[Federal Register Volume 61, Number 236 (Friday, December 6, 1996)]
[Notices]
[Pages 64727-64731]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31065]
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DEPARTMENT OF ENERGY
Office of Energy Efficiency and Renewable Energy
Building Energy Standards Program: Determination Regarding Energy
Efficiency Improvements in the 1995 CABO Model Energy Code for Low-Rise
Residential Buildings
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy (DOE).
ACTION: Notice.
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SUMMARY: The Department of Energy (DOE or Department) today determines
that the 1995 version of the Council of American Building Officials
(CABO) Model Energy Code (Model Energy Code or MEC) would achieve
greater energy efficiency in low-rise residential buidings than the
1993 version of the MEC. This Notice also provides guidance and
procedures covering State Certifications, Statements of Reasons and
Requests for Extensions of Deadlines.
DATES: Certifications, Statements of Reasons, or Requests for
Extensions with regard to the 1995 Model Energy Code are due on or
before December 6, 1998.
ADDRESSES: Certifications, Statements of Reasons, or Requests for
Extensions of Deadlines for Certification Statements by States should
be directed to the Assistant Secretary for Energy Efficiency and
Renewable Energy, Office of Codes and Standards, Mail Station EE-43,
1000 Independence Avenue, SW, Washington, D.C. 20585-0121. Envelopes or
packages should be labeled, ``State Certification of Residential
Building Codes Regarding Energy Efficiency''.
FOR FURTHER INFORMATION CONTACT: Stephen Turchen, U.S. Department of
Energy, Office of Energy Efficiency and Renewable Energy, Forrestal
Building, Mail Station EE-43, 1000 Independence Avenue, S.W.,
Washington, D.C. 20585-0121, Phone: 202-586-6262, FAX: 202-586-4617.
SUPPLEMENTARY INFORMATION:
I. Introduction
A. Statutory Requirements
Title III of the Energy Conservation and Production Act, as amended
(ECPA), establishes requirements for the Building Energy Standards
Program. 42 U.S.C. 6831-6837.
ECPA requires each State, not later than October 24, 1994, to
certify to the Secretary of Energy (Secretary) that it has reviewed the
provisions of its residential building code regarding energy efficiency
and made a determination as to whether it is appropriate for such State
to revise its residential building code provisions to meet or exceed
the 1992 Model Energy Code. The determination is to be: (1) made after
public notice and hearing; (2) in writing; (3) based upon findings
included in such determination and upon evidence presented at the
hearing; and (4) available to the public. 42 U.S.C. 6833(a)(1) and
(a)(2). In addition, if a State makes a determination that it is not
appropriate to revise its residential building code, the State is
required to submit to the Secretary, in writing, the reasons for that
determination, which is to be made available to the public. 42 U.S.C.
6833(a)(4).
ECPA also provides that whenever the 1992 Model Energy Code, or any
successor to that code, is revised, the Secretary must make a
determination, not later than 12 months after such revision, whether
the revised code would improve the energy efficiency of residential
buildings and to publish notice of such determination in the Federal
Register. 42 U.S.C. 6833 (a)(5)(A). If the Secretary determines that
the revision of the 1992 Model Energy Code, or any successor thereof,
improves the energy efficiency in residential buildings, then not later
than two years after the date of the publication of such determination,
each State is required to certify that it has reviewed the provisions
of its residential building code regarding energy efficiency with
respect to the revised or successor code, and has made a determination
as to whether it is appropriate for the State to revise its residential
building code to meet or exceed the provisions of the revised or
successor code. 42 U.S.C. 6833(a)(5)(B). A previous Federal Register
notice (59 FR 36173, July 15,1994) provided notice of the Secretary's
determination that the 1993 Model Energy Code was an improvement over
the 1992 version.
ECPA authorizes the Secretary to permit extensions of the deadlines
for filing the certification described above if the State can
demonstrate that it has made a good faith effort to comply with the
requirements and that it has made significant progress in doing so. 42
U.S.C. 6833(c).
