Note to the reader: The following is a critique of the National Institute for Standards and Technology (NIST) report on the World Trade Center (WTC) collapse. The 43 volume NIST report was the result of a 3 year investigation, and was released in September 2005. It remains the official US government explanation for why the WTC collapsed on 9/11. As you are about to discover, the report itself collapses under scrutiny. There is no doubt that the NIST investigation was politically controlled by limiting its scope. This is one way to kill an investigation.
Edgar’s collapse model sounded plausible enough–––but the NIST investigation didn’t bear it out.
Because the NIST did not have the necessary facilities, it contracted Underwriter Laboratories to conduct a series of fire endurance tests on trusses like those in the WTC. (The recovered truss samples were too badly deformed during the collapse to test them directly, so NIST fabricated new trusses identical in design.) The purpose of the tests was to establish a baseline, and the results were surprising. Not one of the truss assemblies failed during a series of four tests, not even the truss sprayed with the minimum amount of fireproofing. “The floors continued to support the full design load without collapse for over two hours.” The investigative team cautiously noted that the exposure of the floor systems to fire on 9/11 was “substantially different” than the conditions in the test furnaces, which was true enough. Yet, the
team noted that “this type of assembly was capable of sustaining a large gravity load without collapsing for a substantial period of time relative to the duration of the fires in any given location on September 11.” The UL tests not only laid to rest the theory that the trusses were the cause of the collapse on 9/11, if anything, the tests demonstrated the fundamental soundness of the WTC truss design.
Another finding: The WTC steel turned out to be significantly stronger than expected. Tests showed that the yield strengths of 87% of the perimeter/core columns, and all of the floor trusses samples, exceeded the original specifications by as much as 20%. “The yield strengths of many of the steels in the floor trusses were above 50 ksi, even when specifications required 36 ksi.” (1 ksi = 1,000 lb/per square inch) The NIST performed similar tests on a number of recovered bolts, and found that these too were “much stronger than expected, based on reports from the contemporaneous literature.” Notice–––none of these findings support the NIST’s official explanation for the WTC collapse. On the contrary.
Another series of tests sought to address the alleged weakening of the WTC support columns. During a first-run investigators placed an uninsulated steel column in a 2,012ºF (1,100ºC) furnace and measured the rise in its surface temperature. Notice, this laboratory furnace was significantly hotter than the fires on 9/11 caused by jet fuel or any other combustible in the WTC. The column reached 600ºC in just 13 minutes–––the temperature range where significant loss of strength occurs. When the test was repeated again with an insulated column, the steel did not reach 600ºC even after ten hours. The NIST concluded that “the fires in WTC 1 and WTC 2 would not be able to significantly weaken the insulated….columns within the 102 minutes and 56 minutes, respectively, after impact and prior to collapse.”[my emphasis]
The NIST interpreted these results as validating its favored hypothesis that the critical factor on 9/11 leading to the global failure of the WTC’s support columns was the damage to the fireproofing insulation caused by the Boeing 767 impacts. But was this an unwarranted leap? It certainly was not supported by the NIST’s metallurgical analyses, which showed that not even one of the 236 steel samples, including those from the impact areas and fire-damaged floors, showed evidence of exposure to temperatures in excess of 1,110ºF (600ºC) for as long as 15 minutes. In fact, out of more than 170 areas examined on 16 recovered perimeter columns, only 3 reached temperatures in excess of 250ºC (450ºF) during the fires. And why ? Well, perhaps, in part, because, as Shyam Sunder, the lead NIST investigator, admitted, “the
jet fuel….burned out in less than ten minutes.” Also, NIST scientists made another surprising discovery: The actual amount of combustibles on a typical floor of the WTC turned out to be less than expected, only about 4 lbs./sq. foot. Furthermore, “the fuel loading in the core areas….was negligible.” The shocking fact is that the World Trade Center was fuel-poor, compared with most other buildings. The NIST estimated that a fire in a typical area of the building would have burned through the available combustibles at maximum temperatures (1,000ºC) in about 15-20 minutes. Not nearly long enough even at that temperature to cause exposed steel to lose 80% of its strength.
