A NEW CORRELATION FOR BENCH-SCALE PILOTED IGNITION DATA OF WOOD

This paper presents the results of a combined experimental and theoret ical study of piloted ignition of cellulosic materials. The main objec tive is to present an engineering solution to the piloted ignition pro blem for wood exposed to radiant heat in a bench-scale piloted ignitio n test. This has been motivated by the need to have simple models of i gnition for use in a computational fluid dynamics (CFD) model of fire spread and extinguishment in building fires. The experiments were cond ucted on oven-dry and moisture conditioned samples of three wood speci es using a cone calorimeter. As expected, the experimental data reveal ed that the effect of moisture content on the piloted ignition process is significant. It was also found that the ignition temperature depen ds on the external heat flux, which supports other recent studies. Bas ed on the experimental observations, an approximate analytical equatio n was derived and then used for correlating the ignition data, as well as extracting the piloted ignition properties. The chief distinguishi ng feature of the present equation over other similar equations is tha t it takes into account the variation of the ignition temperature with external heat flux. (C) 1997 Elsevier Science Ltd.