(Effective Until July 1, 2010.)
WAC 51-11-1004
Section 1004: Floors over unconditioned
space.
1004.1 General: Tables 10-3, 10-4 and 10-4a list
heat-loss coefficients for floors over unconditioned spaces in
units of Btu/h • ft2 • °F.
They are derived from procedures listed in RS-1, listed
in Chapter 7, assuming an average outdoor temperature of 45°F,
an average indoor temperature of 65°F, and a crawlspace area
of 1350 ft2 and 100 ft of perimeter. The crawlspace is assumed
to be 2.5 feet high, with 24 inches below grade and 6 inches
above grade.
1004.2 Crawlspace Description: Four configurations are
considered: Vented crawlspace, unvented crawlspace, heated
plenum crawlspace and exposed floor.
Vented crawlspaces: Assumed to have 3.0 air-changes per
hour, with at least 1.0 ft2 of net-free ventilation in the
foundation for every three hundred ft2 of crawlspace floor
area. The crawlspace is not actively heated.
Floors over unheated areas, such as garages, may only use
those values which have R-0 perimeter insulation.
Unvented crawlspaces: Assumed to have 1.5 air changes
per hour, with less than 1.0 ft2 of net-free ventilation in the
foundation for every three hundred ft2 of crawlspace floor
area. The crawlspace is not actively heated. Floors over
unheated basements may only use those values which have R-0
perimeter insulation.
Heated-plenum crawlspaces: Assumed to have 0.25
air-changes per hour, with no foundation vents. Heated supply
air from central furnace is blown into a crawlspace and
allowed to enter the living space unducted via holes cut into
the floor.
Enclosed floors: Assumes no buffer space, and a covering
of one-half inch of T1-11 on the exterior of the cavity
exposed to the outside air or rigid insulation below a
concrete floor, such as over parking garages.
1004.3 Construction Description: Floors are assumed to
be either joisted floors framed on sixteen inch centers, or
post and beam on four by eight foot squares. Insulation is
assumed to be installed under the subflooring between the
joists or beams with no space between the insulation and the
subfloor. Insulation is assumed to be uncompressed. Exposed
floors also include concrete with continuous rigid insulation
assumed.
Perimeter insulation is assumed to extend from the top of
the rim joist to the crawlspace floor and then inward along
the ground (on top of the ground cover) for at least
twenty-four inches.
Floor coverings are assumed to be light carpet with
rubber pad.
TABLE 10-3
DEFAULT U-FACTORS FOR FLOORS OVER VENTED
CRAWLSPACE OR
UNHEATED BASEMENT
| Nominal R-value |
U-factor |
| Floor |
Perimeter |
Post & Beam |
Joists |
| 0 |
0
11
19
30 |
|
0.112
0.100
0.098
0.093 |
0.134
0.116
0.114
0.107 |
| 11 |
0
11 |
|
0.052
0.048 |
0.056
0.052 |
| 19 |
0
11 |
|
0.038
0.036 |
0.041
0.038 |
| 22 |
0
11 |
|
0.034
0.033 |
0.037
0.035 |
| 25 |
0
11 |
|
0.032
0.031 |
0.034
0.033 |
| 30 |
0
11 |
|
0.028
0.027 |
0.029
0.028 |
| 38 |
0
11 |
|
0.024
0.024 |
0.025
0.024 |
TABLE 10-4
DEFAULT U-FACTORS FOR FLOORS OVER HEATED
PLENUM CRAWLSPACES
Nominal R-value
Perimeter |
U-factor |
| 11 |
0.085 |
| 19 |
0.075 |
| 30 |
0.069 |
TABLE 10-4A
EXPOSED FLOOR
Nominal
R-value |
U-factor |
| Concrete |
Wood Joist |
Metal Joist |
| R-11 |
0.077 |
0.088 |
0.14 |
| R-15 |
0.059 |
0.076 |
0.12 |
| R-19 |
0.048 |
0.062 |
0.11 |
| R-21 |
0.043 |
0.057 |
0.11 |
| R-25 |
0.037 |
0.051 |
0.10 |
| R-30 |
0.031 |
0.040 |
0.09 |
| R-38 |
0.025 |
0.034 |
0.08 |
| Note: |
Crawlspaces used as heated plenums have approximately 30% higher heat-loss rate than unvented crawlspaces with the
same assumed ACH. Default U-values in Table 10-4 reflect this higher rate of heat loss. |
[Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106,
§ 51-11-1004, filed 12/17/03, effective 7/1/04. Statutory
Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, §
51-11-1004, filed 1/5/01, effective 7/1/01; 98-03-003, §
51-11-1004, filed 1/8/98, effective 7/1/98. Statutory
Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, §
51-11-1004, filed 12/19/90, effective 7/1/91.]
