Thermophysiological response of Newton manikin equipped with power-assisted filtering device incorporating a full-face mask in hot environment.

One of the most common reasons inducing discomfort in wearing a respirator is an unpleasant local thermal perception. In this study, the effect of a power-assisted filtering device incorporating a full-face mask on the thermophysiological response was investigated by performing tests on a Newton manikin in a climatic chamber, where hot conditions were simulated setting the ambient temperature at 34 °C and the relative humidity at 32%. Two different levels of metabolic rate (1 MET and 3 MET) were considered. Results show that the variation of metabolic rate plays an important role in the heat exchanges with the environment causing different values of the local and global temperatures. At 1 MET the manikin is in thermal balance with the external environment with or without respirator. At 3 MET although the thermoregulation system is very stressed (the rectal temperature Tre increases continuously with or without respirator), the effect of the respirator produces a small decrease of the local and global temperatures and also of the amount of sweat generated by active thermoregulation Swa  (reaching its maximum value of 30 g/min when the respirator is not worn). Furthermore, a little amelioration of the face and body sensation and comfort was observed. In any case, wearing the respirator seems not to provide additional thermal load.