Time—temperature profile across a lumber section exposed to pyrolytic temperatures

This paper presents a closed‐form solution with empirical adjustments to predict the time–temperature profile across a lumber section when the exposure history of its surface is known. The formulation is based on the two‐dimensional heat‐conduction equation that includes the effects of moisture evaporation and pyrolysis of wood. The kinetic constants and adjustment factors needed in the model were estimated from the temperature profile test data of dimension lumber and other published sources. This technique offers a simple practical means to estimate the internal temperatures of structural lumber exposed to high temperatures, and has been effectively implemented in the analyses of protected wood assemblies exposed to fire situations.