(Effective July 1, 2010.)
WAC 51-11-1004
Section 1004: Floors over unconditioned
space.
1004.1 General: Tables 10-3, 10-4 and 10-4a list
heat-loss coefficients for floors over unconditioned spaces in
units of Btu/h•ft2•°F.
They are derived from procedures listed in RS-1, listed
in Chapter 7, assuming an average outdoor temperature of 45°F,
an average indoor temperature of 65°F, and a crawlspace area
of 1350 ft2 and 100 ft of perimeter. The crawlspace is assumed
to be 2.5 feet high, with 24 inches below grade and 6 inches
above grade.
1004.2 Crawlspace Description: Four configurations are
considered: Naturally ventilated crawlspace, mechanically
ventilated crawlspace, heated plenum crawlspace and exposed
floor.
Naturally ventilated crawlspaces: Assumed to have 3.0
air-changes per hour, with at least 1.0 ft2 of net-free
ventilation in the foundation for every three hundred ft2 of
crawlspace floor area. The crawlspace is not actively heated.
Floors over unheated areas, such as garages, may only use
those values which have R-0 perimeter insulation.
Mechanically ventilated crawlspaces: Assumed to have 1.5
air changes per hour, with less than 1.0 ft2 of net-free
ventilation in the foundation for every three hundred ft2 of
crawlspace floor area. The crawlspace is not actively heated.
Floors over unheated basements may only use those values
which have R-0 perimeter insulation.
Heated-plenum crawlspaces: Assumed to have 0.25
air-changes per hour, with no foundation vents. Heated supply
air from central furnace is blown into a crawlspace and
allowed to enter the living space unducted via holes cut into
the floor.
Enclosed floors: Assumes no buffer space, and a covering
of one-half inch of T1-11 on the exterior of the cavity
exposed to the outside air or rigid insulation below a
concrete floor, such as over parking garages.
1004.3 Construction Description: Floors are assumed to
be either joisted floors framed on sixteen inch centers, or
post and beam on four by eight foot squares. Insulation is
assumed to be installed under the subflooring between the
joists or beams with no space between the insulation and the
subfloor. Insulation is assumed to be uncompressed. Exposed
floors also include concrete with continuous rigid insulation
assumed.
Perimeter insulation is assumed to extend from the top of
the rim joist to the crawlspace floor and then inward along
the ground (on top of the ground cover) for at least
twenty-four inches.
Floor coverings are assumed to be light carpet with
rubber pad.
