Fire behavior in compartment containing timber constructions focusing on pressure increase owing to pyrolysis gas

Abstract

A series of full-scale compartment fire experiments was carried out to understand the fire behavior in compartment containing wooden constructions. The opening size and the surface area of combustible materials were adjusted to investigate the differences between ventilation-controlled and fuel-controlled fires. The results show that there was a time lag between when heat release rate (HRR) began to decrease and the time when the temperature in the compartment began to decrease in the case of with a wooden wall and ventilation-controlled fire; the HRR at the time when the temperature began to decrease was about the peak HRR of the case without a wooden wall. Although the HRR in case with a wooden wall was much higher than those without it, the temperature in the compartment with a wooden wall was slightly lower under ventilation-controlled conditions. These suggest that the amount of inflow air was limited by the increase in pressure in compartment due to pyrolysis gas.Furthermore, a model of compartment fires that takes this increase in pressure into account was developed, and it is able to more accurately reproduce the temperature characteristics than models that do not.