79
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 Materials
The server room should be free from explosive, conductive, magnetism-permeable,
and corrosive dust. Table 8-9 lists the requirements for concentration of the
mechanically active materials in the server room.
Table 8-9 Requirements for Concentration of Mechanically Active Materials
Mechanically Active Materials Unit
Concentration
Sand
mg/m
3
≤
30
Suspending dust
mg/m
3
≤
0.2
Dust deposit
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.
8.9
Electromagnetic Compatibility
Requirements
1.
As per GB/T 17626.3 (IEC 61000-4-3) & GB/T 17626.6(IEC 61000-4-6) & GB/T 17626.8
(IEC 61000-4-8), the recommended electromagnetic environment is as follows:
Table 8-10 Recommended Electromagnetic Environment
Electromagnetic Phenomenon
Specifications
Power frequency
magnetic field
Frequency (Hz)
50
A/m (rms)
≤
1
RF electromagnetic
field amplitude
modulation
Frequency (MHz)
80 - 1000
V/m (rms, unmodulated)
≤
3
%AM (1kHz)
80
