Revisions to UL Design No. D982 in the UL Fire Resistance Directory, based on recent fire tests, have heated up long-standing differences between structural-steel interests and fire-protection suppliers and installers about the amount of sprayed-on fire-protection material needed for structural-steel floor assemblies.
The American Institute of Steel Construction and the American Iron and Steel Institute (AISI), which sponsored the UL 263 tests that resulted in the revised D982, maintain that structural steel assemblies now qualify for half the customary fire-protection thickness, regardless of the building’s design detail (ENR 11/28/16-12/5/16 p. 13). D982 covers all common steel-framed floor configurations, says Charles J. Carter, AISC’s president. D982 does not and never has covered steel joist assemblies or roof assemblies, he adds.
Because it can moderate the damaging effects of earthquakes, base-isolation is a technique used primarily in seismically active regions. ENR takes a look at some of the largest applications of base-isolation technologies in the world.