Get full text report (pdf file; Read by ADOBE Acrobat Reader)
J Occup Health year 2003 volume 45 number 3 page 153 - 159
Classification Original
Title Evaluating the Efficacy of a Thermal Exposure Chamber Designed for Assessing Workers' Thermal Hazard
Author Perng-Jy TSAI1, Chuh-Lun LO1, Yih-Min SUN2, Yow-Jer JUANG2, Hung-Hsin LIU2, Wang-Yi CHEN3 and Wen-Yu YEH3
Organization 1Department of Environmental and Occupational Health, Medical College, National Cheng Kung University,
2Departement of Occupational Safety and Hygiene, Chung Hwa College of Medical Technology and
3Institute of Occupational Safety and Healthy, Council of Labor Affairs, Executive Yuan, Taiwan
Keywords Thermal exposure chamber, Environmental factors, Uniformity, Monte Carlo simulation, Sensitivity analysis
Correspondence P.-J. Tsai, Department of Environmental and Occupational Health, Medical College, National Cheng Kung University. 138 Sheng-Li Road, Tainan 70428, Taiwan.
Abstract Evaluating the Efficacy of a Thermal Exposure Chamber Designed for Assessing Workers' Thermal Hazard: Perng-Jy TSAI, et al. Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, Taiwan-This study was conducted on a thermal exposure chamber designed for assessing workers' thermal hazard. In order to assess the efficacy of the studied chamber, three environmental conditions were selected to simulate high, middle and low thermal impact situations, with air temperatures (Ta) of 43.12, 36.23 and 25.77degree, globe temperatures (Tg) of 44.41, 41.07 and 29.24degree, relative humidity (RH) of 77, 59 and 39 %, and air flow velocities (Va) of 1.70, 0.91 and 0.25 m/s, respectively. For the three specified thermal impact conditions, results show that the coefficients of variation (CVs) for Ta, Tg, RH and Va measured in the chamber studied were consistently less than 10%, except for Va under the low thermal impact condition (=50%). For each specified thermal impact condition, we generated 1,000 environmental combinations by using the Monte Carlo simulation approach according to the variations obtained from the four environmental factors. We directly adopted the ISO 7933 approach to estimate the allowable exposure time (AET) for each simulated environmental condition. This study yielded a range in the 95% confidence interval (95% CI) of the estimated AETs for the three specified thermal impact conditions which were consistently less than 5 min. We further conducted the sensitivity analysis to examine the effect of the four environmental factors on estimating AETs. We found Va was the least important factor in estimating AETs for any specified thermal impact condition. In conclusion, although Va was found with great variation for the chamber specified in the low thermal impact condition, the exposure chamber studied can still be regarded as a feasible one for assessing workers' thermal hazard.