Nor is this all. I searched the NIST report in vain for any acknowledgment that here, as in the case of the truss assembly test, the actual fire conditions on 9/11 were substantially different from the UL laboratory furnace. In fact, with respect to the columns the differences were at least as significant as with the truss assembly test, and call into sharp question the NIST’s conclusion that damaged insulation was the critical factor. Although the NIST took the position that “temperatures and stresses were high in the core area,” as I’ve noted the investigation suffered from a persistent lack of information about real conditions at the core. The NIST had no hard evidence about the actual amount of protective insulation damaged/dislodged during the impacts. The NIST report acknowledges this, then goes on to assume that all structural members in the debris path at the time of impact suffered 100% loss of insulation. Surely, we are safe to conclude that the Boeing 767 impacts did cause damage to, or strip away, a substantial portion of the fireproofing material. Exactly how much is not knowable. But even if the NIST estimate of total loss of fireproofing is correct, there is virtually no chance that the fires on 9/11 weakened the WTC’s core piers within the allotted span of time: 56/103 minutes.
The reason for this, nowhere acknowledged in the NIST report, ought to be obvious: The WTC’s support columns did not exist in isolation. This was no laboratory furnace. The columns in each tower were part of an interconnected steel framework that weighed at least 100,000 tons; and because steel is known to be an excellent conductor of heat this massive steel superstructure functioned on 9/11 as an enormous energy sink. The total volume of the steel framework was vast compared with the relatively small area of exposed steel, and would have wicked away the fire-caused heat almost as quickly as it was generated. Anyone who has repaired a copper water pipe with a propane torch is familiar with the principle. One must sit and wait patiently for the pipe temperature to rise to the point where the copper finally sucks the solder into the fitting. While it is true that copper is more conductive than steel, the analogy holds, regardless. The fact that only three recovered steel samples showed exposure to temperatures above 250ºC indicates that the steel superstructure was indeed behaving as a heat sink. The fires on 9/11 would have taken many hours, in any event, much longer than the brief allotted span of 56/103 minutes respectively, to slowly raise the temperature of the steel framework as a whole to the point of weakening the exposed members.
And there are other problems. Since in a global collapse all of the columns by definition must fail at once, this implies a more or less constant blaze across a wide area. But this was not the case on 9/11. As already noted, the NIST’s lead investigator, Shyam Sunder, admitted that the jet fuel was consumed within minutes. Also, the NIST found that the unexpectedly light combustibles in any given area of the WTC were mostly consumed in about 15-20 minutes. At no point on 9/11 did the fires rage through an entire floor of the WTC at the same time–––as Thomas Eagar implied in his interview. The fires in WTC 1 were transient. They flared up in a given area, reached a maximum intensity within about 10 minutes, then gradually died down as the fire front moved on to consume combustibles in other areas. But notice what this means: As the fires moved away from the impact zone to areas with little or no damage to the fireproofing, the heating of the steel columns and trusses in those areas would have been negligible. The NIST’s own data showed that, overall, the fires on floor 96–––where the collapse began–––reached a peak 30-45 minutes after the impact and waned thereafter. Temperatures were actually cooling across most of floor 96, including the core, at the moment of the collapse. But if this is true, the central piers were not losing strength at that point but regaining it. How, then, did they collapse? Finally, the NIST’s insistence that “temperatures and stresses were high in the core area” is not consistent with their finding that the fuel load of combustibles in the core was negligible. On this point the NIST contradicts itself.
In short, the NIST report fails to explain how transient fires weakened WTC 1’s enormous central piers in the allotted span of 103 minutes and triggered a global collapse.
