Skin burn induced by thermal radiation or heat source is one of the common but severe, injuries in firefighting and some industry work exposed to intensive radiation. In this article, a multi-layer skin model on heat and mass transfer is presented article to investigate the effects of blood perfusion, water diffusion, and vaporization on tissue temperature and skin burn after removing the heat source. The numerical results of the model are in good agreement with previous experimental results. A parametric study is carried out to investigate the effects of skin geometrical and thermal parameters, and initial tissue temperature on skin temperature distribution and burn injuries after the removal of the heat source. The results show two-sided effects on tissue temperature, i.e., heat loss due to water vaporization and water diffusion can cool the epidermis; however, blood perfusion and water diffusion heat the subcutaneous tissue incurring skin damage. It is found that the epidermis and dermis thickness, the dermal and subcutaneous tissue thermal conductivity, and the subcutaneous tissue heat capacity have significant impact on tissue temperature and burn injuries, while the epidermis thermal conductivity, the epidermis and dermis heat capacity, the blooding perfusion rate, and the water diffusivity have little influence.

The thermal performance of firefighters' protective clothing entrapping multiple air gaps and exposed to low heat fluxes has been studied using a newly designed bench-scale test apparatus. Different air gap sizes (0, 2 and 5 mm), and entrapped positions within the multiple fabric system between the outer shell, the moisture barrier, and the thermal liner, respectively, were investigated at three levels of thermal radiation (2, 5 and 10 kW/m²) over a prolonged period. The effect of air gap size and its position on the heat transfer in a multilayer fabric system are interpreted in terms of a theoretical flat multi-wall structure. The results show that the thermal protective performance of a multilayer fabric system is reduced under low-level heat flux with and without an air gap. It is indicated that the time for skin to burn in direct contact with the inner layer is increased with the size of the air gap, due to an increase in the total thermal resistance of the fabric combination and a decrease in heat radiation between two adjacent fabric layers separated by an air gap. The results also provide an insight into the contribution of the thermal resistance of each fabric layer and each air gap to the overall protective effect of the clothing system. The difference in the received heat flux with different air gap sizes in different positions shows that the effect of air gap size is related to its position.

The aerodynamic effects of human movement can significantly influence the airflow motion and contaminants transmission in enclosed environments such as in aircraft cabins, cinema and conference room, and so it is necessary and important to study the characteristics of these aerodynamic effects. This work focuses on the aerodynamic characteristics of human movement behaviours including limbs pendulum and body motion. A thermal manikin is used in the corresponding environments to simulate these behaviours. The step frequencies of 20, 30, 40, 50 and 60 double steps per minute for limbs pendulum and the moving speeds of 0.5, 0.75, 1.0, 1.25 and 1.5 m/s for body motion are investigated in the experiments. In each case, the velocity distribution around the human body is measured by using hot-wire anemometers. The experimental results show that the characteristics of the velocity distribution induced by limbs pendulum depend on pendulum frequency and spatial location, and for body motion, it depends on moving speed, moving distance and spatial location. The analysis results show that body motion has a significant influence on the flow field, and its aerodynamic effects are greater than those due to limbs pendulum. When a human moves, more detailed profile of the human body leads to more complicated flow field in the nearby area.