If the scientific fight over the World Trade Center was not so hugely important, it might be viewed as simply ridiculous that core elements of an event could be so severely disputed by people equally pledged to the scientific method. But with the stakes so immense, the vastness of the gap is far from ridiculous and is, in fact, of such magnitude that it is almost certainly going to take wide public understanding of the elements of the dispute to force re-examination of the evidence in a manner that would win the trust of both the public and the experts.
For the record, here is a summary of just some of the technical areas in dispute and what the National Institute for Standards and Technology (NIST) and its building trade and science allies on one side and its equally credentialed science, professional and licensed critics (building and structural engineers, architects, physicists, chemists) on the other side, put forward as their cases. It was compiled from NIST’s official report and from analysis that included papers and reports by independent professionals or members of groups representing each side of the argument, as well as from some other independent technical experts who have not taken sides.
The dispute takes place in a context that no other high-rise steel buildings ever collapsed in such a manner without the use of explosives. NIST alleges that in this special-circumstances case the buildings, like the “unsinkable” Titanic, did just that. NIST’s independent critics believe that what is “titanic” here are NIST’s scientific mistakes, evasions and willful refusal to examine all evidence.
Impact of Planes on Steel Columns
NIST reports that of the 47 core columns in each tower, three in WTC 1 were severed, four sustained heavy damage and five sustained moderate damage, adding up to about 25% of the columns. In WTC2 five core columns were severed, four sustained heavy damage and one sustained moderate damage, adding up to about 21% of the columns. NIST argues that in combination with the steel beams weakened by fire after the plane impact stripped fireproofing from the beams, this was sufficient to trigger a general collapse in both towers. Moreover, in both buildings perimeter columns on the exterior were severed, in one of them 35 such columns out of the 240 in each tower.
NIST critics among building professionals argue that the towers were built to survive even if more than 50% of the columns were severed or weakened. A favorite 1964 quote from the professional magazine Engineering News-Record cites the assertions of WTC designers that a catastrophe “could cut away all the first story columns on one side of the building, and partway from the corners of the perpendicular sides, and the building could still withstand design live loads and a 100 mph wind from any direction.” NIST responds that designers did not allow for the “unique conditions” of the tower events. Some independent NIST supporters add that the magazine quote itself is more self-promotion than construction reality.
NIST estimates that after the airplane crashes severed some beams in each tower, loads on some columns increased by up to 35%. NIST allows that, just as it should have been, the weight of the stories above the severed beams was efficiently distributed to intact beams and to other support elements but notes that, even so, once the fires softened the steel core and trusses bearing the extra load, there was sufficient give to allow the perimeter columns to bend inward and thereby touch off the collapse.
Opposing professionals note that the WTC designers specifically designed for airplane impact (though they concede for a somewhat smaller jet plane). Moreover, to assist load redistribution and for other safety reasons, the designers used a super-strong steel in the beams that, critics say, gave a margin of error allowing beams to handle three times their load capacity. Some critics cite a statistic that the outside perimeter columns could handle increases of 2000% above the designed live load. NIST says it never heard of such a number and doesn’t know its derivation (the authors of this article could not verify its source). Such a number is clearly inaccurate given the events, NIST says.
Absolutely essential to the NIST case is its finding via computer modeling of the damage that “significant amounts” of fireproofing protecting the core steel beams were dislodged from both towers by the impact of the aircrafts, allowing the steel to soften sufficiently (not melt) in the ensuing fires to destabilize the entire building. In one building 43 of the 47 core beams on at least one floor were estimated by NIST to be so damaged. Without this dislodgment, NIST concedes, the airplane crashes and subsequent fires could not have caused the collapse of the two buildings.
Critics point out that there is no hard evidence the fireproofing was stripped on impact or that so many core beams were damaged by fire, the hard evidence having been destroyed or carted away. NIST therefore had to rely on computer models to determine this a process in which the information chosen to be input was all important. They note that it is simply a NIST hypothesis that significant dislodging occurred. To support this theory, NIST performed laboratory tests in which shotguns pellets were fired at steel surfaces coated with spray-on foam insulation like that used in the twin towers. Critics note that the underlying assumption is that a crashing Boeing 757 would have been transformed into the equivalent of the thousands of shotgun blasts needed to dislodge fireproofing from the 6,000 square meters of surface area of structural steel in the fire areas.
