(Abbreviated WBGT.) A simple measure of human heat stress in direct sunlight that takes into account air temperature
, wind speed
, and radiant heat load (from the sun and other sources). The index combines the dry-bulb temperature Td
with two derived parameters, natural wet-bulb temperature Tnw
and globe temperature Tg
, as follows:
The WBGT value is considered along with metabolic rate to assess the potential for heat stress in occupational and athletic settings. It differs from the heat index
, which takes into consideration the air temperature and humidity
and is calculated for shady areas (ISO 2017).
International Organization for Standardization (ISO) 2017: ISO 7243: Ergonomics of the thermal environment—Assessment of heat stress using the WBGT (wet-bulb globe temperature) index. Accessed 25 September 2019. Available at https://www.iso.org/obp/ui/#iso:std:iso:7243:en.
Term edited 25 September 2019.