EXCEPTION: | For roof insulation installed above the deck, the R-value shall be labeled as required by the material standards specified in Table 1508.5 of the International Building Code or Table R906.2 of the International Residential Code. |
R303.1.1.1 Blown or sprayed roof/ceiling insulation. The thickness of blown-in or sprayed roof/ceiling insulation (fiberglass or cellulose) shall be written in inches (mm) on markers that are installed at least one for every 300 square feet (28 m2) throughout the attic space. The markers shall be affixed to the trusses or joists and marked with the minimum initial installed thickness with numbers a minimum of 1 inch (25 mm) in height. Each marker shall face the attic access opening. Spray polyurethane foam thickness and installed R-value shall be listed on certification provided by the insulation installer.
R303.1.2 Insulation mark installation. Insulating materials shall be installed such that the manufacturer's R-value mark is readily observable upon inspection.
R303.1.3 Fenestration product rating.U-factors of fenestration products (windows, doors and skylights) shall be determined in accordance with NFRC 100.
EXCEPTION: | Where required, garage door U-factors shall be determined in accordance with either NFRC 100 or ANSI/DASMA 105. |
U-factors shall be determined by an accredited, independent laboratory, and labeled and certified by the manufacturer.
Products lacking such a labeled U-factor shall be assigned a default U-factor from Table R303.1.3(1), R303.1.3(2) or R303.1.3(4). The solar heat gain coefficient (SHGC) and visible transmittance (VT) of glazed fenestration products (windows, glazed doors and skylights) shall be determined in accordance with NFRC 200 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled SHGC or VT shall be assigned a default SHGC or VT from Table R303.1.3(3).
EXCEPTIONS: | 1. Units without NFRC ratings produced by a small business may be assigned default U-factors from Table R303.1.3(5) for vertical fenestration. |
| 2. Owner-built, nonoperable wood frame window consisting of a double pane unit with low-e (E = 0.04 or less), 1/2-inch air space with argon fill. |
R303.1.4 Insulation product rating. The thermal resistance (R-value) of insulation shall be determined in accordance with the U.S. Federal Trade Commission R-value rule (C.F.R. Title 16, Part 460) in units of h × ft2 × °F/Btu at a mean temperature of 75°F (24°C).
R303.1.4.1 Insulated siding. The thermal resistance (R-value) of insulated siding shall be determined in accordance with ASTM C1363. Installation for testing shall be in accordance with the manufacturer's installation instructions.
[Statutory Authority: RCW
19.27A.045 and chapter
19.27A RCW. WSR 20-21-081, § 51-11R-30310, 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-30310, filed 12/9/19, effective 7/1/20. Statutory Authority: RCW
19.27A.020,
19.27A.045,
19.27A.160, and
19.27.074. WSR 16-02-127, § 51-11R-30310, filed 1/6/16, effective 7/1/16. Statutory Authority: RCW
19.27A.020,
19.27A.045 and chapters
19.27 and
34.05 RCW. WSR 13-04-055, § 51-11R-30310, filed 2/1/13, effective 7/1/13.]