Inter-laboratory proficiency tests in measuring thermal insulation and evaporative resistance of clothing using the Newton-type thermal manikin

Abstract

Clothing acts as an important barrier for heat and vapor transfer between the human body and the environment. Parameters that could describe that transfer include, inter alia, thermal insulation (the so-called dry heat exchange) and evaporative resistance (the so-called wet heat exchange). Once the above-mentioned parameters are determined, it is possible to consciously adapt clothing ensembles to the existing thermal environment in the workplace. In order to validate the mentioned method of thermal insulation and evaporative resistance measurements, proficiency tests (PTs) were organized. The main goal of the PT was to compare thermal insulation and evaporative resistance for one set of clothing using the Newton-type thermal manikin. In total, four laboratories participated in the PT study. The reference value of the thermal insulation ( It) and evaporative resistance ( Ret) were calculated as the mean of all the results. The assessment criteria included permissible errors for thermal insulation and evaporative resistance measurements, which were 4% and 10%, respectively. Calculations included, inter alia, z-scores and indicators, such as the inter-laboratory coefficient of variation or the reproducibility limit. The results contribute to the worldwide discussion on standardized studies of evaporative resistance of clothing.