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51-11R-40213  <<  51-11R-40215 >>   51-11R-40220

(Effective July 1, 2020)

PDFWAC 51-11R-40215

Target/Proposed UA equations.

EQUATION 1 - GROUP R OCCUPANCY
TARGET UA
UAT = UWAW + UBGWABGW + UVGAVG + UOGAOG + UFAF + URCARC + UDAD + FSPS + FBGSPBGS
Where:
 
 
UAT
=
The target combined thermal transmittance of the gross exterior wall, floor and roof/ceiling area.
 
UW
=
The thermal transmittance value of the opaque above grade wall found in Table R402.1.3.
 
AW
=
Opaque above grade wall area.
 
UBGW
=
The thermal transmittance value of the below grade opaque wall found in Table R402.1.3.
 
ABGW
=
Opaque below grade wall area.
 
UVG
=
The thermal transmittance value of the fenestration found in Table R402.1.3.
 
AVG
=
(a) The proposed glazing area; where proposed fenestration glazing area is less than 15 percent of the conditioned floor area, minus AOG.
 
 
 
(b) 15 percent of the conditioned floor area; where the proposed fenestration glazing area is 15 percent or more of the conditioned floor area, minus AOG.
 
UOG
=
The thermal transmittance value of the skylight glazing found in Table R402.1.3.
 
AOG
=
Skylight glazing area (if the proposed AOG exceeds 15 percent, the target AOG shall be 15 percent of the total floor area of the conditioned space).
 
UF
=
The thermal transmittance value of the floor found in Table R402.1.3.
 
AF
=
Floor area over unconditioned space.
 
URC
=
The thermal transmittance value of the ceiling found in Table R402.1.3.
 
ARC
=
Roof/ceiling area.
 
UD
=
The thermal transmittance value of the fenestration found in Table R402.1.3.
 
AD
=
Opaque door area.
 
FS
=
Concrete slab on grade component F-factor found in Table R402.1.3.
 
PS
=
Lineal ft. of concrete slab on grade perimeter.
 
FBGS
=
Concrete below grade slab component F-factor found in Table R402.1.3.
 
PBGS
=
Lineal ft. of concrete below grade slab perimeter.
EQUATION 2 - GROUP R OCCUPANCY
PROPOSED UA
UA = UWAW + UBGWABGW + UVGAVG + UOGAOG + UFAF + URCARC + UDAD + FSPS + FBGSPBGS
Where:
 
 
UA
=
The combined thermal transmittance of the gross exterior wall, floor and roof/ceiling assembly area.
 
UW
=
The thermal transmittance of the opaque above grade wall area.
 
AW
=
Opaque above grade wall area.
 
UBGW
=
The thermal transmittance value of the below grade opaque wall.
 
ABGW
=
Opaque below grade wall area.
 
UVG
=
The thermal transmittance value of the fenestration glazing.
 
AVG
=
Fenestration glazing area, including windows in exterior doors.
 
UOG
=
The thermal transmittance value of the skylight glazing.
 
AOG
=
Skylight glazing area.
 
UF
=
The thermal transmittance of the floor.
 
AF
=
Floor area over unconditioned space.
 
URC
=
The thermal transmittance of the ceiling.
 
ARC
=
Ceiling area.
 
UD
=
The thermal transmittance value of the opaque door area.
 
AD
=
Opaque door area.
 
FS
=
Concrete slab on grade component F-factor.
 
PS
=
Lineal ft. of concrete slab on grade perimeter.
 
FBGS
=
Concrete below grade slab component F-factor.
 
PBGS
=
Lineal ft. of concrete below grade slab perimeter.
NOTE:
Where more than one type of wall, window, roof/ceiling, door and skylight is used, the U and A terms for those items shall be expanded into subelements as:
 
UW1AW1 + UW2AW2 + UW3AW3 + ...etc.
NOTE:
Below grade walls: The wall is assumed to extend from the slab upward to the top of the mud sill for the distance specified in Table A104.1, with 6 inches of concrete wall extending above grade. This will be calculated separately from above grade walls using the wall height that best describes the system.
[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160 and chapter 19.27 RCW. WSR 20-01-047, § 51-11R-40215, filed 12/9/19, effective 7/1/20.]
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