3Com Router 3016 Installation Manual page 20

20 C 2: P
HAPTER REPARING TO
Dust
Gases
Static Electricity
I R
NSTALL THE OUTER
the router. If the equipment is always very hot, the aging process of insulating
materials accelerates, which affects the reliability of the router and even its
operational lifetime. The requirements for the temperature and humidity of the
router installation site are listed in Table 1.
Table 1 Temperature and Humidity Requirements
Temperature
0 0 0 0
0 to 40 C (32 to 104 F)
Dust is harmful to the safe operation of the router. Dust on the chassis can result
in static absorption and cause faulty contact between metal connection
components or points. Especially when indoor humidity is low, dust is absorbed
more easily which not only shortens the operational lifetime of the equipment, but
also can result in communication failure. The specifications for the dust content
and diameter of the granule within the equipment room are listed in Table 2.
Table 2 Specification for Dust Content
Maximum diameter (µ m)
Maximum density (the number
of granules per cubic meter)
Besides the dust specification, the equipment room should also meet strict
requirements for the content of salt, acid and sulfide. These harmful gases can
accelerate the metal erosion and the aging process of some parts. The presence of
harmful gases, such as SO
specific limitation values of these harmful gases are given in Table 3.
Table 3 Harmful Gas Limitation Values in Equipment Room
Gas
SO
2
H S
2
NO
2
NH
3
Cl
2
Although careful considerations in preventing electrostatic discharge (ESD) have
been taken in the design of the router, if the level of static electricity exceeds a
certain threshold, it will cause great damage to the circuit and even to the entire
router.
On the communication network connected to the router, the electrostatic
induction comes mainly from two aspects: one is from the outside electrical fields,
such as the outdoor high-voltage power cable and lightning, and the other is from
the inside system, such as indoor environment, floor material and the system
structure.
Relative humidity
5% to 85%
0.5 1
1.4 x 10 7 7 x 10 5
, H S, NO , NH , and Cl
2 2 2 3
Average (mg/m 3 )
0.2
0.0
0.04
0.05
0.01
3 5
2.4 x 10 5 1.3 x 10
, should be prevented. The
2
Maximum (mg/m 3 )
1.5
0.03
0.15
0.15
0.3
5