Video & Evidence There Was No Controlled Demo

Originally posted by Damocles
you seem pretty certain that the IC ordered the building to be "pulled" and im just curious as to what brings you to this conclusion. is there some bit of data that i (and apparently many others) have overlooked in regards to this that CLEARLY and without question indicates the IC ordered it, or are you drawing your own conclusion based on your research?

also, are you saying flat out that it was the guys in the hardhats that were leaving the building who were the ones to actually set it into motion using these chemical and mechanical cutters? if so again id like to ask if thats based on some documented data or is it another conclusion you came to on your own?

Well i am mostly going by my education and experience, but also some of the research i have done.

I will see what documentation i can find for you.

But reports from firemen, police, and first responders are quoted as saying they were told to leave the area because the building was going to be brought down. Plus the report of the 20 second countdown heard over the radios.

Also as you probly know Silverstein has no authority to tell the fire commander what to do with the firemen.

Do you think that if the fire commander believed his firmen were in trouble, the building was going to cause more damage and spread more fires that he would not be able to decide to bring a building down, or have someone above him give the ok for bringing the building down.




[edit on 17-6-2007 by ULTIMA1]

Originally posted by ULTIMA1

But reports from firemen, police, and first responders are quoted as saying they were told to leave the area because the building was going to be brought down. Plus the report of the 20 second countdown heard over the radios.

well i have to ask myself questions about stuff i read online, like were they told it was going to be "brought down" or that it was "going to come down", that would be a huge difference.

the countdown i think ive only seen one place online and it wasnt what id call an "official" report...we all see these quotes online that are reputedly from "guys that were there" but just like i think some of the stuff out there is from people that so desparatly want the official story to be true they may make stuff up, i think the same of those that dispute the official story. bottom line is that i believe little of what i read online unless it can be easily verified, and i dont recall that countdown comment to be something i wouldnt question. if you have somewhere i can read that report again that comes from (even a website) say, a professional journal etc for fire/ems organizations id love to read it (jems for example?)

Also as you probly know Silverstein has no authority to tell the fire commander what to do with the firemen.

totally agree with that, in the grand scheme of things that day he's a nobody. my opinion for a LONG time about his "pull it" comment was that he WAS referring to the fire teams and that his ONLY reason for saying it was to imply that he wanted the firechief to pull the teams out and let his building burn so that he could appear to be more concerned about the firemen then he was about his building and thus play the hero by counting on the avg joe out there ignorant of the fact that the firemen had been pulled back long before his phone call and also ignorant of the fact that he had NO say in what the firechief did. he wanted good PR thats it.

Do you think that if the fire commander believed his firmen were in trouble, the building was going to cause more damage and spread more fires that he would not be able to decide to bring a building down, or have someone above him give the ok for bringing the building down.

IF he thought that he may have considered it...

BUT

its not in his authority to make that call.

if the buildign wasnt burning that badly as many would have us believe, how then could it cause more fire to spread if no other buildings were butted up against it

even if other buildings nearby werent on fire and IF 7 was in fact fully involved yet unsafe for fire crews to go into, why worry about other buildigns as much, if they werent as damaged as 7 then its a matter of just going into the adjacent buildings and putting out the new fires as they started before they got out of control.

and why would they worry about it causing more damage, im guessing you meant in a collapse scenario? why would they consider that if no other steel buildigns in history had ever collapsed due to fire? (i mean, that is an often repeated statement on this board right?)

if the building isnt safe for firefighters why on earth would he send in demo crews? by the time this would have all gone down, werent all the surrounding buildings evactuated? why risk lives to save damaged property? because lets face it, regardless of what they may have used to bring the building down, its not a 5 minute job. in a building that IS damaged (to whatever extent) and IS on fire (also to whatever extent). why not just let it burn.

also, dont buildings start on fire in large cities pretty regularly? how often do they implode buildings in order to keep the fires in them from spreading elsewhere?

so, why would they "pull" building 7? if the fires werent that bad, and the damage wasnt that bad...

if they did pull it why is it a source of speculation?

i think they pulled the teams out becuase they did feel there was a collapse risk (isnt that mentioned a couple places in all these quotes of the day?) if they felt there was a danger of collapse, why is everyone so suprised that it DID collapse?

