The Limitations of WBGT Index for Application in Industries: A Systematic Review

Abstract Introduction: The Wet Bulb Globe Temperature (WBGT) is still widely applied as a preliminary tool for evaluating the heat stress. This index faces some limitations not considered yet. This systematic review was conducted aiming at highlighting some limitations for development of the WBGT index. Method: The present study was organized using more extensive databases: PubMed, Google Scholar, Scientific Information Databases (SID), Elsevier, Web of Science, Scopus, Irandoc, Magiran, and Iran Medex. The used search terms were WBGT index, Heat stress, Thermal Stress, Heat strain, Wet Bulb Globe Temperature, Hot Condition, Occupational Health and Occupational Exposure indices. In this study, 69 articles from 1950 to December 2020 were assessed. Conclusion: The WBGT index, despite having some advantages, suffers limitations which should be considered for a more accurate estimate of thermal stress. This study pointed to the new limitations; including, the value of WBGT is not clear for persons whose working in a seated posture. In addition, this index is used for adapted people who have used enough water and salt while water and salt are not always available to workers in all hot working environments, hence using this index will come with an error. Also, in heterogeneous environments, if the heat source is at the height of the face and legs, no coefficient would be taken into account for these areas.