Thermal and Moisture Properties of Mission Oriented Protective Posture (MOPP)Clothing at High Altitude

摘要

The effects of hypobaria on the thermal insulative properties and heat transfercharacteristics of the BDU and BDO in all four MOPP configurations were examined. Barometric pressure of 429 Torr (mmHg) was created in the USARIEM hypobaric chamber. The sea level environment was used as a baseline condition. Skin, clothing, and dew point temperatures were measured on subjects standing and walking on a treadmill. We found that hypobaria had minimal effect on the intrinsic clothing insulation values. For the less insulative BDU, hypobaria did not appreciably affect clothing insulation values. For the more insulative BDO, an average difference of 0.2 clo was found between the sea level and the altitude environments. The BDO MOPP level increase, from MOPPO (BDU) to MOPP4, was also accompanied by a gradual increase in the average skin temperature difference between sea level and altitude environments. An interesting outcome of clothing insulation was that it segregated, thermally, the skin surface from the clothing surface. At one site, the heat transfer processes operated almost independently from the other site. As a result, in hypobaric environment, the skin temperature was found to be lower, but the clothing temperature higher, than at sea level.