the damaged area of 7 was in the hotzone, why are we suprised there arent photos of it? its not like a reporter could walk in and stand next to the debris of the WTC towers and take pics of the damage to 7.

the only real FACT we have in regards to wtc7 is that we have NO idea EXACTLY how much damage was done to it. there are conflicting reports as to how many floors were damaged but NO indication of how far into the building the damage extended. did it just tear off the outter facade or did it dig in 3/4 of the way to the other side of the building?

we do not know.


but, based on your training and experience...dont you think that somethign like ordering the destruction of a building would be something youd write down if for no other reason than to CYA?

Originally posted by ULTIMA1

But reports from firemen, police, and first responders are quoted as saying they were told to leave the area because the building was going to be brought down. Plus the report of the 20 second countdown heard over the radios.

Also as you probly know Silverstein has no authority to tell the fire commander what to do with the firemen.

Do you think that if the fire commander believed his firmen were in trouble, the building was going to cause more damage and spread more fires that he would not be able to decide to bring a building down, or have someone above him give the ok for bringing the building down.

Again the 1/2 truths to fit an agenda. The IC ordered a "COLLAPSE ZONE". This was to protect the firefighters!! This haulted rescue attempts for those trapped in the North Tower rubble. If you happen top read ANY of the interviews from ANY of the firefighter near WTC7 you will see that most of them heard the building creaking and leaning. And that fires were all over the place.

There is ZERO evidence of a "countdown" over ANY radio. Another claim that has NEVER been proven.

your entire post is pure specualtion.

Originally posted by Damocles
totally agree with that, in the grand scheme of things that day he's a nobody. my opinion for a LONG time about his "pull it" comment was that he WAS referring to the fire teams and that his ONLY reason for saying it was to imply that he wanted the firechief to pull the teams out and let his building burn so that he could appear to be more concerned about the firemen then he was about his building and thus play the hero by counting on the avg joe out there ignorant of the fact that the firemen had been pulled back long before his phone call and also ignorant of the fact that he had NO say in what the firechief did. he wanted good PR thats it.

Well thanks for agreeing with me on that. Most people will not even consider that point.

As stated i am trying ot find documnetation but since we do not have the FBI and NTSB crime scene reports i doubt if i can find other reports.

[edit on 17-6-2007 by ULTIMA1]

Originally posted by CaptainObvious
If you happen top read ANY of the interviews from ANY of the firefighter near WTC7 you will see that most of them heard the building creaking and leaning. And that fires were all over the place.

And for every report you say a firemen heard creaking and saw leaning i can find at least 1 or 2 that states they did not.

Originally posted by Fowl Play
Looks in a pretty bad state to me, funny how a lot of truth sites show mainly North side pictures, but looking at the south side hole, and fire.. we can see what was going on a bit clearer..

If that smoke is what people call fully involved fire, then they are wrong IMO. If that was a fully involved fire, we would see the windows broken out (which is an indication of how hot the fires are BTW) and we would see flames shooting out the broken windows. I have yet to see flames in any of the pictures of WTC 7's smoke. Except for a few floors that is.

Originally posted by ULTIMA1

Originally posted by CaptainObvious
If you happen top read ANY of the interviews from ANY of the firefighter near WTC7 you will see that most of them heard the building creaking and leaning. And that fires were all over the place.

And for every report you say a firemen heard creaking and saw leaning i can find at least 1 or 2 that states they did not.

PROVE IT! I have at least 35 i can post... that means you need at LEAST 35 to back up your claim. Keep in mind your quotes need to be from Firefighters that were there at least an HOUR after the North Tower collapsed. Posting quotes from firefighters immediatley after the collapse will not be an accurate portrayal of the condition of WTC 7. You need to provide a source for all of yours as I will with mine.

I will post mine. now...

EDIT...im sorry i assumed you were talking about large fires. By someone NOT saying the building was creaking does not mean that it WASN'T. I would like to to concede that the fires were not little though.

[edit on 17-6-2007 by CaptainObvious]

Originally posted by Damocles
so, in the end the ONLY evidence that indicates a CD is the fact that it fell straight down...thats it.

