Correlation of bench scale and manikin testing of fire protective clothing with thermal shrinkage effect considered

Abstract

Bench scale test and flame manikin test are two typical methods to evaluate the thermal protection provided by flame resistant fabrics or clothing. In this paper, the correlation between the test results of the two protocols was investigated. A group of fabrics commonly used in fire protective clothing were evaluated by a thermal protective performance (TPP) tester. Conditions with or without an air spacer were applied. Protective performance of the garments made of these fabrics with identical design feature was evaluated by a flame manikin testing system. Portable 3D body scanning technique was firstly used to characterize the air gap size change between the garment and manikin after flash fire exposure. The results showed that there was no significant correlation between the bench scale test and flame manikin test results in terms of TPP value and percent body burn. Thermal shrinkage which was not included in the bench scale test was demonstrated to be a key factor contributing to the weak correlation. It significantly decreased the air gap size between the garment and manikin and greatly affected the heat transfer after the flash fire exposure had ceased in the manikin test. Besides the TPP value, thermal shrinkage was suggested to be considered in the bench scale test as a parameter to predict the thermal protective property of flame resistant fabrics when made into garments.