[AF] The SF Overpass

[Phil Alexander]

On 1 May 2007 at 9:13, Dana  Puopolo wrote:

> The overpass had NO fire retardent. The towers had some type of rated fire
> retardent. No, it wasn't asbestos, but that's not the only one out there.
> http://en.wikipedia.org/wiki/Passive_fire_protection

If memory serves, the twin towers DID have asbestos concrete sputtered over
the beams part way up the towers and further application was stopped by
the environmental outcry WRT asbestos. Beyond that point, I'm not sure
if the steel was naked or some other less effective coating was used.

The design of the towers WITH asbestos insulation of the steel was to
withstand a direct hit by a fully loaded 707 of the largest configuration
(similar to the old AF-1) because that was the biggest plane flying when
the structures were designed.

Had the insulation been carried out as designed, the structures might 
have stood, and at the very least far more time to evacuate would have
been available.

Once again the law of unintended consequences rears its ugly head.

---------------------------------------------
Phil Alexander, CSRE, AMD
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037