CHARRING OF WOOD WITH THERMAL-RADIATION . 2. CHARRING RATE CALCULATEDFROM MASS-LOSS RATE

In past studies, char depth has been measured directly, or estimated b y the temperature changes inside the wood. With these methods, continu ous charring rate data cannot be obtained because the measuring points are limited. In this study, a Cone Calorimeter was used to overcome t his problem. Thirteen wood species were tested (softwood: 5, hardwood: 8). The results were as follows: 1) There was a good correlation betw een the mass loss and the char depth. It is possible to estimate the c harring rate using the mass loss rate data which are input into a comp uter at a constant interval. 2) The charring rate fell when a specimen 's thickness increased. 3) The density and structural elements of wood seemed to affect the mass loss rate of the wood specimen when it was burned. The mass loss rates of wood specimens increased linearly with increases in sample densities ignoring vessel elements. 4) Although th e charring rates of wood specimens varied with species, each charring rate was uniform between the first and second peaks of the heat releas e rate. This phenomenon can be explained with a stationary combustion model for liquid fuel. 5) The heat flux at the char base was proportio nal to the mass loss rate.