Mathematical Models of Skin Burns Induced by Simulated Postcrash Fires as Aids in Thermal Protective Clothing Design and Selection

The design and selection of thermal protective clothing takes into account many factors, e.g., appearance, comfort, durability, cost, and thermal protective capability. To aid in determining the appropriate balance among these factors, thermal protective capability must be measured in a quantitative and clinically meaningful way. To provide such a valid assessment of thermal protective capability, two mathematical models were developed to predict skin burn damage based on data derived from 95 domestic white pigs exposed to simulated postcrash fires. The first model, a multidiscriminate statistical model derived from experimental data, was used to determine the importance of many variables, e.g., incident heat flux, exposure time, initial skin temperature, and color of the skin. The second, an analytical model, assumes that tissue damage proceeds as a first order chemical reaction dependent on tissue temperature, and that total damage is merely the time integral of tissue damage during heating and cooling. It also takes into account tissue water boiling and thermal shrinkage which alter burn depth in more severe burns. The predicted burn depths from measurements of thermal energy transfer through or emanating from burning fabrics when combined with burn area, age, and sex yield predicted survivability. Predictions of changes in survivability allow rational judgments to be made regarding the effectiveness of implementing proposed flight suit clothing fabric and design changes.