Effects of incident solar radiation on evaporative heat loss through firefighter turnout composites incorporating microporous and bi-component type moisture barrier components

Solar radiation is a significant source of firefighter heat stress. In this study, the influence of solar radiation on heat transfer through firefighter fabric composites was evaluated using a modified sweating guarded hotplate exposed to simulated solar radiation. It demonstrated that the heat transfer depended on the intensity of the incident radiation, the color of the outer shell materials, and the type of moisture barrier incorporated in the composite. For ensembles with microporous moisture barrier, evaporative resistance decreased steadily with radiation. In contrast, the evaporative resistance of firefighter ensembles with bi-component moisture barriers initially increased in lower-level radiation intensity and then dropped as the exposure became more intense. To the best of our knowledge, these have never been reported before. The new findings from this study demonstrate the need to address the property change in bi-component moisture barriers under radiant heat load in material design, testing, and mathematical modeling.