FM Global Approval

Key Takeaways

• FM Global Approval = insurance-driven equipment listing.
• Common in HVHZ regions, high-fire areas.
• FM 4476 + 4478 for PV roof attachment.
• May be required by commercial insurance carrier.
• Solar racking brands offer FM-listed product lines.

What FM 4476 and FM 4478 Cover

FM Global’s approval standards for roof-mounted PV racking test the mounting system as a whole, not just its individual parts: wind uplift resistance, fire propagation across the roof membrane, and hail impact resistance all get evaluated together. That’s a different bar than a typical UL listing, which is mostly concerned with component-level electrical shock and fire-ignition safety.

FM Global’s testing instead asks whether the racking will stay attached in a severe wind event and whether a fire starting on one section of the roof will spread the length of the array.

In practice, this is why FM-listed hardware turns up most often in two situations: coastal HVHZ projects, and buildings insured by a carrier that has adopted FM Global’s property-loss-prevention data sheets as a policy condition, a requirement that can apply regardless of geography.

When FM Global Approval Actually Gets Required

FM Global Approval isn’t written into the IBC or IRC the way structural load standards are, no building code section mandates it directly. It becomes a project requirement because the property insurance carrier underwriting the building asks for it, most commonly on large commercial and industrial roofs where a wind-uplift failure or roof fire represents a significant loss exposure for the insurer.

That means a design team can’t assume code compliance alone covers it; checking the project’s insurance requirements early, alongside the AHJ’s structural and fire code requirements, is the only reliable way to know whether FM-listed racking needs to be specified before the structural calc package and permit set go out.

Related Reading

Because insurance-driven equipment requirements like FM Global Approval tend to surface late if they’re not checked early, they’re worth confirming during the same intake step where a design team pins down local permitting rules, a step covered in more detail in our guide to submitting a solar permit package to an AHJ.

This kind of insurance-versus-code distinction also shows up when comparing large commercial roofs against smaller residential jobs, a contrast our commercial vs. residential solar permit design piece walks through. FM Global’s approval sits alongside, not instead of, component-level electrical certification, the parallel process for inverters and modules is summarized in this overview of the IEC 61730 module safety standard.

Disclosure: Qbits Energy is a Heaven Designs group company.