Fire and Steel Softening
NIST argues that once the fireproofing was dislodged, the combination of gasoline fire and huge paper and office furniture fires created sufficient general area heat in sufficient time (with the air heated up to 1000C in some areas) so that the steel beams with dislodged fireproofing were able to reach temperatures of 700C, at which point they lost slightly more than half their load-bearing capacity, initiating the collapse. How did NIST come to cite the crucial 700C number? In its own lab tests, NIST found that the steel would soften sufficiently to allow floors to sag if it reached 700C. NIST further notes: “Bare structural steel components, when exposed to a large and sustained fire, can heat rapidly to the point where their ability to support their load is compromised.”
Said NIST spokesman Michael Newman: “NIST conducted simulations of the fires in each of the towers from the time of airplane impact to the collapses. The computational model used to simulate the fires was the Fire Dynamics Simulator. This model had been validated in numerous experiments and fire recreations prior to the WTC investigation. Additional large-scale experiments conducted during the investigation provided further assurance of the validity of the model output. This output was in the form of maps of the air temperatures on each of the floors over the duration of the fires.
“In a set of computations using the Fire Structure Interface, the evolving temperatures of the concrete and steel structural components of the towers were calculated by exposing them to the mapped air temperatures. Both sets of computations are based on the fundamental laws of combustion, heat transfer, and air flow. The methods have been documented extensively and have been successfully subjected to technical peer review and published in professional journals.”
Opposing experts, some with sophisticated calculations in hand, dispute that the temperatures from the fires ever reached the levels cited by NIST in the areas around the core beams. They point out that (1) NIST’s own display chart shows that the highest air temperatures, which NIST estimated lasted only 15 to 20 minutes, were not in the area of the core inner beams and that only 3 perimeter columns of 16 studied had reached a temperature above 250C, while two core columns studied had not even reached 250C. (2) Even in the unlikely event the beams lost 50% of their load- bearing capacity, they had capacity to handle three times the load they were carrying. (3) Steel rapidly transfers heat elsewhere such that no one spot is likely to have become sufficiently hot to lose its load-bearing capacity. (4) NIST states there is no visual evidence for fires close to or in the core of the buildings. (5) In the case of WTC2, all the NIST-claimed fire damage would have had to happen within 52 minutes whereas it took almost an hour and three quarters (102 minutes) for the impact-fire events allegedly to collapse WTC1.
NIST reports that impact-area floors sagged just before the collapse, as has happened in other steel-framed buildings under the duress of fire. With its computer-modeling of the collapse, NIST estimated the floors sagged 54 inches, pulling perimeter columns inward, which placed more load on the fire-weakened inner steel columns. For NIST this is another key element in the collapse scenario.
Opposing building professionals argue that no other fire in a steel-framed building ever caused so much floor sag and that in fact NIST’s own tests demonstrated only a few inches of sagging in the middle - and this after two hours in a high-temperature furnace. NIST, some critics allege, could have pumped the statistics fed into the computer in order to achieve a pre-desired outcome, justifying doing so with its questionable hypothesis that the fire-proofing was stripped as severely as NIST estimates.
NIST responds that it tested 17-foot and 35-foot trusses “at two Underwriters Laboratories for impact of the heat. The actual floor trusses that pulled on the perimeter columns were longer spans than we could test, so there would be more sagging than occurred in the laboratory mockups. The 54 inches is the calculated number [by the computer simulators] based on the fire test data.”
Perimeter Column Buckling
NIST claims that crucial evidence that helped steer its research into what brought on the collapse is a film by two Czech brothers showing perimeter support columns near the area of impact bending inwards, thus “applying an inward pressure” on the inner support beams, forcing them to bear some of the load of the perimeter columns. Once it saw the perimeter beams bend in, NIST says, it began to search for the cause which led to its understanding of the sagging floors.
Outside experts find two problems with this. One, NIST has never released the supporting film so that independent tests can be done on whether the perimeter columns actually bent inward or only appeared to do so because of light refraction. Second, to bolster its computer model’s outcome as to the effects of the columns supposedly moving inward, NIST, according to former Underwriters Lab chemist and whistleblower Kevin Ryan, fed into the computer information that “doubled the height of the unsupported wall sections [moving inward], doubled the temperatures, doubled the duration of the stress, and ignored the effect of insulation.”
