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6. Measuring method
About Heat Index (WBGT)
Heat index (WBGT) is the index which focuses on heat balance - the
exchange of heat between human body and outside air. This index
adopts three factors
–
humidity
that has a large effect on the heat
balance of the human body, the surrounding thermal environment such
as sunlight and solar radiation, and temperature - that considerably
affect the heat balance on human body. This index is used to prevent
heat stroke during work or exercises. The calculation of this index is made
with dry-bulb temperature, wet-bulb temperature, and globe
temperature. The unit is [°C].
Under sunlight
0.7 x wet-bulb temperature + 0.2 x globe temperature + 0.1 x dry-bulb
temperature
Without sunlight
0.7 x wet-bulb tempe 0.3 x globe temperature
This product determines the dry-bulb temperature by temperature sensor,
and the wet-bulb temperature by calculating the relative humidity
measured by humidity sensor and the dry-bulb temperature. The globe
temperature is a value converted from 30mm-diameter globe
temperature to the standard 150mm-diameter globe temperature.
* Refer to page 22 for details on switching o
f ‘Under sunlight’ and ‘Without
sunlight
’
.
About the measurement position
WBGT reading should be measured at the height of the human abdomen
area (1.1 m in the standing position, 0.6 m in the sitting position).
