Efficfncy of Combinations of Cooling for Microclimate Cooling Suit Design, Tested in Man at 100°f with Exercise

A recent concern in hazardous materials containment, removal, and military operations has been the heat and work stress imposed on personnel wearing chemical and biological protective clothing (Chemical and Biological Protection Suit, Carbon Sphere #8415-01-333-7578 and gas maskkowl, MSA91J012-013; CBR). Several microclimate-cooling systems have been tested as possible solutions (1). Although these systems may extend work time in heat stress environments, many models have limitations that prevent extended use with CBR. These limitations include effectiveness only during conditions of light to moderate work loads, requirement of a significant amount of support materials for sustained operations, removal of protective clothing for re-supply, and necessity of low ambient humidity for evaporative cooling (1-5). The following tests confirmed that several configurations of one model (FlexithermTM vest, leg panels, and cap, Life Support Systems Inc., Mountain View, CA), in conjunction with a thermoelectric coolingheating unit (Carlson Technology Inc., Livonia, MI), are effective in reducing cardiovascular load and extending work time during heat stress and moderate work loads (6,7).