SUITABLE HEAT STRAIN INDEX FOR WORKERS INA FOUNDRY

Abstract

          A cross-sectional study was conducted in a foundry factory to explore heat strain index among the foundry workers with light, moderate and heavy workloads. The most suitable heat strain index correlating best with heat stress (Wet Bulb Globe Temperature (WBGT), and workload) would be identified. The body core temperature, peak heart rate and recovery heart rate were monitored using Personal Heat Stress Monitor, 3MTM QUESTEMP oII and Polar A300 Heart Rate Monitor Watch respectively. In addition WBGT wasmonitorby3M QUESTemp 34°C - WBGT Model Serial Number TPI050069 The metabolic rate of each participant was estimated in 2 hours in the same period with all above monitoring according to the guide­lines of the Occupational Safety and Health Administration (OSHA), USA. The participants were 58 volunteer workers who work in hot processes among these 19, 25, and 14 were classified in light, moderate and heavy work. The result of the study showed that only the body core temperature was correlated with workload and WBGT (P<0.05) when analyzed by the Multiple Regression, and the correlation coefficient (r) were 0.282 and 0.379, respectively. Conversely, working heart rate and recovery heart rate were not correlated with workload and WBGT. Thus it may conclude that the body core tempera­ture is better indicator for heat strain than the working heart rate and recovery heart rate. The regression equation was Body Core Temperature=30.971+0.188 (WBGT) + 0.003 (work load); R2= 0.312 and P-value < 0.05