Ignitability and heat-release properties of forest products

Abstract

Forest products comprising sawn boards of seven timber species, plywoods of three timber species, two hardboards and one particleboard have been tested to ASTM E 906—Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products. One plywood was also tested after fire-retardant treatment by pressure impregnation. The fire-retardant treated plywood was also tested after being overlaid with untreated face and back veneers. One sawn board product was also tested after coating with an intumescent fire retardant. The ignition times of the forest products that had not been fire-retardant treated increased with density when exposed to heat fluxes of 20 and 40 kWm−2. The maximum rate of heat release and the cumulative heat released rose with increasing impressed heat flux over the range 20–60 kWm−2. Heat-release properties were dependent upon the impressed heat flux. Relationships were also established between the maximum rate of heat release and the cumulative heat released for heat flux exposures of 20, 40 and 60 kWm−2. The ignition times of plywood were increased by pressure-impregnated fire retardants. Fire-retardant treatment by pressure impregnation prevented the ignition of a plywood and reduced its heat-release properties. The heat-release properties of a sawn board product were reduced by a fire-retardant surface coating.