Review Committee
Sarah Chaplin, Architect and Urban Development Consultant, Former Head of School of Architecture and Landscape, Kingston University, London
Dr. Mohibullah Durrani, Professor of Engineering and Physics, Montgomery College, Maryland
Richard Gage, AIA, Founder and CEO of Architects & Engineers for 9/11 Truth
Dr. Robert Korol, Professor Emeritus of Civil Engineering, McMaster University, Ontario
Dr. Graeme MacQueen, Retired Professor of Religious Studies and Peace Studies, McMaster University, Ontario Robert McCoy, Architect
Dr. Oswald Rendon-Herrero, P.E., Professor Emeritus of Civil and Environmental Engineering, Mississippi State University
Author
Ted Walter, Director of Strategy and Development, Architects & Engineers for 9/11 Truth
Technical Editor
Chris Sarns
Contributing Writers
Craig McKee
Chris Sarns
Andrew Steele
BEYOND MISINFORMATION
What Science Says About the Destruction of World Trade Center Buildings 1, 2, and 7
Architects & Engineers for 9/11 Truth
2342 Shattuck Avenue Suite 189 Berkeley, CA 94704
Introduction
What caused the destruction of the World Trade Center Twin Towers and
Building 7 on September 11, 2001? More than a decade later, this question
continues to be discussed by many people around the world.
According to the official explanation, the World Trade
Center Twin Towers (W.T.C 1 and W.T.C 2) collapsed
due to damage from airplane impacts and ensuing
fires, while World Trade Center Building 7 (W.T.C 7), a
47-story skyscraper also in the World Trade Center
complex, collapsed completely and symmetrically
into its own footprint due to office fires ignited by
debris from the earlier collapse of W.T.C 1. Though
few people have studied it closely, a majority of the
public, including most architects, engineers, and
scientists, accept the official explanation.(1)
Much of the public, however, including a considerable
number of architects, engineers, and scientists,
do not accept the official explanation.(2)(3) Among
those who reject it, the most common explanation
is that W.T.C 1, W.T.C 2, and W.T.C 7 were destroyed
in a procedure known as “controlled demolition,”
whereby carefully placed explosives or other devices
are detonated to bring down a structure in a
desired manner. September 11, 2001, aside, every
total collapse of a steel-framed high-rise building
in history has been caused by controlled demolition.
According to this second explanation, the demolition
of W.T.C 1, W.T.C 2, and W.T.C 7 would need to
have been prepared before September 11, 2001, by
demolition experts who had unrestricted access to
the buildings. This explanation also implies that the
demolition was planned in coordination with the
other attacks of that day. Most importantly, if the
goal were to make it appear that the airplanes had
caused the destruction of the buildings, it could not
be left to chance that airplanes would successfully
crash into W.T.C 1 and W.T.C 2. This explanation,
therefore, contradicts the official account of 9/11.
What Does Science Say?
The purpose of this booklet is to provide a careful
examination of these competing explanations —
which we will refer to as “hypotheses” from this
point forward — and a comprehensive overview of
the available evidence, so that readers can begin
to evaluate which of the two hypotheses is more
consistent with the evidence. Because this booklet
only skims the surface of this subject, readers are
strongly encouraged to study the official reports and
the papers referenced herein before reaching their
own conclusions.
The position taken in the following chapters is that
very little of the evidence can be explained by the
hypothesis of fire-induced failure and that all of it
can be explained by the hypothesis of controlled
demolition. Nonetheless, this booklet will make the
best attempt to describe how the authors of the official
reports have explained the evidence according
to their hypothesis. In many cases, however, we will
find that the authors of the official reports denied or
ignored the available evidence.
In the end, the goal is to move our collective understanding
of the World Trade Center’s destruction
beyond misinformation so that we as a society may
arrive at an accurate account of one of the most
important events in our recent history.
1
Formulating
a Hypothesis
This chapter provides a starting point from which to examine the competing
hypotheses of fire-induced failure and controlled demolition. First, it will
review the history of high-rise building fires and failures. Then it will examine
the features that distinguish fire-induced failure and controlled demolition.
Before and after photos of World Trade
Center Building 7.
