HEAT EXPOSURE ASSESSMENT IN THE WORKING ENVIRONMENT OF AGLASS MANUFACTURING UNIT

Heat stress is a common health problem throughout indust ry. Any heat stress evaluation requires someexposure assessment of climatic conditions, especially air temperature , humidity, and speed, along withthe average temperature of the solid surroundings. In this paper workpla ce environmental climaticparam eters were measured and then evaluated by Wet Bulb Globe Temperature, Corrected EffectiveTemperature, Heat Stress Index, and Allowable Exposure Time indices among 40 workers in a glassmanufactur ing unit in Tehran. Also, the effect of available heat control devices on heat stress indices wasinvestigated. The results of this study showed that the obtained heat stress index in individual section andpress units is exceeded from 100 (in individual section unit: 302 .6, in pre ss unit : 283.6). Also, it is foundthat the mean average of allowable exposure time in individual section and press units were 13.15 and12.26 minutes exposure for one hour, respectively. No significant relationship was found betweenenvironmental parameters in three parts of body regions (height of head, abdomen and ankle) except formeasured air velocity in both units (P 0.007). Positive corr elation was found between wet bulb globetemperature, correc ted effective temperature and heat stress index indices, but negative corre lation wasfound between allowable exposure time and other indices. Mann Whitn ey non-parametric test revealedsignificant relationships in wet bulb globe temperature, corrected effective temperature, heat stress indexand allowable exposure time indices when metall ic shield was used as heat absorber.