Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-11R - State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Residential › Section 51-11R-40215 - Target/Proposed UA equations

Current through Register Vol. 24-14, July 15, 2024
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 R402.1.2.
AW = Opaque above grade wall
				area.
UBGW = The thermal transmittance value
				of the below grade opaque wall found in Table R402.1.2.
ABGW = Opaque below grade wall
				area.
UVG = The thermal transmittance value of
				the fenestration found in Table R402.1.2.
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 R402.1.2.
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 R402.1.2.
AF = Floor area over unconditioned
				space.
URC = The thermal transmittance value of
				the ceiling found in Table R402.1.2.
ARC = Roof/ceiling area.
UD = The thermal transmittance value of
				the fenestration found in Table R402.1.2.
AD = Opaque door area.
FS = Concrete slab on grade component
F
-factor found in Table R402.1.2.
PS = Lineal ft. of concrete slab on
				grade perimeter.
FBGS = Concrete below grade slab
				component
F
-factor found in Table R402.1.2.
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.