from here on January 05, 2008
The NIST Report
on the World Trade Center Collapse one year later:
Still Dead On
note to the reader: In December 2006 Mark H. Gaffney posted a scathing
critique of the US government’s official report about the WTC collapse on
9/11. One year later, the case is stronger than ever.
" -- - -In August 2002 the US Congress authorized the
National Institute for Safety and Transportation (NIST) to investigate the
collapse of the World Trade Center on 9/11. The official instruction was not
limited to conducting a building performance study, as some have
claimed. The primary stated objective of the investigation was to determine
the cause of the collapse–––no less.
When NIST released its
final report in September 2005, critics charged that the agency had ignored
evidence of explosions in the towers. The agency responded by asserting its
scientific laurels. NIST insisted that its “200 technical experts” had
conducted “an extremely thorough investigation.” NIST boasted that its staff
“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,” yet, found “no corroborating evidence for
a controlled demolition.” NIST also claimed that it had considered “a number
of hypotheses for the collapse of the towers.”
No doubt, many Americans
were persuaded by this snow-job. Sad to say, few of our countrymen (or women)
bother to read official reports, especially when they run to 10,000 pages. The
persistent individuals who do, however, know that there are sound reasons to
question all of the above; because a close reading of the NIST report shows
that the agency assumed from the beginning that the Boeing 767 impacts and
subsequent fires were responsible for the collapse of the twin towers. The
report gives no consideration whatsoever to alternative hypotheses, including
the possible use of explosives, the leading candidate. Far from exploring
other scenarios, NIST simply took it for granted that the impacts set in
motion a chain of events leading to a catastrophic structural failure. Working
backwards, NIST scientists searched for evidence that supported their
predetermined conclusion. Everything else was ignored or excluded. If it is
not already evident to the reader, this is no way to conduct a scientific
investigation. NIST then had the audacity to imply that it arrived at its
favored collapse model through an exhaustive process of elimination. Most
readers who merely browsed NIST’s 2005 Executive Summary probably were not
aware that NIST’s stated conclusion was really an assumption. Consider
this passage, for example:
“The tragic consequences
of the September 11, 2001 attacks were directly attributable to the fact that
terrorists flew large jet-fuel laden commercial airliners into the WTC towers.
Buildings for use by the general population are not designed to withstand
attacks of such severity; building codes do not require building designs to
consider aircraft impact.”
The above comment about
building codes is deceptive–––NIST readily concedes in its report that the
towers survived the initial impacts. In fact, John Skilling, the structural
engineer who designed the WTC, always claimed that they would. The towers
survived, despite serious damage, because they were hugely overbuilt,
redundant by design. Although the WTC’s soaring lines gave the impression of a
relatively light frame, in fact, the twin towers were extremely rugged
buildings, engineered to withstand hurricane-force winds and even a direct hit
by a Boeing 707, the largest commercial jetliner of the day. Some have argued
that the newer Boeing 767s caused much more damage because of their larger
size, but in fact, the two Boeings are comparable. Although slightly smaller,
the 707 has a greater cruise speed of 600 mph (as compared with 530 mph for a
Boeing 767). Assuming both were to crash at this speed, the 707 would actually
have greater kinetic energy.
After the Boeing 767
impacts on 9/11 the severed steel columns simply transferred the weight of the
building to other undamaged columns. The NIST report even states that the
towers would probably have stood indefinitely, if the impacts had not
dislodged the fireproofing material that protected the steel from
fire-generated heat. Construction-grade steel begins to lose strength at
425°C (~800°F) and is only about half as strong at 650°C (1,202°F). NIST
argues in its report that the crashed jetliners damaged or dislodged 100% of
the protective insulation within the impact zone, while also spilling many
thousands of gallons of jet fuel over multiple floors. The resulting
800-1,000°C (1,440-1,800°F ) blaze–––the report claims–––seriously weakened
the now-exposed steel, leading to a global structural failure. In order to
understand the official story, however, and why it fails to explain the WTC
collapse, it is necessary to know more about the World Trade Center and how it
Upon its completion in
1970 the north tower of the Trade Center soared 1,368 feet tall–––100 feet
higher than the Empire State Building. In addition to being the world’s
tallest skyscraper, it was a state-of-the-art achievement of high-rise
construction. Designed by architect Minoru Yamasaki, the WTC was one of the
first skyscrapers to feature large expanses of unobstructed floor space within
a steel-frame building. Although commonplace today, this was a novel idea in
the 1960s, as it required doing away with the forest of columns so typical of
the skyscrapers of former years. Chief engineer John Skilling achieved the
objective of open space with a double support system: the first so-called
tubular design, consisting of a dense array of 240 columns around the outer
wall or perimeter, and a network of 47 huge columns at the core. The core
columns supported about 53% of the weight of each building, and were massive,
up to 52 inches wide. The steel in these monster columns was seven inches
thick at the base.
The core columns were of
two types: box columns at the foot of the buildings, gradually transitioning
to rolled wide-flange beams (“I” beams) higher up. The core of each tower,
including the elevators and stairwells. was surrounded by expansive office
space. The perimeter wall supported 47% of the weight and also resisted the
force of the wind. These exterior columns were reinforced with broad steel
plates known as “spandrels,” which girdled the building, like ribs, at every
floor. Although the core columns gradually increased in size from top to
bottom, for aesthetic reasons the external dimensions of the perimeter columns
had to be the same all the way down, hence, required the use of heat-treated
steel. For this reason Skilling’s new tubular concept only became possible
with the introduction of high-strength steels in the 1960s. Prefabrication and
a modular design were other innovations that kept costs down and allowed for
Both inner and outer
sets of columns were joined together by an innovative system of lightweight
steel trusses. Each floor consisted of a truss assembly, over which was laid a
corrugated steel deck–––the bed for a poured four-inch slab of concrete.
Although lightweight, the floor design was so sound that it easily supported
the weight of libraries, file rooms, and heavy safes without the need for
additional strengthening. The lightweight truss assemblies
were vulnerable to fire damage, however, because they consisted of rather thin
steel members. For this reason, at the time of construction the trusses were
spray-coated with protective insulation, 0.75 inch thick, and this was later
upgraded to an average thickness of more than two inches. (The technical
term for this insulation is Spray-applied Fire Resistant Material = SFRM) The
core columns had a fire-barrier of gypsum wallboard.
argues that the Boeing impacts jarred loose this protective insulation from
the steel trusses and columns. The subsequent fires then weakened the exposed
trusses, causing them to sag. This, in turn, pulled the perimeter columns
inward. The fires also weakened both sets of columns and at a critical point
the perimeter wall buckled.
