Underwriters Laboratories (UL) Inc. is revising its standard for evaluating the safety of photovoltaic (PV) modules and panels. Because this revision will directly affect rooftop rack-mounted PV installations, you should be aware of the revisions taking place and their effects on these installations.
UL 1703, "Flat-Plate Photovoltaic Modules and Panels," is the basis for UL's evaluation of PV modules and panels. UL 1703 currently references UL 790, "Standard Test Methods for Fire Tests of Roof Coverings," for determining a panel's fire classification; UL 790 is the same test method used to determine roof assemblies' Class A, B and C fire classifications.
In 2008, the Solar America Board for Codes and Standards (Solar ABCs), a collaboration of PV industry stakeholders, identified PV module-specific fire research, testing and rating systems as high priorities. In subsequent research programs sponsored by Solar ABCs and funded by the Department of Energy, UL has conducted numerous fire tests of rooftop rack-mounted PV installation configurations.