A Review on Ignition of Cellulose Materials under External Heat Flux

Ignition is the initial stage of burning the materials. The consequent flame spread over the materials, heat release rate, fire spread across the rooms, and other issues for building fires all depend on that. Numerous studies on the ignition of cellulose materials, especially wood, were reported in the literature. There are smoldering or glowing ignition (self-heating ignition) and flaming ignition including piloted and spontaneous ignition. A review of the literature on flaming ignition will be reported in this paper. The ignition temperature, critical mass flux of volatiles, time to ignition, critical heat flux and critical heat release were measured experimentally and applied as key ignition criteria for theoretical analysis. Models of flaming ignition are well-developed from those well-validated experimental data. However, most of the flaming ignition models of wood are only on the solid phase. New theory on gas phases should be developed for further studying flaming ignition, especially the spontaneous ignition of wood. Quantitative study on modeling smoldering ignition of cellulosic materials is not yet well understood as experimental data are inadequate. This part is only briefly discussed.