NIST flatly denies Ryan’s claim that any data was doubled or altered at all. It also responds that it does not have the right to release the films and that independent investigators need to deal directly with the film owners, for whom NIST will provide contact information.
A NIST defender, scientist turned computer artist Mike King, wrote on his skeptics website, jnani.org, of the critics collapse theories: “They do not consider the NIST explanation, which points out that the core columns were designed only to withstand compressive loads, whereas the outer columns were the ones designed to withstand all lateral loadings (principally winds up to hurricane speed). As each floor collapsed it would have created lateral forces on the core columns which were sufficient to either tear away the bolts or sever the columns themselves as they ‘peeled’ away from the center.”
Shared Column Instability
NIST reports that the instability in the perimeter columns that spread to the core columns was then sent back to the perimeter columns, magnifying the shock.
Critical building experts dismiss this theory as speculation that is unproven by evidence in the NIST report. Given that each tower’s perimeter measured 832 feet, for such shock to spread to all the columns in the fraction of a second in which the buildings commenced their collapse, would require “a supersonic rate of propagation,” as one critic argues. No such event has ever happened in steel building history, the critics say.
Global Collapse Theory
In its most controversial finding, NIST argues that “global collapse” or “total progressive collapse” of the floors beneath the impact areas of both buildings ensued instantaneously after the impact area gave way and the tops of the buildings came crashing down into the lower sections. The lower sections “provided little resistance to the tremendous energy released by the falling building mass,” NIST reported. This happened with near free-fall speed despite the known load-bearing strength of the steel beams holding up the lower floors. As NIST spokesman Newman put it, “It is a simple matter of physics: force equal mass (of the upper stories) plus acceleration. We believe our calculations are accurate and we have had top physicists confirm this is how it could happen.”
NIST adds that the mass of the buildings coming down from the top were sufficient to collapse the lower floors even though photos and videos show the top of both towers breaking up before reaching the crash zone, with a significant amount of the rubble appearing to fall outside of the towers’ footprint, thus not impacting at all the lower floors.
Critical outside building professionals and others note that NIST provides no detailed calculations as to how the force of the upper stories was received by the lower ones, only a formula as to how it might have happened, and they cite Newton’s Law of Conservation of Momentum in which, quite logically they say and as evidenced by other damaged steel buildings, the upward strength and sheer size of the lower buildings mass with its huge steel columns would slow the descent of the upper portion of the buildings, not yield to it and collapse en mass. Not even if all the core steel beams in the fire area gave way, they argue, could global collapse ever occur absent some other force weakening the steel of the lower floors, which would have to come from pre-planted explosives. Absent such explosives, the “weak link” of the most severed or heated steel would have given first, at most causing the upper stories to topple to one side and not, as in two identical buildings, causing a mass and fairly straight-down collapse.
Tellingly, the critics note that the NIST report focuses in massive detail on its analysis of the damage to the impact area that allegedly initiated the collapse and does not provide similar detailed studies of how the lower floors supposedly collapsed. As the NIST report itself concedes, “It [the report] does not actually include the structural behavior of the tower after the conditions for collapse initiation were reached and collapse became inevitable.” The critics insist that such an admission itself invalidates the report.
NIST counters that, to the contrary, once the collapse started, the fact that the lower floors gave way is proof enough that the initiating events were sufficient to cause them to give way. As spokesman Newman said: “In the towers we believe we understand the physics of what happened and it’s a fairly simple conclusion after that. There was no need to build computer models after that as the results were already explained.”
One member of AE911Truth counters, “That is science by imperial fiat, reminiscent of the Catholic Church in the time of Galileo.”
Crucially, NIST denies that any of the building steel ever turned molten before the collapse, which would take a temperature much greater than it says the fires in the building reached but which an explosive such as thermite would easily generate. NIST argues that the yellow-reddish molten metal clearly seen pouring from one of the buildings was the aluminum from one of the planes turned yellow likely by blending with burning elements of furniture, computers and the like. NIST spokesman Newman further argues that any possible photographic evidence and eyewitness testimony of molten steel being removed from Ground Zero, if such evidence even exists (NIST says it has none), was either aluminum mistaken as steel or steel that had cooked in the heat and fires under the pile generated after the collapse and which were trapped, oven-like, in the debris and earth.