NIST makes the claim that its investigation showed conclusively that the
initiation occurred in the perimeter wall, triggering a global
collapse. Did the agency prove its case? In a moment I will explore this
question. Before I do, however, it is important to understand what NIST did
What NIST failed to
Despite its broad charge
to investigate the WTC collapse, NIST limited the scope of its investigation
to the sequence of events from the first plane impacts to the onset of
collapse. This means, of course, that NIST failed to study the collapse
itself. This narrow focus–––some would call it sleight-of-hand–––allowed NIST
to side-step a number of important issues. No doubt, this was the intent,
since investigating them would surely have led NIST scientists to very
different conclusions. The first and foremost of these issues was the near
free-fall speed of the collapse. Videos filmed on 9/11 confirm that the towers
plummeted as if there was no resistance whatsoever. But how can this be, given
the enormous inertial mass of the building itself, which should have resisted
and slowed the fall considerably? Even if we assume that the columns in the
impact zone failed, the rest of the columns in the towers were untouched by
the plane impacts and fires, therefor, suffered no loss of strength. These
stone-cold columns should have resisted the fall. Although the exact time of
the collapse of WTC 1 and 2 cannot be determined with precision because of the
growing dust cloud, each collapse took approximately 10-12 seconds, only 1-2
seconds slower than the time for a billiard ball to free-fall from the WTC
roof to the plaza. But how can this be? By what special dispensation did the
collapsing WTC violate the laws of physics? The reader will search the NIST
report in vain for any discussion of this important anomaly. Why not?
Obviously. because agency officials made a political decision not to go there.
No less puzzling was the
fact that the collapses were total and nearly symmetrical. This means, of
course, that when the collapses began all of the columns on that floor failed
at precisely the same moment. But, again, how could this happen? Even if we
assume that the plane impacts severed or damaged a number of columns in the
impact zone, and even if we also assume that the fires weakened a number of
other nearby columns, the majority of columns in the buildings and even on the
affected floors were still at full strength at the moment of collapse. The
collapses were also total. The rubble from the buildings fell through the
plaza level and piled up in the basements. Photos by Joel Meyerowitz and
others show that the piles of wreckage were about six stories high, as
evidenced by surviving portions of the perimeter wall. The wreckage reached
the level of the column tree–––a convenient reference point–––where the larger
exterior columns around the base divided into three smaller columns above. The
totality of the collapse is hard to explain because, as noted, the largest and
strongest columns were in the lower part of the buildings. The towers
encountered increasing mass, i.e., resistance, as they fell. For this reason,
at least one engineer has argued that the WTC collapse should at some point
have self-arrested. Other experts hotly dispute this, however, and the
matter remains controversial. Engineers clearly are fascinated by this
question. Although a more detailed discussion is beyond the scope of this
article, it is evident that media coverage has often served to confuse the
issue rather than clarify. In a recent 9/11 documentary on the History
Channel, for example, a debunker glibly described the events at Ground
Zero as a “classic progressive collapse,” as if this were a well-known or
frequent phenomenon. But this is plainly false. As noted–––and I must
emphasize it again–––no steel-frame skyscraper had ever collapsed before 9/11,
nor has any since.
By the way, there is an
excellent reason why they do not fall down. Structural steel happens to be an
extremely tough and forgiving substance–––the reason it is the pre-eminent
building material used in high-rise construction. As the 9/11 Commission
Report concedes, none of the NYFD chiefs anticipated a catastrophic
structural failure on 9/11, despite the fires and impacts. Had they
believed a general collapse was possible, the chiefs would not have
established their emergency command posts in the lobbies of the stricken
towers. Nor would they have ordered hundreds of New York City firemen to begin
the long climb up the stairwells to aid the victims and assist with the
evacuation. As we know, 343 of them perished. According to the official
report, at least one of the fire chiefs did express concern about the danger
of a partial collapse on the upper floors. No doubt, this individual was
as shocked as everyone else by the totality and near-perfect symmetry of the
collapses that ensued–––both standard features of controlled demolitions and
virtually unknown in random fire events. After I posted a critique of the NIST
report in December 2006, I received a letter from a retired fireman who
informed me that over the course of his twenty-odd years of service he had
fought many types of fires, involving residential, commercial and industrial
structures, including high-rise buildings. He explained that on a number of
occasions, when his crew lost the battle to save a structure “some of the
times the building would collapse…. in a random, haphazard, piecemeal fashion.
Not once,” he wrote, “did I personally witness one of those structures
collapsing in the rather controlled...fashion as the WTC towers and Building
Another anomaly was the
pulverization of material. Through history, concrete buildings have been known
to collapse during powerful earthquakes, and when this occurs they typically
fold up like an accordion, leaving a succession of concrete slabs, one piled
on top of another, each plainly discernible in the rubble. But nothing like
this occurred on 9/11. Photos of the mountain of wreckage at Ground Zero show
very few, if any, large chunks of concrete. The rubble pile consisted almost
exclusively of twisted steel. The conspicuous absence of concrete is
remarkable, since concrete was the main constituent of the 500,000 ton towers.
As noted, each floor of the 110-story building, roughly an acre in size,
consisted of a slab of poured concrete, most of which was pulverized during
the collapse into small pieces and fine dust. Some have attributed this to the
force of gravity, but videos of the collapse dispute this. The buildings were
not pulverized as they hit the ground, they disintegrated in midair. As the
south tower started to collapse, for example, the entire upper section tipped
as a unit, then inexplicably turned to dust before our eyes. Much of this dust
settled a foot deep on the sixteen-acre WTC site. The rest was deposited
across lower Manhattan. Nor was the pulverization limited to concrete. Other
construction materials also disappeared without a trace, including glass,
office furniture and tens of thousands of computers, not to mention the many
victims. It’s a fact that less than 300 corpses were recovered. Most of the
victims were identified solely from body parts. Strangely, when workmen began
to dismantle the badly damaged Deutsch Bank on December 8, 2006, they found
more than 700 slivers of bone on the roof and within the structure. This
bizarre report has never been explained.
