The Solar America Board for Codes and Standards (Solar ABCs) has conducted limited testing of the fire resistances of rack-mounted photovoltaic (PV) panels installed over fire-classified roof coverings. If you are involved with the design or installation of roof-mounted PV systems, I encourage you to be aware of this testing and the concerns it raises.
Solar ABCs testing
Underwriters Laboratories (UL) Inc.'s classifications for PV modules and panels indicate installing them on a roof system may or may not adversely affect the roof system's external fire exposure if the PV modules or panels have a lesser fire-resistance rating than the roof system.
To determine whether rack-mounted PV modules or panels affect roof systems' fire classifications, Solar ABCs conducted a series of spread-of-flame and burning-brand tests on representative rack-mounted PV panels installed on fire-classified roof systems. The tests are similar to those conducted on PV panels and roof systems to determine their individual fire classifications.