II. Discussion.
A. Improvements in Energy Efficiency for Low-Rise Residential Buildings
as Reflected in the 1995 CABO Model Energy Code
DOE Determination of Improved Energy Efficiency From a Revised Model
Energy Code
DOE believes, the significant differences between the 1995 version
and the 1993 version are as follows: (1) the 1995 MEC incorporates
revised Uo1 values for metal-framed walls; (2) the 1995 MEC
includes revised air infiltration control requirements; (3) the 1995
MEC provides additional instructions for performing whole building
energy analyses in accordance with Chapter 4 of the MEC; and (4) the
1995 MEC provides improved guidance for dealing with thermal
performance of
[[Page 64728]]
fenestration products, air distribution ducts, and crawl space
foundations. The 1995 MEC also includes several minor technical changes
that improve energy efficiency in low-rise residential buildings. These
differences, and their impacts on energy efficiency, are discussed in
further detail below. Based on a review of the differences between the
1993 and 1995 versions of the MEC, as discussed below, the Department
has determined that the 1995 MEC would improve the energy efficiency of
low-rise residential building codes.
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\1\ Uo=the area-weighted average thermal transmittance of
the gross area of the building envelope; i.e., the exterior wall
assembly including fenestration and doors, the roof and ceiling
assembly, and the floor assembly, British thermal unit/
(hour x square feet x degrees Fahrenheit).
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B. Specific Changes in the 1995 Model Energy Code
Inputs for Energy Simulation Analyses
Chapter 4 of both the 1993 and 1995 MEC allows the code user to
perform an energy simulation analysis of the proposed building and the
``standard design'' building (a hypothetical building which meets the
MEC requirements). If the energy consumption of the proposed building
is less than or equal to that of the standard design building, then the
proposed building complies with the MEC. Since this analysis is complex
and often requires the use of computerized energy simulation tools,
Chapter 4 is not widely used in practice.
Chapter 4 in the 1995 MEC specifies assumptions for design
parameters such as air infiltration, distribution system efficiency,
window shading and orientation, internal heat gains, and domestic hot
water consumption that did not appear in the 1993 MEC. Previously, the
selection of input values for these parameters, which are usually
required when performing an energy analysis, was left to the discretion
of the user. Depending on the user's assumptions, the energy
consumption of the proposed and standard design buildings could be
significantly affected.
The 1995 MEC changes in Chapter 4 limit the users' ability to
manipulate many of the required input values, thereby preventing
artificial reductions in the stringency of the code. As an example,
window area and orientation are now specifically addressed. The 1995
MEC stipulates that the window area of the standard design building
must equal the area of the proposed building, with the area equally
distributed on the north, south, east, and west exposures. Since the
1993 MEC had no such stipulations, a Chapter 4 user could assume that
the windows in the standard design could be oriented primarily on the
north side, a high energy use orientation. A large energy ``credit''
towards compliance could then be obtained simply by placing the windows
in the proposed orientation; placing most windows on the south side
results in a low energy use configuration. Thus the Chapter 4 changes
serve to improve the energy efficiency of the 1995 version by ensuring
that reasonable assumptions for the standard design building and
proposed building are made before performing the energy analyses, and
an artificially high ``target'' for energy consumption in the standard
design does not appear.
Recessed Lighting Fixtures
The 1995 MEC limits heat loss and air infiltration through recessed
lighting fixtures located in the building envelope. For buildings using
recessed lighting fixtures, this requirement will improve energy
efficiency. Recessed lighting fixtures were not explicitly addressed in
the 1993 MEC.
Thermal Performance Ratings of Windows and Doors
Windows and doors are a large source of heat loss in today's
insulated residences. Even a small change in window or door U-values
(their proclivity for transmitting heat energy) can have a significant
effect on the energy use in the house. According to a study in 1993 by
the Department's Lawrence Berkeley Laboratory, heating and cooling
energy lost through residential windows alone accounts for 3 percent of
the nation's energy use.
The 1995 MEC incorporates a consistent test procedure that can be
used to determine the thermal performance of fenestration products.
