Ejections Witnessed at 10:18
The event seen from the north
Seen From the west
As mentioned at
this link , all 47 core column splices are at the same elevations separated by 3 floors in the region of interest (they are not staggered). There are horizontal planes separated by 3 floors which contain all the splice connections. The floors are 89, 92, 95, 98, 101, 104. The splice locations are about 3 ft above the flooring. The splices in this region are all bolted with no welds.
Rather important because the building failed through the 98th floor at an angle of less than 1 degree. Even if you think the tower failed naturally, because the failure angle was within 1 degree of plumb the splice connections are the natural place to look.
The smoke ejections in the previous gif are on the 95th and 92nd floors. So, initiation on floor 98 and the smoke ejections on fls 95 and 92.
Core column bolted splices would be a natural target. Why cut columns if they are already cut and held together with only bolts and bolt plates? It is much easier to just crack the bolted splice plates and displace the columns slightly. Much less energy required.
The NIST offers the following comments on the event and nothing else:
"At 10:18:48 a.m., a pressure pulse pushed large amounts of smoke and fire out of open windows on
multiple floors and faces of WTC 1. The most dramatic effect of this pressure pulse was on the 92nd
floor, where a long line of smoke appeared from open windows on the north face. Up until this time,
there had been very little smoke coming through the open windows from the widespread fires burning on
this floor. During the final ten minutes prior to the collapse of WTC, a large fire grew on the 92nd floor
in the large open area on the west side of the north face. A large burst of fire was pushed from the area
when WTC 1 collapsed.
The pressure pulse at 10:18:48 a.m. also seemed to cause a fire burning in a room in the northwest corner
of the 95th floor to suddenly intensify and to extend flames from north face windows."
-NCSTAR 1-5A Draft, p 290
...............
"Two pressure pulses that were large enough to force smoke and fire from open windows on multiple faces
and floors were observed during the period. The first occurred at 10:18:48 a.m. and the second just
seconds prior to the collapse of the tower at 10:28:22 a.m. The sources for these pressure pulses are
unknown, but it seems likely that they resulted from significant structural changes within the tower."
p 280
................
"With the exception of the fires that grew on the 96th and 97th floors shortly after the aircraft impact, it
has generally been observed that very little smoke and/or extended flames flowed from open windows on
the north face where fires were visible. This has been interpreted to indicate that the smoke from these
fires was venting elsewhere within the tower. The fact that smoke and fire continued to vent from the
north face following the pressure pulse may be an indication that the internal ventilation pathways were
changed as the result of the event responsible for the pressure pulse."
p 257
...................
"At 10:18:48 a.m. an event took place within the tower that created a pressure pulse of sufficient
magnitude to force smoke out of numerous windows on the north face, as well as from the other faces.
The most obvious effect of this pressure pulse was the release of a dense line of smoke along a length of
the 92nd floor on the north face, extending from roughly window 94-110 to window 94-139. This smoke
release was evident in numerous videos, including a number shot at great distances. Figure 8"95
compares two frames taken from a video showing the north face just prior to the smoke release and the
appearance just over 4 s later. Even though the video was shot from a distance, the line of smoke that has
appeared from the 92nd floor is readily apparent. It is significant that until this time very little smoke had
been observed coming from the open windows on this floor, even though fires had been burning on the
floor for some time.
Closer inspection of this video, as well as others, shows many additional effects of the pressure pulse at
other locations on the tower. Smoke and/or dust were pushed out of windows on the east side of the north
face at the 94th floor. This material is responsible for the light-colored “smoke” seen near the eastern
edge of the building immediately above the darker smoke released from the 92nd floor in Figure 8"95."
p 253
>>>>>>>>>>>>>
Kind of odd how this event can send pulses through fls 98, 95 and 92 at the same time and be seen along fl 92 on the SW corner. The reference to 94 is a slight drifting of grey smoke along the east side of the north face.
The pressure pulse video of the NIST Cumulus Video Database is incomplete. The beginning is missing. Nevertheless, the 92 west ejection isn't smoke but material as seen here:
http://img824.imageshack.us/img824/8789/pressurepulsedebris.gif
and it really looks like the "93 smoke" was already in the air before it reached the elevation and the sun light, as seen here:
http://img404.imageshack.us/img404/422/pressurepulsesmoke2.gif
Created on 10/15/2010 02:12 PM by admin
Updated on 10/24/2010 07:26 PM by admin
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