MCI WorldCom fiber cut - Syracuse, NY

Wed Oct 6 17:44:16 UTC 1999

"Matthew D. Lammers" wrote:
> 
> Andrew, by far one of the best explanations I've read!  Excellent
> illustrations.  You're suppositions are indeed correct.
> 
> In addition to which, fiber doesn't emit a nice electrical signature that
> can be detected easily, making it hard to avoid.  Plastic, glass,
> fiberglass, kevlar and the other elements of most fiber runs lay invisible
> to many detection devices that rely upon metals content or electrical
> impulse emission (crosstalk, noise, EMF...) for detection purposes.

When gas installers lay underground plastic gas lines (I have such
running to my backup generator) they lay a wire in the ground next to
the pipe. The wire is not attached to anything at the ends, just wrapped
around the gas line where it comes out of the soil.  The idea is to use
this with a signal generator/receiver, much like the devices we use to
chase down wire pairs. Addition of an electrical conductor, with
attachment points for tracers might make a LOT of sense.

The next thing done when an underground gas pipe is laid, is a mylar
film is buried, a foot or so above the pipe, which has all kinds of
warnings on it about the gas line below. The tape is mirror-reflective
mylar. It's sure to catch some attention if the backhoe operator doesn't
wail right through and beyond... Perhaps those laying fiber should
consider (perhaps they already do?) such methods.

It's unclear if there are laws against putting up "gas pipeline, do not
dig" signs where there really aren't gas pipelines, but that might be
another way to deter the backhoes...

Finally, though, I wonder if any of the fiber cable manufacturers have
data on the susceptibility of their jacket material to the various gases
pumped by the gas pipeline companies. Laying the fibers inside active
gas pipelines would sure be a deterrent to those digging, though in the
case of a cut, you'd need a significant piece of fiber to replace that
part which had melted in the fire...

-- 
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Daniel Senie                                        dts at senie.com
Amaranth Networks Inc.            http://www.amaranthnetworks.com