Abstract:  In order to ensure the life safety of firefighters and improve disaster response capability, a numerical simulation of firefighters' skin burn injuries was conducted. Firstly, the heat transfer model of the skin-underclothing air layer-fire suit system was proposed. Secondly, the heat transfer model was improved taking account of the fabric's periodic movement and the variation of heat exposure distance. Finally, the skin temperature was calculated by solving the differential equations, based on which the degree and time to skin burn injuries were calculated. The results indicated that the proposed model can well predict skin burn injuries with a relative error of 5.45%~13.6% for the time to 2nd degree burn. During the exposure to the thermal radiation of 20 kW/m2, the time to 2nd degree burn went ahead 28.4% or delayed 6.7%, respectively, when either the human movement was represented by fabric movement or distance between the body and heat source was considered, resulting in a serious over/under?estimation of skin burn. Moreover, a negative correlation between fabric movement amplitude and the time to skin burn was observed. This study can offer fundamental knowledge for the safety warning systems of firefighting and the development of high?performance protective clothing.

Key words: firefighting and rescue, heat transfer model, motion state, skin burn