Section 51-11C-61051. Section A105.1—General.  


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  • A105.1 General. Tables A105.1(1), A105.1(2) and A105.1(3) list heat loss coefficients for floors over unconditioned spaces in units of Btu/h • ft2 • °F.
    They are derived from procedures listed in the ASHRAE Fundamentals Handbook, assuming an average outdoor temperature of 45°F, an average indoor temperature of 65°F and a crawlspace area of 1350 ft2 and 100 feet of perimeter. The crawlspace is assumed to be 2.5 feet high, with 24 inches below grade and 6 inches above grade.
    Table A105.1(1)
    Default U-factors for Wood-Framed Floors
    over Vented Crawlspace or
    Unheated Basement
    Table A105.1(2)
    Default U-factors for Wood-Framed Floors over Heated Plenum Crawlspaces
    Note:
    Crawlspaces used as heated plenums have approximately 30 percent higher heat loss rate than unvented crawlspaces with the same assumed ACH. Default U-factors in Table A105.1(2) reflect this higher rate of heat loss.
    Table A105.1(3)
    Default U-factors for Exposed Floors
    [Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-61051, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61051, filed 2/1/13, effective 7/1/13.]
RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-61051, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61051, filed 2/1/13, effective 7/1/13.