
The artist revealing New York’s secretive, hidden network - CapitalistCartr
http://www.bbc.com/future/story/20161012-the-artist-revealing-new-yorks-secretive-hidden-network
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greenyoda
_" In the summer you sometimes see tanks of liquid nitrogen on the street,
says Burrington. It turns out these are brought in by telecoms companies to
cool cable ducts that lie alongside steam vents in the sidewalk. “The cables
will melt if they get too hot,” she says."_

This makes no sense. The melting point of the glass in optical fibers is close
to 1000 degrees F. If the sun could heat things up that much on a summer day,
we'd all be dead.

If I remember correctly, the nitrogen is actually used to purge moisture from
traditional phone cables. Keeping it in liquid form just makes the tanks more
compact - it turns back into a gas as soon as it exits the insulated tank, at
which point it isn't very cold anymore.

 _" and shows us how to track buried fibre-optic cables by decoding the spray-
painted symbols that telecoms companies use to mark their territory."_

The spray-painted symbols on the street are used to protect the underground
infrastructure when the street is being excavated. There are different colors
for water mains, gas lines, and electrical and other cables. I'm pretty sure
you can't differentiate the internet backbone from cable TV feeders using
these markings, and they probably go through the same ducts. The people who
actually maintain the cables know where they are without the markings - they
have maps.

