Instructions

HD32.2 - 7 - V1.4
In the following table are indicated the limit values of the WBGT thermal stress index taken from
ISO 7243 regulation:
LEVEL CLASS
METABOLIC
METABOLIC LEVEL, M WBGT LIMIT VALUE
RELATIVE TO A
SINGLE SKIN
SURFACE
W/m
2
TOTAL (FOR A
MEDIUM AREA OF
1,8 m
2
SKIN SUR-
FACE)
W
ACCLIMATIZED BEING TO
HEAT
°C
NON- ACCLIMATIZED BEING TO
HEAT
°C
0
(RESTING)
M ≤ 65 M ≤ 117 33 32
1 65 < M ≤ 130 117 < M ≤ 234 30 29
2 130 < M ≤ 200 234 < M ≤ 360 28 26
3 200 < M ≤ 260 360 < M ≤ 468
STAGNANT
AIR
25
NO STAGNANT
AIR
26
STAGNANT
AIR
22
NO STAGNANT
AIR
23
4 M > 260 M > 468 23 25 18 20
NOTE: THE VALUES ARE STABILIZED, CONSIDERING A MAXIMUM RECTAL TEMPERATURE OF
38° C FOR THE CONSIDERED BEINGS.
To calculate WBGT index, it’s necessary that to the instrument are connected:
• HP3201.2, HP3201 or TP3204S temperature probe with natural ventilation wet bulb.
• TP3276.2 or TP3275 globe thermometer.
• TP3207.2 or TP3207 wet bulb temperature probe if the detection is made in presence
of solar irradiation.
To measure WBGT index consider the following regulations:
• ISO 7726
• ISO 7243