Fire Safety Science Digital Archive

Char depths in wood, produced by irradiating the surface of the specimen with intense beams of thermal radiation have been reviewed and the results correlated with data from different laboratories. Charring rates over a wide range of irradiance levels were found to be directly proportional to the incident flux. Standard furnace tests for the endurance of timber beams and laminated columns indicates that resulting charring rates were produced by an equivalent square wave heat pulse. The equivalent heat input into the char layer of irradiated wood required to produce the observed charring rates is approximately 1/3 the heat of combustion of the wood.