Thermal Resistance Testing

Thermal resistance testing quantifies the dry heat transfer resistance of fabrics and clothing assemblies — the insulation value that determines how effectively a textile retards heat flow from a warm body surface to a cooler environment. The sweating guarded hotplate method measures thermal resistance by maintaining a heated plate at skin-equivalent temperature in a controlled ambient environment, calculating resistance from the steady-state heating power required. Clothing insulation is expressed in CLO units where one CLO represents the insulation of a standard business suit, ranging from lightweight single-layer fabrics through to heavy multi-layer protective ensembles. Thermal manikin testing extends flat-plate measurements to three-dimensional garment assemblies, accounting for garment fit, trapped air layers, and body movement effects on heat transfer.