Recent tests have resolved a longstanding debate among designers over the amount of fire protection appropriate for a steel floor assembly.
Revisions to UL Design No. D982 in the Underwriter Laboratories Fire Resistance Directory, based on fire tests sponsored by the American Institute of Steel Construction and the American Iron and Steel Institute (AISI), mean steel assemblies qualify for half the customary fire-protection thickness, regardless of the design detail in the building, says Charles J. Carter, AISC’s vice president and chief structural engineer. The appropriate thickness had long been argued, he adds.