title: Immersion suit insulation: the effect of dampening on survival estimates.
abstract: Immersion suit leakage values were obtained from realistic testing of helicopter passenger immersion suits using eight subjects. Simulated helicopter underwater escape resulted in mean leakages of 198 +/- 103, 283 +/- 127, 203 +/- 179, and 45.7 +/- 31.6 g (mean +/- S.D.) when wearing four different immersion suits. Suit leakages obtained from a 20-min swim test to simulate vital in-water survival actions produced leakages of 213 +/- 224, 1398 +/- 691, 145 +/- 96.5, and 177 +/- 139 g (mean +/- S.D.). Dampening of undergarments during simulated helicopter travel at an elevated cabin temperature of 30 degrees C was 115 +/- 47.3 (mean +/- S.D.; n = 4) when wearing an impermeable suit and 19 +/- 16.7 g (mean +/- S.D.; n = 4) when wearing a vapour-permeable suit. The commensurate loss of insulation with the impermeable suit at the upper level of temperature could reduce clothing insulation by 17%. A reduction of less than 5% may result under similar conditions when wearing the permeable suit. The combined dampening effect of sweating, helicopter underwater escape, and performance of vital survival actions could result in a total dampening of 247-1712 g, depending on the type of suit worn. The respective loss of insulation would be 15% and 50% respectively. This could reduce, for the 10th percentile thin man, his survival time in water at 5 degrees C from 3.5 h to between 2.4 h and 1.1 h, respectively.
authors: Robert Gordons Institute of Technology, Offshore Survival Centre, Aberdeen, Scotland.
authors: I M
authors: IM
authors: Light
authors: A
authors: A
authors: Avery
authors: A M
authors: AM
authors: Grieve
mesh_terms: D000328:Adult; D000401:Aircraft; D003080:Cold Temperature; D006801:Humans; D007101:Immersion / Q000009:adverse effects; D008297:Male; D009026:Mortality; D010539:Permeability; D011481:Protective Clothing; D013546:Sweating; D013550:Swimming; D014867:Water
chemical_list: D014867:Water