4Temperature/humidityMaintain temperature and humidity in the equipment room as described in "Technical specifications."• Lasting high relative humidity can cause poor insulation, electricity leakage, mechanicalproperty change of materials, and metal corrosion.• Lasting low relative humidity can cause washer contraction and ESD and cause problemsincluding loose mounting screws and circuit failure.• High temperature can accelerate the aging of insulation materials and significantly lower thereliability and lifespan of the switch.For the temperature and humidity requirements of different switch models, see "Appendix A Chassisviews and technical specifications."CleanlinessDust buildup on the chassis might result in electrostatic adsorption, which causes poor contact ofmetal components and contact points, especially when indoor relative humidity is low. In the worstcase, electrostatic adsorption can cause communication failure.Table 2 Dust concentration limit in the equipment roomSubstance Concentration limit (particles/m³)Dust ≤ 3 x 10 4 (no visible dust on the tabletop over three days)NOTE:Dust diameter ≥ 5 μmThe equipment room must also meet strict limits on salts, acids, and sulfides to eliminate corrosionand premature aging of components, as shown in Table 3.Table 3 Harmful gas limits in the equipment roomGas Maximum concentration (mg/m 3)SO2 0.2H2 S 0.006NH3 0.05Cl 2 0.01EMIAll electromagnetic interference (EMI) sources, from outside or inside of the switch and applicationsystem, 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:• If AC power is used, use a single-phase three-wire power receptacle with protective earth (PE)to filter interference from the power grid.
