WAC 51-11-1322   Opaque envelope.  Roof/ceilings, opaque exterior walls, opaque doors, floors over unconditioned space, below grade walls, slab on grade floors, and radiant floors enclosing conditioned spaces shall be insulated according to Section 1311 and Tables 13-1 or 13-2. Compliance with nominal R-values shall be demonstrated for the thermal resistance of the added insulation in framing cavities and/or insulated sheathing only. Nominal R-values shall not include the thermal transmittance of other building materials or air films.


     For metal frame assemblies used in spaces with electric resistance space heat, compliance shall be demonstrated with the component U-factor for the overall assembly based on the assemblies in Chapter 10.


EXCEPTIONS: 1. Opaque smoke vents are not required to meet insulation requirements.
2. For prescriptive compliance only.
a. For glazing areas that are 30% and less of the gross wall area, the insulation of the perimeter edge of an above grade floor slab which penetrates the exterior wall may be reduced to R-5 provided the glazing U-factor is reduced by U-0.05 below that required in Tables 13-1 and 13-2.
b. For glazing areas that exceed 30% of the gross wall area, the perimeter edge of an above grade floor slab which penetrates the exterior wall may be left uninsulated provided that the glazing U-factor is reduced by U-0.10 below that required in Tables 13-1 and 13-2.




[Statutory Authority: RCW 19.27A.025, 19.27A.045 and chapters 19.27, 19.27A, and 34.05 RCW. 05-01-013, § 51-11-1322, filed 12/2/04, effective 7/1/05. Statutory Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, § 51-11-1322, filed 1/5/01, effective 7/1/01. Statutory Authority: RCW 19.27A.025. 93-21-052, § 51-11-1322, filed 10/18/93, effective 4/1/94.]