Effects of moisture content on burn injuries in firefighter protective clothing exposed to flash fire

Firefighters wear personal protective equipment (PPE) to protect themselves from high-temperature working environments during fire suppression operations as burn injuries can impose both physical and psychological burdens on firefighters. The Korea Fire Service recorded 140 reports of burn injuries among firefighters in the 3 years from 2021 to 2023, with an annual average increase of 29.8%. However, the burn studies conducted to evaluate the efficacy of firefighter protective clothing (FPC) under various conditions have typically employed simulations and bench-scale tests, which fail to consider the effects of air gaps between the layers and various components of FPC. Therefore, this study conducted full-scale manikin flame tests with all PPE to assess the burn severity and time to pain according to the moisture contents of the outer shell and thermal inner layers of the FPC. The results indicated that the risk of burn injury was relatively less severe when all FPC layers were dry or the outer shell was saturated. However, first- and second-degree burns were observed, and the time to pain was significantly reduced when the moisture content of the thermal inner was 10%, 20%, or 40%, indicating an elevated risk of injury. This study offers valuable insights for the prevention of burn injuries among firefighters exposed to unpredictable hazardous thermal environments.