Volume 2, Issue 2 (February 2005)
Evaluating the Physiological Performance of a Liquid Cooling Garment Used to Control Heat Stress in Hazmat Protective Ensembles
The purpose of this study was to evaluate the physiological performance of a liquid cooling garment in controlling heat stress in individuals wearing Hazmat protective ensembles. Five heat-acclimated male subjects completed three trials each: standard work clothing (WC), Hazmat suit (H), and a Hazmat suit with torso cooling (HC). All testing took place in an environmental chamber (35°C and 50 % relative humidity) with subjects walking on a treadmill at a metabolic rate of 300 W. Trials were performed until subjects completed the maximum 90 min, achieved the predetermined endpoints in core temperature (38.5°C) or heart rate (95 % of age predicted maximum), or symptoms of fatigue, disorientation, and discomfort forced the participant to discontinue or the researchers to end the test. A significant difference (P<0.05) between HC and H was found in final heart rate and core temperature (Tre), rate of change in heart rate and Tre, and exposure time. As well, HC was similar to WC in all measured physiological variables. It was concluded that a liquid cooling vest was beneficial in alleviating the heat stress caused by Hazmat protective ensembles.