Ambient condi‐
tions
Permissible range
Comments
Concentration of
pollutants
• SO
2
: <0.5 ppm
• RH: <60%, no condensation
• H
2
S: <0.1 ppm
• RH: <60%, no condensation
Test: 10 ppm; 4 days
Test: 1 ppm; 4 days
ISA-S71.04 severity level G1; G2; G3 -
Derating
The cooling effect of air decreases at higher altitudes as a result of its lower density.
The table shows the derating factor for the maximum permissible ambient temperature
depending on the use of the devices at an elevation above sea level.
Table B-2
Derating when devices are used at an elevation above sea level
Elevation above sea level
1)
Derating factor for ambient temperature
2)
(-1 000 m) up to 2 000 m
1.0
3 000 m
0.9
4 000 m
0.8
1)
Note that I/O modules with relay contacts are only suitable for an elevation up to 3 000 m.
2)
Relating to the maximum permissible ambient temperature in °C for 2 000 m
Technical specifications
B.1 Ambient conditions
BusAdapter for Distributed I/O
40
Equipment Manual, 10/2021, A5E39261458-AC