I think that is enough to know that it was some sort of CD. It takes lots of explosives to have a controlled demolition as neat as was observed on 9/11. No one can tell me assymetrical damage and fires can do what it takes months of planning and rigging to do. No one. Just my opinion though but I'll stick with my structural engineering knowledge. Not a rant directed at you Damocles.

personally i havnt seen any good photos of the buildings damaged side to have an opinion of why it fell at all.

And NIST is obviously having a hard time figuring it out also. Or we'd have the report by now.

Originally posted by CaptainObvious
EDIT...im sorry i assumed you were talking about large fires. By someone NOT saying the building was creaking does not mean that it WASN'T. I would like to to concede that the fires were not little though.

[edit on 17-6-2007 by CaptainObvious]

But you can not come up with any photos showing larger fires.



[edit on 17-6-2007 by ULTIMA1]

Originally posted by ULTIMA1
Well thanks for agreeing with me on that. Most people will not even consider that point.

As stated i am trying ot find documnetation but since we do not have the FBI and NTSB crime scene reports i doubt if i can find other reports.

[edit on 17-6-2007 by ULTIMA1]

no problem, i have always thought that the silverstein comments were the biggest nonevent of the whole situation. every single time i see someone trying to prove an inside job based on his "pull it" comment i just want to gouge out my own eyeballs. if thats what passes for PROOF of ANYTHING then the truth movment is in real trouble.

but what are your thoughts on the bottom half of my last post? you really dont need anyone elses reports to have an opinion on the pionts i raised there, just looking for your professional opinions trying to see if i can understand why you think the IC had anything to do with 7 coming down.

i mean surely you can see why it would have made more sense for them to just do what i think they did with 7, which was nothing as brining it down, even if it was within their authority, was likely more risk than reward.

i mean you have a fire contained in a building with only a small risk of it jumping to other buildings vs the chance its going to do something unexpected if you demo it on the fly like they would have had to do.

and you have to agree that had the IC actually ordered it dropped then it should be documented somewhere and would have been just put out in the open to the press or at the very least to the 911commission right? i mean someone would have told nist that it had been dropped on the authority of the IC so that they wouldnt waste their time doing a study on it, wouldnt they?

im just trying to undertand your point of view. youve stated flat out in this thread (and possibly in one other ive read) that it was a FACT that the IC ordered the building destroyed, and youve cited your training in IC to support your statments in regards to wtc7, so having had some of the same training and being at a loss as to the basis for your statements im just trying to understand where yer coming from. i am willing to admit i may have overlooked some facts in the course of my research. but unless you can clarify some of the pionts i raised in my last post im just afraid ill have to disagree with you.

Originally posted by Damocles
just saying we dont know what we dont know

You make good points. Too bad the permits for work on WTC 7 are mostly hidden. There are 7 listed in the NYC department of Buildings website. WTC 1 & 2 has 2 permits listed for both. What are they trying to hide by hiding the permits issued? Any other building on that website has pages worth of permits issued. WTC 2 has NONE listed. It would be nice to see what they did at WTC 7. Also, any type of construction that you mention would definately have to have a permit issued for it.

And we can't say that it is because it's owned by the PA. Because I believe (I could be wrong) that Silverstein had owned WTC 7 since erection.

So, where are the permits?

Again. This rant is not directed at you Damocles.

Originally posted by Damocles
the damaged area of 7 was in the hotzone, why are we suprised there arent photos of it? its not like a reporter could walk in and stand next to the debris of the WTC towers and take pics of the damage to 7.

What about the news crew helicopters? Why is there no footage? Obviously they would have been filming the damage to all the buildings. I have yet to see any.

all we can do is speculate.

could be that the govt confiscated all the media for itself

could be that since they wouldnt be directly over GZ they'd have to be far enough away they didnt get really good footage,

but id think it was likely that since there was at least SOME fire and at least SOME smoke and given they'd have a top-down angle on it, they just didnt get clear shots

all speculation, i really have no idea. just know that without really clear footage of the damage we're hamstrung trying to figure out what really happened

You see the outer wall crumble, not "support columns" or any other columns for that matter , you don't see whats causing the collapse or the support structure of the building since all support features of both WTC 1 and 2 buildings were internal around the shafts, 50 or so gigantic support beams, surrounded by all the office space and floors. The same columns that made the pancake theory impossible (by NISTs own admission) and the same columns that were found after the collapse to be nice, evenly sized chunks that fit perfectly on the trucks that then carried them away to be melted (destruction or even removal of evidence from a crimescene is a federal crime ya know).

