Fire Safety Science Digital Archive

To use wood as a building interior material, it is necessary to understand the fire-resistant qualities of wood. This paper describes the experiments conducted to investigate the ignitability and combustibility of wooden interior materials. In general, wood has complicated structure and composition. Moreover, the structures and constituent elements from different types of trees differ. Therefore, the ignitability and combustibility of wood are greatly affected by the physical and chemical properties. In this paper, we focuses on density, the most important physical index of wood, because density has an extremely intricate relationship with the other physical properties of wood and is the most representative index of the ignitability and combustibility of wood. With an aim of expressing the fire-resistant qualities of wood with density, the relationship between density and the ignitability and combustibility of wood was investigated. Assuming that when the surface temperature of the wood approached the ignition point it would ignite, ignition problems can be lumped together and dealt as thermal problems of the wood. Based on an equation of thermal conductivity, a quantitative model was prepared to represent time of ignition. Several other assumptions were made, and the model was simplified. Cone calorimeter tests were conducted on 8 types of wood to investigate the relationship between the ignitability and combustibility of these materials on the one hand, and density on the other. From the experimental results, the model coefficients were derived. The model obtained was expressed only in terms of wood density and heat flux, allowing us to make highly accurate predictions of time of ignition. Although the total heat release (THR) due to combustion showed a positive correlation with density, it was apparent that other factors besides density were also influential.