nanog mailing list archives

Re: Points of Failure (was Re: National infrastructure asset) (fwd)


From: David Lesher <wb8foz () nrk com>
Date: Tue, 25 Sep 2001 17:30:10 -0400 (EDT)


Unnamed Administration sources reported that George William Herbert said:


Let's look at the "worst credible case" though, jet aircraft.
Nuclear reactor domes are rated to survive jumbo jet hits.

Better check this one out; there is considerable dispute
of late on this very point.. A F4 !=747 after all.

Jet aircraft are remarkably poor penetrators, in military terminal
ballistics terms.  Ten feet of good reinforced concrete, at
$400/cu yd or so installed, will do the job nicely, though there
may be some spalling inside the aircraft won't penetrate.  For a 3
story, 120,000 sq ft 200x200x30 ft building that would be about
$9.3 million, about $77.70/ft^2.  

No help. You'll have intact but long since roasted into
atoms building, hardware and employees. How many KWH of heat
from the 57,285 gallons of kerosene?

Not that I'm recommending every telco facility be hardened to
resist a direct jumbo jet hit.  But it's not that ridiculous
a task, and lesser hardening (half or 1/3 that level) would be
downright reasonable compared to the other costs of making these
sorts of buildings for these roles.  A 2 foot thick reinforced
concrete wall, for example, might well be extremely reasonable.

But every n of wall thinkness is f(n^2) less interior space;
f(n^3) more cost to build, and f(n^8) more crap from local
pols who really want retail space downtown instead of tombs.

There are many many angles to all of this.

And who will pay?




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