The NIST concluded that in WTC 2 the fire behaviour was substantially different: more continuous (rather than transient), especially on the east side of the building where the impacting Flight 175 allegedly piled up combustibles. This–––we are informed–––in addition to more extensive impact damage of the core columns, helps to explain why WTC 2 fell first, even though it was impacted after WTC 1. Videos filmed on 9/11 do show inward bowing of WTC 2’s eastern wall, although its actual extent and significance remain disputed. But perhaps the most serious challenge to the official view that fires were gravely weakening WTC 2 comes from an audiotape released in August 2002 by the Port Authority of New York. The tape, which was lost or neglected for more than a year, is the only known recording of fire fighters inside the towers. When city fire officials belatedly listened to it they were surprised to discover that firemen actually reached the impact/fire zone of WTC 2 about 14 minutes before the building collapsed. On climbing to the 78th floor sky lobby Battalion Chief Orlo J. Palmer and Fire Marshall Ronald P. Bucca found many dead or seriously injured people, but no raging inferno. The audio transmission between Palmer and another fireman shows no hint of panic or fear, as the following transcript shows:
Battalion Seven Chief: “Battalion Seven … Ladder 15, we’ve got two isolated pockets of fire. We should be able to knock it down with two lines. Radio that, 78th floor numerous 10-45 Code Ones.
Ladder 15: “Chief, what stair you in?”
Battalion Seven Chief: “South stairway Adam, South Tower.”
Ladder 15: “Floor 78?”
Battalion Seven Chief: “Ten-four, numerous civilians, we gonna need two engines up here.”
Battalion Seven Chief: “Tower one. Battalion Seven to Ladder 15.”
Battalion Seven Chief: “I’m going to need two of your fire fighters Adam stairway to knock down two fires. We have a house line stretched we could use some water on it, knock it down, okay.”
Ladder 15: “Alright ten-four, we’re coming up the stairs. We’re on 77 now in the B stair, I’ll be right to you.”
Battalion Seven Operations Tower One: “Battalion Seven Operations Tower One to Battalion Nine, need you on floor above 79. We have access stairs going up to 79, kay.”
Battalion Nine: “Alright, I’m on my way up, Orio.”
Here, Battalion Chief Orlo Palmer calls for hoses to be brought up to put out the fires. His expression “10-45 Code Ones” is a reference to dead bodies, of which, evidently, there were many. The tape shows that the firemen were not turned back by heat, smoke, or a wall of flames.
They were able to function within the impact zone and were prepared to help the injured and combat the small fires they found. Palmer even mentions that the stairwell up to the next floor, i.e., 79, was passable. Minutes later the building came down on their heads.
Inexplicably, the NIST never considered this important evidence. The question is why? Their omission is especially damning, since, as I’ve stressed, the NIST investigation suffered from a persistent lack of information about actual conditions at the core. Here was real-time testimony from fire fighters who were on the scene, and the NIST simply ignored it.
Of course, it’s possible that more intense fires were raging several floors above the two brave firemen–––fires that did cause fatal weakening of columns. This is possible, but the available evidence does not support it. Among the steel samples recovered by NIST investigators were two core columns (C-88a and C-88b) from higher up in the impact zone. Actually, these were two different pieces from the same column (801). The NIST pinpointed their location on floors 80 and 81, several floors above the firemen–––very near but just outside the path of Flight 175. Both samples were physically damaged, but the NIST reported no evidence of the kinds of distortion, i.e., bowing, slumping, or sagging that are typical of heat-weakened steel. Nor was the NIST able to glean any evidence of high temperatures from the columns. On what, then, do they base their conclusion that “Dire structural changes were occurring in the building interior”? If anything, the paucity of evidence calls into question the NIST’s declaration that their sampling effort was adequate.
Moreover, as we’ve already noted, the NIST’s computer simulation predicting extreme damage to the core of WTC 2 is dubious, since it is also unsupported by hard evidence. In fact, the NIST’s preferred extreme alternative was, from a predictive standpoint, no better than the lesser alternatives, which the NIST rejected. Even the extreme alternative failed to predict a global collapse, without “additional inputs.” As for the inputs, it would be interesting to know more about them. Unfortunately, the NIST’s global collapse analysis is so highly technical as to be almost incomprehensible to a non programmer. I was struck by the number of assumptions it makes, one piled on another.
