Washington Administrative Code

R303.1 Identification. Materials, systems and equipment shall be identified in a manner that will allow a determination of compliance with the applicable provisions of this code.R303.1.1 Building thermal envelope insulation. An R-value identification mark shall be applied by the …

TABLE R303.1.3(1)DEFAULT GLAZED WINDOW, GLASS DOOR AND SKYLIGHT U-FACTORFRAME TYPESINGLE PANEDOUBLE PANE Metal1.200.80SKYLIGHTMetal with Thermal Breaka1.100.65See Table R303.1.3(4)Nonmetal or Metal Clad0.950.55 Glazed Block0.60aMetal Thermal Break = A metal thermal break framed w…

TABLE R303.1.3(2)DEFAULT OPAQUE DOOR U-FACTORSDoor 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…

TABLE R303.1.3(3)DEFAULT GLAZED FENESTRATION SHGC AND VT SINGLE GLAZEDDOUBLE GLAZEDGLAZED BLOCK ClearTintedClearTintedSHGC0.80.70.70.60.6VT0.60.30.60.30.6[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-30313, filed 2/1/13…

TABLE R303.1.3(4)DEFAULT U-FACTORS FOR SKYLIGHTS Frame Type Aluminum WithoutThermal BreakAluminum WithThermal BreakReinforced Vinyl/Aluminum-Clad Wood or VinylWood or Vinyl-Clad Wood/Vinyl Without ReinforcingFenestration TypeSingle Glazing glassU-1.58U-1.51U-1.40U-1.18 acrylic/po…

TABLE R303.1.3(5)SMALL BUSINESS COMPLIANCE TABLEDEFAULT U-FACTORS FOR VERTICAL FENESTRATIONVertical Fenestration DescriptionFrame TypeAny FrameAluminumThermal Break2Wood/Vinyl/FiberglassPanesLow-e1SpacerFillDouble3AAnyArgon0.480.410.32 BAnyArgon0.460.390.30 CAnyArgon0.440.370.28 …

R303.2 Installation. All materials, systems and equipment shall be installed in accordance with the manufacturer's installation instructions and the International Building Code or International Residential Code, as applicable.R303.2.1 Protection of exposed foundation insulation. …

R303.3 Maintenance information. Maintenance instructions shall be furnished for equipment and systems that require preventive maintenance. Required regular maintenance actions shall be clearly stated and incorporated on a readily visible label. The label shall include the title o…

[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40000, filed 2/1/13, effective 7/1/13.]Reviser's note: The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency.

R401.1 Scope. This chapter applies to residential buildings. Group R-2 occupancy areas with dwelling units accessed from enclosed interior corridors or other enclosed interior spaces must comply with the Washington State Energy Code (WSEC), Commercial Provisions. Other Group R-2 …

[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40200, filed 2/1/13, effective 7/1/13.]

R402.1 General. The building thermal envelope shall meet the requirements of Sections R402.1.1 through R402.1.6.EXCEPTION:The following buildings, or portions thereof, separated from the remainder of the building by building thermal envelope assemblies complying with this code sh…

TABLE R402.1.2INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTaCLIMATE ZONE 5 AND MARINE 4Fenestration U-factorb0.30Skylight U-factor0.50Ceiling U-factor0.024Above-Grade Wall U-factor0.056Floor U-factor0.029Slab on Grade F-factor0.54Below Grade 2' Depth Wall U-factor0.042 Sl…

TABLE R402.1.3INSULATION MINIMUM R-VALUES AND FENESTRATION REQUIREMENTS BY COMPONENTSaClimate Zone 5 and Marine 4Fenestrationb,jU-Factor0.30SkylightbU-Factor0.50CeilingeR-Value60Wood Frame Wallg,iR-Value20+5 or 13+10Floor R-Value30Below-Grade Wallc,hR-Value10/15/21 int + 5TBSlabd…

EQUATION 1 - GROUP R OCCUPANCYTARGET UAUAT = UWAW + UBGWABGW + UVGAVG + UOGAOG + UFAF + URCARC + UDAD + FSPS + FBGSPBGSWhere: UAT=The target combined thermal transmittance of the gross exterior wall, floor and roof/ceiling area. UW=The thermal transmittance value of the opaque ab…

