Meteorology

Simplified Wet-Bulb Globe Temperature

The Wet-Bulb Globe Temperature (WBGT) is a bioclimatic index proposed as a risk indicator for thermal stress. It was developed by the Greek engineer-researcher Konstantinos Prodromos Yaglou and the American physiologist David Minard for the United States Army (Yaglou & Minard, 1957). Practically speaking, the WBGT index estimates the maximum ability of the environment to support evaporative cooling as reflected in the natural wet bulb temperature and the heat exchange by radiation and convection reflected in the globe temperature.

The values of WBGT under different conditions can be also calculated from data on temperature, humidity, air movement and heat radiation which avoids the need to use specialized equipment for monitoring. In cases where only air temperature and relative humidity information is available, the simplified WBGT index can be used, which is automatically calculated here:

References:

• Yaglou CP, Minard D. Control of heat casualties at military training centers. AMA Arch Ind Health. 1957; 16(4):302-316.
• ISO 7243:2017. Ergonomics of the thermal environment — Assessment of heat stress using the WBGT (wet bulb globe temperature) index. International Organization for Standardization: Geneva.

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