Accurate thermal performance ratings are necessary to ensure that when
these products are claimed to be energy efficient, there is a
standardized, widely recognized test procedure that can substantiate
the claim. Just as there are standardized methods for rating the R-
value of insulation products, the fenestration product U-value test
helps to ensure that the new home does in fact comply with the MEC.
The 1995 MEC includes a testing and rating procedure developed by
the National Fenestration Rating Council (NFRC) pursuant to Section 121
of EPACT. 42 U.S.C. 6292. EPACT assigned the NFRC the responsibility
for developing a window rating system. Specifically the 1995 MEC
requires that:
Fenestration products, if tested for thermal performance,
shall use the NFRC testing and simulation procedure;
If tested for thermal performance, fenestration products
shall have their U-value determined by ``an accredited, independent
laboratory'';
If tested, fenestration products shall be ``labeled and
certified by the manufacturer'' with their U-value rating; and
If the NFRC procedure is not used to test certain
fenestration products, a limited default table appearing in the 1995
MEC shall be used to determine the U-value of those products.
The 1995 MEC will therefore help eliminate intentional and
unintentional discrepancies in tested U-values by referencing only one
test procedure, NFRC 100-91, Procedure for Determining Fenestration
Product Thermal Properties. Previously, the use of different thermal
performance tests by the various fenestration product manufacturers
often resulted in different U-values for the same tested fenestration
products. When fenestration products were ``rated'' based on various
procedures, tests, and assumptions, the meaning of the U-value obtained
using those previous methods was not always clear. For example, some
windows were rated given a ``center-of-glass'' U-value while others
were given ``whole unit'' U-values. Since the former only addressed
heat transmission through the glass at the center of the window, while
the latter evaluated overall performance of the glass, frame, and sash
components, the two values obtained did not represent the same type of
thermal performance and are thus were not comparable. Since the whole
window assembly is clearly the available ``path'' for heat transfer in
the building envelope, the whole window U-values are more appropriate.
The NFRC test procedure is based on a whole unit U-value test
procedure. By referencing this procedure, the 1995 MEC encourages the
use of the whole unit U-value as a measure of window and door
performance, instead of just the center-of-glass U-value.
When specific fenestration product U-values were not available in
the past, the products were often given ``rule-of-thumb'' or arbitrary
ratings. For example, in California, the energy code required a maximum
U-value for windows of 0.65. Until NFRC ratings were required in
California, an operable aluminum framed, dual glazed window was deemed
to satisfy this requirement. After the NFRC rating procedures were
established, these windows were found to have U-values of approximately
0.90.
Because not all windows and doors are NFRC-rated at this time, and
because the 1995 MEC does not require that they be tested using the
NFRC procedure, a default fenestration U-value table is provided for
products which are not NFRC rated. The default table appearing in the
1995 MEC is based on whole-
[[Page 64729]]
product U-values taken from the 1993 ASHRAE Handbook of Fundamentals.
This table accounts for field verifiable fenestration options only,
such as frame construction material, number of panes of glass, or
presence of storm doors when determining the appropriate default U-
value. In this manner, the table ensures that the efficiency of the
windows is not overstated if a default value is used.
The 1995 MEC provision for an accredited, independent laboratory to
perform the U-value tests reduces the potential for inaccurate testing
and ensures unbiased results. Labeling and certification by the
manufacturers will help builders, code officials, and home buyers
recognize the energy efficiency of the fenestration products. Window
labels and certified product directories also simplify compliance and
code enforcement, thereby ensuring that the energy efficiency claimed
for proposed designs will actually be built into the new house.
Overall, the new fenestration product rating, certification, and
labeling procedures in the 1995 MEC will increase energy efficiency of
low-rise residences by ensuring that the thermal performance of the
fenestration products, reflected in their U-value ratings, are based on
a common accurate rating procedure or a field-verifiable default table,
so that the claimed thermal performance is achieved, and by increasing
MEC compliance, awareness, and enforcement through product labeling.
