Cleanness; Emi - H3C S5500-HI Switch Series Installation Manual

Lasting high relative humidity can cause poor insulation, electricity creepage, mechanical property
•
change of materials, and metal corrosion.
Lasting low relative humidity can cause washer contraction and ESD and bring problems including
•
loose captive 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, see
specifications."

Cleanness

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.
Table 1 Dust concentration limit in the equipment room
Substance
Dust
NOTE:
Dust diameter ≥ 5 μm
The equipment room must also meet limits on salts, acids, and sulfides to eliminate corrosion and
premature aging of components, as shown in
Table 2 Harmful gas limits in the equipment room
Gas
SO
2
H S
2
NH
3
Cl
2

EMI

Electromagnetic interference (EMI) might be coupled from the source to the switch through the following
coupling mechanisms:
• Capacitive coupling
Inductive coupling
•
Radiative coupling
•
• Common impedance coupling
Conductive coupling
•
To prevent EMI, take the following actions:
Concentration limit (particles/m³)
≤ 3 x 10 4 (no visible dust on the tabletop over three days)
Table
2
"Appendix A Chassis views and technical
2.
Maximum concentration (mg/m
0.2
0.006
0.05
0.01
)
3