12 APPENDIX A: Heat Exposures Tables
Electrical power research institute (EPRI)
The recommended working hours are shown based on a maximum of
four hours. A time of 4:01 indicates greater than 4 hours.
WBGT°C
Light
Moderate
Heavy
28
4:01
4:01
3:00
29
4:01
4:00
2:00
30
4:01
3:00
1:30
31
4:01
2:00
1:15
32
4:00
1:30
1:00
33
3:30
1:15
0:45
34
3:00
1:00
0:40
35
2:30
0:53
0:35
36
2:00
0:45
0:30
37
1:45
0:40
0:25
38
1:30
0:35
0:20
39
1:15
0:33
0:18
40
1:00
0:30
0:15
41
0:53
0:28
0
42
0:45
0:25
0
43
0:38
0:23
0
44
0:30
0:20
0
45
0:28
0:18
0
46
0:25
0:15
0
47
0:23
0
0
48
0:20
0
0
49
0:18
0
0
50
0:15
0
0