Always funny seeing a bunch of "new" accounts popping up with supposed "new" information, while all this "new" information is, is just the same old twisting and misrepresenting of easily verifiable facts usually disguised as an expression of "patriotic" ignorance..

Originally posted by thematrix
You see the outer wall crumble, not "support columns" or any other columns for that matter , you don't see whats causing the collapse or the support structure of the building since all support features of both WTC 1 and 2 buildings were internal around the shafts, 50 or so gigantic support beams,....

hey, thematrix. you're half right. the outer cage, or perimeter columns with spandrel plates, WERE load bearing. the core supposedly took 60% of the load, while the perimeter took 40%, and this was a dynamic ratio which varied through the action of the hat truss(a structure connecting the perimeter to the core at the top of the building).

Originally posted by thematrix
You see the outer wall crumble, not "support columns" or any other columns for that matter , you don't see whats causing the collapse or the support structure of the building since all support features of both WTC 1 and 2 buildings were internal around the shafts, 50 or so gigantic support beams, surrounded by all the office space and floors. The same columns that made the pancake theory impossible (by NISTs own admission) and the same columns that were found after the collapse to be nice, evenly sized chunks that fit perfectly on the trucks that then carried them away to be melted (destruction or even removal of evidence from a crimescene is a federal crime ya know).

Always funny seeing a bunch of "new" accounts popping up with supposed "new" information, while all this "new" information is, is just the same old twisting and misrepresenting of easily verifiable facts usually disguised as an expression of "patriotic" ignorance..

I am a member of ATS for around 7 years, before the boards changed... Im not Patriotic of America, as i am British... Many people in the thread had not seen the Video, and it had not previously been posted on ATS, that to me is " new evidence" also the debate in the thread has been excellent till the last post.
If you read properly, you will see both sides of the issues discussed at length, with people posting evidence, videos, statements and images to back up their opinions.. You bring nothing to the table, and would be laughed out of debate for such trite.... either step out.. or step up

Originally posted by Damocles
all we can do is speculate.

could be that the govt confiscated all the media for itself

This "could be" is supported by the fact that NIST is sitting on top of thousands of photographs and video recordings that were confiscated and never released to the public.

Right, lets try and get some of these Phtographs and Vids then..
Maybe it is fruitless, but i will try my best

Questions put to NIST.. wtf is wrong with these explanations, are all the 100s of professionals involved in this BSin? do you a CT know better than these highly trained individuals? Is any 9/11 truth ORG or Truther Vid makers know better than all of these experts combined Answers??

1. If the World Trade Center (WTC) towers were designed to withstand multiple impacts by Boeing 707 aircraft, why did the impact of individual 767s cause so much damage?

As stated in Section 5.3.2 of NIST NCSTAR 1, a document from the Port Authority of New York and New Jersey (PANYNJ) indicated that the impact of a [single, not multiple] Boeing 707 aircraft was analyzed during the design stage of the WTC towers. However, NIST investigators were unable to locate any documentation of the criteria and method used in the impact analysis and, therefore, were unable to verify the assertion that “… such collision would result in only local damage which could not cause collapse or substantial damage to the building.…”

The capability to conduct rigorous simulations of the aircraft impact, the growth and spread of the ensuing fires, and the effects of fires on the structure is a recent development. Since the approach to structural modeling was developed for the NIST WTC investigation, the technical capability available to the PANYNJ and its consultants and contactors to perform such analyses in the 1960s would have been quite limited in comparison to the capabilities brought to bear in the NIST investigation.

