H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 9)

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Table 2 Dust concentration limit in the equipment room
Substance Concentration limit (particles/m 3 )
Dust particles
≤ 3 x 10 4
(No visible dust on desk in three days)
NOTE:
Dust particle diameter ≥ 5 μm
To eliminate corrosion and premature aging of components, the equipment room must also meet limits on
salts, acids, and sulfides, as shown in Table 3 .
Table 3 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 device uses left to right airflow for heat dissipation. Plan the installation site for adequate ventilation.
• H3C recommends that you leave a minimum of 10 cm (3.94 in) of clearance around the air vents.
• Make sure the rack is well ventilated.
Figure 1 Airflow through the device chassis
ESD prevention
To prevent electrostatic discharge (ESD), follow these guidelines:
• Ground the device properly.
• Take dust-proof measures for the equipment room. For more information, see " Cleanness ."
• Maintain the humidity and temperature at a proper level. For more information, see " Temperature
and humidity ."