4
NOTE:
The ventilation performance of the device depends on the installation density and ventilation in the
rack. In a high-density environment, the available operating temperature might decrease.
Cleanliness
Dust buildup on the chassis might 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.
Table1-3 Dust concentration limit in the equipment room
Substance
Particle diameter
Concentration limit
Dust particles
≥ 5 µm
≤ 3 x 10
4
particles/m
3
(No visible dust on desk in three days)
Dust (suspension)
≤ 75 µm
≤ 0.2 mg/m
3
Dust
(sedimentation)
75 µm to 150 µm
≤ 1.5 mg/(m
2
h)
Sand
≥ 150 µm
≤ 30 mg/m
3
The equipment room must also meet limits on salts, acids, and sulfides to eliminate corrosion and
premature aging of components, as shown in
Table1-4 Harmful gas limits in the equipment room
Gas
Max. (mg/m
3
)
SO
2
0.2
H
2
S
0.006
NH
3
0.05
Cl
2
0.01
NO
2
0.04
Cooling
To provide adequate cooling for the device, follow these guidelines:
•
Reserve a minimum clearance of 10 cm (3.94 in) around the device.
•
Make sure the installation site has a good cooling system.
•
Identify the cold and hot aisle arrangement at the installation site, and make sure the device
draws in air from the cold aisle and exhausts air to the hot aisle.
•
Identify the airflow directions of the upper and lower devices, and make sure hot air exhausted
from the lower devices does not circulate into the upper devices.
