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Re: manhole covers
From: Sean Donelan <sean () donelan com>
Date: Thu, 20 Feb 2003 17:43:54 -0500 (EST)

Check out Georgetown in Washington DC, the exploding manhole capital of
the world.  They have a lot of experience with exploding manholes, from
many different causes.  The most recent incident was in the last couple of
days.  There is a lot of energy in being pumped into utility lines.  A
short circuit can release that energy into the underground vaults, and
blow the manhole cover a considerable distance.


The Washington Post also has a special report covering exploding manholes


On Thu, 20 Feb 2003, Allen Hamner wrote:

I am a chemist who consults with the mayor of Bluefield WV where an
incident two weeks ago (a cold day) blew a 70 pound iron cover 10 feet
from an conduit tunnel containing several public untility lines.  We
believe we can exclude a natural gas leak.  Rumor has it that hydrogen
is involved, which may arise by electrolysis (?) or pyrolysis of
insulation (?).  A previous incident had done no damage but this
explosion destroyed a nearby plate-glass window.

There is no coal in the area so mine gas seepage is excluded.  Sewer
gas is tentatively not an issue.  The source of the spark is unknown.

I would like to participate in the exchange on this topic.

Allen Hamner (Ph.D.)
hamner_a () wvwc edu

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