60
Group
Corrosive Gas
Unit
Concentration
NH
3
ppb
< 500
O
3
ppb
< 2
a: Parts per billion (ppb) is a unit of concentration, and 1 ppb represents 1 part
per billion.
Group A and group B are common gas groups in a data center. Group A's or group
B's concentration limitation values correspond to copper and silver reactivity level
G1.
Corrosion is not determined by a single factor, but by comprehensive
environmental factors such as temperature, relative humidity and corrosive
airborne contaminants. Any change of the environmental factors may affect the
gaseous corrosively level. Therefore, the concentration limitation values specified
in the previous table are for reference only. If the actual mixed gas concentration is
not listed in the table, refer to chemically active substance level in IEC-60721-3-3 or
GB/T 4798.3-2007 to choose the concentration range.
4.
Mechanically Active Substances
The server room must be free of explosive, conductive, magnetic, and corrosive
dust. The table below lists the requirements for mechanically active substances.
Table 8-9 Requirements for Concentration of Mechanically Active Substances
Mechanically Active
Substances
Unit
Concentration
Sand
mg/m
3
≤ 30
Floating dust
mg/m
3
≤ 0.2
Dust deposits
mg/(m
2
h)
≤ 1.5
To meet these requirements, take the following measures in the server room:
Use dustproof materials on the ground, wall, and ceiling of the server room.
Adopt few or no windows design in the server room and use dustproof
materials for outer windows.
Clean the server room, especially the air filters periodically.
Wear shoe covers and ESD clothing before entering the server room.
