The 9/11 Forum

According to the NIST report at 10:18 a pressure pulse occurred inside WTC1. NIST had no explanation for the event. Several floors were involved.

The pulse started a fire at the 92nd floor north side that quickly moved towards the NW corner. At 10:24 the fire crossed the corner moving south. For a short time we see smoke from the entire width of 92W (starting near the center opposite to the core) indicating that the windows were blown out. After some seconds the smoke disappeared again. At 10:27 (the next time CNN shows a close up of the top floors) about 2/3 of the west side showing heavy smoke and some spots of fire.
The fire at 92 was ignored in the NIST report.


At 10:18 CNN aired the event live:


The aerial photographs of the inward bowing used by NIST were taken at 10:22. The tilt of the antenna happened also at about that time.
The Lucia Davis video of the firefighters...
http://www.youtube.com/watch?v=0YvrKfWkxdw
... was taken at about 10:15 but, of course, the watch of the firefighter might be wrong for 2-3 minutes. The angle of the shadows in the street confirm the time within some minutes.

The video was taken at 67 Murray St (found by Yougene Debs). After the loud noise of an explosion the firefighters thought "Seven's exploding" and turn the heads towards the towers.
This is a little strange in itself because the fires in WTC7 were started after the WTC1 collapse.

There were reports of exploding cars but I'm not sure if these reports came prior to the WTC1 collapse. At least the cars in the parking area along North End Ave were not on fire at that time. Some rare videos from the bottom of WTC7 at that time show no burning cars but ATF personnel.
The "working hypothesis" of the FBI at that time was a car bomb in the basement of the towers. Several News channels reported it.

Finally that pressure pulse is the second unexplained event at that time. At about 4 seconds after the onset of the collapse of WTC2 two darting flames emerged from the south side of WTC1 IZ. Immediately after that a huge fire developed across the south side. Now - after 75 minutes burning in the SW half of the impacted floors - the fire swapped to the SE half. A new fire started at 105 SE corner.
After that event only one 911 call from the upper floors of WTC1 was made (connected). NIST noted a sharp decrease of 911 calls from above the burning floors.

Is it possible to connect these events by some further research or maybe by known details e.g. burning cars etc.? Or to delimit the possible meanings?

Watches, cool!

Anyway, please edit your post, I think you should add that the 9:59 south side pressure pulse originated just in front of the core hallway and elevator shaft(s) 6A/7A, which were out of service for at least a month....... .

achimspok wrote:The Lucia Davis video of the firefighters...
http://www.youtube.com/watch?v=0YvrKfWkxdw
... was taken at about 10:15 but, of course, the watch of the firefighter might be wrong for 2-3 minutes. The angle of the shadows in the street confirm the time within some minutes.

Do you have a better quality video ?

There's a couple of processes I can apply to have a clearer view.

http://www.youtube.com/watch?v=lNeZ0mTAa4s at 0:27
a clip from HBO's "In Memoriam"

Credit for Matt. He found it.

femr2 wrote:

Hmmm. Best I could get...

Thanks, that's great. Now we can separate the grays and get this:

Apparently the watch has those indicators for date and day. The pointers (maybe blue or silver) showing an angle of ... at least it is shocking close to 10:18.

The corner:


The simulation:

Why floor 92? What do you think the targets would be?

I can only think of CC connections on that floor. But why attack CC connections there?

If yes, they are leaving some CCs hanging above floor 92? Cut some at 92, some at 95 and the rest at 98 during collapse initiation?

So, cuts at 104, 98, 95 and 92? And maybe 101th floor was involved too? We should figure it out in another thread!!!!! (translate: this is a must for the bowing thread)

Why floor 92?

Can we exclude some local collapse that affected e.g floor 95 at the very same time (but without effect on the floors in between)? Just a question of the smoke conditions? There is simultaneous smoke from 93 and 96 but with a little delay after 92-95. While (92-)95 seems to be directed towards west the smoke from (93-)96 appears to be just in the east.
Imo, the pattern don't look like some local collapse. It looks like overpressure.
Would overpressure at 92-95 suggest an attack at the very same floors? Considering heavy damage to the inner structure (shafts, hallways, stairwells) at these floors...

Let's assume for argument that the 10:18 overpressures are an attack on CC connections on the 92nd and 95th floors.

Why? In ten minutes they will attack CC connections across the 98th floor, south to north, for collapse initiation.

We also see the lowest points of the south wall IB just along the 95th floor slab.


I'm just speculating here but....

If CC connections were separated and displaced for certain groups of columns along the 95th and 92 floors before collapse initiation, why would a demo team recut the same columns along the 98th floor CC connection during collapse initiation? If it is already cut 3 or 6 floors below, why cut it again at the 98th floor during the initiation? Why not just leave that column hang with the break where it already is?


This would mean that the bottom ends of certain groups of columns could have been moving downwards inside the core 3 or 6 floors below the visible collapse front during the earliest part of the fall. This means some of the core destruction may actually start at floors 95 or 92 during collapse initiation.

Just one idea.

The general idea (which I tend to agree on with achimspok) is that the 800 and 700 row columns were cut at the basement level.

The general idea (which I tend to agree on with achimspok) is that the 800 and 700 row columns were cut at the basement level.

You have at least 1 700, 800 pair spotted in the surviving core section. It stood about 50 floors high. Probably 703, 803.

If cut at basement level but attached to the "upper block", att that dead weight would be suspended from the "upper block"?

When the upper portion starts to move down, would there be hanging elements inside the core that would start moving with it? So the early upper block movement downwards would cause downward movement through the whole core?

Some columns could have been excluded. To your questions: I don't know bad the lover the cuts the worser it is for the structure....

i'm putting together a video regarding the fireman explosion / 10:18am business.

i'll run it past you guys before i post it anywhere (i'll do a private-upload to youtube and get your opinions), but before i do, i thought i'd get your views on any video made of the subject.


femr2, achimspok, peterene, majortom, any details you think i should be including in this clip?
i think its worth including the pressure pulse situation, for instance.

I think the upper floors of WTC1 may have been too far away to have been so loud. That bang was freakin' loud! I vote WTC7 was being hollowed out.