 18
LIST OF TABLES
------------------------------------------------------------------------
Table
No. Title
------------------------------------------------------------------------
1 Portable power cable ampacities--600 volts.
2 Portable cord ampacities--600 volts.
3 Portable power cable ampacities--601 to 5,000 volts.
4 Normal diameter of round cables with tolerances in inches--600
volts.
5 Nominal dimension of flat cables with tolerances in inches--600
volts.
6 Nominal diameter of heavy jacketed cords with tolerances in
inches--600 volts.
7 Nominal diameter of three-conductor portable power cables with
tolerances in inches--601 to 5,000 volts.
8 Fuse ratings or instantaneous settings of circuit breakers for
short-circuit protection of portable cables.
9 Specifications for portable cables longer than 500 feet.
10 High voltage trailing cable ampacities and outside diameters.
------------------------------------------------------------------------
Table 1--Portable Power Cable Ampacities--600 Volts (Amperes Per Conductor Based on 60 C. Copper Temperature--40
C. Ambient)
----------------------------------------------------------------------------------------------------------------
2- 3-
Single conductor, conductor,
Conductor size--AWG or MCM conductor round or round or 4-conductor 5-conductor 6-conductor
flat flat
----------------------------------------------------------------------------------------------------------------
8................................. 45 40 35 30 25 20
6................................. 60 50 50 40 35 30
4................................. 85 70 65 55 45 35
3................................. 95 80 75 65 55 45
2................................. 110 95 90 75 65 55
1................................. 130 110 100 85 75 65
1/0............................... 150 130 120 100 90 80
2/0............................... 175 150 135 115 105 95
3/0............................... 205 175 155 130 120 110
4/0............................... 235 200 180 150 140 130
250............................... 275 220 200 160 ........... ...........
300............................... 305 240 220 175 ........... ...........
[[Page 133]]
350............................... 345 240 235 190 ........... ...........
400............................... 375 280 250 200 ........... ...........
450............................... 400 300 270 215 ........... ...........
500............................... 425 320 290 230 ........... ...........
----------------------------------------------------------------------------------------------------------------
Table 2--Portable Cord Ampacities--600 Volts (Amperes Per Conductor Based on 60 C. Copper Temperature--40 C.
Ambient)
----------------------------------------------------------------------------------------------------------------
Conductor size--AWG 1-3 conductor 4-6 conductor 7-9 conductor
----------------------------------------------------------------------------------------------------------------
14......................................... 15 12 8
12......................................... 20 16 11
10......................................... 25 20 14
----------------------------------------------------------------------------------------------------------------
Table 3--Portable Power Cable Ampacities--601 to 5,000 Volts (Amperes Per Conductor Based on 75 C. Copper
Temperature--40 C. Ambient)
----------------------------------------------------------------------------------------------------------------
3-conductor types G-GC and SIIC-GC 3-conductor type SHD-GC 2,001-5,000
Conductor size--AWG or MCM 2,000 volts volts
----------------------------------------------------------------------------------------------------------------
6............................. 65 65
4............................. 85 85
3............................. 100 100
2............................. 115 115
1............................. 130 130
1/0........................... 145 145
2/0........................... 170 170
3/0........................... 195 195
4/0........................... 220 220
250........................... 245 245
300........................... 275 275
350........................... 305 305
----------------------------------------------------------------------------------------------------------------
Table 4--Nominal Diameters of Round Cables With Tolerances in Inches--600 Volts
--------------------------------------------------------------------------------------------------------------------------------------------------------
2-conductor 3-conductor 6-conductor
------------------------------------------------------- -------------------
Type 4-conductor-- 5-conductor--
Conductor size--AWG or MCM Single Types W Type Type Type PCG, 3 Types W & G Types W & G
conductor & G PG, 2 PCG, 3 Types W PG, 3 power, 2 Type w Tolerance
twisted power power, & G power, control,
ground ground ground
--------------------------------------------------------------------------------------------------------------------------------------------------------
8............................. 0.44 0.81 0.84 0.94 0.91 0.93 1.03 0.99 1.07 1.18 0.03
6............................. .51 .93 .93 .98 1.01 1.03 1.18 1.10 1.21 1.31 .03
4............................. .57 1.08 1.08 1.10 1.17 1.20 1.29 1.27 1.40 1.52 .03
3............................. .63 1.17 1.17 1.20 1.24 1.27 1.31 1.34 1.48 1.61 .03
2............................. .66 1.27 1.27 1.29 1.34 1.34 1.39 1.48 1.61 1.75 .03
1............................. .74 1.44 1.44 1.44 1.51 1.52 1.52 1.68 1.88 2.05 .03
1/0........................... .77 1.52 1.52 1.52 1.65 1.68 1.68 1.79 1.96 2.13 .04
2/0........................... .82 1.65 1.65 1.65 1.75 1.79 1.79 1.93 2.13 2.32 .04
