The protective clothing for fire-fighter formed into closed mold accumulates metabolic heat of human body and gives excess heat stress to fire- fighter. In this study, the physiological impacts of four different protective clothing ensembles (A ~ D) were evaluated and subjective surveys were also taken using 5 levels. The experiment was composed of 20 minutes bicycle ergometer exercise and 5 minutes idle periods before and after the task in the climate chamber controlled at 30 ± 1℃ and 50 ± 3% relative humidity simulating summer season. The subjects were four healthy males, and each person wore two ensembles in a day, one in the morning, the other in the afternoon respectively.
Test subjects experienced 1.9 ~ 2.4℃ mean skin temperature rise, 0.8 ~ 1.1℃ tympanic temperature rise from the start to the end of the experiment. The heart rate reached 145 (for ensemble D), 170 (for ensemble A) at the end of the exercise. The sweat absorbed in underwear and jersey uniform weighted from 168g (ensemble C) to 258g (ensemble A). These values were significantly larger than those for just wearing jersey uniform.
The changes in mean skin temperature, tympanic temperature, and heart rate depended on protective clothing, provided same rank ordering A> B> C> D, that was nearly consistent with the subjective differentiation level ranging very hot/damp or moreover. These physiological indexes and their rate of increase may suggest a criterion for working time of fire fighter.
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