H3C Technologies H3C S7500E Series Switches - Manual (Page 14)

3
Temperature Range
Storage temperature –40°C to +70°C (–40°F to +158°F)
Humidity
Maintain appropriate humidity in your equipment room, as described in Table 2 .
• Lasting high relative humidity tends to cause poor insulation, electricity creepage, mechanical
property change of materials, and corrosion of metal parts.
• Lasting low relative humidity is likely to result in loose screws due to washer contraction, and even
electrostatic discharge (ESD), which causes the circuits to fail.
Table 2 Humidity requirements
Humidity Range
Operating humidity (noncondensing) 10% to 95%
Storage humidity (noncondensing) 5% to 95%
Cleanness
Maintain appropriate cleanness in your equipment room.
• Dust is a hazard to the operating safety of your switch. 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 3 shows the dust concentration limit in the equipment room.
• The equipment room should meet limits on salts, acids and sulfides to eliminate corrosion and
premature aging of components, as shown in Table 4 .
Table 3 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)
IMPORTANT:
Dust particle diameter ≥ 5 μm
Table 4 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