The association between wet-bulb globe temperature and other thermal indices (DI, MDI, PMV, PPD, PHS, PSI and PSIhr): a field study

The current study aimed at comparing the correlation coefficients between wet-bulb globe temperature (WBGT) and a number of parameters, including the discomfort index (DI), modified discomfort index (MDI), predicted mean vote (PMV),
predicted percentage of dissatisfaction (PPD), predicted heat strain (PHS), physiological strain index (PSI) and physiological strain index heart rate (PSIhr). In total, 30 workers of a pelletizing factory participated in this study. Environmental
parameters and workers’ physiological parameters were measured in 10 working stations. The results showed that effective
WBGT (WBGTeff) strongly correlates with DI, MDI, PMV, PPD, PHS, PSI and PSIhr. WBGTeff had the highest correlation
coefficients with PMV, MDI, PHS and PSIhr. Based on the obtained results, it was concluded that heat stress exceeded the
standard limit for a number of indices in some of the working stations. Thus, some controlling measures should be taken to
reduce heat stress in these stations.