And there were other
anomalies. The video record plainly shows that during the WTC collapse,
perimeter columns weighing twenty tons or more were hurled as far as 500-600
feet from the towers. One remarkable photo of Ground Zero taken from above
shows that entire sections of WTC-1’s western perimeter wall were thrown 500+
feet toward the Winter Garden. Could a gravitational collapse do this?
Doubtful. The NIST report not only fails to address any of these issues, it
doesn’t even try. The report makes reference to the “global collapse” of
the towers, but we never learn precisely what this means because NIST never
informs us. By limiting the scope of its inquiry NIST rendered the truth
unobtainable–––an effective way to neuter an investigation.
With all of this in
mind, let us now explore what NIST did investigate.
The Special Projects
The NIST investigation
was comprised of eight separate projects, which all together produced 43
volumes of supporting documentation. The projects included metallurgical
studies, an impact analysis, an attempt to reconstruct the fires, and a
computer model of the probable sequence of events leading to the collapse of
each tower. Some of the agency’s research was of excellent quality–––some was
not. But the main problem is that none of it lends credence to NIST’s official
Probably the most
serious obstacle NIST investigators faced was a lack of information about the
dynamic conditions that existed in the core of the towers on 9/11. To be
sure, thousands of photographs and hundreds of hours of videotape made it
possible to study in detail the damage to the WTC exterior, and to gain a
reasonable understanding about conditions in the outer offices. Fires were
often visible through the windows, despite dense smoke, and structural damage
in the impact zone, such as collapsed floors, was also discernible. However,
as the NIST report states, “Fires deeper than a few meters inside the building
could not be seen because of the smoke obscuration [sic] and the steep viewing
angle of nearly all the photographs.” This is an important admission, and
one that NIST repeats a number of times. For example, in one of the
supplementary documents NIST scientists qualify their analysis of the effects
of the fire upon the steel with the following caveat:
“As conditions within
the building core could not be determined from the photographic database, it
was unknown what environment the recovered core columns may have
As we will see, this
candid statement haunts the entire report. In fact, the only physical evidence
NIST had about the actual conditions at the core was the data it was able to
glean from 236 steel columns, panels, trusses, and other smaller samples
recovered from the WTC ruin. Metallurgical testing of these steel samples
was probably the most important work NIST carried out, because this was the
foundation for the rest of the investigation.
Thanks to the original
labeling system used during the construction of the WTC, NIST was able to
identify many of the samples it had gathered, and to determine with precision
their locations in the WTC. As it happened, a number of the columns were from
the impact and fire zones. Although the collection represented only 0.25 -
0.5 % of the 180,000 total tons of structural steel used in the two towers,
NIST scientists believed their sampling was adequate to determine the quality
of the steel and to evaluate its performance on 911.
findings decisively refuted the pancake theory of collapse widely reported in
the media after 9/11. The pancake enthusiasts had argued that the weak link in
the WTC was the point of attachment where the trusses connected with the inner
and outer columns. These junctions, referred to as angle-clips, were made of
relatively lightweight steel and were secured by steel bolts. During a 2002
NOVA television special MIT engineer Thomas Eagar explained the pancake model
and why in his opinion the trusses had failed:
“...the steel had plenty
of strength, until it reached temperatures of 1,100º to 1,300ºF. In this
range, the steel started losing a lot of strength, and the bending became
greater. Eventually the steel lost 80 percent of its strength, because of this
fire that consumed the whole floor....then you got this domino effect. Once
you started to get angle-clips to fail in one area, it put extra load on other
angle-clips, and then it unzipped around the building on that floor in a
matter of seconds. If you look at the whole structure, they are the smallest
piece of steel. As everything begins to distort, the smallest piece is going
to become the weak link in the chain. They were plenty strong for holding up
one truss, but when you lost several trusses, the trusses adjacent to those
had to hold two or three times what they were expected to hold.”
According to the pancake
theory, when one floor collapsed it set in motion a chain reaction. Although
this initially seemed plausible, it turned out that Eager seriously
underestimated the robustness of the World Trade Center. The earlier FEMA
study found no indication of substandard materials or construction. On the
contrary, FEMA found that “many structural and fire protection features of the
design and construction were….superior to the minimum code
requirements.” The NIST investigation bore this out. For example, NIST
confirmed that the truss assemblies were not only bolted to the outer
perimeter wall, they were also welded, hence, were considerably
stronger than expected–––not prone to pancaking. Nor could the pancake
model explain the failure of the core columns.
The WTC steel turned out
to be significantly stronger than expected. Tests showed that the yield
strengths of 87% of all steel tested exceeded the original specifications. For
instance, the perimeter columns exceeded their specifications by more than
10%. The strength of the steel in the truss assemblies was also much higher
than required. In many of the trusses, 50 ksi steel was used, even though the
specifications called for only 36 ksi.” (1 ksi = 1,000 lb/per square inch)
NIST also tested a number of recovered bolts, and found that these too were
stronger than expected, based on reports from the contemporaneous
literature. While all of these findings refuted the pancake theory,
notice, they also failed to support NIST’s own preferred collapse model. One
need not be a rocket scientist to see that the stronger the steel the less
likely it was to fail on 9/11.
The Fire Tests:
In another series of
tests NIST sought to address the alleged weakening of the WTC support columns.
During a first-run, investigators placed an uninsulated steel column in a
furnace where temperatures reached 1,100ºC (2,012ºF). During the test the
surface temperature of the exposed column reached 600ºC in just 13
minutes–––the temperature range where significant loss of strength occurs.
When the test was repeated with a column treated with SFRM insulation, the
steel did not reach 600ºC even after ten hours. NIST concluded that “the fires
in WTC-1 and WTC-2 would not be able to significantly
weaken….insulated.…columns within the 102 minutes and 56 minutes,
respectively, after impact and prior to collapse.” NIST interpreted these
results as validating its theory that the critical factor on 9/11 leading to
the global failure was the damage to and removal of the SFRM fireproofing
insulation caused by the Boeing 767 impacts. But was this an unwarranted leap?
Let us now explore this question.
developed a novel way to evaluate the impact of the fire on the WTC steel.
According to the report, the approach was “easy to implement and robust enough
to examine the entire component in the field.” They found that the
original primer paint used on the steel beams and columns was altered by high
heat. This made it possible to determine the level of exposure by analyzing
the paint on the samples. But the results were surprising. NIST found no
evidence that any of the steel samples, including those from the impact areas
and fire-damaged floors, had reached temperatures exceeding 1,110ºF
(600ºC). Sixteen recovered perimeter columns showed evidence of having
been exposed to fire, but even so, out of 170 areas examined on these columns
only three locations had reached temperatures in excess of 250ºC
(450ºF). Moreover, NIST found no evidence that any of the recovered core
columns had reached even this minimal temperature. The startling fact is
that NIST’s own data failed to support its conclusion that the fires of 9/11
heated up the steel columns, causing them to weaken and buckle.