Critical independent professionals pounce on all this, noting that:
(1) NIST only surmised but did not actually test the hypotheses that silvery molten aluminum could turn yellowish-red when compounded with building contents; (2) NIST only studied carefully-selected whole steel sections; (3) there is some eyewitness testimony and a few photos showing that quantities of non-aluminum molten metals were seen above ground and so could not be explained by underground fires; (4) metal fires burned for weeks “consistent with the use of high-temperature cutter charges such as thermite … routinely used to melt/cut/demolish steel,” producing temperatures above 2000C, as one NIST-rebutting technical essay claims, and (5) it is physically impossible and absurd beyond science that fires in trapped rubble could burn hotter than the building fires and thus melt fallen steel unless some other chemical element were in place to reinforce those fires. A chemical such as thermite, which contains its own oxygen, would allow burning in oxygen-less underground spaces. The critics also note that NIST admits it never saw or tested any of the molten steel itself, and some of NIST’s lead scientists even deny its existence.
Missing evidence is also an important element here to the critics. NIST based its findings on analysis of 236 steel structure elements, which account for less than 1% of the total steel in the buildings. The vast bulk of the remaining steel was, as is routine with building debris, ordered to be broken up and was sold as scrap, largely to China, within a short time after the cleanup began. Critics say this business-as-usual was akin to selling off evidence from a crime scene and further undermines NIST’s assertions that its investigation comprehensively followed where the evidence led.
The question of molten steel sightings is important and unresolved. AE911 posts some photos and eyewitness accounts of molten steel on its website that its critics challenge as misrepresentative. Brent Blanchard, senior editor for the demolition industry magazine Implosionworld.com and director of field operations for a New Jersey company called Protec Documentation Services, which provides extensive building technical services to the demolition industry, supports NIST with a claim that of numerous debris crew members interviewed by him and his colleagues, none reported seeing molten steel.
Other NIST supporters accept the eyewitness accounts of molten steel cited by AE911 (though the “debunker” website 911myths.com challenges all the eyewitnesses it can identify). They argue, however, that if any melting occurred underground, the oxygen to fuel the fires would have derived from particulate matter in the building walls and contents. One NIST-supporting chemist, Dr. Frank R. Greening, former senior research scientist at Ontario Power Generation, argues that the great amount of aluminum from the cladding of the towers as well as from the planes might well have supplied both the fuel and oxygen needed to help melt the steel in the towers and later underground.
Predictably in the punch-counterpunch world of WTC scrutiny, some technical experts have sought to refute Greening’s claims with their own computations.
The Incendiary “Super” Thermite
Most NIST critics cite as the most devastating potential evidence of explosives the work of Dr. Steven E. Jones, a physicist who was forced to retire from his tenured professorship at Brigham Young University in Utah after he wrote a highly critical analysis of the NIST twin towers report that was severely rebuked by BYU”s own building engineering department as mistake-ridden because it was outside Jones area of expertise. Based on the article, however, four New Yorkers sent Jones what they claimed was WTC dust for testing. Jones and two other scientists, using BYU’s superb electronic microscope lab, then analyzed and, in a peer-reviewed scientific journal, reported and showed photographs last April of what they said was clear evidence of nano-thermite, otherwise known as super thermite, in the dust. Super thermite easily cuts through steel and is used by the military.
After Jones informed NIST of his findings and invited a dialogue, NIST countered that there was no “clear chain of custody” proving that the dust indeed came un-tampered from Ground Zero. Jones then invited NIST to conduct its own studies using its own known “chain of custody” dust. NIST has refused to take up the challenge.
Overwhelmingly, the independent professional critics accuse NIST of both gross negligence and making a mockery of the scientific method, given that eight years after the event no tests for explosives residues have been performed. Some assert that NIST willfully violated fire investigation regulations in not testing for explosives and note that many members of the NIST science panel have expertise in thermite and other explosives. The critics attribute such neglect to the self-protective peer-pressure effect of NIST scientists being government employees or contractors, including many defense contractors.
