[Duration limit of moderately heavy work activity in technically unfavorable environments]

The working time in work places thermically uncomfortable must be limited in order to prevent the risk of thermal stress. The Authors measure the environmental microclimatic parameters (dry bulb temperature, wet bulb temperature, globe temperature, natural wet bulb temperature, air speed, vapor pressure) in twenty working sites of a thermal power plant. Starting from the values obtained, they calculate the safe exposure times under unfavourable thermal conditions by means of four different methods (WBGT, time weighted average WBGT, allowable exposure time-AET, required sweat rate index). The results are critically analysed.