The 9/11 Forum

The video clip linked below is by Etienne Sauret.

There are clear, rather powerful variations in pressure along the roofline near the SW, SE and a bit at the NE corners during particular moments leading up to collapse initiation.

http://www.youtube.com/watch?v=xGAofwkAOlo&feature=channel_page

These pressure variations can be seen in momentary concentrated smoke puffs at the following times

SW corner (to the right): :07, :16, :21, :27

SE corner (to the left): :30


The aspect I've found most strange is how, when watching the clip, I know at what moment the collapse begins by the rapid, concentrated smoke release upwards from the SE corner just before the building starts to move (at 0:31)



These puffs...

1) are so large they are easy to notice
2) accelerate upwards faster than the surrounding smoke movement
3) are always near or at the corners of the roof


Can the good readers please help me understand what could have caused such large, distinct puffs?


Thanks

The upper mechanical floors are not far below. Possibly the corners had HVAC ducting? IF so, then there is a pathway for any sudden pressure variations from below to send particles upwards.

You might care to look carefully at the video, possibly frame by frame, to see if these pulses did not orginate from the exterior ventilators on the upper mechancial cores, where the winds blew them into the corners.

I'll follow your recomendation, David. Follow-up to be posted in a bit.

Most curious, as mentioned before, is the upward accelerated puff from the SE corner (left and back) just BEFORE collapse begins.

It can also be seen in the following clip (from the farthest back corner away from the viewer).

http://video.google.com/videoplay?docid ... 4880&hl=en

I'm interested in the clear force behind these upward "puffs" and in the fact that they are clearly directed upwards. This is why I do not believe ventilation systems can be the cause. Due to rain, ventilation systems will be on the highest floors (?) with the vents facing downwards. Nobody would suggest that there would be venting on the roof with no rain caps.

I don't think people would suggest that these puffs were originally ejected in a different direction (outwards and slightly downwards) and then changed direction to move upwards with such force.

They appear to be originally ejected from near the top of the building upwards with over-pressure bursts.

If natural from fires, there must be something within the building design that explains this.

Note how near the end of the above clip you can see similar concentrated "puffs" also shooting upwards at a similar angle, velocity and force as the one in the SE corner before. These obviously are from the movement of the building and make sense.

But the original SE pulse happens before the building moves, though the extreme similarities are obvious.


Thanks for the feedback.

My hypothesis is that partial floor collapses occurred, sending pulses of smoke and fire through the HVAC ducting to the venilators. Upon exiting, these are much hotter that the surrounding air, so immediately rapidly rise.

I've seen pictures taken on the roof. Other than the antenna tower, there were no other features. This doesn't mean, of course, that their were none out of view. For example, the window washing apparatus was parked towards the NW corner.

My hypothesis is that partial floor collapses occurred, sending pulses of smoke and fire through the HVAC ducting to the venilators. Upon exiting, these are much hotter that the surrounding air, so immediately rapidly rise.

I've seen pictures taken on the roof. Other than the antenna tower, there were now other features. This doesn't mean, of course, that their were known out of view. For example, the window washing apparatus was parked towards the NW corner.

I agree there is nothing in the form of a duct opening on the roof.

I have a bit of a problem accepting a pulse originally ejected horizontally and then accelerating upward with such force as to be clearly more rapid in the upward direction than the surrounding smoke.

But I'll consider this and thanks for the reply.

David B. Benson wrote:My hypothesis is that partial floor collapses occurred, sending pulses of smoke and fire through the HVAC ducting to the venilators. Upon exiting, these are much hotter that the surrounding air, so immediately rapidly rise.

I've seen pictures taken on the roof. Other than the antenna tower, there were no other features. This doesn't mean, of course, that their were none out of view. For example, the window washing apparatus was parked towards the NW corner.

Partial floor-collapses, where? You certainly aren't suggesting that the force of impact some 12+ floors below would cause partial collapses near or on the mechanical floors, are you? Bazant showed that elastic waves would not cause any problematic strain on any of the above floors, until those floors were met by lower structure parts after the floors below are destroyed, since he assumes only the crushing front produces the destruction. Of course, the obvious problem of "upper floor accretion" has yet to be calculated or postulated on any serious level.

Ian --- One the fire and damage affected floors down below. THe hypothesis is that these fan out hot gases, still conbusting, so that these 'fireballs' rise rapidly.

David B. Benson wrote:Ian --- One the fire and damage affected floors down below. THe hypothesis is that these fan out hot gases, still conbusting, so that these 'fireballs' rise rapidly.

That makes more sense, thanks.

The editor of the following video clip also notices curious sharply accelerated smoke activity jsut before WTC 1 collapse initiation.

Please note the sharply accelerated pulses of smoke coming from near the SE and SW corners of the building (you are looking from the north).

http://www.youtube.com/watch?v=NoTcQxizw1U&NR=1

Between 0:00 to 0:34, please note the distinct rising pulses of smoke.

It is easy to contrast these distinct pulses to the consistent smoke drift in which all the other smoke is moving.

If all this isn't strange enough, please notice that the last of these pulses, from the SE corner, is perfectly timed with collapse initiation.

One the fire and damage affected floors down below. THe hypothesis is that these fan out hot gases, still conbusting, so that these 'fireballs' rise rapidly.

No evidence of fireballs. We would all agree that these are the result of sharp localized pressure expansions occuring at distinct moments in time.

The question is: What is actually causing these?

For the folks arguing for the official story, these pulses are probably key in explaining the trigger of collapse initiation. Especially the last pulse from the SE corner which appears perfectly timed with collapse initiation.

Guys, I'm counting at least 6 distinct accelerated pulses from the SW corner, 5 from the SE corner.

I could understand a naturally occurring pulse or 2.

How do you explain about 10 of these? There must be localized sources for such distinct phenomena.

Vapor explosions? So many of them coming from the same locations, quickly following one another?