Other Evidence of Explosives
NIST concedes it never tested for explosives or residues largely because no credible evidence of explosives appeared, just as no molten steel samples were presented to it by the independent civil engineers who gathered up the steel to be tested. NIST states there were no credible eyewitness accounts of explosions from 10,000 interviews. And it argues that what appeared to be explosive-like puffs of light and smoke pushing out from various sections of the buildings were “squibs” of heated air and debris forced outward by the immense downward air pressure created as the mass of the buildings collapsed.
Given that the evidence that was available led so clearly to its final published conclusions, NIST says, there was and remains no reason to conduct explosives tests. “We know it wasn’t explosive that brought down the building so why waste the taxpayers money,” is the way NIST spokesman Newman put it.
Critical professional outsiders often angrily dispute every element of this. Their refutations include:
(1)A body of hundreds of eyewitnesses testimony reporting hearing and seeing loud explosions taking place in rapid sequence, including testimony from first responders and live news reports. NIST defenders argue the explosions and explosive sounds likely came from transformers blowing up, particularly the generators along the elevator shafts; from the floors crashing on one another, and from rivets popping en mass from the pressure of the fall. Janitorial staff reports of a huge explosion in the basement of one of the towers before it fell have not been explained.
(2) The fact that the light flashes and smoke emissions NIST labeled dust “squibs” developed in such an unusual pattern in lower floors, far from where the crunch was happening, that they cried out for closer investigation as explosives.
(3) In Building 7, these squibs occurred in a distinct rapid and symmetrical pattern along the line of the building that exactly mirrors controlled demolitions.
(4) Lab evidence from FEMA’s analysis of metal debris, ignored in the NIST report, showed large traces of unexplained sulfur, suggesting to FEMA a “severe high-temperature corrosion attack.” Another lab test by the EPA found the dust contained “one molecule 1.3 diphenylpropane.” According to outside experts, both sulfur and diphenylpropane are by-products of the military super-explosive thermite, whose potential use is also suggested by the severe high temperature damage FEMA found. For its part, NIST notes the EPA study found that 1.3 diphenylpropane was a common ingredient in plastics found in large quantities at Ground Zero and that sulfur from gypsum was also common.
(5) The official lab tests conducted for NIST and for the WTC-adjacent damaged Deutche Bank found widespread evidence of “iron-rich microspheres” which, NIST critics assert, is a byproduct of steel becoming molten, a challenge to NIST’s claim that molten steel existed only in small pockets underground.
(6) NIST itself reported an “unusual flame” right near the molten metal pouring from one of the towers that it said was aluminum from the plane. NIST could not explain what caused the flame and acknowledged it was not the burning aluminum.
The Iron-rich Microspheres
Three separate laboratory tests of dust and materials from the site reported the presence or iron-rich microspheres that, NIST critics assert, could only derive from high pressure or high temperature explosives. The tests were made by the US Geological Survey at the request of NIST, by the independent firm R.J Lee for an insurance investigation, and by NIST-challenger and former BYU physicist Dr. Steven Jones and some scientist colleagues.
Says AE911’s Gage: “The dust clouds are full of these iron-rich microspheres. In the dust from the WTC, you have millions of these tiny, perfectly spherical microspheres of iron. Now, where did they come from? The only way they could have been formed is to have molten iron and then a series of explosions whose incredible force atomizes, if you will, the molten iron into these tiny microspheres.”
Although NIST itself offers no explanation for the microspheres other than some might have formed from underground fires, others do. One of the leading critics of the microspheres and thermite theories is chemist Dr. Frank R. Greening. Greening argues that any thermite-like pockets of heat in the towers might well have derived from the incendiary qualities and heat of aluminum once it reaches a critical temperature a notion that Dr. Jones and others question in light of Jones’ research that reported finding direct evidence of thermite. Of the microspheres, Greening notes: “The formation of iron-rich microspheres below the [melting point] of pure iron: is possible, indeed probable, in an environment containing HCl/Cl2 and SO2/SO3 in the presence of O2 and H2O. The WTC fires produced lots of HCl from the combustion of PVC [plastics]and oxides of sulfur were present from sources such as lead acid batteries, residual fuel oil and gypsum:.These complex Al/Si/K/Ca/O phases readily combine with iron oxide at 1000 deg C to form iron-rich calcium/potassium aluminosilicate microspheres on cooling.”
