Experimental research on gas fire backdraft phenomenon

The fire triggered by the leak of combustible gas is a serious threat to the safety of the public and firefighters. Backdraft is a special fire phenomenon in a limited-ventilation apartment. It can develop from fires of combustibles that become oxygen-starved and continue to generate a fuel-rich environment. If abundant fresh air is abruptly supplied by opening a door or a window, the hot gas in this vitiated apartment will rapidly combust and a fire ball and a blast wave will take place. This paper presents laws of gas fire backdraft phenomenon based on series of experimental tests in a reduced-scale compartment (length×width×height with 1.08m×0.36m×0.72m), fitted with an opening which could be changed in six cases quickly. The effects of varying ventilation conditions, ignition locations, and mass fluxes of gas leakage are discussed. In addition, the effect of the gas fire backdraft phenomenon on the temperature of the compartment is analyzed. The experimental results and the analysis show that the smaller the opening is, the further the ignition osition is away from the center of the compartment and the larger the mass flux of gas leakage is, the more easily the gas fire backdraft is produced. Furthermore, it is found that the ventilation condition is the key parameter determining the occurrence of gas fire backdraft, followed by the ignition position, and the mass flux of gas leakage through the analysis of orthogonal experiments.