Abstract
This paper deals with the variability of wettedness in hot environments and with the effect of its characteristics on the equi-skin temperature line. The experiments were carried out using young male subjects in a climate chamber. The tests were conducted on sitting-resting subjects dressed in athletic shorts. We conducted the studies in such environments that average skin temperature indicated in each environment be equal or close. The combinations of air temperature T_a and relative humidity RH were: (T_a≒33℃, RH≒80%), (T_a≒36℃, RH≒50%) and (T_a≒39℃, RH≒20%). From the basic measurements of both environmental parameters and human physiological responses, we obtained the following results. Under the conditions of constant activity level, of constant clothing worn, of constant air velocity and of constant average skin temperature, 1) the wettedness value in a high humidity environment is larger than that in a low humidity environment. 2) the evaporative heat loss from the skin surface is proportional to the wettedness. 3) the evaporative heat loss in a low humidity environment is larger than that in a high humidity environment. From the above-mentioned items, the locus of the equi-skin temperature is not a straight line but is plotted as a curve on the psychrometric chart.
