Incorporation of phase change materials in fire protective clothing considering the presence of water

Abstract

When firefighters face a heat exposure, free water may be present in the fire protective clothing (FPC). Recently, the incorporation of Phase Change Materials (PCMs) into FPC has shown great promise to increase thermal performance when in the dry state. However, the presence of water in firefighting garments is expected and how this alters the thermal behavior of a PCM FPC assembly still remains to be discussed in the literature. Hence, this study concerns the effect of free water presence in the outer shell and/or thermal inner of a PCM FPC assembly consisting of 3 layers. A new mathematical model is proposed where the PCM is assumed to be incorporated in the thermal inner. A numerical analysis is performed where PCM textile latent heat, water distribution, and heat flux intensity are varied. Skin temperature, skin heat flux, and PCM liquid fraction profiles are obtained along with second-degree burn times to measure thermal performance. It is found that steam condensation at the skin reduces PCM liquid fraction at second-degree burn time, when compared to the dry case. This study tends to shine a light on the importance of considering moisture management in PCM FPC assemblies so as to promote maximum PCM efficiency.