Experimental study of woods under external heat flux by autoignition: Ignition time and mass loss rate

Piloted ignition of woods has been commonly investigated, which is accelerated by a spark plug. Autoignition is a complex phenomenon that combustible materials are ignited by internal heating, without the spark plug. Compared with piloted ignition, process of autoignition is closer to the development of real fire. Very few studies have focused on the prediction of ignition time and average mass loss rate by autoignition. Therefore, ignition time and mass loss rate on six species of commonly used wood samples, namely pine, beech, cherry, oak, maple, and ash, were studied under external heat flux by autoignition in a cone calorimeter. Three mass loss stages of woods under external heat flux was observed. Empirical models of ignition time and average mass loss rate for woods under external heat flux were developed. These empirical models can be used not only for fire risk evaluation, but also for modeling input and validation.