How might we explain
this absence of evidence? Shyam Sunder, NIST’s lead scientist, probably
offered a partial answer when he admitted that “the jet fuel....burned out in
less than ten minutes.” Also, the actual amount of combustibles in the WTC
turned out to be less than expected–––considerably less. In its 2002 report
FEMA had noted that
“fuel loads in
office-type occupancies typically range from about 4-12 psf [pounds per square
foot], with the mean slightly less than 8 psf….At the burning rate necessary
to yield these fires, a fuel load of about 5 psf would be required to maintain
the fire at full force for an hour...”
Yet, when NIST
scientists crunched the numbers they found that a typical floor of the WTC did
not even have this minimum level of combustibles. The average was only about 4
psf. The shocking fact is that the twin towers were fuel-poor, compared
with other office buildings: a finding, notice, that does not support the
frequent depictions in the media of a ferocious inferno raging beyond anything
in human experience. More importantly, neither does it support NIST’s favored
collapse scenario. The spillage of jet fuel ignited the combustibles,
spreading the fires at a faster rate than would otherwise have occurred. Yet,
for this same reason the fires also burned out sooner, because the fuel load
was so low. Indeed, NIST scientists estimated that on average the WTC fires
burned through the available combustibles at maximum temperatures (1,000ºC) in
only about 15-20 minutes. After which, the fires began to subside. To make
matters worse for the official collapse theory, NIST also found that “the fuel
loading in the core areas....was negligible.” It’s easy to understand why
all of these facts are downplayed in the NIST summary report. Taken together,
they are fatal to NIST’s collapse model, which requires that high temperatures
be sustained. Fires that subside after only 15-20 minutes simply cannot weaken
enormous steel columns and cause them to buckle.
I searched the NIST
report in vain for any acknowledgment that the fire conditions in the
laboratory furnace were substantially different from the actual conditions on
9/11. This fact, which is undeniable, calls into question NIST’s conclusion
that damaged SFRM insulation was the critical factor. Although NIST took the
position that “temperatures and stresses were high in the core area,” on
what basis did they reach this conclusion? As I’ve noted, NIST suffered from a
persistent lack of information about the actual conditions in the core of the
Surely, it is safe to
conclude that the crashed Boeing 767s damaged and/or stripped away a
substantial portion of the protective SFRM insulation from the steel beams and
trusses in the impact zone. Exactly how much is not knowable. NIST
acknowledges in its report that it had no hard evidence about the amount of
protective insulation damaged or dislodged during the
impacts. Incredibly, however, the agency then assumes that all structural
members in the debris path at the time of impact suffered 100% loss of
The only physical
evidence NIST presents in its report in support of this conclusion is a series
of photos of the exterior of the towers. The photos do show that within
the impact zone much of the SFRM foam insulation is indeed missing from the
perimeter columns. In places the original anti-rust paint is clearly
visible on the exposed columns, indicating that the insulation is gone from
these areas. NIST is also probably correct that the loss occurred during the
impacts. But it does not follow on this basis that all of the
insulation in the impact zone was similarly lost. In fact, not only does the
photographic evidence in the report not prove this, the photos show
decisively that at least some of the insulation remained in place. NIST even
acknowledges this in its discussion of the photos. The report states, for
example, that one photo “shows the absence of at least some, if not most SFRM
from the center region of the outer web of the column.” Here, “the absence of
at least some” of the insulation can only mean that some of it also remained
in place. The next passage goes on to describe one column in the same area on
which the SFRM was “nearly intact.” In another section the report
explicitly mentions that some of the insulation had apparently been treated
with a special sealant, which “prevented the loss of SFRM in a great many
locations where the SFRM was knocked off both above and below this
location.” In short, NIST flatly contradicts itself regarding the
disposition of the SFRM; and this is crucial because it means NIST’s own data
fails to support its conclusions.
For the sake of
argument, however, let us for the moment ignore this glaring problem and
assume that NIST’s estimated total loss of SFRM was correct. As I will now
show, even in this worst case scenario there is virtually no chance that the
fires on 9/11 weakened the WTC’s core and perimeter columns within the
allotted span of time.
A Vast Heat Sink
The reason is
acknowledged nowhere in the NIST report, but ought to be self-evident. The
WTC’s support columns did not exist in isolation. The WTC was no laboratory
furnace. The columns in each tower were part of an interconnected steel
framework that weighed some 90,000 tons; and because steel is known to be at
least a fair conductor of heat, on 9/11 this massive steel superstructure
functioned 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 much of the fire-generated heat. 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 draws the solder into the fitting. While it is true
that copper is several times more conductive than steel, the fact that only
three 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 relatively
brief allotted span of 56/102 minutes, respectively, to slowly raise the
temperature of the steel framework as a whole to the point of weakening even a
few 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 such was not the case on 9/11. As I’ve already noted, NIST found that the
unexpectedly light fuel load in any given area of the WTC was mostly consumed
in about 15-20 minutes. At no time on 9/11 did the fires rage through an
entire floor of the WTC–––as Thomas Eagar implied in his interview. The fires
were not sustained, on the contrary, they were transient. This was
especially true in WTC-1. The fires 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 also means: As the fires moved away from the impact zone into areas with
little or no damage to the SFRM fireproofing, the heating of the steel columns
and trusses in those areas would have been inconsequential. The NIST’s own
data showed that, overall, the fires on floor 96–––where the collapse
supposedly 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 correct,
the central piers at that point were not losing strength but regaining
it. How, then, did they collapse? Moreover, NIST’s assertion that
“temperatures and stresses were high in the core area” is not supported by its
finding that the fuel load in the core was negligible. On this point NIST
again contradicts itself. For all of these reasons, NIST fails to explain in
its report how transient fires weakened WTC-1’s enormous core columns and
perimeter columns in the allotted span, triggering a global collapse.