Metal Framed Walls
The 1995 MEC includes criteria that specifically correct for metal
stud framing when calculating the thermal performance of walls using
the ``Design by Component Performance Approach'' of Chapter 5. Because
metal conducts heat more rapidly than wood, metal stud framing results
in a less thermally efficient wall compared to wood framing. Metal
framed walls must increase the wall cavity insulation levels or utilize
insulated sheathing to meet the equivalent efficiency of a wood framed
wall. For example, when R-19 insulation is placed in a wood framed wall
with non-insulated sheathing, the resulting wall U-value is
approximately 0.05. For the same insulation in a metal framed wall the
U-value is approximately 0.10. (A higher U- value means poorer thermal
performance.) Since the wall assembly must still achieve a required U-
value, the metal framed wall will require more installed insulation
than the wood framed wall.
The 1995 MEC will result in improved energy efficiency in buildings
with metal framing by ensuring that the thermal performance of metal
framed walls are calculated accurately when evaluating component
performance under Chapter 5.
Ventilated Crawlspaces
The 1995 MEC requires insulation in the floor above a ventilated
crawl space. When the crawl space wall is insulated and the crawl space
is ventilated, the effectiveness of the crawl space wall insulation is
very limited because outdoor air is allowed into the space through the
vents, thereby bypassing the insulation. Requiring floor insulation for
ventilated crawlspace will improve the energy efficiency of residential
buildings by ensuring that conditioned space is truly thermally
isolated from outside air or unconditioned spaces.
Air Infiltration
The 1995 MEC enhances the air infiltration control provisions
related to caulking and sealing of openings and joints in the building
shell. Provisions are added requiring sealing around tubs and showers,
at attic and crawl space access panels, and around plumbing and
electrical penetrations through the exterior envelope of the building.
The new code clarifies acceptable sealing methods.
Infiltration significantly affects the energy efficiency of any
residential building by allowing unconditioned air into the conditioned
space. This additional outside air must be either heated or cooled,
requiring additional energy consumption. Application of the additional
1995 MEC provisions will increase energy efficiency by decreasing
unwanted air infiltration.
Duct Sealing
The 1995 MEC strengthens the duct sealing provisions of the earlier
code by applying them to all supply and return ducts, allowing the use
of mastic with backing tape only for sealing of non-fiberglass ducts,
and excluding the use of ``duct tape.''
Studies have shown that improper duct sealing significantly
increases energy consumption in houses with forced-air distribution
systems. Conditioned air on the supply side can leak into unconditioned
spaces and dissipate to the outdoors. Leaks on the return duct systems
will draw unconditioned air into the intake of the heating or air-
conditioning equipment, requiring additional energy to heat or cool the
air to the desired delivery temperature. For example, the Appliance
Doctor Project in California (Home Energy, March/April 1991 and May/
June 1991) found that duct leaks increased heating and cooling loads by
16 and 25 percent, respectively, as compared to well-sealed
distribution systems.
Because the majority of residential buildings have air transport
ducts for their heating and cooling distribution system, the new duct
sealing provisions will help to reduce energy consumption attributable
to duct leaks and thereby increase the energy efficiency of new
residential buildings being built to comply with the 1995 MEC.
Miscellaneous Additional Technical Changes
Insulation marking
This new provision requires that all insulation placed in walls,
ceilings, and floors must be installed so that the manufacturer's R-
value marking can be inspected. Additionally, loose-fill insulation
blown into attics must be accompanied by depth markers affixed to the
roof/ceiling structure. These markers will help to ensure that the
certified depth of loose- fill insulation, which is critical for
providing the claimed R-value, has actually been installed by the
builder or subcontractor.
Definition of basement wall
Under the 1993 and 1995 MEC editions, the required thermal
performance of basement walls differs from that of exterior walls which
are totally above grade. The 1993 and all earlier MEC editions state
that ``* * * basement walls with an average below-grade area less than
50% of the total wall area * * *'' must be considered part of the gross
(exterior) wall area. MEC users have often asked if this refers to the
total area of all basement walls lumped together, or each individual
wall section. The 1995 MEC clarifies that each individual wall
enclosing the basement, i.e., each colinear wall section, must be
addressed separately for purposes of evaluating which wall sections
must be treated as exterior walls. This approach avoids the possibility
of aggregating all basement wall sections together before determining
if they are ``exterior walls.'' Basement walls mistakenly evaluated as
exterior walls negatively impact energy efficiency because the thermal
performance of exterior walls is less stringent than that for basement
walls in all climates.
