UL Design D925

1-Hour Fire Rated D925 assembly

UL Design D925 — Concrete-on-steel-deck floor with spray-applied fire resistive material, restrained assembly ratings of 3/4, 1, 1-1/2, 2 or 3 hr (unrestrained beam ratings up to 4 hr). Concrete is normal weight (147-153 pcf, 3500 psi, from 3-1/2 in. at 1 hr up to 5-1/4 in. at 3 hr) or lightweight (107-120 pcf, 3000 psi, from 2-1/2 in. at 3/4-1 hr up to 4-7/16 in. at 3 hr) cast on galvanized steel deck 1-1/2, 1-5/8, 2 or 3 in. deep (min 22 MSG fluted; 4-1/2 in. non-composite units also permitted), supported on a W8x28 or alternate steel beam. Deck underside and beam are protected with Monokote spray-applied fireproofing, thickness ranging from 5/16 in. (1 hr) to 2-13/16 in. (3 hr unrestrained beam) depending on configuration.