Flame Extinction in a Ventilation-controlled Compartment

The extinction characteristics of heptane pool fires were studied in a reduced-scale fire compartment with controlled ventilation. Temperatures at different heights above the flame and at a corner of the compartment, oxygen concentration at ceiling and floor level, carbon monoxide concentration, fuel-mass-loss rate, compartment pressure and ventilation rate were measured. Several tests were performed at very low ventilation rates leading to the extinction of the flame. It is shown that the fuel-mass-loss rates are reduced in these burning conditions compared to free-burning cases. The oxygen concentration at flame extinction was about 14% and did not vary significantly between the different tests. This threshold value is discussed and compared to values obtained by other studies.