Heating degree day data
The thermal performance requirements of ceilings or roofs, walls,
floors, and foundations are solely a function of ``Heating Degree
Days''
[[Page 64730]]
(HDD), a measure of the severity of the heating load at a particular
geographic location, under all MEC editions. MEC Chapter 3, ``Design
Conditions,'' does not state where the HDD value for the building
location shall be obtained. The 1995 MEC corrects this oversight by
referring to reliable sources of HDD data. These sources include the
National Oceanic and Atmospheric Administration, ASHRAE, nearby
military installations with long-term weather data, or any other data
source acceptable to the Building Official. In view of the criticality
of the HDD parameter for determining the ultimate energy efficiency
performance of the residential building, the 1995 MEC can improve
energy savings by ensuring that thermal performance requirements are
not understated by using inappropriate HDD data.
Foundations Supporting Masonry Veneers
In low-rise residential buildings, masonry veneer construction
generally occurs in two situations: A basement foundation wall or a
monolithic slab foundation is often built with a horizontal ``ledge''
on the exterior edge that will be used to support a brick veneer on the
outside face of the building. If the builder or designer chooses to
insulate either foundation on the exterior perimeter, then, under the
1993 MEC requirements, insulation (usually rigid plastic foam) should
be placed on the ledge to provide a continuous thermal barrier around
the foundation. (Ledge insulation is not at issue if the basement wall
is insulated on the interior side or if a non-monolithic slab
foundation is insulated on the interior side.) However, the weight of 1
to 3 stories of brick veneer bearing on a small thickness of foam
insulation will normally cause the foam to compress and deform,
resulting in unacceptable settlement of the veneer. To address this
problem, the 1995 MEC specifically exempts that portion of the
foundation wall that supports the veneer from insulation requirements.
Of all substantive differences between the 1993 and 1995 MEC, this
change is the only one, in the Department's opinion, which has the
potential for marginally increasing energy consumption in a residential
building using a masonry veneer in combination with particular
foundation types. Nonetheless, the possible increase in energy
consumption does not alter DOE's determination that the 1995 MEC, taken
as a whole, improves energy efficiency in low-rise residential
buildings.
C. Filing Certification Statements with DOE
1. Determination
On the basis of today's DOE determination, each State is required
to make its own determination as to the appropriateness of revising its
residential building code to meet or exceed the provisions of the CABO
Model Energy Code, 1995 edition. Section 304(a)(5)(B). This
determination must be made not later than two years from the date of
today's notice, unless an extenstion is provided. The State
determination shall be: (1) Made after public notice and hearing; (2)
in writing; (3) based upon findings and upon the evidence presented at
the hearing; and (4) made available to the public. The States have
considerable discretion with regard to the hearing procedures they use,
subject to providing an adequate opportunity for members of the public
to be heard and to present relevant information. The Department
recommends publication of any notice of public hearing in newspapers of
general circulation.
The Department recognizes that some States do not have a State
residential code or have a code that does not apply to all newly
constructed residential buildings. If local building codes regulate
residential building design and construction rather than a State code,
the State must provide for review of those local codes and determine
whether it is appropriate for each of its units of general purpose
local government to revise the provisions of its residential building
code regarding energy efficiency to meet or exceed the 1995 MEC. States
may base their determinations and certifications on reasonable
preliminary determinations by units of general purpose local
government. Each such State must still hold an adequate public hearing
to review the information obtained from the local governments and to
gather any additional data and testimony for its own determination.