R402.2 Specific insulation requirements. In addition to the requirements of Section R402.1, insulation shall meet the specific requirements of Sections R402.2.1 through R402.2.11.R402.2.1 Ceilings with attic spaces. Where Section R402.1.3 would require R-60 in the ceiling or atti…

R402.3 Fenestration. In addition to the requirements of Section R402, fenestration shall comply with Sections R402.3.1 through R402.3.6.R402.3.1 U-factor. An area-weighted average of fenestration products shall be permitted to satisfy the U-factor requirements.R402.3.2 Glazed fen…

R402.4 Air leakage. The building thermal envelope shall be constructed to limit air leakage in accordance with the requirements of Sections R402.4.1 through R402.4.4.R402.4.1 Building thermal envelope air leakage. The building thermal envelope shall comply with Sections R402.4.1.…

TABLE R402.4.1.1AIR BARRIER, AIR SEALING AND INSULATION INSTALLATIONaCOMPONENTAIR BARRIER CRITERIAINSULATION CRITERIAGeneral requirementsA continuous air barrier shall be installed in the building envelope.Air-permeable insulation shall not be used as a sealing material.Breaks or…

R402.5 Maximum fenestration U-factor. The area-weighted average maximum fenestration U-factor permitted using tradeoffs from Section R402.1.5 or R405 shall be 0.48 for vertical fenestration, and 0.75 for skylights.EXCEPTION:The maximum U-factor and solar heat gain coefficient (SH…

[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40300, filed 2/1/13, effective 7/1/13.]

R403.1 Controls. Not less than one thermostat shall be provided for each separate heating and cooling system.R403.1.1 Programmable or connected thermostat. Where the primary heating system is a forced-air furnace, at least one thermostat per dwelling unit shall be Energy Star cer…

R403.2 Hot water boiler temperature reset. The manufacturer shall configure each gas, oil, and electric boiler (other than a boiler equipped with a tankless domestic water heating coil) with an automatic means of adjusting the water temperature supplied by the boiler to ensure in…

R403.3 Ducts. Ducts and air handlers shall be installed in accordance with Sections R403.3.1 through R403.3.7.R403.3.1Ducts located outside conditioned space. Supply and return ducts located outside conditioned space shall be insulated to an R-value of not less than R-8 for ducts…

R403.4 Mechanical system piping insulation. Mechanical system piping capable of carrying fluids above 105°F (41°C) or below 55°F (13°C) shall be insulated to a minimum of R-6.EXCEPTION:Up to 200 feet of hydronic system piping installed within the conditioned space may be insulate…

R403.5 Service hot water systems. Energy conservation measures for service hot water systems shall be in accordance with this section. Service water-heating equipment shall meet the requirements of DOE 10 C.F.R. Part 430 Uniform Energy Factor or the equipment shall meet the requi…

R403.6 Mechanical ventilation. The buildings complying with Section R402.4.1 shall be provided with mechanical ventilation that meets the requirements of Section M1505 in the International Residential Code or Section 403 in the International Mechanical Code, as applicable, or wit…

TABLE R403.6.1WHOLE HOUSE MECHANICAL VENTILATION SYSTEM FAN EFFICACYaSystem TypeAir Flow Rate (cfm)Minimum Efficacy (cfm/watt)HRV, ERV or balancedAny1.2Range hoodsAny2.8In-line supply or exhaust fanAny3.8Other exhaust fan<902.8Other exhaust fan≥903.5For SI: 1 cfm = 28.3 L/min.a. …

R403.7 Equipment sizing and efficiency rating. Heating and cooling equipment shall be sized in accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies. The output capacity of…

R403.8 Systems serving multiple dwelling units. Systems serving multiple dwelling units shall comply with Sections C403 and C404 of the WSEC—Commercial Provisions in lieu of Section R403.[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160 and chapter 19.27 RCW. WSR 20-01…

R403.9 Snow melt system controls. Snow and ice-melting systems, supplied through energy service to the building, shall include automatic controls capable of shutting off the system when the pavement temperature is above 50°F, and no precipitation is falling and an automatic or ma…

R403.10 Energy consumption of pools and spas. The energy consumption of pools and permanent spas shall be controlled by the requirements in Sections R403.10.1 through R403.10.4.2.R403.10.1 Heaters. The electric power to heaters shall be controlled by an on-off switch that is an i…

R403.11 Portable spas. The energy consumption of electric-powered portable spas shall be controlled by the requirements of APSP-14.R403.12 Residential pools and permanent residential spas. The energy consumption of residential swimming pools and permanent residential spas shall b…

[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160, and chapter 19.27A RCW. WSR 24-03-084, § 51-11R-40392, filed 1/16/24, effective 3/15/24; WSR 23-02-060, 23-12-102, and 23-20-022, § 51-11R-40392, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24.]