3/0........................... .87 1.77 1.77 1.77 1.89 1.93 1.93 2.07 2.26 2.49 .05
4/0........................... .93 1.92 1.92 1.92 2.04 2.13 2.13 2.26 2.46 2.71 .05
250........................... 1.03 2.16 2.16 2.16 2.39 2.39 2.39 2.66 ................ ....... .06
300........................... 1.09 2.32 ....... ....... 2.56 ....... ........ 2.84 ................ ....... .06
350........................... 1.15 2.43 ....... ....... 2.68 ....... ........ 2.98 ................ ....... .06
400........................... 1.20 2.57 ....... ....... 2.82 ....... ........ 3.14 ................ ....... .06
450........................... 1.26 2.67 ....... ....... 2.94 ....... ........ 3.26 ................ ....... .06
500........................... 1.31 2.76 ....... ....... 3.03 ....... ........ 3.40 ................ ....... .06
--------------------------------------------------------------------------------------------------------------------------------------------------------
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Table 5--Nominal Dimensions of Flat Cables With Tolerances in Inches--600 Volts
--------------------------------------------------------------------------------------------------------------------------------------------------------
2-conductor 3-conductor--Type G
-----------------------------------------------------------------------------------------------------------------------
Type W Type G Major Minor
Conductor size--AWG -----------------------------------------------------------------------------------------------------------------------
Major Minor Major Minor
-------------------------------------------------------------------------------- O.D. Tolerance O.D. Tolerance
O.D. Tolerance O.D. Tolerance O.D. Tolerance O.D. Tolerance
--------------------------------------------------------------------------------------------------------------------------------------------------------
8............................... 0.84 0.04 0.51 0.03
6............................... .93 .04 .56 .03 1.02 .04 0.56 .03 1.65 0.06 0.67 0.05
4............................... 1.05 .04 .61 .03 1.15 .04 .61 .03 1.85 .06 .75 .05
3............................... 1.14 .04 .68 .03 1.26 .04 .68 .03 1.99 .06 .77 .05
2............................... 1.24 .04 .73 .03 1.35 .04 .73 .06 2.10 .06 .81 .05
1............................... 1.40 .04 .81 .03 1.55 .04 .81 .03 2.43 .06 .97 .05
1/0............................. 1.51 .04 .93 .03 1.67 .04 .93 .03
2/0............................. 1.63 .04 .99 .03 1.85 .04 .99 .03
3/0............................. 1.77 .04 1.03 .03 2.00 .04 1.03 .03
4/0............................. 1.89 .04 1.10 .03 2.10 .04 1.10 .03
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6--Nominal Diameters of Heavy Jacketed Cords With Tolerances In Inches--600 Volts
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2-conductor 3-conductor 4-conductor 5-conductor 6-conductor 7-conductor
Conductor size--AWG -----------------------------------------------------------------------------------------------------------------------------
Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance Diameter Tolerance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
14................................................................ 0.64 0.02 0.67 0.02 0.71 0.02 0.78 0.03 0.83 0.03 0.89 0.03
12................................................................ .68 .02 .72 .03 .76 .03 .83 .03 .89 .03 .98 .03
10................................................................ .73 .03 .80 .03 .84 .03 .90 .03 1.00 .03 1.07 .03
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 7--Nominal Diameters of Three-Conductor Portable Power Cables With Tolerances in Inches--601 to 5,000 Volts
--------------------------------------------------------------------------------------------------------------------------------------------------------
Type G-GC Type SHC-GC (shielded Type SHD-GC Type SHD-GC
(nonshielded) 2,000 overall) 2,000 volts (individually (individually
volts ----------------------- shielded power shielded power
Conductor size--AWG or MCM ----------------------- conductors) 2,001- conductors) 3,001-
3,000 volts 5,000 volts
Diameter Tolerance Diameter Tolerance ---------------------------------------------
Diameter Tolerance Diameter Tolerance
--------------------------------------------------------------------------------------------------------------------------------------------------------
6........................................................... 1.25 + 0.10, 1.39 + 0.11, 1.62 + 0.13, 1.78 + 0.14,
^0.06 ^0.07 ^0.08 ^0.09
4........................................................... 1.40 + .11, 1.55 + .12, 1.77 + .14, 1.90 + .15,
^.07 ^.08 ^.09 ^.10
3........................................................... 1.48 + .12, 1.62 + .13, 1.84 + .15, 1.98 + .16,
^.07 ^.08 ^.09 ^.10
2........................................................... 1.55 + .12, 1.71 + .14, 1.92 + .15, 2.09 + .17,
^.08 ^.09 ^.10 ^.11
1........................................................... 1.74 + .14, 1.89 + .15, 2.04 + .16, 2.18 + .17,
^.09 ^.09 ^.10 ^.11
1/0......................................................... 1.84 + .15, 2.02 + .16, 2.18 + .17, 2.34 + .19,
^.09 ^.10 ^.11 ^.12
2/0......................................................... 1.99 + .16, 2.16 + .17, 2.29 + .18, 2.46 + .20,
^.10 ^.11 ^.12 ^.12
3/0......................................................... 2.12 + .17, 2.30 + .18, 2.45 + .20, 2.62 + .21,
^.11 ^.11 ^.12 ^.13
4/0......................................................... 2.30 + .18, 2.48 + .20, 2.62 + .21, 2.76 + .22,
^.12 ^.12 ^.13 ^.14
250......................................................... 2.46 + .20, 2.70 + .22, ........ ........... ........ ...........
