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 MIL-HDBK-1012/3
f)
Year round access; and
g)
The presence of asbestos on utility service pipes
If conduit is installed in a tunnel as a pathway for
backbone cabling factors such as fill ratio and pull/splice
points must be addressed. Limitations on lengths, bends, and
separations are delineated in NFPA 70. EIA/TIA 569 and EIA/TIA
472B, Fiber Optic Communication Cables for Underground and Buried
Use provide information regarding placement of backbone cables in
the tunnel environment.
1.8.4.4
Aerial
a) The aerial backbone support structure is the least
desirable method for routing cables between buildings because of
the following considerations:
(1)
High initial costs associated with pole
placement;
(2) Subject to damage because of extreme
(3)
Subject to damage because of casual
negligence;
(4)
Higher maintenance requirements versus other
methods;
(5)
Poor aesthetic quality; and
(6) The installation of aerial utilities is
usually prohibited on facilities where airfields or helicopter
pads are located.
b) If aerial routing of a backbone cable is the only
method available or use of an existing pole line is directed by
the cognizant authority, the RCDD must consider several factors.
These factors include:
(1)
Vertical clearance to the grade surface;
(2) Existing fill of the pole line by type,
quantity, and services of other cables on poles;
(3)
Separation clearances from other cables on
poles;
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