Evaporative cooling in protective clothing - efficiency in relation to distance from skin

Evaporation of moisture, usually sweat, is essential for the maintenance of heat balance under most conditions when personal protective clothing is worn. Evaporation provides cooling where otherwise body heat losses would not be able to match metabolic heat generation (7). The energy equivalent of evaporating water or sweat from the skin is deemed only to be dependent on the temperature at which it takes place (5) (with skin temperature ranging typically from 30-36oC), but otherwise not influenced by factors such as clothing. When moisture evaporates from the skin in a person wearing clothing and travels towards the environment, it may be sorbed and subsequently desorbed by textile fibers (3), it may condensate in outer layers if these are colder than the skin (12, 8, 4) and subsequently evaporate again, it may be ventilated from the clothing microclimate through openings in the clothing or may finally diffuse through the outer clothing layer. Each of the phase changes mentioned will cause heat to be released or absorbed (8).