This document provides the general principles of a test method for evaluating the physiological impact of garments or protective clothing ensembles in a series of simulated activities (phases) under defined ambient conditions. This standard test method characterizes the essential properties of fabric assemblies of a representative garment or clothing ensemble for thermo-physiological assessment: dry thermal insulation; measures for cooling properties during average metabolic activity and moisture management (dry and wet heat transfer); drying behaviour. Optionally and in addition to the standard test method, the same testing protocol can be applied to characterise more complex protective clothing ensembles including underwear, air layer and design features.1) This document is intended to be used to measure and describe the behaviour of fabric assemblies of a garment or clothing ensemble in response to a simulated series of activities under controlled laboratory conditions, with the results used to optimize garment combinations and material selection. Furthermore, this document is intended to be used to describe the thermo-physiological impact of protective clothing but not the risk for heat stress under actual fire conditions. The results of this test can be used as elements of a risk assessment with respect to thermo-physiological load.