Abstract: By taking men’s thermal underwear as example, the thermal resistance and moisture resistance of the underwear were measured by using a thermal manikin, the volume of the air layer between the thermal underwear and the thermal manikin was also measured with a 3D body scanner, and a multivariate regression model between the volume of the air layer and the thermal resistance and moisture resistance of the thermal underwear was built. The result shows that within the measurements of the underwear, the thermal resistance first increases and then decreases when the size increases, and the moisture resistance increases along with the increase of sizes. From further study it is found out that the moisture permeability decreases along with the increase of sizes, indicating the larger the sizes, the poorer the thermal comfort.

Key words: double-layer thermal underwear; thermal resistance; moisture resistance; moisture permeability index; volume of air layer