Hardware Installation and Reference Guide Preparing for Installation
11
more easily when the relative humidity is low, not only affectin g the service life of the device, but also causing
communication faults. Table 2-1 describes the requirements for the dust content and granularity in the equipment
room.
Table 2-1
Requirements for Dust
Dust
Unit
Content
Dust particles (diameter
≤ 0.5 μm)
Particles/m
3
≤
1.4
×
10^7
Dust particles (0.5 μm ≤ diameter ≤ 1 μm)
Particles/m
3
≤
7
×
10^5
Dust particles (1
μm ≤ diameter ≤ 3 μm)
Particles/m
3
≤
2.4
×
10^5
Dust particles (3
μm ≤ diameter ≤ 1 μm)
Particles/m
3
≤
1.3
×
10^5
Apart from dust, the salt, acid, and sulfide in the air in the equipment room must meet strict requirements. These
harmful substances will accelerate metal corrosion and component aging. Therefore, the equipment room should
be properly protected against the intrusion of harmful gases, such as sulfur dioxide, hydrogen sulfide, nitrogen
dioxide, and chlorine gas. Table 2-2 lists limit values for harmful gases.
Table 2-2
Requirements for Gases
Gas
Average (mg/m
3
)
Maximum (mg/m
3
)
Sulfur dioxide (SO
2
)
0.2
1.5
Hydrogen sulfide (HS)
0.006
0.03
Nitrogen dioxide (NO
2
)
0.04
0.15
Ammonia gas (NH
3
)
0.05
0.15
Chlorine gas (CI
2
)
0.01
0.3
Note
Average
refers to the average value of harmful gases measured in one week.
Maximum
refers to the upper
limit of harmful gases measured in one week, and the maximum val ue lasts up to 30 minutes every day.
2.2.6
Anti-interference Requirements
Take interference prevention measures for the power supply system.
Keep the device away from the grounding equipment or lightning and grounding equipment of the power
device as much as possible.
Keep the device far away from high-frequency current devices such as high-power radio transmitting station
and radar launcher.
Take electromagnetic shielding measures when necessary.
