Evaluation of an Instrumented Sweating Manikin for Predicting Heat Stress in Firefighters' Turnout Ensembles

Abstract

This research studies relationships between measurements of heat loss through firefighter turnout ensembles measured using a sweating thermal manikin and a guarded sweating hot plate. Measurement techniques and results are compared. These two measures of heat loss are also compared on their ability to explain thermal heat stress. The assessments of thermal heat stress were provided in a report from an earlier physiological study where human responses were evaluated during wear trials of firefighter protective gear.

The focus of this research was on the role of the instrumented sweating manikin as a supplemental tool in predicting heat stress. Its human form makes it a logical intermediary tool between a flat skin model (hot plate) and human subject testing. Thus, it was decided to investigate its role by using it to evaluate six firefighter turnout ensembles where there was existing data available for comparison to both hot plate and physiological test results.

The results of this study indicate that sweating thermal manikin measurements provide a fuller explanation and prediction of heat stress assessments in physiological wear trials than provided by a sweating hot plate. This is attributed to the ability of manikin tests to evaluate the effects of garments' insulating air layers and the contribution of clothing design features to the total thermal burden. This research provides insights into the use of instrumented manikins as research tools and as means of providing information useful for predicting and explaining the results of physiological wear trials of firefighter protective clothing. Thermal manikins are also shown to be valuable tools for evaluating the distribution of heat loss through different areas of protective gear.