Title
Moisture accumulation in sleeping bags at 7 and 20 ºC in relation to cover material and method use
Author
Havenith, G.
den Hartog, E.A.
Heus, R.
Publication year
2004
Abstract
Moisture accumulation in sleeping bags during extended periods of use is detrimental to thermal comfort of the sleeper, and in extreme cases may lead to sleep loss and hypothermia. As sub-zero temperatures were expected to affect vapour resistance of microporous membranes, the effect of using semipermeable and impermeable rain covers for sleeping bags on the accumulation of moisture in the bags during 6 days of use at -7 and 5 days at -20 ºC were investigated. In addition the routine of shaking off hoarfrost from the inside of the cover after the sleep period as a preventive measure for moisture accumulation was studied. Moisture accumulation (ranging from 92 to 800 grams) was found to be related to the vapour resistance of the materials used. The best semipermeable material gave the same moisture build-up as no cover at -7ºC, though build-up increased substantially at -20ºC. Shaking off the hoarfrost from the inside of the cover after each use was beneficial in preventing a high moisture build-up. It was concluded that semipermeable cover materials reduce moisture accumulation in sleeping bags at moderate sub-zero temperatures, but in more extreme cold (-20ºC) the benefits are reduced in comparison to routinely shaking frost from impermeable covers. Compared to fixed impermeable covers, the benefits of all semi-permeable covers are large. For long-term use without drying facilities, the differences observed do favour the semi-permeable covers above impermeable ones, even when regularly removing the hoar frost from the inside in the latter.
Subject
Microporous materials
Moisture
Thermal effects
Sleeping bags
Textiles
condensation
evaporation
membrane
permeability
condenser
fabric property
permeability
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DOI
https://doi.org/10.1080/00140130410001704428
TNO identifier
12819
Source
Ergonomics, 47 (47), 1424-1431
Document type
article