The Fires in the South
NIST determined that the
fire behavior in the south tower was substantially different: more continuous
rather than transient, at least, on the east side of the building where the
remains of Flight 175 supposedly came to rest. This, in addition to more
extensive impact damage, NIST informs us, explains why WTC-2 collapsed first,
even though it was hit after WTC-1. It is now known, however, that NIST
ignored important evidence that calls into question its assertion that fires
were gravely weakening the core of WTC-2. An audio-tape released in August
2002 by the Port Authority of New York, which apparently was lost or neglected
for more than a year, is the only known recording of firefighters inside the
towers. When city fire officials belatedly listened to it they were surprised
to discover that two NYC firemen actually reached the impact/fire zone of the
south tower about fourteen minutes before it collapsed. The long climb up the
stairs was so arduous that most of the NYC firemen, heavily burdened with
equipment, were exhausted before they reached the 20th floor. However, these
two, Battalion Chief Orlo J. Palmer and Fire Marshall Ronald P. Bucca, were in
excellent physical condition. Palmer, reportedly, was a marathon runner. On
reaching the 78th floor sky lobby they found many dead or seriously injured
people; but no raging inferno. Palmer’s radio exchange with another fireman
shows no hint of panic or fear, as the following transcript shows:
Battalion Seven Chief
(Palmer): "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 firefighters Adam stairway to knock down two
fires. We have a house line stretched we could use some water on it, knock it
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."
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."
"Alright, I'm on my way up, Orlo."
Here, Battalion Chief
Palmer calls for more men and water to put out the isolated fires. His
expression “10-45 Code Ones” refers to dead bodies, of which apparently there
were many. The tape shows that the two firemen were not turned back by heat,
smoke, or a wall of flames. They were able to function within the fire zone
and were prepared to help the injured and combat the few isolated fires they
found. Palmer even mentions that the stairway up to the next level, i.e.,
floor 79, was passable. Minutes later the building came down on their heads.
NIST knew about this
testimony. The NIST report briefly mentions that firemen reached the 78th
floor of WTC-2. Inexplicably, however, the matter is simply dropped, as if
it had no bearing on the status of the fire in the core. The omission is
conspicuous, because, as I’ve stressed, NIST suffered from a persistent lack
of information about the dynamic conditions in the interior of the
buildings. Here was a real-time eyewitness account by trained
professionals who were on the scene. Yet, NIST ignored it. Why? Well,
obviously, because their testimony does not support the official story.
Curiously, the 9/11 Commission Report also briefly mentions this
episode, but, likewise, fails to discuss its possible significance, no doubt,
for the same reason.
According to NIST, the
78th floor of WTC-2 had fewer combustibles than other floors because it was a
sky lobby, and on this basis the report leads us to believe that much more
intense fires were raging several floors above the two brave firemen–––fires
that did cause fatal weakening of the columns. The problem for NIST,
however, is that survivors from these higher floors tell a very
different story. As we know, WTC-2 was unlike WTC-1 in that a number of
individuals in the south tower did manage to escape the impact zone via
stairwell “A,” which luckily remained passable. (In his radio message Orlo
Palmer refers to it as “south stairway Adam.”) One of these survivors was
Stanley Praimnath, an employee of Fuji Bank who was on the 81st floor when
Flight 175 crashed into the south tower. In fact, the wing of the plane
reportedly passed within twenty feet from him. Yet, Praimnath escaped without
serious burns and in his testimony mentions nothing about a raging
inferno. Brian Clark, another survivor, was an executive vice-president of
Euro Brokers, based on the 84th floor. As Clark descended the stairs, he heard
someone crying out for help. It was Praimnath, who at the time was still
trapped on the 81st floor in the rubble. Clark found and freed the man,
whereupon, the two escaped together down the stairs. These two survivors are
living proof that the official story cannot be right. Both were in the fire
zone during and immediately after the impact, when the fires were most intense
due to the spilled jet fuel. If the temperatures in the core were 1,000ºC or
higher, as NIST would have us believe, the two men would have died within
minutes. Yet, both survived, and here is Clark’s description of the fire: "You
could see through the wall and the cracks and see flames just, just licking
up, not a roaring inferno, just quiet flames licking up and smoke sort
of eking through the wall." [my emphasis] Quiet flames. No roaring
inferno. It is not surprising that NIST chose to ignore the testimony of these
I’ve shown that the
known accounts of eyewitnesses do not support the official story regarding
conditions at the core of WTC-2–––testimonials that NIST likely excluded from
consideration for this reason. But what about empirical evidence? Among the
steel samples that NIST investigators recovered from WTC-2 were two core
columns (C-88a and C-88b) from the impact zone. Actually, they were two
different members from the same column (801). The NIST pinpointed their
location on floors 80 and 81, several floors above the firemen, very near the
path of Flight 175. Both samples had been physically damaged, yet, NIST found
no evidence of the kinds of distortion, i.e., buckling, bowing, slumping, or
sagging, that would be expected in cases of heat-weakened steel. Furthermore,
although the samples came from within the fire zone, NIST was unable to show
that the steel had been exposed to high temperatures. This finding is so
astonishing it bears repeating: The NIST report presents no physical evidence
whatsoever that the fires in the core of WTC-2 were raging infernos. On what,
then, does the agency base its conclusion that “Dire structural changes were
occurring in the building interior”? The answer, apparently, is the
following strange hedge:
“Note that these core
columns represent less than 1 percent of the core columns on floors involved
with fire and cannot be considered representative of any other core
In other words, we are
supposed to accept NIST’s theory about the fire solely on the basis of its
opinion that a larger sampling of columns would have enabled NIST to prove its
case. But this is hogwash! It simply is not the way science is done. Indeed,
the paucity of evidence, if anything, calls into question NIST’s earlier
assertion that its sampling was adequate.
What is even more
amazing is that NIST’s own computer simulations of the WTC fires tend to bear
this out. Any curious reader who invests the time to review the relevant NIST
document (i.e., CSTAR 1-5) will find page after page of color-coded graphic
diagrams of these simulations, one set for each floor in the fire zone. Nearly
all of them show that the core remained cool throughout the fires. The burden
of proof was on NIST to demonstrate how the fires weakened the core columns in
the allotted time; and the only reasonable conclusion one can draw is that the
agency fails to present even a minimal case. This also means, of course, that
NIST likewise fails to explain the global collapse.
For the sake of
argument, however, in order to show just how weak the official collapse model
is, let us assume that the fires did burn hot enough and were sustained
long enough, and caused numerous exposed columns in the impact zone to lose
roughly half of their strength. As I will now show, even if this did occur it
still fails to account for the global collapse of either tower.
