1-2
Temperature/humidity
Maintain appropriate temperature and humidity in the equipment room.
•
Lasting high relative humidity can cause poor insulation, electricity leakage, mechanical
property change of materials, and metal corrosion.
•
Lasting low relative humidity can cause washer contraction and ESD and cause problems
including loose screws and circuit failure.
•
High temperature can accelerate the aging of insulation materials and significantly lower the
reliability and lifespan of the switch.
For the temperature and humidity requirements of different switch models, see "
views and technical specifications
."
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.
Table1-1 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 strict limits on salts, acids, and sulfides to eliminate corrosion
and premature aging of components, as shown in
Table1-2 Harmful gas limits in the equipment room
Gas
Maximum concentration (mg/m3)
SO
2
0.2
H
2
S
0.006
NH
3
0.05
Cl
2
0.01
EMI
All electromagnetic interference (EMI) sources, from outside or inside of the switch and application
system, adversely affect the switch in the following ways:
•
A conduction pattern of capacitance coupling.
•
Inductance coupling.
•
Electromagnetic wave radiation.
•
Common impedance (including the grounding system) coupling.
To prevent EMI, use the following guidelines:
