Various intensity heat fluxes firefighters encountered will produce thermal stress on skin, resulting in thermal pain and tissue damage. In this paper, a new approach to evaluate thermal stress under flashover with short duration was carried out based on plain-stress theory. Instant heat flux under fabric was calculated so as to determine temperature and thermal stress distribution. The results obtained were as follows: temperature increased slightly at initial stage and then sharply increased linearly, moreover, temperature was much higher when sensor directly contacted with specimen, comparing with that of 6mm air gap; heat flux under fabric quickly reached its maximum, and higher heat flux was observed as no air gap generated; thermal stress rapidly increased and then gradually decreased, moreover, higher thermal stress produced without air gap. The newly proposed method could well distinct heat transfer performance of fabric under different conditions, which might provide helpful guideline to performance evaluation of thermal protective clothing.
