H3C Technologies H3C SecPath U200-A U200-M U200-S - Manual (Page 17)

8
Cleanness
Dust buildup on the chassis may result in electrostatic adsorption, which causes poor contact of metal
components and contact points, especially when indoor relative humidity is low. In the worst case,
electrostatic adsorption can cause communication failure.
Table 4 Dust concentration limit in the equipment room
Substance Concentration limit (particles/cu m)
Dust particles
≤ 3 x 10 4
(No visible dust on desk in three days)
NOTE:
Dust particle diameter ≥ 5 μm
The equipment room must also meet strict limits on salts, acids, and sulfides to eliminate corrosion and
premature aging of components, as shown in
Table 5 .
Table 5 Harmful gas limits in an equipment room
Gas Max. (mg/m 3 )
SO
2
0.2
H
2
S 0.006
NH
3
0.05
Cl
2
0.01
Cooling
The UTM device adopts left to right airflow for heat dissipation. Plan the installation site for adequate
ventilation.
• Leave at least 10 cm (3.94 in) of clearance at the inlet and outlet air vents.
• The installation site has a good cooling system.
Figure 10 Airflow through the chassis (U200-A)