Effect of heat stress on physiological factors for industrial workers performing routine work and wearing impermeable vapor-barrier clothing.

The thermal hazards of suits impermeable to water vapor have been documented where fatal heat strokes have occurred during exercise in plastic suits at ambient temperatures as low as 26.7 degrees C. Research has shown that during work with impermeable vapor-barrier clothing (VB) the body temperature rises at a faster rate than without VB clothing. The purpose of this work was to study the effect of wearing VB clothing in hot environments on physiological responses (body temperature and pulse rates) for a group of workers performing routing work and to demonstrate the ease with which meaningful physiological measurements can be made on individual workers. Workers who wore VB clothing reached an extrapolated 37.6 degree C oral temperature at a 2.8 degrees C lower WBGT index that workers not wearing the VB clothing. When work durations in VB clothing exceeded 45 minutes, the oral temperature exceeded 37.6 degrees C. Also, these workers had no recovery pulses rates about 65% of the time after they worked in VB clothing for 15 minutes. The implementation of engineering and administrative controls and the use of a vortex-cooled air suit significantly reduced the stress produced by the physical labor, the VB clothing and the heat exposure.