[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40400, filed 2/1/13, effective 7/1/13.]

R404.1 Lighting equipment. All permanently installed lighting fixtures, excluding kitchen appliance lighting fixtures, shall contain only high-efficacy lighting sources.R404.1.1 Exterior lighting. Connected exterior lighting for residential buildings shall comply with Section C40…

[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160, and chapter 19.27A RCW. WSR 23-02-060, 23-12-102, and 23-20-022, § 51-11R-40500, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. W…

R405.1 Scope. This section establishes criteria for compliance using total building performance analysis. Such analysis shall include heating, cooling, mechanical ventilation, and service water heating energy only.[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160, and …

R405.2 Performance based compliance. Compliance based on total building performance requires that a proposed design meet all of the following:1. The requirements of the sections indicated within Table R405.2.2. For structures less than 1,500 square feet of conditioned floor area,…

R405.3 Documentation. Documentation of the software used for the performance design and the parameters for the building shall be in accordance with Sections R405.3.1 through R405.3.2.2.R405.3.1 Compliance software tools. Documentation verifying that the methods and accuracy of th…

R405.4 Calculation procedure. Calculations of the performance design shall be in accordance with Sections R405.4.1 and R405.4.2.R405.4.1 General. Except as specified by this section, the standard reference design and proposed design shall be configured and analyzed using identica…

[Statutory Authority: RCW 19.27A.020, 19.27A.045, 19.27A.160, and chapter 19.27A RCW. WSR 23-02-060, 23-12-102, and 23-20-022, § 51-11R-40550, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. W…

TABLE R405.4.2(1)SPECIFICATIONS FOR THE STANDARD REFERENCE AND PROPOSED DESIGNSBUILDINGCOMPONENTSTANDARD REFERENCE DESIGNPROPOSED DESIGNAbove-grade wallsType: Mass wall if proposed wall is mass; otherwise wood frame. Gross area: Same as proposed U-factor: From Table R402.1.2Solar…

TABLE R405.4.2(2)DEFAULT DISTRIBUTION SYSTEM EFFICIENCIES FOR PROPOSED DESIGNSaDISTRIBUTION SYSTEM CONFIGURATION AND CONDITIONDISTRIBUTION SYSTEM EFFICIENCYDistribution system components located in unconditioned space 0.88Distribution systems entirely located in conditioned space…

R405.5 Calculation software tools. Calculation software, where used, shall be in accordance with Sections R405.5.1 through R405.5.3.R405.5.1 Minimum capabilities. Calculation procedures used to comply with this section shall be software tools capable of calculating the annual ene…

[Statutory Authority: RCW 19.27A.020, 19.27A.045 and chapters 19.27 and 34.05 RCW. WSR 13-04-055, § 51-11R-40600, filed 2/1/13, effective 7/1/13.]

R406.1 Scope. This section establishes additional energy efficiency requirements for all new construction covered by this code, including additions subject to Section R502 and change of occupancy or use subject to Section R505 unless specifically exempted in Section R406. Credits…

R406.3 Additional energy efficiency requirements. Each dwelling unit in a residential building shall comply with sufficient options from Table R406.2 and R406.3 so as to achieve the following minimum number of credits:1.Small Dwelling Unit:5.0 credits Dwelling units less than 150…

TABLE 406.3ENERGY CREDITSOPTIONDESCRIPTIONCREDIT(S)All OtherGroup R-2b1. EFFICIENT BUILDING ENVELOPE OPTIONSOnly one option from Items 1.1 through 1.4 may be selected in this category.Compliance with the conductive UA targets is demonstrated using Section R402.1.5, Total UA alter…

R407.1 General. Projects shall comply with Section R407.2 or R407.3.R407.2 Passive House Institute U.S. (PHIUS). Projects shall comply with PHIUS+ 2018 Passive Building Standard, including its USDOE Energy Star and Zero Energy Ready Home co-requisites, and performance calculation…