The Issue of Reserve
As the NIST report
“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 above passage
informs us that WTC-2 gave no sign of instability after the impact of Flight
175. Unfortunately, although NIST’s summary report provides a wealth of
information about how the World Trade Center was constructed it fails to
clarify the important matter of the WTC’s “considerable reserve capacity.” At
any rate, I scoured the report in vain for a clear discussion of the issue. In
frustration, I finally called NIST for assistance and was guided to several of
the project reports and supplementary documents. I also consulted with Gary
Nichols, an expert at the International Code Council (ICC), and with Ron
Hamburger, a leading structural engineer. These conversations were an
education. I learned that estimating the overall reserve capacity of a steel
structure is by no means a simple matter. 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 reasonable 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,
Factor of Safety
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 down this more
general figure 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 NIST crunched the numbers for the 47 core columns of WTC-1
(in the impact zone, between the 93rd and 98th floors) it calculated that the
factor of safety ranged from 1.6 to 2.8, the mean value being 2.1. This
means that the average core column in the impact zone of 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. My grateful thanks to the NIST
investigative team for helping me locate these numbers, which were buried in
It is important to
realize that the factor of safety is not a threshold for collapse, but a value
beyond which permanent damage may begin to occur. As the NIST report admits,
even “after reaching the yield strength, structural steel components continue
to possess considerable reserve capacity.” This is why steel beams and
columns typically do not 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, none had ever collapsed–––until 9/11–––nor
has any since. What all of this means, of course, is that even in the most
improbable worst case, in which many or all WTC core columns lost half of
their strength, there was still sufficient reserve capacity to support the
The Perimeter Wall
With regard to the WTC’s
perimeter columns, the factor of safety fluctuated from day to day and even
from hour to hour, because, in addition to supporting 47% of the WTC’s gravity
load, the perimeter wall also had to withstand the lateral force of the wind,
which is highly variable given the whims of Mother Nature. A single face of
the WTC presented an enormous “sail” to the elements, for which reason John
Skilling vastly overbuilt this part of the structure. According to the NIST
report, the outer wall’s factor of safety against wind shear on 9/11 was
extraordinary, i.e., in the 10-11 range. Why so high? The answer is
simple: On the day of the attack there was essentially no wind, only a slight
breeze. For this same reason 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.” When 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. Assuming this average figure is a typical value we arrive at a
reasonable estimate of the perimeter wall’s amazing reserve capacity. Even if
we subtract those columns severed/damaged by the impact of Flight 175, and the
lost capacity due to the alleged (but unproven) buckling along the eastern
perimeter wall, there was still a wide margin of safety, more than enough by
several times over to support the outer wall’s share of the gravity load, with
plenty to spare.
The WTC’s tremendous
reserve capacity was no secret. In 1964, four years before the start of
construction, an article about the planned WTC appeared in the Engineering
News-Record. The article declared that “live loads on these [perimeter]
columns can be increased more than 2,000 percent before failure occurs.” A
careful reading of the piece also gives insight into why the plane impacts
were not fatal to the integrity of the outer wall. The reason is simple: the
perimeter columns were designed to function together as an enormous truss,
specifically, a Vierendeel truss. The wall was inherently stable. After the
plane impacts it behaved like an arch, simply transferring the load to the
surrounding columns. As the 1964 article states,
“the WTC towers will
have an inherent capacity to resist unforeseen calamities. This capacity stems
from its Vierendeel wall system and is enhanced through the use of
In short, NIST’s own
data fails to support its conclusions about the cause of the WTC collapse. The
official theory requires the fatal weakening of both sets of columns, and NIST
came up short on both counts due to insufficient evidence. Indeed, I would
call it woefully insufficient.
Today, more than two
years after NIST released its report, it is increasingly obvious that NIST
attempted to overcome the lack of physical evidence by resorting to computer
simulations. This was problematic, however, because computer models are no
better than the quality of input and the accuracy of the programmer’s
assumptions. Architect Eric Douglas identified another issue in his 2006
analysis of the NIST report: “a fundamental problem with....computer
simulation is the overwhelming temptation to manipulate the input data until
one achieves the desired results.” Did NIST investigators fall prey to
this tendency? Or were they somehow able to overcome the absence of physical
evidence? I must ask the reader to bear with me a little longer while we
explore these important questions.
The purpose of NIST’s
global impact analysis (NCSTAR 1-2) was to estimate the structural damage to
the WTC caused by the Boeing 767s. In this project NIST considered three
different scenarios, ranging from less damage to extreme damage, with a
moderate alternative (described as “the base”) in the middle. As it happened,
all three accurately predicted the impact damage to the WTC exterior at the
point of entry; although with regard to WTC-1 the moderate case was a slightly
better match. The three differed greatly, however, in predicting the
number of severed columns at the WTC core, a datum that was obviously of great
importance. In the case of WTC-1 the lesser alternative predicted only one
severed core column, the moderate alternative predicted three, while the
extreme alternative predicted five to six. In the case of WTC-2 the disparity
was even greater: The lesser alternative predicted three severed columns, the
moderate five, and the extreme case no less than ten. Although NIST never
satisfactorily resolved these differences, it immediately threw out the less
severe alternatives, citing two reasons in the summary report: first, because
they failed to predict observable damage to the far exterior walls; and
second, because they did not lead to a global collapse.
On September 11, 2001
the north tower sustained visible damage to the wall opposite the impact of
Flight 11. This was caused by an errant landing gear and by a piece of the
fuselage, which passed through the tower and came out the other side. Both
parts were later recovered. During the second impact (of Flight 175) the same
phenomenon was repeated: A jet engine was seen exiting WTC-2’s opposite wall
at high speed and was later found on Murray Street, several blocks northeast
of the WTC. In its summary report, NIST leads us to believe that the
observable damage to the far walls caused by these ejected Boeing 767 parts
validated its simulations. Yet, in one of its supplementary documents NIST
admits that “because of [computer] model size constraints, the panels on the
south side of WTC-1 were modeled with a coarse resolution...[and for this
reason] The model....underestimates the damage to the tower on this
face.” But, notice, this means that none of the three alternatives
accurately predicted the exit damage.
This admission, deeply
buried in the 43-volume report, is fatal to NIST’s first rationale for
rejecting the lesser alternative, since it was no less accurate than the
moderate and extreme cases. (Or, put differently: It was no more inaccurate.)
