Methods to Determine Drying Time of Wet Clothing Using a Thermal Manikin

摘要

Standard test methods for measuring thermal resistance (R_t) are intended for items in a dry state. Water is introduced to clothing by perspiration, condensation, precipitation, or immersion, which significantly reduces insulation. This study determined clothing dry times using a whole-body thermal manikin to examine the length of time and the transient nature of reduced insulation of wet clothing. Two methods were used to wet the clothing: method E submerged clothing in water before dressing on the manikin and method I used the thermal manikin sweating mechanism to wet the clothing. In conjunction with the wetting methods, two methods were used to determine clothing dry time: in method S, the clothing was considered to be "dry" based on steady-state heat flux values, and in method N, the clothing was considered to be "dry" when the R_t measurement of wet clothing reached 90% of the dry baseline R_t. The environmental conditions were specific to the wetting methods and set to air temperature (T_a) 10°C, relative humidity (RH) 50%, and air velocity (v_a) 0.4 m/s for method E, and T_a 35°C, 40 %RH, and v_a 0.4 m/s for method Ⅰ. Drying times for method I-N were 195 ± 12, 114 ± 17, and 171 ± 34min (mean ± SD) for cotton blend, lightweight synthetic, and midweight synthetic ensembles, respectively. Method E-S produced drying times of 267 ±19, 353 ± 75, and 268± 4 min (mean ± SD), and method E-N produced drying times of 218 ± 7, 216 ± 7, and 104 ± 7 min (mean ± SD) for cotton, synthetic, and wool ensembles, respectively. Method E-N provided the most consistent results based on a low standard deviation for repeated trials of ensembles and therefore would be the recommended approach for determining clothing dry time on a thermal manikin.