One principle of the scientific method is especially
relevant in the early stage of an investigation when
data is being gathered and a hypothesis is being
formulated. “Unprecedented causes should not,
without good reasons, be posited to explain familiar
occurrences,” observes David Ray Griffin, a professor
emeritus of Philosophy of Religion and Theology
who has written extensively about the philosophy
of science and about the events of September 11,
2001. “We properly assume, unless there is extraordinary
evidence to the contrary, that each instance
of a familiar occurrence was produced by the
same causal factors that brought about the previous
instances.”(1)
With that principle in mind, we will review the history
of high-rise building fires and failures to help
us establish what should be considered, or should
have been considered, the most likely hypothesis for
the destruction of W.T.C 1, W.T.C 2, and W.T.C 7.
High-Rise Building Fires
and Failures
The history of steel-framed high-rise buildings
spans about 100 years. Setting aside the events of
September 11, 2001, every total collapse of a steel framed
high-rise building during that period of
time has been caused by controlled demolition. In
comparison, fires have never caused the total collapse
of a steel-framed high-rise building, though
high-rise building fires occur frequently.
Modern steel-framed high-rises generally endure
fires without being structurally compromised because
they have fire protection to prevent the steel
from heating to the point where it loses a significant
amount of its strength. This is usually in the form
of gypsum board (drywall), concrete, or sprayed-on
insulation.
To illustrate the performance of steel-framed high rise
buildings throughout history, let us first examine
the instances in which fires have caused the total
or partial collapse of high-rise buildings.
In 2002, the National Institute of Standards and
Technology (N.I.S.T) conducted an international
historical survey of fires in multi-story buildings
(defined as four or more stories) of all kinds that
resulted in total or partial
collapse.(2) From news databases,
published literature,
and direct inquires with 23
organizations, the survey
identified 22 fire-induced
collapses between 1970 and
2002.
Originally, the survey included W.T.C 1, W.T.C 2, and
W.T.C 7. However, it was revised in 2008 to remove
W.T.C 1 and W.T.C 2, because, according to N.I.S.T, their
destruction did not result solely from fire, but from
a combination of structural damage, dislodged fireproofing,
and fire caused by the airplane impacts.
However, in this chapter, because fire was reportedly
the proximate cause, we will discuss W.T.C 1
and W.T.C 2 as fire-induced failures. In the chapters
ahead, we will examine whether the structural
damage and reported dislodging of fireproofing are
sufficient reasons to differentiate W.T.C 1 and W.T.C
2 from other steel-framed high-rise buildings that
have experienced fires.
The results of N.I.S.T’s survey were as follows:
Partial Collapses
Of the 22 fire-induced collapses, 15 were partial
collapses, with five of those occurring in buildings
that were comparable to W.T.C 1, W.T.C 2, and W.T.C 7
in terms of size or construction (over 20 stories or
steel-framed or both). The five are:
■ One New York Plaza, a 50-story steel-framed
building that experienced local connection
failures resulting in filler beams on the 33rd
and 34th floors dropping onto their supporting
girders;
■ Alexis Nihon Plaza, a 15-story steel-framed
building in Montreal, Canada, that experienced
a partial collapse of its 11th floor;
■ W.T.C 5, a nine-story steel-framed building
in the W.T.C complex that experienced partial
collapses of four floors and two bays on
September 11, 2001;
■ The Jackson Street Apartments, a 21-story
reinforced concrete building in Hamilton,
Ontario, Canada, that experienced the partial
collapse of a floor/ceiling assembly; and
■ C.E.S.P 2, a 21-story reinforced concrete
building in Sao Paulo, Brazil, that experienced
a substantial partial collapse of its
central core.
The remaining 10 partial collapses occurred in
buildings with eight or fewer stories and constructed
of materials including concrete, brick, wood, or
masonry with cast iron. None were steel-framed.
Total Collapses
Of the 22 fire-induced collapses, seven of them
(including W.T.C 1, W.T.C 2, and W.T.C 7) were total collapses.
W.T.C 1, W.T.C 2, and W.T.C 7 stand out from the other four buildings, which ranged from four stories
to nine stories and were made of concrete, wood, or
unknown materials.
In summary, the survey identified four other documented
instances in which fires caused the total
collapse of a multi-story building. None were steel framed
and the tallest was nine stories. Fifteen
buildings suffered partial fire-induced collapse, but
only five of them occurred in buildings that were
over 20 stories and/or steel-framed. The survey
concluded, “A fire-induced collapse in a multi-story
building can be classified as a low-frequency,
high-consequence event.”
