Transient Heat Transfer through Protective Clothing at Sea Level and High Altitude.
Abstract
-:3. A':%ST.%CT v%xjp%,% 2CQ' vc%fs) Skin, clothing and dew point temperatures were measured on subjects walking and then resting on a treadmill, wearing U.S. Army BDU and BDO (MOPP 1). Sea level and a high altitude environment were tested. The altitude environment, comparable to the condition at terrestrial elevation of 4,570 m (1 5,000 tt) above sea level, was simulated in the U.S. Army Research Institute of Environmental Medicine (USARIEM) Hypobaric Chamber. For both environments, we found a marked increase in the weighted average clothing temperature, T ci' during the transient period immediately after the cessation of walking. The similarly weighted average skin temperature, Tsk, did not exhibit any corresponding change, thus eliminating a metabolic origin of the observed increase in Tci. Moreover, since the same effect was found at both sea level and altitude, hypobaria also must not be a primary cause. A large release of heat stored within clothing is suggested as a source. When walking ceased, this stored heat, resident within the air mass between clothing layers, was driven outward by the large temperature gradient between skin and ambient temperatures. Other alternative mechanisms such as the pumping effect of clothing and the regain phenomenon were also examined and discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1995
- Accession Number
- ADA297229
Entities
People
- L. A. Blanchard
- R. R. Gonzalez
- Shi Chang
- W. R. Santee
Organizations
- United States Army Research Institute of Environmental Medicine