Installation Manual
H3C VG 31-08 Voice Gateway
Chapter 2 Installation Preparations
2-2
2.1.2 Cleanliness
The equipment room must be free of explosive, electric, magnetic,
or corrosive dust. The contents of dust must be limited as shown in the
following table:
Table 2-2
Requirement on dust content in the equipment room
Max. particle size
(
μ
m)
0.5
1
3
5
Max. concentration
(number of particles
per cubic meter)
1.4×10
7
7×10
5
2.4×10
5
1.3×10
5
Besides dust, there are rigorous limits on harmful gases that can
accelerate erosion and aging of metals, such as salts, acids, and
sulfides, as shown in the following table.
Table 2-3
Limits on harmful gas contents in the equipment room
Gas
Average (mg/m
3
)
Maximum (mg/m
3
)
SO
2
0.2 1.5
H
2
S 0
0.03
NO
2
0.04 0.15
NH
3
0.05 0.15
Cl
2
0.01 0.3
