In this study, the spatio-temporal characteristics of the minimum rest time for the safety of South Korean outdoor workers during hot summer months (June to August) are examined based on the hourly wet-bulb globe temperature (WBGT) across 27 weather stations in South Korea. The WBGT thresholds in the work-rest recommendation of the Korea Occupational Safety and Health Agency (KOSHA 2017) for the quantification of the minimum rest time are evaluated through a comparison of the given thresholds with the occurrences of occupational heat-related illness patients due to outdoor work during hot summer months in South Korea. The long-term (2009–2018) average of the hourly WBGT values during summer months shows that outdoor workers with a moderate workload are exposed to heat stress during approximately 30% of the entire daytime working hours (06:00–18:00). According to the WBGT thresholds modified from the KOSHA (2017) guidelines, the daily minimum rest time for a moderate workload noticeably increases up to 18% (11 min/h) in mid-summer (late July and early August). During mid-summer, the minimum rest time for a continuous moderate outdoor workload even increases up to 31% (18 min/h) between 12:00 and 13:00 and is regionally higher in the southwestern than in the southeastern regions of the Korean Peninsula. These results suggest that in summertime high-heat environments, a mandatory rest time must be provided according to appropriate heat management programs for the safety of workers.
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The authors thank the Korea Meteorological Administration and the Korea Centers for Disease Control for the support in providing climate data for the WBGT calculation and heat-related illness data, respectively.
This work was funded by the Korea Meteorological Administration Research and Development Program “Support to Use of Meteorological Information and Value Creation” under grant (KMA2018-00122).
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Lee, S., Kim, I., Kim, H. et al. Spatio-temporal patterns of the minimum rest time for outdoor workers exposed to summer heat stress in South Korea. Int J Biometeorol (2020). https://doi.org/10.1007/s00484-020-01956-3
- Heat stress
- Outdoor workers
- Occupational safety
- Rest time