Heat stress - WBGT

The WBGT comprises

  • Natural wet bulb temperature (Tnwb)
  • Black globe thermometer (Tg)
  • Ambient air temperature (Ta)
  • Stainless Steel stand.

To understand the WGBT you need to calculate a WGBT index using the formula below.

WBGT Calculation

Actual natural wet bulb temperature (Tnwb) 70%
Not shielded from radiation.

Black globe thermometer (Tg) 20%

Ambient air temperature (Ta) 10%
(In the shade)

 

(Tnwb) 70%
(Tg) 20%
(Ta) 10%

Example: The following readings would calculate as follows.

Actual natural wet bulb temperature (Tnwb) 70% 18.0 ºC = 12.6
Black globe thermometer (Tg) 20% 26.5 ºC = 5.3
Ambient air temperature (Ta) 10% 26.0 ºC = 2.6
WBGT index = 20.5

To make the calculations easier Temperature Controls has prepared an excel program. Available from our office. Contact us

Delivery: Ex stock – subject to price sales.