Numerical Modeling of Simultaneous Heat and Moisture Transport in Fire Protective Suits Under Flash Fire Exposure and Evaluation of Second-Degree Burn Time

Abstract

An improved numerical model is developed for coupled heat and moisture transport in fire protective suit exposed to flash fire. This model is combined with Pennes' bio-heat transfer model and subsequently, second-degree burn time is estimated using Henriques' burn integral. Natural convection is considered inside the air gap present between the multilayer clothing ensemble and the skin. Comparisons of temperature and moisture distribution within the multilayer clothing, air gap, and the skin during the exposure are presented considering combined heat and moisture transport and only heat transport. Effect of moisture transport on the protective performance of the fire protective suit is shown. Impact of both horizontal and vertical air gap orientations on second-degree burn time is studied. Effect of temperature-dependent thermo-physical properties, relative humidity, fiber regain, different exposure conditions and fabric combinations for the fire protective suits on burn time is analyzed.