ABSTRACT
Clothing will provide insulation (thermal resistance) between the skin and the environment and reduce or prevent heat transfer. The transfer of water vapor through clothing is termed vapor permeability. It is important to heat stress assessment as it determines the rate at which sweat can evaporate from the skin and cool the body. Gaps, flaps, and openings in clothing as well as air permeability, can alleviate heat stress by directly transferring hot moist air from the skin to the environment. Under heat stress, the body survives by evaporating sweat. Under compensable conditions (the body can achieve heat balance by thermoregulation), equivalent heart rate may indicate equivalent thermal strain and, hence, show how clothing can influence the ability to carry out physical work during heat stress. A comprehensive database of the thermal properties of clothing, for garments, ensembles, and textiles, as well as a description of parameters and measurement methods, is provided in international standard ISO 9920.