States should be aware that the Department considers high-rise
(greater than three stories) multi-family residential buildings and
hotel, motel, and other transient residential building types of any
height as commercial buildings for energy code purposes. Consequently,
residential buildings, for the purposes of certification, would include
one- and two-family detached and attached buildings, duplexes,
townhouses, row houses, and low-rise multi-family buildings (not
greater than three stories) such as condominiums and garden apartments.
2. Certification
Section 304(a) of ECPA requires each State to certify to the
Secretary of Energy that it has reviewed the provisions of its
residential building code regarding energy efficiency and made a
determination as to whether it is appropriate for such State to revise
the provisions of such residential building code to meet or exceed the
1995 MEC. The certification must be in writing and submitted within two
years from the date of publication of this notice. If a State intends
to certify that a residential building code already meets or exceeds
the requirements of the 1995 MEC, it would be appropriate for the State
to provide an explanation of the basis for this certification, e.g.,
the 1995 MEC is incorporated by reference in the State's building code
regulations. The Department believes that it would be appropriate for
the chief executive of the State (e.g., the Governor) to designate a
State official, such as the Director of the State energy office, State
code commission, utility commission, or equivalent State agency having
primary responsibility for residential building codes, to provide the
certification to the Secretary. Such a designated State official could
also provide the certifications regarding the codes of units of general
purpose local government based on information provided by responsible
local officials.
3. Statement of Reasons
ECPA Section 304(a)(4) requires that if a State makes a
determination that it is not appropriate to revise the energy
efficiency provisions of its residential building code to meet or
exceed the 1995 MEC, the State must submit to the Secretary, in
writing, the reasons for this determination. The statement of reasons
should define and summarize the pertinent issues regarding the
determination and provide an explanation for the State's conclusion. If
local building codes are applicable in the absence of a State code, the
State may rely on reasons provided by the units of general purpose
local government. Upon receipt, the Department will publish in the
Federal Register a notice of availability, stating that a copy has been
placed in its Freedom of Information Reading Room in the Forrestal
Building in Washington, DC, so that members of the public may inspect
it.
4. Submission of Certification Statements
A previous DOE determination (59 FR 36173, July 15, 1994) requires
States to file a certification statement regarding
[[Page 64731]]
the 1993 MEC by July 15, 1996. States that have not yet made
substantial progress in reviewing the energy efficiency provisions of
their residential building codes with respect to the 1993 MEC may wish
to proceed directly with review and certification of their codes with
respect to the 1995 MEC. States that have made substantial progress in
reviewing the energy efficiency provisions of their residential
building codes in light of the 1993 Model Energy Code may wish to
complete their review and submit an appropriate certification before
considering the 1995 MEC.
5. Request for Extensions
Section 304(c) of ECPA requires that the Secretary permit an
extension of the deadline for complying with the certification
requirements described above if a State can demonstrate that it has
made a good faith effort to comply with such requirements and that it
has made significant progress toward meeting its certification
obligations. Such demonstrations could include one or more of the
following: (1) A plan for response to the requirements stated in
section 304; (2) a statement that the State has appropriated or
requested funds (within State funding procedures) to implement a plan
that would respond to the requirements of section 304; or (3) a notice
of public hearing.
In the event that a State has not met the July 15, 1996 deadline
for certifying to the 1993 MEC, and has not filed a request for
extension, it must do so. Alternatively, some States may desire to
promptly certify to the 1995 MEC in response to this notice, in lieu of
certifying to the 1993 MEC. In this latter instance, if a State can
demonstrate that it is making significant progress towards early
certification with respect to the MEC 1995, the Department will
consider such a demonstration as a basis to grant a State's request for
certification to the 1995 MEC in lieu of certification to the 1993 MEC.
States should submit separate requests for extension of deadline
for certification to the 1995 MEC.
6. Submittals
When submitting any certification documents in response to this
notice, the Department requests that the original documents be
accompanied by one copy of the same.
Issued in Washington, DC, on November 29, 1996.
Christine A. Ervin,
Assistant Secretary, Energy Efficiency and Renewable Energy.
[FR Doc. 96-31065 Filed 12-5-96; 8:45 am]
BILLING CODE 6450-01-P