Installing rooftop solar systems that consistently meet waterproofing code requirements rests on understanding the relationship between code, roofing manufacturers and best practice guidelines. This knowledge can make the difference between passing and failing an inspection, and it helps maintain any roof warranties as well as reduce long-term liability.
Quick Mount PV created the Wheel of Accountability to help solar designers and installers better understand the relationships between relevant codes, standards and best practices—guidelines that impact rooftop structures and waterproofing.
The AHJ (authority having jurisdiction)—typically the local building department—is at the center of the wheel. The AHJ has final say on how rooftop solar systems will be installed. The AHJ is empowered to interpret codes and standards and enact special requirements that address climatic, geological, seismological or topographical conditions unique to an area.
OSHA establishes workplace safety requirements and can shut down any jobsite or fine an installer for unsafe workplace practices.
The National Fire Protection Association (NFPA) publishes the National Electric Code that governs equipment-grounding requirements for PV systems. UL develops the UL 2703 standard for rack-mounted PV systems which outlines the proper methods for ensuring a reliable equipment ground for the modules and rack to minimize the potential for shock or fire hazard in the event of an accidental fault.
Building codes are developed by the International Code Council (ICC), which publishes the International Building Code and International Residential Codes, which are used as the basis for almost every State Building Code. Building codes require that all roof penetrations be waterproofed with flashing that complies with the roofing manufacturer requirement. The NRCA and ARMA publish installation guidelines used by the overwhelming majority of shingle manufactures, and the Tile Roofing Institute publishes flashing guidelines used by the vast majority of tile manufacturers.
The roofing manufacturer is included in the Wheel of Accountability, as building code establishes the manufacturer as the entity that determines proper flashing procedure. It is necessary to follow roofing manufacturer flashing installation instructions to comply with code and maintain the roof warranty.
This tip was contributed by Jeff Spies, senior director of policy of Quick Mount PV.