To perform a WBGT and a UTCI shade heat stress calculation enter a temperature and humidity value below and click the Calculate button.
UTCI is calculated using the method described on www.utci.org
The WBGT heat stress is calculated by the Liljegren method where climatic variables of temperature, humidity, solar radiation and wind speed are used in a rational thermodynamic heat exchange model.
Approximations: no direct sunlight, wind speed of 1m/s.
Formula are for indoor conditions or outdoors in the shade.
A wind speed of 1m/s was chosen because working people are moving arms/legs generating an apparent wind speed of at least 1m/s. Higher wind speeds at warm temperatures do not have a significant effect on WBGT.
The Liljegren method is described in: Liljegren et al (2008) “Modeling the wet bulb globe temperature using standard meteorological measurements” J Occup Environ Hyg 5 (10) 645-55. An analysis of the Liljegren method, the effect of wind speed and formulas used can be found in Lemke & Kjellstrom (2012) "Calculating workplace WBGT from meteorological data" Ind Health 50(4) page 267-78