Wash. Admin. Code § 51-11R-30315
TABLE R303.1.3(5) SMALL BUSINESS COMPLIANCE TABLE DEFAULT U-FACTORS FOR VERTICAL FENESTRATION
Vertical Fenestration Description | Frame Type | |||||
Any Frame | Aluminum Thermal Break2 | Wood/Vinyl/ Fiberglass | ||||
Panes | Low-e1 | Spacer | Fill | |||
Double3 | A | Any | Argon | 0.48 | 0.41 | 0.32 |
B | Any | Argon | 0.46 | 0.39 | 0.30 | |
C | Any | Argon | 0.44 | 0.37 | 0.28 | |
C | High Performance | Argon | 0.42 | 0.35 | Deemed to comply5 | |
Triple4 | A | Any | Air | 0.50 | 0.44 | 0.26 |
B | Any | Air | 0.45 | 0.39 | 0.22 | |
C | Any | Air | 0.41 | 0.34 | 0.20 | |
Any double low-e | Any | Air | 0.35 | 0.32 | 0.18 | |
1 | Low-eA (emissivity) shall be 0.24 to 0.16. |
Low-eB (emissivity) shall be 0.15 to 0.08. | |
Low-eC (emissivity) shall be 0.07 or less. | |
2 | Aluminum Thermal Break = An aluminum thermal break framed window shall incorporate the following minimum design characteristics: |
a) The thermal conductivity of the thermal break material shall be not more than 3.6 Btu-in/h/ft2/°F; | |
b) The thermal break material must produce a gap in the frame material of not less than 0.210 inches; and | |
c) All metal framing members of the products exposed to interior and exterior air shall incorporate a thermal break meeting the criteria in a and b above. | |
3 | A minimum air space of 0.375 inches between panes of glass is required for double glazing. |
4 | A minimum air space of 0.25 inches between panes of glass is required for triple glazing. |
5 | Deemed to comply glazing shall not be used for performance compliance. |
Wash. Admin. Code § 51-11R-30315
Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. 13-04-055, § 51-11R-30315, filed 2/1/13, effective 7/1/13.