PDFWAC 51-51-03240

Section R324Solar energy systems.

R324.3 Photovoltaic systems. Installation, modification, or alteration of solar photovoltaic power systems shall comply with this section and the International Fire Code. Section R104.11 alternative materials and methods of this code shall be considered when approving the installation of solar photovoltaic power systems. Photovoltaic systems shall be designed and installed in accordance with Sections R324.3.1 through R324.6 and chapter 19.28 RCW. Inverters shall be listed and labeled in accordance with UL 1741. Systems connected to the utility grid shall use inverters listed for utility interaction.
Detached, nonhabitable Group U structures shall not be subject to the requirements of this section for structural and fire safety.
R324.4 Rooftop-mounted photovoltaic systems. Rooftop-mounted photovoltaic panel systems installed on or above the roof covering shall be designed and installed in accordance with Section R907.
The roof structure shall be deemed adequate to support the load of the rooftop solar photovoltaic system if all of the following requirements are met:
1. The solar photovoltaic panel system shall be designed for the wind speed of the local area, and shall be installed per the manufacturer's specifications.
2. The ground snow load does not exceed 70 pounds per square foot (3.35 kPa).
3. The total dead load of modules, supports, mountings, raceways, and all other appurtenances weigh no more than 4 pounds per square foot (19.5 kg/m2).
4. Photovoltaic modules are not mounted higher than 18 inches (457 mm) above the surface of the roofing to which they are affixed.
5. Supports for solar modules are to be installed to spread the dead load across as many roof-framing members as needed, so that no point load exceeds 50 pounds (22.7 kg).
R324.7.1 This section is not adopted.
[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-23-104, § 51-51-03240, filed 11/15/23, effective 3/16/24; WSR 20-21-041, § 51-51-03240, filed 10/13/20, effective 11/13/20; WSR 20-03-023, § 51-51-03240, filed 1/6/20, effective 7/1/20; WSR 16-03-025, § 51-51-03240, filed 1/11/16, effective 7/1/16.]