Hardware Installation
12
such as SO
2
, H
2
S, NO
2
, NH
3
and Cl
2
, etc. The table below details the threshold value.
Gas
Average (mg/m³)
Max (mg/m³)
SO
2
0.2
1.5
H
2
S
0.006
0.03
NO
2
0.04
0.15
NH
3
0.05
0.15
Cl
2
0.01
0.3
Table 2-2 Environmental Requirements: Particles
2.1.1.2
Temperature and Humidity
Although the switch is designed to use 4 fans, the site should still maintain a desirable
temperature and humidity. High-humidity conditions can cause electrical resistance degradation or
even electric leakage, degradation of mechanical properties and corrosion of internal components.
Extreme low relative humidity may cause the insulation spacer to contract, making the fastening
screw insecure. Furthermore, in dry environments, static electricity is liable to be produced and
cause harm to internal circuits. Temperature extremes can cause reduced reliability and premature
aging of insulation materials, thus reducing the switch‟s working lifespan. In the hot summer, it is
recommended to use air-conditioners to cool down the site. And the cold winter, it is
recommenced to use heaters.
The recommended temperature and humidity are shown below:
Temperature:
Relative humidity
Long term condition
Short term condition
Long term condition
Short term condition
15 ~ 30°C
0 ~ 50°C
40 ~ 65%
10 ~ 95%
Table 2-3 Environmental Requirements: Temperature and Humidity
Caution!
A sample of ambient temperature and humidity should be taken at 1.5m above the floor and
0.4m in front of the switch rack, with no protective panel covering the front and rear of the rack.
Short term working conditions refer to a maximum of 48 hours of continued operation and an
annual cumulative total of less than 15 days. Formidable operation conditions refers to the ambient
temperature and relative humidity value that may occur during an air-conditioning system failure,
and normal operation conditions should be recovered within 5 hours.