Fire Safety Science Digital Archive

Thermal degradation and ignition of selected wood samples will be studied in this paper. Firstly, experiments were conducted on samples of surface size 100 mm by 100 mm and thickness 15 mm thick. The samples of moisture content varied from 5% to 44% were exposed to uniform heat flux from 20 to 70 kW/m². Temperature profiles, mass loss rate, ignition temperature and ignition time of wood were all examined. A partial differential equations (PDE) model was then proposed to study the effect of heat flux on the pyrolysis and ignition of wood with different moisture content. The heat of thermal decomposition and effect of evaporation of water were also considered in the model. It is observed that temperature distributions, mass loss rate and ignition time predicted by this PDE model matched the experiments well. Results were also compared with an integral model predicting ignition characteristics based on energy balance and ignition criterion. This sample integral model did not give good predictions because most of the physical and chemical effects were not yet included under experimental conditions.