Fire Resistance of Wood-Framed Exterior Walls: Model and Full-Scale Test

摘要

The paper describes a heat transfer model for prediction of the thermal response of wood-framed exterior walls constructed with 38-mm by 89-mm wood-studs, gypsum board attached to the studs on the interior side of the wall, OSB sheathing attached to the side of the studs opposite to the gypsum board, insulation foam (EPS) outside the OSB sheathing, an air cavity for ventilation purposes, and a 12-mm or 15-mm thick noncombustible (ceramic) exterior siding attached to the wall over the wood strapping. This paper examines the fire resistance of this type of wall when the exterior face of the wall is exposed to fire. The model calculates heat transfer through the siding, the air cavity, the external foamed-plastic insulation, OSB sheathing, wood studs, the cavities between the studs, and the gypsum board on the interior face. When the calculated results were compared to the results from full-scale fire-endurance tests, very good agreement was observed.