EFFICACY OF A WATER-COOLED GARMENT FOR AUXILIARY BODY COOLING IN HEAT

The efficacy of a water-cooled jacket for auxiliary body cooling was e xamined under a simulated hot environment. The personal garment compri sed of a water re-circulating three-layered vest of cotton fabric line d with 2 mm diameter latex tubing and inter-spaced coating of rubberiz ed solution. Four subjects wearing the water-cooled jacket were tested in the environment chamber (30, 35 and 40 degrees C DB, 50-60% RH, ai r velocity 0.3, 0.6 and 0.9 mis, with corresponding average effective temperature of 26+/-2.3, 33+/-1.1 and 36+/-1.5 degrees C). The inlet w ater temperature was maintained at 10-12 degrees C, with flow rates of 2.6+/-0.3, 4.3+/-0.3 and 5.1+/-0.3 l/h). At 30 degrees C DB, variatio n in water how had marginal effect on microclimate, while at higher te mperatures (35 and 40 degrees C DB), the re-circulating cooled water h ad noticeable effects in lowering microclimate, trunk and other skin t emperatures, and maintaining the body core within 36.7+/-0.2 to 37.5+/ -0.2 degrees C, over 2 h exposure at 35 and 40 degrees C DB. The obser vation indicates that the water-cooled jacket provided auxiliary cooli ng to maintain comfortable microclimate, skin and body core temperatur es. This enabled subjects to sustain comfortable heat balance over 2 h heat exposure without any noticeable heat strain.