July 15, 2022

Updated Standard: FM 4478, Roof-Mounted Rigid Photovoltaic Module Systems

Examination Standard 4478, Roof-Mounted Rigid Photovoltaic Module Systems, has undergone a revision as part of FM Approvals' efforts to ensure our standards are aligned with latest product developments. The updated standard includes the following updates:

  • For wind uplift resistance, all rigid photovoltaic (PV) modules are tested in the same manner regardless of the slope of the module versus the slope of the roof
  • The minimum rating for Approval for PV module systems has been reduced to Class 1‑45