20CAUTION:If condensation appears on the switch when you move it to a high-temperature environment, dry the switchbefore powering it on to avoid short circuits.Humidity requirementsMaintain appropriate humidity in your equipment room, as described in Table 9.Table 9 Humidity requirementsHumidity RangeOperating humidity (noncondensing) 5% to 95%Storage humidity (noncondensing) 5% to 95%Lasting high relative humidity tends to cause poor insulation, electricity creepage, mechanical propertychange of materials, and corrosion of metal parts. Lasting low relative humidity is likely to result in loosescrews due to washer contraction, and even electrostatic discharge (ESD), which causes the circuits tofail.Cleanness requirementsDust is a hazard to the operating safety of your switch. Dust buildup on the chassis may result inelectrostatic adsorption, which causes poor contact of metal components and contact points, especiallywhen indoor relative humidity is low. In the worst case, electrostatic adsorption can causecommunication failure.Table 10 Dust concentration limit in the equipment roomSubstance Concentration limit (particles/cu m)Dust particles ≤ 3 x 104(No visible dust on desk in three days)NOTE:Dust particle diameter ≥ 5 μmIn addition, the equipment room should meet strict limits on salts, acids and sulfides to eliminatecorrosion and premature aging of components, as shown in Table 11.Table 11 Harmful gas limits in an equipment roomGas Average (mg/m3 ) Max. (mg/m 3 )SO2 0.3 1.0H2 S 0.1 0.5NO2 0.004 0.15NH3 1.0 3Cl2 0.1 0.3