In order to show just how weak the official 9/11 narrative is, let us assume, for the sake of argument, that local fires did burn long and hot enough to weaken exposed columns in the impact zone of WTC 2. As I will now show, even if this did occur it still fails to account for the global collapse of the second tower. As the NIST report states,
both towers had considerable reserve capacity. This was confirmed by analysis of the post-impact vibration of WTC 2, the more severely damaged building, where the damaged tower oscillated at a period nearly equal to the first mode period calculated for the undamaged structure.[my emphasis]
The data showed that WTC 2, the more seriously damaged tower, gave no hint of instability after the initial impact. Unfortunately, although the NIST summary report provides a wealth of information it fails to clarify this important matter of the WTC’s “considerable reserve capacity.” I scoured the full summary report, as well as the preliminary 2004 report–––in vain–––for any discussion of the issue. I then called the NIST for assistance and was guided to several of the project reports and supplementary documents. I also consulted with experts at the International Code Council (ICC) and with a leading structural engineer. I learned that estimating the overall reserve capacity of a steel structure is no simple task. Numerous factors are involved. Moreover, there are different ways to approach the problem.
Perhaps the simplest measure of reserve capacity are the standards for the material components of a building. In the late 1960s when the WTC was constructed the applicable standard was the New York City Building Code, which required a builder to execute computations for the various structural members to show that they met the specified requirements. However, the code also allowed for actual testing of members, in the event that computations were impractical. The testing standards applicable in 1968 give a good idea of the required level of reserve strength in the steel columns and other materials used in the WTC. For example, in the most stringent test a steel member had to withstand 250% of the design load, plus half again its own weight, for a period of a week, without collapse.
Another widely used measure of reserve capacity is the so called “factor of safety.” This varies for different structural elements, but for steel columns and beams typically ranges from 1.75-2.0. The NIST report actually breaks this more general figure down into two separate and slightly different measurements for stress: yielding strength (1.67) and buckling (1.92). For our purposes, however, the more general figure is adequate. So, for example, a steel column with a factor of safety of 1.75 must support 1.75 times the anticipated design load before it begins to incur damage. While this value is typical of steel beams in general, the actual reserve strength of the steel columns in the WTC was higher. When the NIST crunched the numbers for the 47 core columns of WTC 1 (between the 93rd and 98th floors) it found that the factor of safety ranged from 1.6 to 2.8, the average value being 2.1. This means that the average core column in WTC 1 could support more than twice its design load before reaching the yield strength, i.e., the point where damage may begin to occur.
Notice, the factor of safety is not a threshold for collapse, but a value beyond which permanent damage may occur. As the NIST report states, even “after reaching the yield strength, structural steel components continue to possess considerable reserve capacity.” This is why steel beams and columns do not typically fail in sudden fashion. The loss of strength is gradual. No doubt, this helps to explain why, although fires have ravaged many steel frame buildings over history, not a one had ever collapsed–––until 9/11–––nor has any since. So we see–––it should be obvious–––that even in the highly improbable worst case, in which many of the WTC columns lost half of their strength, there was still plenty of reserve capacity to support the building.
With regard to the WTC’s perimeter columns, the factor of safety varied from day to day and even from hour to hour, because, in addition to supporting about half of the WTC’s gravity load, the perimeter wall had to withstand the force of wind–––which is highly variable given the whims of Mother Nature. A single face of the WTC presented an enormous “sail” to the elements, which is why John Shilling vastly overbuilt this part of the structure. According to the NIST report, the wall’s factor of safety against wind shear on 9/11 was extremely high, i.e., 10-11. Why so high? The reason is simple: On the day of the attack there was almost no wind. As a result, nearly all of the perimeter wall’s design capacity was available to help support the gravity load. As the NIST report states, “On September 11, 2001 the wind loads were minimal, thus providing significantly more reserve for the exterior walls.” Of course, because wind is mostly a lateral force the additional capacity that was available to help support the gravity load was less than one-to-one. When the NIST crunched the numbers for a representative perimeter column in WTC 1 (column 151 — between the 93rd and 98th floors), they arrived at a factor of safety of 5.7. If we take this average figure as a typical value we arrive at an accurate estimate of the perimeter wall’s amazing reserve strength. Even if we subtract the columns severed/damaged by the impact of Flight 175, and the lost capacity due to buckling along one perimeter wall, there was still a wide margin of safety–––more than enough by several times over to support half of the structure’s gravity load, which overall did not change. Of course, the wrecked jetliner added substantial mass. On the other hand, due to the successful evacuation of people the live load, i.e., the total body mass of the occupants, was reduced by 75%.
