Effects of moisture content and clothing fit on clothing apparent ‘wet’ thermal insulation: A thermal manikin study

Abstract

‘Wet’ thermal insulation, defined as the thermal insulation when clothing gets partially or fully wet, is an important physical parameter to quantify clothing thermal comfort. As the water/sweat gradually occupies the intra-yarn and inter-yarn air voids of the clothing material, the clothing intrinsic thermal insulation will be diminished and, hence, contribute to the loss of total insulation. In cold conditions, a loss in total thermal insulation caused by sweating may result in an inadequate thermal insulation to keep thermal balance and eventually leads to the development of hypothermia and cold injuries. Therefore, it is imperative to investigate the effect of clothing fit and moisture content on clothing ‘wet’ insulation. In this study, the ‘wet’ thermal insulation of three two-layer clothing ensembles was determined using a Newton thermal manikin. Four levels of moisture content were added to the underwear: 100, 200, 500 and 700 g. The clothing apparent ‘wet’ thermal insulation under different testing scenarios was calculated and compared. A third-degree polynomial relationship between the reduction in ‘wet’ thermal insulation and the moisture content added to underwear was obtained. Further, it was evident that the clothing fit has a minimal effect on the apparent ‘wet’ thermal insulation. The findings may have important applications in designing and engineering functional cold weather clothing and immersion suits.

Effect of sweating set rate on clothing real evaporative resistance determined on a sweating thermal manikin in a so-called isothermal condition (T manikin = T a = T r)

“…Previous studies show that the clothing insulation decreases as it gets wet (Hall and Polte 1956;Wang et al 2015a). The clothing thermal insulation presented in Eq.…”

Evaluation of Thermal Properties of 3D Spacer Technical Materials in Cold Environments using 3D Printing Technology

“…The thermal comfort provided by clothing is affected at the scales of the textile, thread, fabric, and clothing [2,3,4,5,6]. Furthermore, cloth-scale effects depend on the shape of the clothing, clothing pressure, area of body exposure, and method of body ventilation [7,8,9,10]. Heat transfer through clothing is affected by the convective current between clothing and environment, conduction, and radiation [11,12].…”

Measurements of clothing evaporative resistance using a sweating thermal manikin: an overview

“…Therefore, the evaporative heat loss measured in the so-called isothermal condition should be corrected before being used to calculate clothing total real evaporative resistance. The correction equation is expressed as 22 , 42 ) where, Q evap is the actual total evaporative heat loss, W; Q´ manikin is the observed heating power supplied to the manikin during the wet test, W; T air and T sk,f are the ambient temperature and the fabric ‘skin’ surface temperature, respectively, °C; I t is the total static dry thermal insulation of the tested clothing, m 2 ·K/W; w t is the amount of moisture contained in the tested clothing after the wet test; 0< w t <900 g.…”