The effects of subfloor and insulation type and thickness on the fire resistance of small-scale floor assemblies

This paper discusses the results of 28 fire resistance tests conducted on unloaded insulated and non-insulated, small-scale frame floor assemblies using the ULC/ASTM fire exposure time-temperature curve. The frames used include either solid wood joist, wood I-joist, parallel-chord wood truss or steel C-joists. Temperatures were measured throughout the assemblies. All frames were protected on the fire-exposed side by Type X gypsum board, 16 mm thick. Parameters investigated in this study include the effects of subfloor type (plywood and oriented strand board), insulation type (glass, rock and cellulose) and insulation thickness (90 mm, 180 mm and full cavity). The impact of these parameters on the fire resistance performance of small-scale floor assemblies is discussed.