I have just shown that the NIST’s own data casts grave doubt on its conclusions about the cause of the global collapse of WTC 2. The official theory requires the fatal weakening of both sets of columns: at the core and along the perimeter wall–––and falls short on both counts, due to insufficient evidence. Indeed, I would go further and call the evidence woefully insufficient.
As mentioned, fires have ravaged many steel frame structures in the past–––and in some cases these fires were much more severe than on 9/11. Even so, not a one of them produced a global collapse. Let us briefly consider one example. In February 2005, the 32-story Edificio Windsor in Madrid was destroyed by a disastrous fire that burned out of control for 18-20 hours–––notice–––much longer than the WTC fire on 9/11. The Edificio Windsor was a ferro-concrete structure, thus, was different in design, but it had a perimeter of steel columns and floors supported by steel beams. The blaze started on the 21st floor, spread to the entire building, and left the superstructure gutted. The Windsor was in compliance with the Spanish building code when constructed in the 1970s, but the code in those days did not require fireproofing. In fact, at the time of the disaster the building’s steel beams and columns were being retrofitted with fireproofing insulation. However, only the bottom 17 floors had been completed. At the time of the blaze the upper 15 floors had no fire protection whatsoever. According to Javier Sanz, the Madrid fire chief, the fire reached temperatures of 800°C (1,472°F)–––sufficient to collapse the upper concrete floors. Numerous steel beams also sagged and columns buckled. But the overall superstructure, which was largely unprotected, never collapsed. The steel framework withstood the disaster, though gravely weakened. By contrast, most of the WTC’s massive central piers and perimeter columns were never even touched by the fires of 9/11, which were confined to a few upper floors.
There are good reasons why fire-ravaged steel buildings typically do not collapse. In a series of fire tests completed in 1996 at the Cardington Lab in the UK the Building Research Establishment (BRE) showed that even unprotected steel frame buildings have large reserves of stability during extreme fire events. In physical tests lasting 2-4 hours–––considerably longer than the fires of 9/11–––lab scientists subjected steel beams, columns and composite steel/concrete floors to fires that at times exceeded 1,000°C. In test after test the unprotected steel beams or columns bowed, buckled and sagged, but not a one of them collapsed. The tests demonstrated that steel buildings are more than the sum of their parts. The lab found that fire resistance is not only a property of individual members, but of the interconnected structure as a whole: For most of the duration of exposure thermal expansion and warping–––and not material degradation–––governed the steel’s response to heat. The Cardington fire tests had relevance to the WTC collapse. The results were readily available and might have informed the NIST investigation. But to the best of my knowledge NIST scientists never considered the Cardington lab test data.
The Cardington fire tests help to explain why no steel frame structures had collapsed, before 9/11–––nor since. Yet, we are expected to believe such a scenario unfolded three times on a single day. I say “three times” because, notice, I have not even discussed the case of WTC 7, which was not hit by a plane, hence, had no spillage of jet fuel, and suffered only some exterior damage and minor fires. Yet, at 5:20 PM on the afternoon of 9/11 the building suddenly collapsed in the manner of a controlled demolition. The video of this, captured on film for the world to see, clearly shows that the 47-story steel-frame structure dropped from the bottom up, into its own footprint. The collapse has never been explained, certainly not by the NIST, which has yet to release a final report about WTC 7.
In conclusion, my reading of the NIST report left me slightly agog, in a state of mild shock at the disparity between the NIST’s research and its conclusions. I agree with whistleblower Kevin Ryan that the report simply does not add up. Notice, this brings us back to the beginning–––hopefully a little wiser. I hereby join with Kevin Ryan, Dr. Steven Jones, and others who have called for a NEW and truly independent 9/11 investigation, one empowered with the necessary resources and with subpoena authority. It’s the only way we will ever finally answer the important question: Why did the WTC collapse? Only the truth about 9/11 can free us from the current tyranny of secrecy, lies and deceit which today is a far greater threat to our liberty than any foreign enemy.
