Effect of clothing insulation beneath an immersion coverall on the rate of body cooling in cold water.

Deep body and skin temperatures were measured on nine subjects during a 1 h immersion in water at 2.5 degrees C whilst wearing an RAF Mark 10 immersion coverall. With no additional insulation, mean skin temperature fell 13.1 degrees C and deep body temperature 0.74 degrees C. When a full Acrilan pile suit was worn beneath the coverall mean skin temperature fell 8.3 degrees C and deep body temperature 0.33 degrees C. With insulation covering the trunk and upper limbs alone, mean skin temperature fell 9.9 degrees C and deep body temperature 0.45 degrees C. Conclusions are drawn concerning the effects on body cooling of changes in insulation of aircrew clothing assemblies designed to protect against immersion in cold water.