Dr. Jones responds that this is speculation and, in light of his finding traces of thermite, the incendiary provides a better explanation for the required tremendous temperatures to get to the point at which miscrospheres would have been created. Moreover, Greening’s 1000C temperature needed is “a significant difference” from the temperatures NIST claims were generally generated by the WTC fires [NIST stated that if temperatures reached that high, it was for a very brief period in a small area]. Absent the presence of something like super thermite, the brief 1000C temperatures, if in fact achieved just from the fires, would not have been of the duration to produce so many microspheres. Jones adds that a USGS scientist had told him the microspheres might have come from “the cleanup process, cutting steel. Problem is that we have samples from long before the cleanup began.”
Dust Clouds and Pulverization
Anyone who watches the videos of the tops of the two towers as they begin to come apart sees a vast, seemingly explosive mushroom cloud or plume of dust and debris spew outward as if a major explosion took place. The dust cloud reached New Jersey and some of the debris was found hundreds of feet away. Moreover, rather than coming straight down as a unit, the upper floors collapse within themselves as if their steel structure was giving way even without being damaged by the fires burning stories below. Then as the entirety of both buildings came down, vast amounts of their innards were completely pulverized, to the degree that much of the building contents were not found intact. The thick layer of pulverized fine dust and residue spread across lower Manhattan, corroding cars as if there were some toxic substance in them.
The NIST report asserts that every single one of these phenomenon was caused by the magnitude of the tons of material from the tops of the buildings that gained speed and added other tons of toxic materials as the buildings collapsed. And the vast dust clouds that appeared to be a massive explosion in the top floors, NIST asserts, were caused by the force of air being compressed and blowing outward from the building, sending debris flying as well.
As for the upper stories collapsing on themselves first - before their mass hit the lower stories - this was an organic part of the process as the building came apart, as was the pulverization into powder-like dust from the tons of materials and the fires. Furthermore, the corrosive effects of the dust could easily have come from building elements that were burned up or pulverized into the dust, NIST maintains.
Critical building experts dispute each of these assertions. NIST provides no calculations to justify its case that the top of the buildings blew out via exhalation of compressed air instead of via explosives. Moreover, they say, large chunks of matter flew off the building and reached outside perimeter distances from a force that could only have come from explosives. Similarly, there is no evidence of any other collapsed building ever experiencing such intense pulverization except where explosives have been used. As for the highly corrosive dust, normal building and office materials would not cause that; only residues from certain explosives would be so toxic to metals, the critics argue.
AE911’s director Richard Gage says it is “scientifically invalid” that the pneumatic pressure was of such force to account for all the seeming explosion effects a point argued for and against by physicists who have posted technical papers online
NIST and its independent supporters respond that, in fact, building matter and debris did not, as critics allege, fly so far from the building as to be outside a normal perimeter that could be calculated from the height from which the topmost debris fell and its push by pneumatic air. As for pulverization, they note that no building the size and mass of the twin towers ever collapsed; accordingly, there is no reasonable comp to prove that the dust was an anomaly.
NIST central argument here is that even though all three buildings seemed to follow the classic footprint of a pre-planned demolition, both in the speed and symmetry of the structural collapse, in fact its global collapse theory better explains the anomalies of the events. It cites demolition experts it consulted affirming that all three buildings did not meet the classic demolition model. Many independent demolition experts also support NIST in this claim.
NIST critics do not allege a classic model of demolition in the towers, though they get close to doing so for Building 7. Instead they argue that incendiaries or explosives were used to assure collapse in a manner that could be obscured as to cause, and they cite by name several demolition experts, including eyewitnesses to the events, who attest their belief that explosives were used. Furthermore, the critics hold as wildly improbable the NIST concept that the impact-area core beams all gave way at once, allowing for a symmetrical collapse of both towers nearly simultaneously and in identical manners. (Even more improbabe, they say, was Building 7 crash footprint, with no plane crash into it). Instead, the critics argue, if there was loss of holding power in some beams, the towers would have tilted and crashed in an asymmetrical manner, as other buildings have.
