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.

Table 1: Dust concentration limit in the equipment room

Substance

Concentration limit (particles/m³)

Dust

≤ 3 x 104 (no visible dust on the tabletop over three days)

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.

Table 2: Harmful gas limits in the equipment room

Gas

Maximum concentration (mg/m3)

SO2

0.2

H2S

0.006

NH3

0.05

Cl2

0.01