RE: NRC News release on Terrorists.

["Neil, David M" <neildm@ID.DOE.GOV>]

Title: RE: NRC News release on Terrorists.

The steel structure of a highrise is relatively exposed compared to structural steel imbedded in concrete.  Typically, it is insulated for the very reason of protecting it from degradation in a fire, but, as I understand it, during construction of the WTC, the insulation of preference was banned and the upper floors had little protection.  Another preferred method of insulation, encasing the steel in concrete, was not feasible for highrise construction.

 

This was abstracted from an article I read, put out by a structural engineer.  I regret not having the URL to give

-----Original Message-----
From: Jacobus, John (OD/ORS) [mailto:jacobusj@ors.od.nih.gov]
Sent: Thursday, September 27, 2001 11:14 AM
To: Franta, Jaroslav; Radsafe (E-mail)
Subject: RE: NRC News release on Terrorists.

Jaro,

I don't think you would say that the WTC buildings were fragile.  They stood for over an hour after inpact.  Will a four foot thick, reinforced concrete wall do as well?  If you don't know, say so.

-- John

-----Original Message-----
From: Franta, Jaroslav [mailto:frantaj@AECL.CA]
Sent: Thursday, September 27, 2001 11:19 AM
To: Radsafe (E-mail)
Subject: RE: NRC News release on Terrorists.

OOOOPS -- I guess John meant burning jet fuel from the airliner ! (thanks Phil !)

...but if nothing gets through the wall, what difference does it make ? (ignoring destruction of the "balance of plant" for the moment).

As we saw in the WTC disaster, much of the fuel was gone in the initial fireball. I suspect this would be even more so in the case of a disintegration of an airliner on the outside of a containment dome.... in contrast to the WTC, where a significant fraction spilled throughout the interior of the structure and ignited any combustible materials there....

Also, in chemical/petrochemical industry, large concrete basins are used for emergency/accidental spills to safely burn-off the flammable liquid.

I think there is a big difference between the relatively skimpy & fragile fireproofing of steel structures in highrises, and rebar embedded in four-foot thick concrete walls !

Jaro