Evaluation of Clothing Heat Transfer by Dry and Sweating Manikin Measurements

Due to effects of, for example, body movements and wetting on clothing heat transfer, measures taken with a standing, static, “dry” manikin are not likely to predict very accurately thermal protection in a real situation. In a proposed European standard (prEN342 Protective clothing against cold), measurement of thermal insulation is made with a “walking” manikin in order to account for some of the dynamic effects. Determination of evaporative resistance with a sweating manikin is still subject to research. In this investigation, five ensembles (one, two and three-layer ensembles) were investigated a) in human wear trials with analysis of heat fluxes, b) by measurements with a dry, standing and walking manikin and c) by measurements with a standing, sweating manikin. Total thermal insulation and evaporative resistance during actual walking was reduced by 20–45 %. Total insulation reduced less with more layers. Subtracting effects on the surface air layer revealed that the wind exerted a lesser effect as the insulation value increased. Wind and “walking” effects were less than 5–10 % for a three layer winter clothing. Evaporation efficiency measured with a sweating manikin provided a similar ranking of ensembles as direct measurements with subjects. Dynamic measurements of heat transfer properties appear to present reliable and realistic values for clothing thermal performance and should be used with prediction models and assesment methods of thermal stress.