20 CHAPTER 2: PREPARING TO INSTALL THE ROUTER
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. 
Tabl e 1   Temperature and Humidity Requirements
Dust 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.
Tabl e 2   Specification for Dust Content
Gases 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
2
, H
2
S, NO
2
, NH
3
, and Cl
2
, should be prevented. The 
specific limitation values of these harmful gases are given in 
Table 3.
Tabl e 3   Harmful Gas Limitation Values in Equipment Room
Static Electricity 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.
Temperature Relative humidity
0
0
 to 40
0
C (32
0
 to 104
0
F) 5% to 85%
Maximum diameter (µ m) 0.5 1 3 5
Maximum density (the number 
of granules per cubic meter)
1.4 x 10
7
7 x 10
5
2.4 x 10
5
1.3 x 10
5
Gas Average (mg/m
3
) Maximum (mg/m
3
)
SO
2
0.2 1.5
H
2
S 0.0 0.03
NO
2
0.04 0.15
NH
3
0.05 0.15
Cl
2
0.01 0.3