^.12 ^.13
300......................................................... 2.63 + .21, 2.84 + .23, ........ ........... ........ ...........
^.13 ^.14
350......................................................... 2.75 + .22, 2.97 + .24, ........ ........... ........ ...........
^.14 ^.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 8--Fuse Ratings or Instantaneous Setting of Circuit Breakers for Short-Circuit Protection of Portable Cables and Cords
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum allowable circuit
Conductor size--AWG or MCM Ohms/1,000 ft. at 25 C. Maximum allowable fuse breaker instantaneous
rating (amperes) setting (amperes) \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
14............................................................ 2.62 20 50
12............................................................ 1.65 30 75
10............................................................ 1.04 40 150
8............................................................. .654 80 200
6............................................................. .410 100 300
4............................................................. .259 200 500
3............................................................. .205 250 600
2............................................................. .162 300 800
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1............................................................. .129 375 1,000
1/0........................................................... .102 500 1,250
2/0........................................................... .081 ............................ 1,500
3/0........................................................... .064 ............................ 2,000
4/0........................................................... .051 ............................ 2,500
250........................................................... .043 ............................ 2,500
300........................................................... .036 ............................ 2,500
350........................................................... .031 ............................ 2,500
400........................................................... .027 ............................ 2,500
450........................................................... .024 ............................ 2,500
500........................................................... .022 ............................ 2,500
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Higher circuit-breaker settings may be permitted for special applications when justified.
Table 9--Specifications for Portable Cables Longer Than 500 Feet \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Normal ampacity at 60 C.
Conductor size--AWG or MCM Max. allowable length (feet) copper temperature (40 C. Resistance at 60 C. copper
ambient) temperature (ohms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
6............................................................. 550 50 0.512
4............................................................. 600 70 .353
3............................................................. 650 80 .302
2............................................................. 700 95 .258
1............................................................. 750 110 .220
1/0........................................................... 800 130 .185
2/0........................................................... 850 150 .157
3/0........................................................... 900 175 .130
4/0........................................................... 1,000 200 .116
250........................................................... 1,000 220 .098
300........................................................... 1,000 240 .082
350........................................................... 1,000 260 .070
400........................................................... 1,000 280 .061
450........................................................... 1,000 300 .054
500........................................................... 1,000 320 .050
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Fuses shall not be used for short-circuit protection of these cables. Circuit breakers shall be used with the instantaneous trip settings not to
exceed the values given in Table 8.
[33 FR 4660, Mar. 19, 1968; 33 FR 6345, Apr. 26, 1968, as amended at 42
FR 8373, Feb. 10, 1977]
Table 10--High Voltage Trailing Cable Ampacities and Outside Diameters
----------------------------------------------------------------------------------------------------------------
Power conductor Ampacity * Outside diameter ** (inches)
----------------------------------------------------------------------------------------------------------------
Amperes per SHD-GC 2001 to SHD-CGC 2001 to SHD-PCG 2001 to
Size AWG or kcmil conductor 5000 volts 5000 volts 5000 volts
----------------------------------------------------------------------------------------------------------------
6....................................... 93 1.56 1.62
4....................................... 122 1.68 1.73
3....................................... 140 1.78 1.82 1.94
2....................................... 159 1.87 1.91 2.03
1....................................... 184 1.95 1.98 2.12
1/0..................................... 211 2.08 2.10 2.26
2/0..................................... 243 2.20 2.20 2.40
3/0..................................... 279 2.36 2.36 2.58
4/0..................................... 321 2.50 2.50 2.76
250..................................... 355 2.69 2.69
300..................................... 398 2.81 2.81
350..................................... 435 2.95 2.95
500..................................... 536 3.31 3.31
----------------------------------------------------------------------------------------------------------------
* These ampacities are based on single isolated conductor in air, operated with open-circuited shield for a 90 C
conductor temperature and an ambient temperature of 40 C.
** Tolerances for the outside diameter are + 8%/^5%.
[75 FR 17549, Apr. 6, 2010, as amended at 75 FR 20918, Apr. 22, 2010]
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