This International Standard specifies methods for estimating the thermal characteristics (resistance to dry heat loss and evaporative heat loss) in steady-state conditions for a clothing ensemble based on values for known garments, ensembles and textiles. It examines the influence of body movement and air penetration on the thermal insulation and water vapour resistance. This International Standard does not — deal with other effects of clothing, such as adsorption of water, buffering or tactile comfort, — take into account the influence of rain and snow on the thermal characteristics, — consider special protective clothing (water-cooled suits, ventilated suits, heated clothing), or — deal with the separate insulation on different parts of the body and discomfort due to the asymmetry of a clothing ensemble.