Among NIST defenders is the demolition company Protec, which had a unique window on the WTC event because of three factors: it was monitoring seismic activity in Manhattan routinely (and says its seismic detectors did not record explosions at WTC); its multiple TV monitors normally used to capture news coverage of demolitions was able to record all the 9/11 news reports and their timing, and it was called in to assist cleanup crews and in doing so gathered much testimony and photographs from the crews.
“Close examination of these events from every video and photographic angle available:rather clearly shows each building beginning to fail at precisely the point where the respective planes struck:That is, no floors above or below the impact points ever move until the structural elements within the impact zone begin to collapse:” Protec’s Blanchard wrote in a report disputing the presence of explosives to which some of his Protec colleagues contributed.
Typically, Protec and Blanchard are challenged in very specific detail by several technically-oriented Truthers. As just one example, the Alameda, CA., software engineer Jim Hoffman, whose specialty is visualization of mathematics and who created his own 9-11 web site, wrote that Blanchard “provides no evidence to support most of his assertions, cherry [picks] a few issues to address, and promotes common misconceptions, such as that demolitions must proceed from the ground up.” Like AE911’s Gage, Hoffman also notes (as do others) that there is distinct evidence of building movement above the impact zone before the collapse.
Says AE911’s Gage: “In the twin towers, it’s very explosive. You can see the explosions in all the videos, and what’s happening is the explosions are creating this incredible dust cloud right in the beginning, even before the gravitational potential of this top portion, which we’re told drove the building all the way down to the ground. But the dust clouds are forming immediately.”
The TV Antenna
Videos show the large transmission antenna atop the north tower began to move downward and slightly laterally just before the outer walls showed movement. The antenna appears to sink somewhat into the building, suggesting that the massive center core steel was collapsing even before there was any visible outside evidence of collapse. NIST attributes this anomaly to events happening to the core columns below: ÂThe videos show tilting southward consistent with the inward bowing of the perimeter columns and the initiation of collapse. The NYPD photographs seven minutes before collapse show the inward bowing clearly.” NIST reports.
Critics point out that NIST provides no quantitative analysis of the anomaly which, they allege, is far more easily explained by the presence of demolition charges going off.
The Computer Modeling
NIST painstakingly built an elaborate computer model to examine the core elements of the initiation of the buildings collapse from impact and fire. (It concedes, as already noted, that it did only calculations and not intense computer simulation of how the lower floors failed to resist the falling upper stories.) Responding to critics assertions that it adjusted some of the data before entry, NIST says it adjusted input only within the bounds of physical reality. It cites as proof of its work that its many safety recommendations have been adopted by the international body that promulgates construction codes.
NIST critics challenge several of the calculation that were input and, perhaps more importantly, note that NIST has not given full disclosure of the data it input, which would allow the data to be tested by others. One engineering magazine reported that NIST has refused to show computer visualizations of the collapse despite a call from fire and building engineers to see the data. NIST has also refused to submit its finding to an independent panel or journal for peer review, relying instead on a form of review from outside contractors it has hired, most of whom have Defense Dept. contracts.
NIST’s Newman responds that NIST is barred from releasing all the data critics want: “Pursuant to section 7 of the National Construction Safety Team Act” (the authority under which the WTC investigation has been conducted), certain evidence received by NIST in the course of this investigation is “voluntarily provided safety-related information” that is “not directly related to the building failure being investigated” and that “disclosure of that information would inhibit the voluntary provision of that type of information: In addition, a substantial portion of the evidence collected by NIST in the course of the investigation has been provided to NIST under nondisclosure agreements. Anyone wanting this information can go to the specific sources and we will provide the contact data. All of the data that NIST generated has been made public.
” NIST established a secretariat to coordinate NIST-level activities in support of the investigation and to maintain ongoing liaison with the Executive Branch, Congress, the public, and the news media. NIST has maintained an ongoing liaison with the professional community, the public, and local authorities over the course of the investigation through briefings, presentations, and opportunity for comment on key investigation reports. NIST also assigned a special liaison to interact with the families of building occupants and first responders. A Web site dedicated to the WTC investigation has been maintained at http://wtc.nist.gov. The final report on the WTC towers is available there in its entirety (43 documents totaling some 10,000 pages). The Web site also provides access to the WTC investigation archives where the public can follow the complete history of the effort so far, including the two interim progress reports, two public updates and 22 news releases issued during the WTC towers portion of the investigation, as well as documentation from eight public meetings, eight media briefings, seven meetings of the NCST Advisory Committee, and the September 2005 technical conference on putting the NIST recommendations from the WTC towers study into practice.”
