On dual performance of protective clothing composites with different air gaps under hot steam exposure

Thermal protective clothing (TPC) may actually have a dual impact on human skin since it not only resists heat and mass transfer from thermal environment, but also imposes thermal hazard through thermal stored energy discharge. The air gap entrapped clothing is an important factor influencing heat and mass transfer properties. This study used several indices to qualitatively explore the impacts of air gap size and its position on the dual performance of protective textile composites. The theoretical heat and mass transfer across an air gap was also analyzed. The results demonstrated that with the increasing of air gap size, heat transmission through textile composites during both exposure and cooling periods decreased, and the 2nd and 3rd degree burn time increased. The thermal protective performance was more affected by an inner air gap rather than by a middle air gap. However, the thermal-hazardous performance caused by the stored energy discharge was more affected by a middle air gap. Empirical models were successfully established to predict the energy absorption of the skin throughout the test. Results from this study could provide proper guidance for researchers and designers to develop new protective materials to prevent burn injuries.