Study of the Heat Stress Indices in a Glass Industry, Tehran, Iran.

Abstract

P-509 Introduction: heat stress is a common problem throughout industry. Its effects range from changes in worker behaviors to heat-related disorders. Heat stress is a common problem throughout industry. Its effects range from changes in worker behaviors to heat-related disorders. Any heat stress evaluation requires some assessment of climatic conditions, especially air temperature, humidity, and speed, along with the average temperature of the solid surroundings. Methods: Workplace environmental parameters such as dry and wet bulb temperatures, globe temperature as well as relative humidity and wind speed were measured and then evaluated by WBGT ‘CET’ HSI and AET indices among 40 workers in IS and Press shops of a glass industry in Tehran. Also, the effect of personal protective equipment or other heat control devices on heat stress indices was investigated. The obtained results were analyzed by t-test, Pearson correlation, non-parametric Mann Whitney test, statistically using SPSS 10. Results: the results of this attempt showed that WBGT-TWA in IS and press shops are 34.57±1.6 and 34.06±1.4, respectively. Also, CET in IS shop was 35.38±1.97, whilst for press shop was found to be 35.8± 2.66. In addition, the obtained HSI in IS and press shops are exceeded from 100 (in IS shop: 302.6, in press shop: 283.6). Furthermore, the mean average of AET in IS and press shops were 13.15 and 12.26 minutes exposure for one hour, respectively. Discussion and Conclusion: This study showed that there are no significant relationships between globe temperature, dry bulb temperature and wet bulb temperature in the height of head, low back and ankle of workers, but significant relationship was found for measured air velocity in both shops (p<0.007). In addition, no obvious differences were found between relative humidity and water vapor pressure in air for both shops. Positive correlation was found between WBGT, CET and HSI indices, but negative correlation was found between AET and other indices. Mann Whitney non-parametric test showed that there are significant relationships in WBGT, CET, HSI and AET indices when personal protective equipment or other heat control devices were used (WBGT: p<0.03; CET: p<0.01; HIS: p<0.037 and AET: p<0.016).