The environment have a big influence on the presence of heat stress. This can be measured easily with the equipment of 3M. With this you can measure the workload on the workplace. With the help of measured air temperature, relative humidity, radiation temperature and wet bulb globe temperature, the WBGT-index can be given.

The WBGT-index is measured in situations inside buildings and oudside in the shadow by the natural wet bulb temperature (tnw) and the globe temperature (tg)with reliable and calibrated equipment.

The natural wet bulb temperature (tnw) is measured with a thermometer surrounded by a moistured wick, which cools down by evaporation through movement of air. This thermometer is mimics the sweaty skin. The globe temperature (tg) is measured by a dry bulb, which is sensitive for radiation.

The combination of these values will lead you to the WBGT-index: WBGT = 0,7 x tnw + 0,3 x tg.

If no constant value over time can be determined, a representive average must be established. The timeframe for calculating the period of work / rest for one hour that is most representative of the exposure to heat to study the situation.

In addition, it is recommended to determine the WBGT under maximum external heat load, that is, in the summer, in the middle of the day when the heat producing equipment is functioning. The measurements are carried out in a homogeneous environment on belly height. If the environment is not homogeneous, the measurements will be on head and ankle height. Then, the average is determined.

Source: ARBOCATALOGUS HEATSTRESS