The damage from the impact of a Boeing 767 aircraft (which is about 20 percent bigger than a Boeing 707) into each tower is well documented in NCSTAR 1-2. The massive damage was caused by the large mass of the aircraft, their high speed and momentum, which severed the relatively light steel of the exterior columns on the impact floors. The results of the NIST impact analyses matched well with observations (from photos and videos and analysis of recovered WTC steel) of exterior damage and of the amount and location of debris exiting from the buildings. This agreement supports the premise that the structural damage to the towers was due to the aircraft impact and not to any alternative forces.

2. Why did NIST not consider a “controlled demolition” hypothesis with matching computer modeling and explanation as it did for the “pancake theory” hypothesis? A key critique of NIST’s work lies in the complete lack of analysis supporting a “progressive collapse” after the point of collapse initiation and the lack of consideration given to a controlled demolition hypothesis.

NIST conducted an extremely thorough three-year investigation into what caused the WTC towers to collapse, as explained in NIST’s dedicated Web site, wtc.nist.gov.... This included consideration of a number of hypotheses for the collapses of the towers.

Some 200 technical experts—including about 85 career NIST experts and 125 leading experts from the private sector and academia—reviewed tens of thousands of documents, interviewed more than 1,000 people, reviewed 7,000 segments of video footage and 7,000 photographs, analyzed 236 pieces of steel from the wreckage, performed laboratory tests and sophisticated computer simulations of the sequence of events that occurred from the moment the aircraft struck the towers until they began to collapse.

Based on this comprehensive investigation, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers. Both photographic and video evidence—as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse—support this sequence for each tower.

NIST’s findings do not support the “pancake theory” of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system—that connected the core columns and the perimeter columns—consisted of a grid of steel “trusses” integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
diagram of composit wtc floor system

Diagram of Composite WTC Floor System

NIST’s findings also do not support the “controlled demolition” theory since there is conclusive evidence that:

*

the collapse was initiated in the impact and fire floors of the WTC towers and nowhere else, and;

*

the time it took for the collapse to initiate (56 minutes for WTC 2 and 102 minutes for WTC 1) was dictated by (1) the extent of damage caused by the aircraft impact, and (2) the time it took for the fires to reach critical locations and weaken the structure to the point that the towers could not resist the tremendous energy released by the downward movement of the massive top section of the building at and above the fire and impact floors.

Video evidence also showed unambiguously that the collapse progressed from the top to the bottom, and there was no evidence (collected by NIST, or by the New York Police Department, the Port Authority Police Department or the Fire Department of New York) of any blast or explosions in the region below the impact and fire floors as the top building sections (including and above the 98th floor in WTC 1 and the 82nd floor in WTC 2) began their downward movement upon collapse initiation.

In summary, NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to Sept. 11, 2001. NIST also did not find any evidence that missiles were fired at or hit the to

3. How could the WTC towers have collapsed without a controlled demolition since no steel-frame, high-rise buildings have ever before or since been brought down due to fires? Temperatures due to fire don't get hot enough for buildings to collapse.

The collapse of the WTC towers was not caused either by a conventional building fire or even solely by the concurrent multi-floor fires that day. Instead, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large, jet-fuel ignited multi-floor fires weakened the now susceptible structural steel. No building in the United States has ever been subjected to the massive structural damage and concurrent multi-floor fires that the towers experienced on Sept. 11, 2001.

4. Weren't the puffs of smoke that were seen, as the collapse of each WTC tower starts, evidence of controlled demolition explosions?

No. As stated in Section 6.14.4 of NIST NCSTAR 1, the falling mass of the building compressed the air ahead of it—much like the action of a piston—forcing smoke and debris out the windows as the stories below failed sequentially.

These puffs were observed at many locations as the towers collapsed. In all cases, they had the appearance of jets of gas being pushed from the building through windows or between columns on the mechanical floors. Such jets are expected since the air inside the building is compressed as the tower falls and must flow somewhere as the pressure builds. It is significant that similar “puffs” were observed numerous times on the fire floors in both towers prior to their collapses, perhaps due to falling walls or portions of a floor. Puffs from WTC 1 were even observed when WTC 2 was struck by the aircraft. These observations confirm that even minor overpressures were transmitted through the towers and forced smoke and debris from the building.

5. Why were two distinct spikes—one for each tower—seen in seismic records before the towers collapsed? Isn't this indicative of an explosion occurring in each tower?