NIST critics often cite the collapse of the 47-story WTC Building 7 as the premier evidence that incendiaries and/or explosives were present given that no fireproof dislodging plane ever struck the high-rise and no other high-rise building of its size had ever collapsed from fire. NIST asserts that its most elaborate computer modeling went into its report on Building 7, which took three years to assemble and, NIST says, demonstrates how the building fell in what seemed to be a controlled demolition pattern without being struck by a plane and without explosives.
Says NIST: “Determining the probable collapse sequence for WTC 7, NIST found that the impact of debris from the collapse of WTC 1 ignited fires on at least 10 floors of WTC 7, and the fires burned out of control on six lower floors. The heat from these uncontrolled fires caused thermal expansion of the steel beams on the lower floors of the east side of WTC 7, damaging the floor framing on multiple floors. Eventually, a girder on Floor 13 lost its connection to a critical interior column that provided support for the long floor spans on the east side of the building. The displaced girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the fifth floor. Many of these floors had already been at least partially weakened by the fires in the vicinity of the critical column. This collapse of floors left the critical column unsupported over nine stories.”
“When this critical column buckled due to lack of floor supports, it was the first domino in the chain,” NIST’s Building 7 Team leader Dr. Shyman Sunder explained. “What followed in rapid succession was a progression of structural failures. Failure first occurred all the way to the roof line-involving all three interior columns on the most eastern side of the building. Then, progressing from east to west across WTC 7, all of the columns in the core of the building failed. Finally, the entire fa§ade collapsed.”
NIST adds that the seven hours of fires were so intense, and with the sprinkler system gone, firefighters were fearful of entering the building.
Independent NIST defenders concede that fire has brought down smaller buildings but none before over 15 stories. They point out, however, that some fires like that of the Bay Bridge between San Francisco and Oakland have caused steel to collapse and have caused partial collapse in some other buildings. Building 7’s collapse, they argue, while it may superficially have resembled a controlled demolition far more than did the twin towers collapse, in fact the seven hours of intense fires would have destroyed any pre-planted explosives which, had they gone off, would have registered on seismic detectors none did, they say, though in another war between technical experts, this is disputed in online papers and blogs.
The NIST defenders also cite firefighter reports that the physical damage to Building 7 was greater than shown by most photos, to the degree that when combined with the fires, fire officials reported that they expected the building to collapse even sooner than it did. NIST defenders also cite a collapse pattern that, when looked at closely, does not in fact replicate that of a controlled demolition. Finally, they point out that most of the eyewitness reports of sounds like explosions occurred at the fall of the towers, not in regard to Building 7.
Independent building professionals dismiss the NIST findings and defenders as prejudiced and irrelevant given that, as with the twin towers, NIST refuses to test for explosives. They note that Building 7 is the single only high-rise to fall solely from fire which, they point out, it was built to withstand. More tellingly, they affirm their professional belief that it is impossible that any modern high-rise designed to meet building code standards could collapse because of failure of one support beam, which building codes specifically guard against. The critics argue that NIST likely pumped wrong data, highly questionable hypotheses and forced extrapolations into its Building 7 computer models in order to explain why Building 7 fell rather than follow the logic of testing for demolition residues.
As to Building 7’s collapse pattern, AE911’s Gage and others concede that a traditional demolition collapse pattern would not have been likely or planned for anyway, even though Building 7’s collapse pattern seemed to come somewhat close to it. Instead, they argue, any culprits who planted either incendiaries such as thermite (their most likely case) or explosives would do so only to magnify the impact of the incoming airplanes. Accordingly, the culprits would not likely have even tried to plant traditional demolition cutter charges (for which they concede there would not likely have been the long and open access time in the building needed) either in the towers or Building 7. Instead, relatively small amounts of super-thermite and detonators placed quickly in obscure areas of the buildings could have accounted for the collapses.