Which, of course, means that the NIST rejected the lesser alternative for one
reason only: because it failed to predict a global collapse. The simulations
for WTC-2 suffered from the same modeling defect. Once again, NIST rejected
the lesser alternative, even though “none of the three WTC-2 global impact
simulations resulted in a large engine fragment exiting the tower.”
 [my emphasis]
We can thank researcher
Eric Douglas for digging deeper than the summary report. Otherwise, this flaw,
tantamount to the devil lurking in the fine print, might never have come to
But the NIST was
undeterred by its own biased reasoning. Later, it also tossed out the moderate
(base) alternatives, and ultimately adopted the most extreme scenarios in its
subsequent global collapse analysis, even though, as noted, the moderate
alternatives were just as accurate, from a predictive standpoint, as the
extreme cases. In fact, with regard to predicting the entry damage to WTC-1,
as noted, the moderate alternative was actually a better match. The NIST
report offers no scientific rationale for this decision, only the pithy
comment that the moderate alternatives “were discarded after the structural
response analysis of major subsystems were compared with observed
events.” Here, of course, “observed events” refers to the ultimate
collapse of the towers. Things get worse.
It would appear that
NIST nearly failed to generate a collapse even with the extreme alternatives,
which required further tinkering. The report informs us that “Complete sets of
simulations were then performed for cases B and D [the extreme alternatives].
To the extent that the simulations deviated from the photographic evidence
or eyewitness reports, the investigators adjusted the input, but only
within the range of physical reality.” [my emphasis] In other words, NIST
scientists, working backwards from the collapse, tweaked the extreme
alternatives until their computer model spat out the desired result,
consistent with their original assumption that the 767 impacts and fires were
responsible for the collapses on 9/11. Needless to say, the NIST report fails
to give specifics about the “additional inputs.” We are left to use our
The late Princeton
astronomer Carl Sagan used to say that “extraordinary claims require
extraordinary proof.” By this tough but reasonable standard, the official
explanation about the collapse of the WTC on September 11, 2001 was without
question an extraordinary claim, because there were no historical precedents.
I will say it once again: No steel-frame skyscraper had ever collapsed due to
fire-weakened columns. By this standard the official account required an
extraordinary level of proof. Yet, as I have just shown, NIST failed to muster
even a minimal evidentiary case. From the start, NIST’s investigation was
biased, hence, unscientific. Indeed, its report is “a triumph” of circular
reasoning. The report actually left me slightly agog, in a state of mild shock
at the disparity between NIST’s research and its conclusions. NIST never
overcame the lack of hard data about actual conditions at the WTC core,
certainly not by resorting to computer models. Had its program been robust
enough to properly characterize the far walls, investigators might have
utilized the known exterior damage to those far walls to discriminate between
the three alternatives and, thusly, to select the best choice, validating the
model. Failing this, the NIST had no sound basis for rejecting the lesser and
moderate alternatives. Both were at least as plausible as the extreme case.
Why were they not given equal weight? The answer is obvious: That would have
compelled NIST investigators to entertain the unthinkable, i.e., the
possibility that some other causative agent was responsible for the WTC
It is high time that
Americans face the shocking reality that explosives were used to bring down
the World Trade Center on 9/11.
Mark H. Gaffney’s
first book was a pioneering 1989 study of Israel’s nuclear weapons program,
Dimona: the Third Temple? Mark’s latest, Gnostic Secrets of the Naassenes, was
a finalist for the 2004 Narcissus Book Award. His forthcoming book, The 911
Mystery Plane and the Vanishing of America, is scheduled for release in
September 2008. Visit Mark’s website at
Mark can be reached for comment at
1 Ryan Mackey, “Examining Dr. David Ray Griffin’s
Latest Criticism of the NIST World Trade Center Investigation, August 31, 2007.
2 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, Preface, xxxi.
3 Answers to Frequently Asked Questions, National
Institute of Standards and Technology (NIST) Federal Building and Fire Safety
Investigation of the World Trade Center Disaster, see question two, posted at
4 NIST NCSTAR, Executive Summary, p. xlvii.
5 After the 1993 bombing of the World Trade
Center Skilling was asked if the towers were vulnerable to a terrorist attack.
He replied that he designed them to withstand the impact of a Boeing 707, the
largest commercial jet liner of the day. In 1993 Skilling evidently saw no
reason to revise his original opinion in light of the more recent Boeing 767s,
which are slightly larger: "Our analysis indicated the biggest problem would be
the fact that all the fuel (from the airplane) would dump into the building.
There would be a horrendous fire. A lot of people would be killed. The building
structure would still be there." Eric Nalder, “Twin Towers Engineered To
Withstand Jet Collision,” Seattle Times, February 27, 1993.
Interestingly, one week before the September 11 attack, Skilling’s partner,
Leslie Robertson, spoke at a conference in Frankfurt, Germany. When asked what
he had done to protect the towers from terrorism, Robertson confirmed Skilling:
“I designed it for a 707 to smash into it.” “Towers Build to Withstand Jet
Impact.” Chicago Tribune, September 12, 2001.
6 NIST NCSTAR 1-5, WTC Investigation, p. xlviii;
also see NCSTAR 1-6, WTC Investigation, p. lxiv.
7 In July 1971 the WTC won a national award when
the American Society of Civil Engineers (ASCE) named it “the engineering project
that demonstrates the greatest engineering skills and represents the greatest
contribution to engineering progress and mankind.” in Angus K. Gillespie, Twin
Towers: The Life of New York City’s World Trade Center, New Brunswick, Rutger’s
University Press, 1999, p. 117.
8 Curiously, the NIST report gives two different
(and conflicting) figures regarding the load distribution. NIST NCSTAR 1-3C, WTC
Investigation, p. 3, asserts that the WTC core columns supported 60% of the
load, and the perimeter columns 40%, while NIST NCSTAR 1-2A, WTC Investigation,
p. 87 gives the figures cited in my paper.
9 NIST NCSTAR 1-3, p. 10.
10 “How Columns Will Be Designed for 110-Story
Buildings,” Engineering News Record, April 2, 1964.
