Effects of Moisture Transfer and Condensation in Protective Clothing based on Thermal Manikin Experiment in Fire Environment

Abstract Protective clothing is important to work and for survival for firefighters in extreme environments, thermo-physical properties of which are influenced by the moisture. Moisture transfer and condensation effects on heat transfer process within the clothing were analyzed in this paper. Thermal manikin experiments were conducted with two kinds of multi-layer protective garments in hot environment, which varied in sweating rates of manikin and ambient humidity ranges. It was observed that temperature variations of the core body and the sweating skin layer were diverse with different conditions of the internal and external moisture difference and the level of vapor permeability of the clothing. The measurement has proved that the level of gas permeability has a great influence on the protective performance in which sweating has two distinct effects on the body. It is concluded that the protective performance is greatly impacted by the formed micro- environment within the clothing with different heat and mass transfer ways. It is demonstrated that the time needed to form the micro- environment is mainly influenced by the internal and external moisture difference and the level of vapor permeability. Those results contribute to understand the mechanism of heat and mass transfer in clothing at multiple internal and external moisture conditions of fire environment.