Total Heat Loss and Evaporative Resistance Measurement
topic
Total heat loss measurement of complete firefighter ensembles uses the sweating guarded hotplate per ISO 11092 for material-level measurements and instrumented thermal manikins with sweating capability per ISO 9920 for ensemble-level assessment, providing intrinsic thermal resistance Rct in square metres Kelvin per watt and evaporative resistance Ret in square metres Pascal per watt that quantify both sensible and evaporative heat transfer capacity of the total clothing system.
Role
Provides the comprehensive physiological performance characterisation of firefighter clothing systems by measuring both the thermal resistance that increases heat stress from impaired sensible heat loss and the evaporative resistance that impairs sweat evaporation cooling, with THL being the single metric combining both heat transfer pathways that best predicts physiological heat stress burden and enables objective comparison of ensemble physiological performance across different clothing designs.