Dehghan Habibolah, Mortazavi Seyed Bagher, Jafari Mohammad J, Maracy Mohammad R
Department of Occupational Health Engineering, Tarbiat Modares University, Tehran, Iran.
J Res Med Sci. 2012 Dec;17(12):1108-13.
Heat exposure among construction workers in the Persian Gulf region is a serious hazard for health. The aim of this study was to evaluate the performance of wet bulb globe temperature (WBGT) Index for estimation of heat strain in hot/humid conditions by the use of Physiological Strain Index (PSI) as the gold standard.
This cross-sectional study was carried out on 71 workers of two Petrochemical Companies in South of Iran in 2010 summer. The WBGT index, heart rate, and aural temperature were measured by Heat Stress Monitor (Casella Microtherm WBGT), Heart Rate Monitor (Polar RS100), and Personal Heat Strain Monitor (Questemp II), respectively. The obtained data were analyzed with descriptive statistics and Pearson correlation analysis.
The mean (SD) of WBGT values was 33.1 (2.7). The WBGT values exceed from American Conference of Governmental Industrial Hygienists (ACGIH) standard (30°C) in 96% work stations, whereas the PSI values were more than 5.0 (moderate strain) in 11% of workstations. The correlation between WBGT and PSI values was 0.61 (P = 0.001). When WBGT values were less and more than 34°C, the mean of PSI was 2.6 (low strain) and 5.2 (moderate strain), respectively.
In the Persian Gulf weather, especially hot and humid in the summer months, due to the WBGT values exceeding 30°C (in 96% of cases) and weak correlation between WBGT and PSI, the work/rest cycles of WBGT Index is not suitable for heat stress management. Therefore, in Persian Gulf weather, heat stress evaluation based on physiologic variables may have higher validity than WBGT index.
波斯湾地区建筑工人面临的热暴露对健康构成严重危害。本研究旨在以生理应变指数（PSI）作为金标准，评估湿球黑球温度（WBGT）指数在炎热/潮湿条件下估算热应激的性能。
本横断面研究于2010年夏季对伊朗南部两家石化公司的71名工人进行。分别使用热应激监测仪（卡塞拉微型WBGT）、心率监测仪（博能RS100）和个人热应变监测仪（Questemp II）测量WBGT指数、心率和耳温。对获得的数据进行描述性统计和Pearson相关性分析。
WBGT值的均值（标准差）为33.1（2.7）。在96%的工作场所，WBGT值超过了美国政府工业卫生学家会议（ACGIH）标准（30°C），而在11%的工作场所，PSI值超过5.0（中度应变）。WBGT与PSI值之间的相关性为0.61（P = 0.001）。当WBGT值小于和大于34°C时，PSI的均值分别为2.6（低应变）和5.2（中度应变）。
在波斯湾气候中，尤其是夏季炎热潮湿时，由于WBGT值超过30°C（96%的情况）且WBGT与PSI之间的相关性较弱，WBGT指数的工作/休息周期不适用于热应激管理。因此，在波斯湾气候下，基于生理变量的热应激评估可能比WBGT指数具有更高的有效性。
