Wash. Admin. Code § 51-11R-30311 – Table R303.1.3(1)—Default glazed fenestration U-factor

TABLE R303.1.3(1)

DEFAULT GLAZED WINDOW, GLASS DOOR AND SKYLIGHT U-FACTOR

FRAME TYPE	SINGLE PANE	DOUBLE PANE
Metal	1.20	0.80	SKYLIGHT
Metal with Thermal Break^a	1.10	0.65	See Table R303.1.3(4)
Nonmetal or Metal Clad	0.95	0.55
Glazed Block	0.60

^a	Metal Thermal Break = A metal thermal break framed window shall incorporate the following minimum design characteristics:
	1) The thermal conductivity of the thermal break material shall be not more than 3.6 Btu-in/h/ft²/°F;
	2) The thermal break material must produce a gap in the frame material of not less than 0.210 inches; and
	3) All metal framing members of the products exposed to interior and exterior air shall incorporate a thermal break meeting the criteria in 1) and 2) above.

[Statutory Authority: RCW 19.27A.045 and chapter 19.27A RCW. WSR 20-21-081, § 51-11R-30311, filed 10/19/20, effective 2/1/21. Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160 and chapter 19.27 RCW. WSR 20-01-047, § 51-11R-30311, filed 12/9/19, effective 7/1/20. Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-30311, filed 2/1/13, effective 7/1/13.]