11 NIST NCSTAR 1-6 p. lxxi.
12 Answers to Frequently Asked Questions,
National Institute of Standards and Technology (NIST) Federal Building and Fire
Safety Investigation of the World Trade Center Disaster, see question two,
13 Gordon Ross, “Momentum Transfer Analysis of
the Collapse of the Upper Storeys of WTC 1,” Journal of 911 Studies, June
2006. Posed at
14 On the sixth anniversary of the September 11,
2001 attack Cambridge University engineer Dr.Keith Steffen fold BBC that his
calculations showed that the WTC’s progressive collapse on 9/11 was a “very
ordinary thing.” His paper will appear in the Journal of Engineering
Mechanics in February 2008. “9/11 demolition theory challenged,” BBC News,
September 11, 2007.
15 The statement was made by a spokesperson for
the official story. “The 9/11 Conspiracies: Fact or Fiction,” A & E television
networks, cat # AAE 103790, 2007.
16 The 9/11 Commission Report, W.W. Norton
& Co., New York, 2004, p. 302.
18 email from Greg Bacon. February 25, 2007.
19 This strange development came to light in
July 2006, long after the cleanup of the Deutsche Bank had supposedly been
completed. The announcement prompted a sharp letter of protest from the
attorney representing the families of the victims. For more details go to
21 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 118; also see NIST NCSTAR 1-2, WTC Investigation, Executive
Summary, p. xli.
22 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 124.
23 NIST NCSTAR 1-3C, WTC Investigation, p. 217.
24 The NIST recovered 12 core columns from the
WTC, but only one (in two separate pieces) from WTC 2 turned out to be from
the area affected by the impacts/fires. A number of flanges from the core were
also recovered. See Table 5-2 in NIST NCSTAR 1-3, WTC Investigation, p. 35.
25 NIST NCSTAR 1-3, WTC Investigation, p. 39.`
26 NIST NCSTAR 1-3, WTC Investigation p. 39.
28 FEMA: Executive Summary: WTC Building
Performance Study, p, 2.
29 NIST NCSTAR 1-3, WTC Investigation,
p. 10; also see p.23.
30 NIST NCSTAR 1, NCSTAR 1-3, WTC
31 NIST NCSTAR 1, NCSTAR 1-3, WTC Investigation,
32 NIST NCSTAR 1, Full Summary Report, WTC
Investigation p. 130.
33 NIST NCSTAR 1-3C , WTC Investigation, p. 218.
35 NIST NCSTAR 1, Full Summary Report, WTC
Investigation p. 88.
36 NIST NCSTAR 1-3, WTC Investigation, p. 101.
38 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
39 FEMA: World Trade Center Building Performance
Study, Chapter Two: WTC 1 & 2, 2002, p. 22.
40 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 76.
41 NIST NCSTAR 1, Full Summary Report, WTC
Investigation p. 127.
42 The NIST makes this important point in two
separate places in the text. NIST NCSTAR 1-5, WTC Investigation, pp. 49 and
43 NIST NCSTAR 1-6, WTC Investigation, p.
44 NIST NCSTAR 1-2, WTC Investigation,
Executive Summary, p. xli.
45 NIST NCSTAR 1-5, WTC Investigation, p. xliv.
46 NIST NCSTAR 1-3, WTC Investigation, see photos
and discussion pp. 49-55.
48 NIST NCSTAR 1-3C, WTC Investigation, p. 24.
49 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 126-127.
50 NIST NCSTAR 1-5, WTC Investigation, p. 121.
51 NIST NCSTAR 1-6, WTC Investigation, p. lxvix;
also see NIST NCSTAR 1-5, WTC Investigation, p. 51.
52 Jim Dwyer and Kevin 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; also
see Christopher Bollyn, “Feds Withhold Crucial WTC Evidence,” American Free
Press, August 8, 2002.
53 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 44.
54 NIST NCSTAR 1-2, WTC Investigation, p. 5.
55 The 9/11 Commission Report, W.W. Norton
& Co., New York, 2004, p. 301.
56 Praimnath’s testimony is posted at
57 “The Fall of the World Trade Center,” BBC
Two, Thursday, March 7, 2002, posted at
58 NIST NCSTAR 1-3, WTC Investigation, p. 95.
59 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 43.
60 NIST NCSTAR 1-3 WTC Investigation p. 95.
61 NIST NCSTAR 1, Full Summary Report, WTC
Investigation p. 144.
62 In the code his was sub-article 1002.0,
adequacy of the structural design. See NIST NCSTAR 1-1A, WTC Investigation, p.
63 Conversation with Ron Hamburger, structural
engineer, Dec 7, 2006.
64 NIST NCSTAR 1-2, WTC Investigation, p. 66.
65 In the NIST report the reserve capacity data
is expressed in the form of demand/capacity ratios, which is simply another
way of expressing the factor of safety. I use the latter because I feel it’s
more comprehensible to the average lay person. Personal communication,
December 14, 2006. See NIST NCSTAR WTC Investigation 1-6, Figure 8-9, p. 233.
66 NIST NCSTAR 1-2, WTC Investigation, p. 66.
67 NIST NCSTAR 1-2, WTC Investigation, p. cxii;
also see NIST NCSTAR 1-2, WTC Investigation, p. 84.
68 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,
69 NIST NCSTAR 1-2, WTC Investigation, p. 66.
70 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.
71 NIST NCSTAR 1-2, WTC Investigation, p. 66.
72 “How Columns Will Be Designed for 110-Story
Buildings,” Engineering News-Record, April 2, 1964.
74 Eric Douglas, R.A., “The NIST WTC
Investigation -- How Real Was The Simulation?”, A review of NIST NCSTAR 1,
Journal of 9/11 Studies, December 2006, p. 8. Posted at
75 NIST NCSTAR 1-2, WTC Investigation,
Executive Summary, p. lxxxvii. The NIST also admitted this in its global
impact study., which states “in terms of structural damage condition in
exterior columns, Case Ai and Case Bi and similarly Case Ci and Case Di
damage sets were identical.” NIST NCSTAR 1-6D, WTC Investigation, p. 10.
76 NIST NCSTAR 1-2, WTC Investigation,
Executive Summary, p. lxxv.
77 NIST NCSTAR 1-2, WTC Investigation, p. lxxv.
78 NIST NCSTAR 1-2B, WTC Investigation, p. 344.
79 NIST NCSTAR 1-2B , WTC Investigation, p.
80 NIST NCSTAR 1-2B, WTC Investigation, p. 353.
81 NIST NCSTAR 1, WTC Investigation, p. 142;
also see NIST NCSTAR 1-6D, WTC Investigation, pp. 131, 174, 150 and 239.
82 NIST NCSTAR 1, Full Summary Report, WTC
Investigation, p. 142
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