Chapter 51-11C State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial.

C502.1 General.Additions to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion of the existing building or building system to comply with this code. Addit…

C503.1 General. Alterations to any building or structure shall comply with the requirements of Section C503 and the code for new construction. Alterations to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to ne…

C504.1 General. Buildings and structures, and parts thereof, shall be repaired in compliance with Section C501.3 and this section. Work on nondamaged components that is necessary for the required repair of damaged components shall be considered part of the repair and shall not be…

C505.1 General. Buildings or spaces undergoing a change in space conditioning alteration shall comply with Sections C505.2 and C505.4. Buildings or spaces undergoing a change in occupancy alteration shall comply with Sections C505.3 and C505.4. Spaces changing from one use type t…

C506.1 Metering in existing buildings. Where new or replacement systems or equipment are installed in an existing building that was constructed subject to the requirements of this section, metering shall be provided for such new or replacement systems or equipment so that their e…

This chapter lists the standards that are referenced in various sections of this document. The standards are listed herein by the promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this document that refe…

[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapters 19.27A and 19.27 RCW. WSR 22-14-091, 23-12-101, and 23-20-021, § 51-11C-61000, filed 7/1/22, 6/7/23, and 9/25/23, effective 3/15/24.]

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61010, filed 2/1/13, effective 7/1/13.]

A101.1 Scope. The following defaults shall apply to Chapter 4 of both the (RE) and (CE) sections of the WSEC. This chapter includes tables of seasonal average heat loss coefficients for specified nominal insulation.[Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. …

A101.2 Description. These coefficients were developed primarily from data and procedures from the ASHRAE Fundamentals Handbook.Coefficients not contained in this chapter may be computed using the procedures listed in this reference if the assumptions in the following sections are…

A101.3 Air films. Default R-values used for air films shall be as follows:R-ValueCondition0.17All exterior surfaces0.61Interior horizontal surfaces, heat flow up0.92Interior horizontal surfaces, heat flow down0.68Interior vertical surfaces[Statutory Authority: RCW 19.27A.020, 19.…

A101.4 Compression of insulation. Insulation which is compressed shall be rated in accordance with Table A101.4 or reduction in value may be calculated in accordance with the procedures in the ASHRAE Fundamentals Handbook.Table A101.4R-value of Fiberglass Batts Compressed Within …

A101.5 Building materials. Default R-values used for building materials shall be as shown in Table A101.5.Table A101.5Default R-values for Building MaterialsMaterialNominal Size (in.)ActualSize (in.)R-Value(Heat Capacityc)Air cavity (unventilated), between metal studs at 16 inche…

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61020, filed 2/1/13, effective 7/1/13.]

A102.1 General. Table A102.1 lists heat loss coefficients for the opaque portion of exterior ceilings below vented attics, vaulted ceilings and roof decks in units of Btu/h • ft2 • °F of ceiling.They are derived from procedures listed in the ASHRAE Fundamentals Handbook. Ceiling …

Table A102.1Default U-factors for Ceilings Standard FrameAdvanced FrameCeilings Below Vented Attics FlatBaffled R-190.0490.047 R-300.0360.032 R-380.0310.026 R-490.0270.020 R-600.0250.017Scissors Truss R-30 (4/12 roof pitch)0.0430.031 R-38 (4/12 roof pitch)0.0400.025 R-49 (4/12 ro…

A102.2 Component description. The four types of ceilings are characterized as follows:A102.2.1 Ceilings below a vented attic. Attic insulation is assumed to be blown-in, loose-fill fiberglass with a K-value of 2.6 h • ft2 • °F/Btu per inch. Full bag count for specified R-value is…

Table A102.2.4(1)Steel Trussa Framed Ceiling UoCavity Truss Span (ft) R-value12141618202224262830323436190.10750.09910.09280.08780.08390.08070.07800.07570.07370.07200.07060.06930.0681300.09070.08230.07600.07100.06710.06380.06120.05890.05690.05520.05380.05250.0513380.08440.07590.0…

Table A102.2.5Default U-factors for Metal Building Roofs Overall U-Factor for Assembly of Base Roof Plus ContinuousInsulation (uninterrupted by framing) Rated R-Value ofContinuous InsulationInsulationSystemRated R-Value ofInsulationOverall U-Factor for Entire Base RoofAssemblyR-6…

Table A102.2.6(1)Assembly U-factors for Roofs with Tapered Insulation Entirely Above Deck Single Slope Rectangular to One-sided,e,f,g,h(Uninterrupted by Framing) Rated R-value of Insulation at Maximum Condition (Rmaxc)151015202530354045505560Rated R-value of insulation at a Minim…

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61030, filed 2/1/13, effective 7/1/13.]

