Thermal energy transfer through heat protective clothing during a flame engulfment test

The flame engulfment test according to ISO 13506 assesses the protective performance of ready-made heat and flame protective clothing when exposed to a flash fire condition using an instrumented manikin. It uses a thermal model of the human skin to predict the risk of skin burns. This evaluation method is based on a pass/fail criterion, as either a burn is predicted or not. Therefore, it provides only limited information about the transfer of heat through the protective clothing. In this study, we investigated the use of the total transferred energy as an improved characterization method of the performance of the garments. We defined an energy transmission factor as the quotient between the transferred energy on the clothed manikin divided by the transferred energy registered by the nude manikin during calibration. We analyzed the performance of seven garments and show that the energy transmission factors can be assessed with very high repeatability. When comparing the results of the right and left arms and legs, we found very high correlation coefficients of 0.96 and 0.98, respectively, showing that the thermal insulation of the garments tested was very symmetrical. This new assessment method will be proposed for the revision of ISO 13506.