WBGT
Wet Bulb Globe Temperature Index
Overview
The Wet Bulb Globe Temperature is the internationally recognised composite heat stress index used in occupational health to assess the thermal environment experienced by workers — combining natural wet bulb temperature, black globe temperature, and dry bulb temperature into a single index value that reflects the actual heat burden on the human body from all environmental heat sources simultaneously. Referenced in ISO 7243, WBGT is the standard method for assessing occupational heat stress in India and internationally — with WBGT action levels defined for different work intensities and acclimatisation stat es. WBGT measurements are taken using a WBGT meter comprising three thermometers — the index is calculated using a weighted formula that gives greatest weight to the wet bulb component, reflecting the dominant role of humidity and evaporative cooling in de termining heat stress.