The seismic spikes for the collapse of the WTC Towers are the result of debris from the collapsing towers impacting the ground. The spikes began approximately 10 seconds after the times for the start of each building’s collapse and continued for approximately 15 seconds. There were no seismic signals that occurred prior to the initiation of the collapse of either tower. The seismic record contains no evidence that would indicate explosions occurring prior to the collapse of the towers.

6. How could the WTC towers collapse in only 11 seconds (WTC 1) and 9 seconds (WTC 2)—speeds that approximate that of a ball dropped from similar height in a vacuum (with no air resistance)?

NIST estimated the elapsed times for the first exterior panels to strike the ground after the collapse initiated in each of the towers to be approximately 11 seconds for WTC 1 and approximately 9 seconds for WTC 2. These elapsed times were based on: (1) precise timing of the initiation of collapse from video evidence, and (2) ground motion (seismic) signals recorded at Palisades, N.Y., that also were precisely time-calibrated for wave transmission times from lower Manhattan (see NCSTAR 1-5A).

As documented in Section 6.14.4 of NIST NCSTAR 1, these collapse times show that:

“… the structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation.

Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass.”

In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.

From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.

7a. How could the steel have melted if the fires in the WTC towers weren’t hot enough to do so?
OR
7b. Since the melting point of steel is about 2,700 degrees Fahrenheit, the temperature of jet fuel fires does not exceed 1,800 degrees Fahrenheit and Underwriters Laboratories (UL) certified the steel in the WTC towers to 2,000 degrees Fahrenheit for six hours, how could fires have impacted the steel enough to bring down the WTC towers?

In no instance did NIST report that steel in the WTC towers melted due to the fires. The melting point of steel is about 1,500 degrees Celsius (2,800 degrees Fahrenheit). Normal building fires and hydrocarbon (e.g., jet fuel) fires generate temperatures up to about 1,100 degrees Celsius (2,000 degrees Fahrenheit). NIST reported maximum upper layer air temperatures of about 1,000 degrees Celsius (1,800 degrees Fahrenheit) in the WTC towers (for example, see NCSTAR 1, Figure 6-36).

However, when bare steel reaches temperatures of 1,000 degrees Celsius, it softens and its strength reduces to roughly 10 percent of its room temperature value. Steel that is unprotected (e.g., if the fireproofing is dislodged) can reach the air temperature within the time period that the fires burned within the towers. Thus, yielding and buckling of the steel members (floor trusses, beams, and both core and exterior columns) with missing fireproofing were expected under the fire intensity and duration determined by NIST for the WTC towers.

UL did not certify any steel as suggested. In fact, in U.S. practice, steel is not certified at all; rather structural assemblies are tested for their fire resistance rating in accordance with a standard procedure such as ASTM E 119 (see NCSTAR 1-6B). That the steel was “certified ... to 2000 degrees Fahrenheit for six hours” is simply not true.

8. We know that the sprinkler systems were activated because survivors reported water in the stairwells. If the sprinklers were working, how could there be a 'raging inferno' in the WTC towers?

Both the NIST calculations and interviews with survivors and firefighters indicated that the aircraft impacts severed the water pipes that carried the water to the sprinkler systems. The sprinklers were not operating on the principal fire floors.

However, there were ample sources of the water in the stairwells. The water pipes ran vertically within the stairwells. Moreover, there would have been copious water from the broken restroom supply lines and from the water tanks that supplied the initial water for the sprinklers. Thus, it is not surprising that evacuating occupants encountered a lot of water.

Even if the automatic sprinklers had been operational, the sprinkler systems—which were installed in accordance with the prevailing fire safety code—were designed to suppress a fire that covered as much as 1,500 square feet on a given floor. This amount of coverage is capable of controlling almost all fires that are likely to occur in an office building. On Sept. 11, 2001, the jet-fuel ignited fires quickly spread over most of the 40,000 square feet on several floors in each tower. This created infernos that could not have been suppressed even by an undamaged sprinkler system, much less one that had been appreciably degraded.

9. If thick black smoke is characteristic of an oxygen-starved, lower temperature, less intense fire, why was thick black smoke exiting the WTC towers when the fires inside were supposed to be extremely hot?