A103.1 General. The tables in this section list heat loss coefficients for the opaque portion of above-grade wood stud frame walls, metal stud frame walls and concrete masonry walls (Btu/h • ft2 • °F). They are derived from procedures listed in the ASHRAE Fundamentals Handbook. F…

A103.2 Framing description. For wood stud frame walls, three framing types are considered and defined as follows:A103.2.1 Standard. Studs framed on 16 inch centers with double top plate and single bottom plate. Corners use three studs and each opening is framed using two studs. H…

A103.3 Component description. Default coefficients for the following types of walls are listed: Single-stud walls, strap walls, double-stud walls, log walls, stress-skin panels, metal stud walls, and metal building walls.[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapte…

A103.3.1 Single-stud wall. Tables A103.3.1(1) through A103.3.1(8): Assumes either 2 x 4 or 2 x 6 studs framed on 16 or 24 inch centers. Headers are solid for 2 x 4 walls and double 2x for 2 x 6 walls, with either dead-air or rigid-board insulation in the remaining space.TABLE A10…

A103.3.2 Strap wall. Table A103.3.2: Assumes 2 x 6 studs framed on 16 or 24 inch centers. 2 x 3 or 2 x 4 strapping is run horizontally along the interior surface of the wall to provide additional space for insulation.Table A103.3.22 x 6: Strap Wall Siding Material/Frame Type Lapp…

A103.3.3 Double stud wall. Tables A103.3.3(1) and A103.3.3(2): Assumes an exterior structural wall and a separate interior, nonstructural wall. Insulation is placed in both wall cavities and in the space between the two walls. Stud spacing is assumed to be on 24 inch centers for …

A103.3.4 Log wall. U-factors for log walls shall be determined using ICC 400 Table 305.3.1.1, U-Factor of log wall (UW) by log thickness (WL) and specific gravity.[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160 and chapter 19.27 RCW. WSR 20-01-047, § 51-11C-610334, f…

A103.3.5 Stress-skin panel. See Table A103.3.5.Table A103.3.5Stress Skin Panel PanelThickness,InchesU-factor NOTE: R-value of expanded polystyrene: R-3.85 per inchFraming: 6%Spline: 8% 3 1/20.071 5 1/20.048 7 1/40.037 9 1/40.030 11 1/40.025 No thermal bridging between interior an…

A103.3.6 Metal stud walls. The nominal R-values in Tables A103.3.6.1 through A103.3.6.3 may be used for purposes of calculating metal stud wall section U-factors in lieu of the ASHRAE zone calculation method as provided in Chapter 27 of the ASHRAE Fundamentals Handbook.A103.3.6.1…

A103.3.7 Concrete and masonry walls.A103.3.7.1 Concrete masonry walls. The nominal R-values in Table A103.3.7.1 may be used for purposes of calculating concrete masonry wall section U-factors in lieu of the ASHRAE isothermal planes calculation method as provided in Chapter 27 of …

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61040, filed 2/1/13, effective 7/1/13.]

A104.1 General. Table A104.1 lists heat loss coefficients for below-grade walls and floors.Coefficients for below-grade walls are given as U-factors (Btu/h • ft2 • °F of wall area). Coefficients for below-grade slabs are listed as F-factors (Btu/h • ft • °F per lineal foot of sla…

A104.2 Component description. All below-grade walls are assumed to be 8 inch concrete. The wall is assumed to extend from the slab upward to the top of the mud sill for the distance specified in Table A104.1, with 6 inches of concrete wall extending above grade.Interior insulatio…

A104.3 Insulation description. Coefficients are listed for the following four configurations:1. Uninsulated: No insulation or interior finish.2. Interior insulation: Interior 2 x 4 insulated wall without a thermal break between concrete wall and slab.3. Interior insulation with t…

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61050, filed 2/1/13, effective 7/1/13.]

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…

A105.2 Crawlspace description. Four configurations are considered: Naturally ventilated crawlspace, mechanically vented crawlspace, heated plenum crawlspace and exposed floor.A105.2.1 Naturally ventilated crawlspaces. Assumed to have 3.0 air changes per hour, with at least 1.0 ft…

A105.3 Construction description. Floors are assumed to be either joisted floors framed on 16 inch centers, or post and beam on 4 foot by 8 foot squares. Insulation is assumed to be installed under the subflooring between the joists or beams with no space between the insulation an…

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61060, filed 2/1/13, effective 7/1/13.]

A106.1 General. Table A106.1 lists heat loss coefficients for heated on-grade slab floors, in units of Btu/h • °F per lineal foot of perimeter.Table A106.1Default F-factors for On-Grade SlabsInsulation TypeR-0R-5R-10R-15R-20R-30 Unheated Slab Uninsulated slab0.73—————2 ft. Horizo…

A106.2 Component description. All on-grade slab floors are assumed to be 6 inch concrete poured directly onto the earth. The bottom of the slab is assumed to be at grade line. Monolithic and floating slabs are not differentiated.Soil is assumed to have a conductivity of 0.75 Btu/…

A106.3 Insulation description. Coefficients are provided for the following three configurations:1. Two foot (or four foot) vertical: Insulation is applied directly to the slab exterior, extending downward from the top of the slab to a depth of 2 feet (or 4 feet) below grade.2. Tw…

[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61070, filed 2/1/13, effective 7/1/13.]

A107.1 Doors without NFRC certification. Doors that do not have NFRC certification shall be assigned the appropriate U-factor from Tables A107.1(1) through A107.1(4).[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-61071, …

Table A107.1(1)Default U-factors for DoorsDoor TypeNoGlazedFenestrationSingleGlazingDoubleGlazingwith 1/4 in.AirspaceDoubleGlazingwith 1/2in.AirspaceDoubleGlazingwithe = 0.10,1/2 in.ArgonSwinging Doors (Rough opening - 38 in. x 82 in.)Slab Doors Wood slab in wood framea0.46 6% gl…

Table A107.1(2)Default U-factors for Revolving DoorsRevolving DoorsSize (W x H)U-Factor3-wing8 ft. x 7 ft.10 ft. x 8 ft.0.790.804-wing7 ft. x 6.5 ft.7 ft. x 7.5 ft.0.630.64Open82 in. x 84 in.1.32[Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WS…