NUMERICAL SIMULATION OF HEAT TRANSFER IN FIREFIGHTERS' PROTECTIVE CLOTHING WITH MULTIPLE AIR GAPS DURING FLASH FIRE EXPOSURE

A finite volume model was developed to simulate transient heat transfer in firefighters' protective clothing during flash fire exposure. The model domain consists of three layers of fire-resistant fabrics (outer shell, moisture barrier, and thermal liner) with two air gaps between the clothing layers, the human skin, and the air gap between the clothing and the skin. The model accounts for the combined conduction-radiation heat transfer in the air gaps entrapped between the clothing layers, and between the clothing and the skin. The variation in the air gap properties and energy content during both the exposure and the cool down periods was accounted for. Predictions were obtained for the temperature and heat flux distributions in the fabric layers, skin, and air gaps as a function of time. The influence of each air gap on the clothing performance was investigated as well. This article demonstrates the importance of accurately modeling the contributions of the air gaps in order to predict the protective clothing performance.