TABLE 10-3
DEFAULT U-FACTORS FOR FLOORS OVER VENTED
CRAWLSPACE OR
UNHEATED BASEMENT
| Nominal R-value |
U-factor |
| Floor |
Perimeter |
Post & Beam |
Joists |
| 0 |
0
11
19
30 |
|
0.112
0.100
0.098
0.093 |
0.134
0.116
0.114
0.107 |
| 11 |
0
11 |
|
0.052
0.048 |
0.056
0.052 |
| 19 |
0
11 |
|
0.038
0.036 |
0.041
0.038 |
| 22 |
0
11 |
|
0.034
0.033 |
0.037
0.035 |
| 25 |
0
11 |
|
0.032
0.031 |
0.034
0.033 |
| 30 |
0
11 |
|
0.028
0.027 |
0.029
0.028 |
| 38 |
0
11 |
|
0.024
0.024 |
0.025
0.024 |
TABLE 10-4
DEFAULT U-FACTORS FOR FLOORS OVER HEATED
PLENUM CRAWLSPACES
Nominal R-value
Perimeter |
U-factor |
| 11 |
0.085 |
| 19 |
0.075 |
| 30 |
0.069 |
TABLE 10-4A
EXPOSED FLOOR
Nominal
R-value |
U-factor |
| Concrete |
Wood Joist |
Metal Joist |
| R-11 |
0.077 |
0.088 |
0.14 |
| R-15 |
0.059 |
0.076 |
0.12 |
| R-19 |
0.048 |
0.062 |
0.11 |
| R-21 |
0.043 |
0.057 |
0.11 |
| R-25 |
0.037 |
0.051 |
0.10 |
| R-30 |
0.031 |
0.040 |
0.09 |
| R-38 |
0.025 |
0.034 |
0.08 |
| Note: |
Crawlspaces used as heated plenums have approximately 30% higher heat-loss rate than unvented crawlspaces with the
same assumed ACH. Default U-values in Table 10-4 reflect this higher rate of heat loss. |
[Statutory Authority: RCW 19.27A.025, 19.27A.045. 10-03-115,
§ 51-11-1004, filed 1/20/10, effective 7/1/10. Statutory
Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, §
51-11-1004, filed 12/17/03, effective 7/1/04. Statutory
Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, §
51-11-1004, filed 1/5/01, effective 7/1/01; 98-03-003, §
51-11-1004, filed 1/8/98, effective 7/1/98. Statutory
Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, §
51-11-1004, filed 12/19/90, effective 7/1/91.]
NOTES:
Reviser's note: Notice of Objection: The Joint Administrative Rules
Review Committee (Committee) finds that, in adopting the 2009 proposed changes
to the State Energy Code, Chapter 51-11 WAC, on November 20, 2009, the State
Building Code Council (Council) failed to comply with all requirements of the
law and failed to adequately respond to the Committee's request for additional
economic impact and cost-benefit analyses prior to adoption.
On October 1, 2009, the Committee found that the Small Business Economic
Impact Statement (SBEIS) for the proposed changes filed with the Code Reviser
failed to comply with all requirements of law. The Committee requested that
the Council conduct a cost-benefit analysis pursuant to RCW 34.05.328 and
amend the SBEIS to provide additional economic impact information, including
an estimate of the number of jobs that would be created or lost as a result of
compliance with all the proposed rules, as required by RCW 19.85.040 (2)(d).
The Council provided the Committee with information and data on November
18, 2009. On December 2, 2009, the Committee found that the Council failed to
adequately respond to the Committee's request for additional data.
Specifically, the Committee found that the Council failed to amend the SBEIS
to (a) estimate the number of jobs that would be created or lost as a result
of compliance with the proposed changes; and (b) support the SBEIS with a
detailed and rigorous costs analysis of the cumulative impact of all the
changes. In addition, the Committee found that the Council failed to provide
the Committee with a cost-benefit analysis of the proposed changes and
pursuant to the requirements of RCW 34.05.328.
The Committee strongly supports a process that makes thoughtful and
informed progress towards changes that result in improved energy efficiency in
our buildings, wherever practicable. While the Council worked diligently, it
is the opinion of the Committee that the Council did not fully develop and
consider the economic impacts and costs versus benefits of these significant
changes to our Energy Code. Furthermore, it is the opinion of the Committee
that the Council and the Legislature need this information to fully evaluate
the value, impacts, and consequences of the proposed codes, with due diligence
to their respective fiduciary responsibilities, in order to create the best
informed public policy.
As a result, the Committee recommends that the Governor suspend the
adoption and implementation of the changes to the Energy Code, Chapter 51-11
WAC, adopted by the Council on November 20, 2009, until such time as a more
adequate analysis has been completed and considered by the appropriate bodies.
For all of the above stated reasons, the Committee objects to the
changes to the State Energy Code, Chapter 51-11 WAC, that were adopted by the
Council on November 20, 2009, and hereby directs the Code Reviser, pursuant to
RCW 34.05.640(4), to publish this Notice of Objection in the Washington State
Register and along with any publication in the Washington Administrative Code
of changes to Chapter 51-11 WAC that were adopted by the Council in 2009 and
filed with the Code Reviser.