A new approach to quantify the thermal shrinkage of fire protective clothing after flash fire exposure

Fire protective clothing made of inherent flame resistant materials shrinks easily when exposed to flash fire. This thermally induced shrinkage affects the thermal protective performance. Methods to evaluate the thermal shrinkage of fire protective garments are under development and there are currently no documentary standards available. The aim of this paper is to provide an effective method to accurately determine the shrinkage magnitude of fire protective clothing after flash fire exposure. This method involved a portable three-dimensional (3D) body scanner that could be mounted into the flame chamber to capture the 3D images of the nude and clothed manikin immediately before and after exposure. Based on the advanced post-processing techniques, the 3D images of the clothed manikin pre- and post-exposure were compared, and thermal shrinkage of the garment was characterized by three parameters, namely garment surface area change and volume and thickness change of the air layers entrapped between the manikin and garment. This method was supposed to provide basic knowledge for the quantitative research into the effect of thermal shrinkage on thermal protective performance.