Reply #127: A collection of links about the metal

[Clarkent]

A collection of links about the metal:

Last spring, the standards institute found the first photographic evidence on the east face of the south tower that a single floor — with its lightweight support system, called a truss — had sagged in the minutes before it started collapsing. Now, detailed analysis of photos and videos has revealed at least three more sagging floors on that face, said William Pitts, a researcher at the institute's Building and Fire Research Laboratory.

In addition, Dr. Pitts said, sudden expansions of the fires across whole floors in each tower shortly before they fell suggested internal collapses — burning floors above suddenly giving way and spreading the blaze below.

Finally, an unexplained cascade of molten metal from the northeast corner of the south tower just before it collapsed might have started when a floor carrying pieces of one of the jetliners began to sag and fail. The metal was probably molten aluminum from the plane and could have come through the top of an 80th floor window as the floor above gave way, Dr. Pitts said.

"That's probably why it poured out — simply because it was dumped there," Dr. Pitts said. "The structural people really need to look at this carefully."

http://www.nytimes.com/2003/12/03/nyregion...HLXBQn0ZEPWxD8A

NIST pg 43 Section H.9 App H Vol 4
Starting at around 9:52 a.m. a molten material began to pour from the top of the window 80-256 on the North face of WTC 2. The material appears intermittently until the tower collapses at 9:58:59. The observation of piles of debris in this area combined with the melting point behaviors of the primary alloys used in a Boeing 767 suggest that the material is molten aluminum derived from aircraft debris located on floor 81.

NIST H-7-2
Molten Material
It has been reported in the FEMA report (McAllister 2002) as well as in the media that what appeared to be molten metal was observed pouring from the north face near the northeast corner. This is the area where the sustained fires were seen. Video records and photography indicate that the material first appeared at 9:51:52 am and continued to pour intermittently from the building until the time of the collapse. Some of that material can be seen falling in Fig. H-21. Close up video and photographs of the area where the material is pouring from have been examined and show that it is falling from near the top of window 80-256. The most likely explanation for this observation is that the material had originally pooled on the floor above, that is 81, and that it was allowed to pour out of the building when this floor either pulled away from the outer spandrel or sank down to the point where the window was exposed. The fact that the material appears intermittently over a several minute period suggests that the floor was giving way bit by bit

The composition of the flowing material can only be the subject of speculation, but its behavior is consistent with it being molten aluminum. Visual evidence suggest that a significant wreckage from the plane passed thought the building and came to rest in the northeast corner of the tower in the vicinity of the location where the material is observed.
Much of the structure of the Boeing 767 is formed from two aluminum alloys that have been identified as 2024 and 7075 closely related alloys. These alloys do not melt at a single temp, but melt over a temp range from the lower end of the range to the upper as the fraction of the liquid increses. The Aluminum association handbook lists the melting point as roughly 500C to 638 C and 475 C to 635C for alloys 2024 and 7075 respectively. These temperatures are well below those characteristic of fully developed fires (ca 1000C ) and any aluminum present is likely to be at least partially melted by the intense fires in the area.

http://wtc.nist.gov/progress_report_june04/appendixh.pdf

But the fires continued to burn. Black smoke poured from shattered windows on floor after floor, fresh oxygen sucked in from the gaping holes caused by the impacts. In the northeast corner of the south tower's 80th floor, where office furniture had been shoved by the plane, the fire burned so hot that a stream of molten metal began to pour over the side like a flaming waterfall.

The apparent source of this waterfall: molten aluminum from the jet's wings and fuselage, which had also piled up in that corner. Within minutes, portions of the 80th floor began to give way, as evidenced by horizontal lines of dust blowing out the side of the building. Seconds later, near the heavily damaged southeasterly portion of this same floor, close to where the aircraft had entered, exterior columns began to buckle.
http://www.meehawl.dyndns.org:1080/Webstor...ort%20Says.html

A photograph leaked from the ASCE-FEMA investigation shows a stream of what appears to be molten aluminum exiting from the northeast corner. This would indicate that what was left of the aircraft when it reached the north end of its travel was massive enough to have destroyed at least one floor.
http://www.scieneering.com/wtc_update.html

Finally see Melted aluminum earler at 9:27 in a area very close to the other liquid
http://wtc.nist.gov/NISTNCSTAR1-5A_chap_9-AppxC.pdf
See fig 9-32
9:27 78th floor

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