Developing a test device to analyze heat transfer combined with radiant exposure and continuous liquid sweating through thermal protective clothing

Human perspiration significantly affects heat and mass transfer in clothing systems and absorbs thermal energy on the skin, especially in radiant exposure and high-intensity work. However, few testing devices simulate human sweating for assessing heat transfer under thermal radiation exposure. Thus, a test device that could realistically simulate specific sweat rates was developed to evaluate the influence of continuous sweating on thermal protective performance (TPP). The TPP of single-layer fabrics at dry (No-sweating) and three constant sweating rates was studied based on the calibrated tester. It was indicated that the new testing apparatus effectively evaluated fabrics' dry and wet thermal protective properties. Furthermore, compared to continuous sweating, the traditional pre-wet method may overestimate the TPP of the single-layer fabric depending on sweating rates. The continuous sweat rates played a dual role in the second-degree burn time and absorbed thermal energy, which is related to the moisture management performance of fabrics. The research provides an effective method to characterize the TPP of materials under continuous sweating/wetting, which will help optimize clothing performance and update relative standards.