[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