Textile Moisture Sensors for Estimating Sweat Evaporation Saturation in Fire Protective Clothing

Heat stress is a major problem for firefighters, which can be alleviated to a certain extent by means of special cooling. A moisture-sensing jacket lining under firefighter clothing is presented and correlated with a measure of relative humidity. The critical heat stress trigger point, sweat evaporation saturation, should be identified by the textile moisture sensors. Different sensor locations are compared to identify accurate moisture-sensing positions. The jacket lining was used in a laboratory study with 19 participants performing a sauna stay to increase the body core temperature. Granger causality tests were conducted to evaluate the relative air humidity forecasting based on the measured sweat rate. The resulting F-test p-values revealed that the moisture-sensing fire jacket lining can forecast the relative air humidity and the back region is the most accurate and robust sensor location. In conclusion, the fire jacket lining can detect sweat evaporation saturation time points and can be used as a data source for automated integrative air body cooling systems to avoid heat stress during firefighting operations.