Notes 52. NIST NCSTAR 1, Executive Summary, p. xlvi. Dead on Arrival: The NIST Report Part I
53. NIST NCSTAR 1, WTC Investigation, p. 141.
54. NIST NCSTAR 1, WTC Investigation, p. 67.
55. NIST NCSTAR 1, WTC Investigation, p. 67.
56. NIST NCSTAR 1, WRC Investigation p. 130.
57. NIST NCSTAR 1, WTC Investigation p. 88.
58. NIST NCSTAR 1, WTC Investigation p. 176.
59. Andy Field, “A Look Inside a Radical new Theory of the WTC Collapse,” Fire/Rescue News, February 7, 2004. Sunder made a similar statement during an October 19, 2004 presentation. See “World Trade Center Investigation Status,” S. Shyam Sunder, lead investigator, Building and Fire Research Laboratory, NIST. This paper can be downloaded as a pdf file at http://www.nist.gov/public_affairs/agenda_oct192004.htm
60. The NIST makes this important point in two seperate places in the text. NIST NCSTAR 1-5, WTC Investigation, pp. 49 and 51.
61. NIST NCSTAR 1, WTC Investigation p. 127.
62. NIST NCSTAR 1-6, WTC Investigation, p. lxvix.
63. NIST NCSTAR 1-2, WTC Investigation, Executive Summary, p. xli.
64. NIST NCSTAR 1-5, WTC Investigation, p. xliv.
65. NIST NCSTAR 1, WTC Investigation, p. 126-127.
66. NIST NCSTAR 1-5, WTC Investigation, p. 121.
67. NIST NCSTAR 1-6, WTC Investigation, p. lxvix; also see NIST NCSTAR 1-5, WTC Investigation, p. 51.
68. Jim Dwyer and Ksvin Flynn, 102 Minutes: The Untold Story of the Fight to Survive Inside the Twin Towers, Times Books, 2005, p. 206; also see Jim Dwyer and Ford fessenden, “Lost Voices of Firefighters, Some on 78th Floor,” New York Times, August 4, 2002; Christopher Bollyn, “Feds Withhold Crucial WTC Evidence,” American Free Press, August 8, 2002.
69. NIST NCSTAR 1-2, WTC Investigation, p. 5.
70. NIST NCSTAR 1-3, WTC Investigation, p. 95.
71. NIST NCSTAR 1, WTC Investigation, p. 43.
72. NIST NCSTAR 1, WTC Investigation p. 144.
73. In the code his was sub-article 1002.0, adequacy of the structural design. See NIST NCSTAR 1-1A, WTC Investigation, p. 32.
74. Conversation with Ron Hamburger, structural engineer, Dec 7, 2006.
75. NIST NCSTAR 1-2, WTC Investigation, p. 66.
76. My thanks to the NIST WTC Investigative Team for helping me to understand the numbers. Although the calculations are expressed as demand/capacity ratios in the NIST report, this easily translates into a value, i.e., factor of safety, which is more comprehensible to the average lay person, which is why I’m stayed with factor of safety. Personal communication, December 14, 2006. See NIST NCSTAR WTC Investigation 1-6, Figure 8-9, p. 233.
77. NIST NCSTAR 1-2, WTC Investigation, p. 66.
78. NIST NCSTAR 1-2, WTC Investigation, p. cxii; also see NIST NCSTAR
1-2, WTC Investigation, p. 84.
79. The NIST report states: “on the day of the attack the towers were subjected to in-service live loads (a fraction of the design live loads) and minimal wind loads.” NIST NCSTAR 1-2 WTC Investigation, p. liv.
80. NIST NCSTAR 1-2, WTC Investigation, p. 66.
81. I received clarification about this from the NIST WTC Investigation Team. Personal communication, December 14, 2006. The number 5.7 is derived from values presented in Figure 4-35, NIST NCSTAR 1-6, WTC Investigation, p. 101.
82. NIST NCSTAR 1-2, WTC Investigation, p. 66.
83. Al Goodman, “The Windsor Tower Fire, Madrid,” posted at
84. Kevin Ryan, a site manager for Underwriter Labs, was terminated after publicly questioning the conclusions of the NIST report.
52. NIST NCSTAR 1, Executive Summary, p. xlvi.
Dead on Arrival: The NIST Report Part I