Kee Jong Yoon

Vol. 56,  No. 1, pp. 51-58, Feb.  2019
10.12772/TSE.2019.56.051

heat stress fire fighter turnout gear radiant heat transfer

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The greatest cause of fatality of fire fighters is heat stress rather than suffocation or burns. Heat stress increases the probability of heart attacks to a great extent and this was found to be the major cause of fatality of fire fighters. The effect of humidity on heat stress has been studied and is widely documented, however it appears that not enough attention is practiced in fire fighting. As fire fighter turnout gear often get wet when they are fighting fire, this paper attempts emphasize the importance of trying to keep the turnout gear as dry as possible to reduce the damaging effect of moisture on the heat stress that fire fighters experience. When fire fighters enter burning buildings other fire fighters spray water from a distance at the point of entry to reduce the intensity of fire there. The effect of added moisture on the temperature and relative humidity between the internal layers of the turnout gear is studied to infer the effect on heat stress. Preliminary experiments exposing a multilayer assembly whose outer layer is either conditioned or wetted on a radiant heat transfer equipment and measuring the change in temperature and humidity at two locations between the layers suggest that the transport of moisture carrying the external heat inward has a significant effect on the heat stress a fire fighter might experience. The data is analyzed with a typical heat stress index table as a first approximation of the heat stress the fire fighter might experience. The results suggests that the presence of moisture has extensive effect on the heat stress and that they should try to keep their turnout gear as dry as possible.