Analytical Evaluation of Current United States Army Guidelines for Soldiers Wearing NBC Protective Overgarments Under Various Environmental Conditions

摘要

This thesis is concerned with the immediate problem of thermal stress experienced by soldiers while wearing MOPP-IV (Mission Oriented Protective Posture) in a hot environment. A Wet-Bulb Globe Temperature (WBGT) piece of equipment is described. Known as the Botsball thermometer, it consists of a hollow copper sphere that is painted black and covered with black cloth. The cloth covering is continuously moistened by water seeping from the reservoir tube attached to the globe. The stem of a dial thermometer passes through the reservoir tube and into the copper globe. This report evaluates the current US Army chemical overgarment in the MOPP-4 configuration under various environmental conditions. The effect of humidity and water loss is discussed in detail. It was found that the current safety guidelines as presented in FM 21-40 are inadequate. An effective temperature vs. tolerance time graph is developed for continuous wear. The graph is also developed for use with the BOTSBALL thermometer. A safety limit for the amount of water that can be lost is presented.