Glossary / Class A

Class A

The most severe roof-assembly class under ASTM E108 or UL 790. Oregon R327’s floor is Class B. IBHS Essential asks for Class A.

Last verified 2026-08-23. JSON (CC BY 4.0)

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Class A. FireApproved glossary. https://fireapproved.com/glossary/class-a/. Last verified 2026-08-23.