The thermal properties of a survival bag incorporating metallised plastic sheeting
Light, I.M.; Norman, J.N.
Aviation Space and Environmental Medicine 51(4): 367-370
1980
ISSN/ISBN: 0095-6562 PMID: 7369972 Document Number: 162599
Five male subjects were exposed to a cooling environment equivalent to 1082 W/M2. The subjects wore a clothing assembly with insulation properties of 1.55 clo. The clo unit (8) is an arbitrary unit of insulation and is the amount of insulation necessary to maintain comfort at a mean skin temperature of 33.3.degree. C in a room at 21.degree. C with an air movement not over 3 m/min, in a room at a humidity of 50% and at a metabolic heat production of 58 W/M2. A casualty bag incorporating metallized plastic sheeting was provided for additional insulation. Deep body temperature fell 1.2.degree. C and mean skin temperature 2.6.degree. C over the 2 h period. Metallized plastic sheeting did not prevent heat loss through the clothing assembly, as indicated by the falls in body and skin temperature and an increase in metabolic heat production. From measurements made during the exposure, the calculated insulation value of the complete assembly of 2.93 clo was close to the predicted value of 2.80 clo calculated from the thermal resistance of the assembly layers. The metallized plastic sheeting in this casualty bag did not provide significant additional thermal insulation. [This study has applicability to the management of accidental hypothermia].