Nearly all indoor large fires, including those of the principal combustibles in the WTC towers, produce large quantities of optically thick, dark smoke. This is because, at the locations where the actual burning is taking place, the oxygen is severely depleted and the combustibles are not completely oxidized to colorless carbon dioxide and water.

The visible part of fire smoke consists of small soot particles whose formation is favored by the incomplete combustion associated with oxygen-depleted burning. Once formed, the soot from the tower fires was rapidly pushed away from the fires into less hot regions of the building or directly to broken windows and breaks in the building exterior. At these lower temperatures, the soot could no longer burn away. Thus, people saw the thick dark smoke characteristic of burning under oxygen-depleted conditions.

10. Why were people seen in the gaps left by the plane impacts if the heat from the fires behind them was so excessive?

NIST believes that the persons seen were away from any strong heat source and most likely in an area that at the time was a point where the air for combustion was being drawn into the building to support the fires. Note that people were observed only in the openings in WTC 1.

According to the International Standard ISO/TS 13571, people will be in severe pain within seconds if they are near the radiant heat level generated by a large fire. Thus, it is not surprising that none of the photographs show a person standing in those gaps where there also was a sizable fire.

The fire behavior following the aircraft impacts is described in NIST NCSTAR 1-5A. In general, there was little sustained fire near the area where the aircraft hit the towers. Immediately upon impact of the aircraft, large fireballs from the atomized jet fuel consumed all the local oxygen. (This in itself would have made those locations rapidly unlivable.) The fireballs receded quickly and were followed by fires that grew inside the tower where there was a combination of combustible material, air and an ignition source. Little combustible material remained near the aircraft entry gashes since the aircraft "bulldozed" much of it toward the interior of the building. Also, some of the contents fell through the breaks in the floor to the stories below.

Therefore, the people observed in these openings must have survived the aircraft impact and moved—once the fireballs had dissipated—to the openings where the temperatures were cooler and the air was clearer than in the building interior.

11. Why do some photographs show a yellow stream of molten metal pouring down the side of WTC2 that NIST claims was aluminum from the crashed plane although aluminum burns with a white glow?

NIST reported (NCSTAR 1-5A) that just before 9:52 a.m., a bright spot appeared at the top of a window on the 80th floor of WTC 2, four windows removed from the east edge on the north face, followed by the flow of a glowing liquid. This flow lasted approximately four seconds before subsiding. Many such liquid flows were observed from near this location in the seven minutes leading up to the collapse of this tower. There is no evidence of similar molten liquid pouring out from another location in WTC 2 or from anywhere within WTC 1.

Photographs, and NIST simulations of the aircraft impact, show large piles of debris in the 80th and 81st floors of WTC 2 near the site where the glowing liquid eventually appeared. Much of this debris came from the aircraft itself and from the office furnishings that the aircraft pushed forward as it tunneled to this far end of the building. Large fires developed on these piles shortly after the aircraft impact and continued to burn in the area until the tower collapsed.

NIST concluded that the source of the molten material was aluminum alloys from the aircraft, since these are known to melt between 475 degrees Celsius and 640 degrees Celsius (depending on the particular alloy), well below the expected temperatures (about 1,000 degrees Celsius) in the vicinity of the fires. Aluminum is not expected to ignite at normal fire temperatures and there is no visual indication that the material flowing from the tower was burning.

Pure liquid aluminum would be expected to appear silvery. However, the molten metal was very likely mixed with large amounts of hot, partially burned, solid organic materials (e.g., furniture, carpets, partitions and computers) which can display an orange glow, much like logs burning in a fireplace. The apparent color also would have been affected by slag formation on the surface.

12. Did the NIST investigation look for evidence of the WTC towers being brought down by controlled demolition? Was the steel tested for explosives or thermite residues? The combination of thermite and sulfur (called thermate) "slices through steel like a hot knife through butter."

NIST did not test for the residue of these compounds in the steel.

The responses to questions number 2, 4, 5 and 11 demonstrate why NIST concluded that there were no explosives or controlled demolition involved in the collapses of the WTC towers.

