Investigation of thermal insulation of cold protective clothing under different underwear and ambient conditions

In this study, the thermal insulation of cold protective outerwear under various clothing combinations and ambient conditions was estimated using a thermal manikin. A series of cold protective outerwear, worn with various types of underwear, were evaluated in a conditioned room to explore the dependence of outerwear thermal insulation on the underwear. Besides, statistical studies were utilized to study the effect of ambient temperature on the thermal insulation performance of cold protective clothing ensembles. The thermal insulation of outerwear was observed to be different when it was measured with various fit styles, thicknesses and combinations of underwear. These discrepancies can be attributed to the variation in the air gap between clothing layers and the presence of stagnant air within the porous clothing. Furthermore, the ambient temperature was found to be a dominant factor affecting the thermal insulation performance of the clothing ensembles with high air content, as the airflow inside the porous material may be aggravated by the larger temperature difference between the clothing and the environment. Based on this study, ambient conditions for the assessments of different kinds of clothing can be divided into five groups, simulating the actual-used scenarios. The findings of this study are anticipated to enhance the comprehensiveness of thermal insulation evaluations for clothing systems and assist in the identification of optimal clothing choices for diverse ambient conditions.