Heat and water vapour transfer of protective clothing systems in a cold environment, measured with a newly developed sweating thermal manikin.

Abstract

A moveable sweating thermal manikin has recently been developed. Thermal and water-vapour resistances of three kinds of cold-protective clothing ensembles, laminated with polytetrafluoroethylene, polyurethane and without a laminate were measured, with the aid of the manikin in a cold environment of 5 degrees C with a relative humidity of 70% and an air velocity of around 1.5 m s(-1). Two sweating rates of 65 and 130 g m(-2) h(-1) were employed. Supplied heat fluxes in both of the sweat rates ranged from 350 W m(-2) to 400 W m(-2). To maintain a comfortable condition, the skin wettedness (w) (mean weighted value) had to be kept at < or = 0.6. The measurements obtained from the manikin when testing the three ensembles were w=0.3 (approximately) for the low sweat rate and w > or = 0.6 for the high sweat rate, irrespective of the property differences among the ensembles. In addition, the condensation in the ensembles in comparison with those calculated from an analytical equation is discussed. Condensation mass fluxes in the ensembles obtained by experiment and those from the calculation agreed sufficiently well. Thus, distribution of the condensation in the ensembles was estimated using the equation.