Installation Manual
H3C VG 21-08 Voice Gateway
Chapter 2 Installation Preparations
2-2
2.1.2 Cleanliness
The equipment room must be free of explosive, electric, magnetic,
and 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 an 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