Furthermore, a very large quantity of thermite (a mixture of powdered or granular aluminum metal and powdered iron oxide that burns at extremely high temperatures when ignited) or another incendiary compound would have had to be placed on at least the number of columns damaged by the aircraft impact and weakened by the subsequent fires to bring down a tower. Thermite burns slowly relative to explosive materials and can require several minutes in contact with a massive steel section to heat it to a temperature that would result in substantial weakening. Separate from the WTC towers investigation, NIST researchers estimated that at least 0.13 pounds of thermite would be required to heat each pound of a steel section to approximately 700 degrees Celsius (the temperature at which steel weakens substantially). Therefore, while a thermite reaction can cut through large steel columns, many thousands of pounds of thermite would need to have been placed inconspicuously ahead of time, remotely ignited, and somehow held in direct contact with the surface of hundreds of massive structural components to weaken the building. This makes it an unlikely substance for achieving a controlled demolition.

Analysis of the WTC steel for the elements in thermite/thermate would not necessarily have been conclusive. The metal compounds also would have been present in the construction materials making up the WTC towers, and sulfur is present in the gypsum wallboard that was prevalent in the interior partitions.

13. Why did the NIST investigation not consider reports of molten steel in the wreckage
from the WTC towers?

NIST investigators and experts from the American Society of Civil Engineers (ASCE) and the Structural Engineers Association of New York (SEONY)—who inspected the WTC steel at the WTC site and the salvage yards—found no evidence that would support the melting of steel in a jet-fuel ignited fire in the towers prior to collapse. The condition of the steel in the wreckage of the WTC towers (i.e., whether it was in a molten state or not) was irrelevant to the investigation of the collapse since it does not provide any conclusive information on the condition of the steel when the WTC towers were standing.

NIST considered the damage to the steel structure and its fireproofing caused by the aircraft impact and the subsequent fires when the buildings were still standing since that damage was responsible for initiating the collapse of the WTC towers.

Under certain circumstances it is conceivable for some of the steel in the wreckage to have melted after the buildings collapsed. Any molten steel in the wreckage was more likely due to the high temperature resulting from long exposure to combustion within the pile than to short exposure to fires or explosions while the buildings were standing.

14. Why is the NIST investigation of the collapse of WTC 7 (the 47-story office building that collapsed on Sept. 11, 2001, hours after the towers) taking so long to complete? Is a controlled demolition hypothesis being considered to explain the collapse?

When NIST initiated the WTC investigation, it made a decision not to hire new staff to support the investigation. After the June 2004 progress report on the WTC investigation was issued, the NIST investigation team stopped working on WTC 7 and was assigned full-time through the fall of 2005 to complete the investigation of the WTC towers. With the release and dissemination of the report on the WTC towers in October 2005, the investigation of the WTC 7 collapse resumed. Considerable progress has been made since that time, including the review of nearly 80 boxes of new documents related to WTC 7, the development of detailed technical approaches for modeling and analyzing various collapse hypotheses, and the selection of a contractor to assist NIST staff in carrying out the analyses. It is anticipated that a draft report will be released by early 2007.

The current NIST working collapse hypothesis for WTC 7 is described in the June 2004 Progress Report on the Federal Building and Fire Safety Investigation of the World Trade Center Disaster (Volume 1, page 17, as well as Appendix L), as follows:

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An initial local failure occurred at the lower floors (below floor 13) of the building due to fire and/or debris-induced structural damage of a critical column (the initiating event) which supported a large-span floor bay with an area of about 2,000 square feet;

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Vertical progression of the initial local failure occurred up to the east penthouse, and as the large floor bays became unable to redistribute the loads, it brought down the interior structure below the east penthouse; and

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Triggered by damage due to the vertical failure, horizontal progression of the failure across the lower floors (in the region of floors 5 and 7 that were much thicker and more heavily reinforced than the rest of the floors) resulted in a disproportionate collapse of the entire structure.

This hypothesis may be supported or modified, or new hypotheses may be developed, through the course of the continuing investigation. NIST also is considering whether hypothetical blast events could have played a role in initiating the collapse. While NIST has found no evidence of a blast or controlled demolition event, NIST would like to determine the magnitude of hypothetical blast scenarios that could have le