(Effective until March 15, 2024)
Section R405.2—Mandatory requirements.
R405.2 Mandatory requirements. Compliance with this section requires compliance with those sections shown in Table R405.2. All supply and return ducts not completely inside the building thermal envelope shall be insulated to a minimum of R-8.
TABLE R405.2
MANDATORY COMPLIANCE MEASURES FOR SIMULATED PERFORMANCE ALTERNATIVE
Section | Title | Comments |
General |
R401.3 | Certificate | |
Envelope |
R402.4 | Air leakage | |
R402.5 | Maximum fenestration U-factor | |
Systems |
R403.1 | Controls | |
R403.1.2 | Heat pump supplemental heat | |
R403.3.2 | Sealing | |
R403.3.1 | Insulation | |
R403.3.3 | Duct testing | |
R403.3.4 | Duct leakage | |
R403.3.5 | Building cavities | |
R403.4 | Mechanical system piping insulation | |
R403.5.1 | Heated water circulation and temperature maintenance system | |
R403.6 | Mechanical ventilation | |
R403.7 | Equipment sizing and efficiency rating | |
R403.8 | Systems serving multiple dwelling units | |
R403.9 | Snow melt system controls | |
R403.10 | Pool and permanent spa energy consumption | |
R403.11 | Portable spas | |
Electrical Power and Lighting |
R404.1 | Lighting equipment | |
R404.1.1 | Lighting equipment | |
R404.2 | Electric readiness | |
Other Requirements |
R406 | Additional energy efficiency requirements | |
[Statutory Authority: RCW
19.27A.045 and chapter
19.27A RCW. WSR 22-10-094, § 51-11R-40520, filed 5/3/22, effective 6/3/22. Statutory Authority: RCW
19.27A.020,
19.27A.045,
19.27A.160 and chapter
19.27 RCW. WSR 20-01-047, § 51-11R-40520, filed 12/9/19, effective 7/1/20. Statutory Authority: RCW
19.27A.020,
19.27A.045 and chapters
19.27 and
34.05 RCW. WSR 13-04-055, § 51-11R-40520, filed 2/1/13, effective 7/1/13.]
(Effective March 15, 2024)
Section R405.2—Performance based compliance.
R405.2 Performance based compliance. Compliance based on total building performance requires the following:
1. The requirements of the sections indicated within Table R405.2(1).
2. For structures less than 1,500 square feet of conditioned floor area, the annual carbon emissions shall be less than or equal to 64 percent of the annual carbon emissions of the standard reference design.
3. For structures 1,500 to 5,000 square feet of conditioned floor area, the annual carbon emissions shall be no more than 47 percent of the standard reference design.
4. For structures over 5,000 square feet of conditioned floor area, the annual carbon emissions shall be no more than 41 percent of the standard reference design.
5. For structures serving Group R-2 occupancies, the annual carbon emissions shall be less than or equal to 61 percent of the annual energy consumption of the standard reference design. See Section R401.1 and residential building in Section R202 for Group R-2 scope.
Carbon emissions for both the standard reference design and the proposed design shall be calculated using Table R405.2(2). Energy use derived from simulation analysis shall be expressed in pounds of carbon per square foot of conditioned floor area.
TABLE R405.2(1)
MANDATORY COMPLIANCE MEASURES FOR TOTAL BUILDING PERFORMANCE
Sectiona | Title | Comments |
General |
R401.3 | Certificate | |
Envelope |
R402.1.1 | Vapor retarder | |
R402.2.3 | Eave baffle | |
R402.2.4.1 | Access hatches and doors | |
R402.2.10.1 | Crawlspace wall insulation installations | |
R402.4 | Air leakage | |
R402.5 | Maximum fenestration U-factor | |
Systems |
R403.1 | Controls | |
R403.3 | Ducts | Except for R403.3.2 and R403.3.3 |
R403.4 | Mechanical system piping insulation | |
R403.5.1 | Heated water circulation and temperature maintenance system | |
R403.5.3 | Drain water heat recovery units | |
R403.5.7 | Heat pump water heating | |
R403.6 | Mechanical ventilation | |
R403.7 | Equipment sizing and efficiency rating | |
R403.8 | Systems serving multiple dwelling units | |
R403.9 | Snow melt system controls | |
R403.10 | Energy consumption of pools and spas | |
R403.11 | Portable spas | |
R403.12 | Residential pools and permanent residential spas | |
R403.13 | Heat pump space heating | |
Electrical Power and Lighting |
R404.1 | Lighting equipment | |
R404.2 | Interior lighting controls | |
a | Reference to a code section includes all the relative subsections except as indicated in the table. |
TABLE R405.2(2)
CARBON EMISSIONS FACTORS
Type | CO2e (lb/unit) | Unit |
Electricity | 0.44 | kWh |
Natural gas | 11.7 | Therm |
Oil | 19.2 | Gallon |
Propane | 10.5 | Gallon |
Othera | 195.00 | mmBtu |
On-site renewable energy | 0.00 | |
a | District energy systems may use alternative emission factors supported by calculations approved by the code official. |
[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-40520, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24. Statutory Authority: RCW
19.27A.045 and chapter
19.27A RCW. WSR 22-10-094, § 51-11R-40520, filed 5/3/22, effective 6/3/22. Statutory Authority: RCW
19.27A.020,
19.27A.045,
19.27A.160 and chapter
19.27 RCW. WSR 20-01-047, § 51-11R-40520, filed 12/9/19, effective 7/1/20. Statutory Authority: RCW
19.27A.020,
19.27A.045 and chapters
19.27 and
34.05 RCW. WSR 13-04-055, § 51-11R-40520, filed 2/1/13, effective 7/1/13.]