A mathematical model for heat transfer in fire fighting suits containing phase change materials

• Modelled heat transfer through fire fighting suit and skin with various heat fluxes.
• Investigated the use of Phase Change Material (PCM) to enhance protection in suits.
• Showed that PCM can increase the protective performance of fire fighting suits.
• Numerical results showed that PCM and air gap can further improve protection.
• Investigated various configurations for PCM and air gaps to determine optimal design.

Fire fighting is a hazardous occupation and the use of good quality thermal protective clothing is vital in the prevention of heat related injuries. Protective fire fighting clothing is generally chosen for its thermal and fire resistant properties, while also considering the weight, bulk and ease of movement of the suit. This research proposes incorporating a phase change material (PCM) into the fabric of the fire fighting suit in conjunction with air gaps to increase the thermal protection. A mathematical model of heat transport through a suit that contains PCMs and air gaps is presented. We investigate the distribution of temperature within the fabric during exposure to different fire situations. To assess the protective nature of the clothing, we model the skin as three layers with differing thermal properties (the epidermis, dermis and the subcutaneous layer) and examine the temperatures within the skin. The model can then be used to determine if the inclusion of a PCM layer would provide increased thermal protection to the fire fighter. Our earlier research has indicated that the most effective position for a PCM layer is near the outside of the suit. This paper will focus on the effect of the PCM layer in combination with air layers in the suit. Our results clearly show that an additional air layer increases the protection provided by the suit. This benefit comes without significantly increasing the overall weight of the suit.