Objective To propose a comprehensive and rational evaluation index for heat working environment based on field surveillance data of high-temperature workstations of Shanghai Railway Bureau from 2005 to 2014.
Methods Typical and fixed workstations (such as tank cleaner, boiler man, metalsmith, and washer) of Shanghai Railway Bureau were selected. Temperature difference was taken to grade and assess working in hot environment for 2005-2009, and Wet Bulb Globe Temperature (WBGT) for 2010-2014. Differences in the judgment results for the same workstation by temperature difference and WBGT were compared and analyzed.
Results The workstations of furnace, washing, drying, and dry cleaning were not graded as working in hot environment when considering temperature difference as the evaluation index; however, all selected workstations were graded as working in hot environment when using WBGT as the evaluation index. Except the yearly variation of temperature difference for tank cleaning in 2005-2009 (P > 0.05), statistical differences were found in the yearly variations of temperature difference for the rest workstations in 2005-2009 and the yearly variations of WBGT for all selected workstations in 2010-2014 (P < 0.01).
Conclusion The WBGT index might over-grade working in hot environment; thus temperature difference is suggested.
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