The Windsor Tower in Madrid, 2005.
The Windsor Tower after having burned
for almost 24 hours.
Other notable fire-induced collapses have occurred
since 2002. In 2005, the 29-story Windsor Tower in
Madrid, Spain, constructed of steel exterior columns
and reinforced concrete core columns, burned for
almost 24 hours and suffered a partial collapse, in
stages over several hours, of floors where the steel
support columns and beams had no fire protection.
In 2008, the 13-story Delft University Faculty of Architecture
Building in the Netherlands, constructed
of reinforced concrete, burned for seven hours and
experienced a partial collapse of a 13-story section
of the building. Yet there remains no documented
instance of a steel-framed high-rise building suffering
total collapse from fire, and only a small number
have experienced partial collapse.
Let us now examine the incidence of high-rise
building fires that do not cause total or partial
collapse. In 2013, the National Fire Protection Association
(N.F.P.A) published the most recent edition
of its periodic report titled High-Rise Building Fires.
According to the report, which defines high-rise
buildings as having seven stories or more, there
were an estimated 15,400 high-rise building fires in
the U.S. annually from 2007 to 2011. Fifty percent
of those occurred in buildings typically considered
high-rise buildings (that is, with multiple separate
floors such as apartments, hotels, facilities that
care for the sick, and offices). The incidence in that
five-year stretch is similar to the number of fires
observed in earlier time periods.
The N.F.P.A report notes that, by most measures, the
risks of fire and of associated losses are lower in
high-rise buildings than in other buildings of the
same property use. The difference, says the report,
can be attributed to the much greater use of fire
protection systems and features in high-rise buildings
as compared to shorter buildings.
In terms of buildings that are more comparable to
W.T.C 1, W.T.C 2, and W.T.C 7, the report estimates that
1,610 fires occur each year in buildings with 13 or
more stories. Since the report does not categorize
fires by size, severity, or duration, it is difficult to tell
how many of these fires are comparable to the fires
in W.T.C 1, W.T.C 2, and W.T.C 7.
One method of comparison, though, is to identify
high-rise building fires that resulted in significant
fire damage and property loss. Using those criteria,
N.I.S.T’s 2002 historical survey (updated in 2008),
referenced above, identified seven major high-rise
building fires that did not result in total or partial
collapse. Those included:
■ One Meridian Plaza in Philadelphia, PA
(height: 38 stories; fire duration: 19 hours)
■ Mercantile Credit Insurance Building in
Basingstoke, United Kingdom (height: 12
stories; fire duration: unknown)
■ Broadgate Phase 8 in London, United
Kingdom (height: 14 stories; fire duration:
4.5 hours)
■ First Interstate Bank in Los Angeles, CA
(height: 62 stories; fire duration: 3.5 hours)
■ MGM Grand Hotel in Las Vegas, NV (height: 26 stories; fire duration: 8 hours)
■ Joelma Building in Sao Paulo, Brazil (height:
25 stories; fire duration: one hour and 40
minutes)
\■ Andraus Building in Sao Paolo, Brazil
(height: 31 stories; fire duration: unknown)
BRE tests in Cardington, United Kingdom.
The N.I.S.T survey also noted two major fire test programs
conducted at the Building Research Establishment
(B.R.E) Laboratories in Cardington, United
Kingdom. The first series of tests, conducted on a
representative eight-story composite steel-framed
office building, resulted in significant fire damage
but did not result in collapse, even with unprotected
steel floors. The second series of tests conducted
on a seven-story concrete building also did not result
in collapse.
Given the high frequency of fires in steel-framed
high-rise buildings and the low frequency of fire-induced
collapses, the probability when a fire occurs
in a steel-framed high-rise building that it will result
in a partial collapse is extremely low. The probability
that it will result in a total collapse appears to be
even lower.
Let us take W.T.C 7 as an example. According to the
official explanation, its collapse was due solely to
normal office fires and not from structural damage
caused by debris. The probability when W.T.C 7
caught fire that it would totally collapse as a result
of those normal office fires was exceedingly low.
The Features of
Controlled Demolition
vs. Fire-Induced Failure
Let us now move from examining the occurrence
of collapse to the manner of collapse produced
by controlled demolition and fire-induced failure,
respectively. Table 1 on the following page lists
several common features that generally distinguish
controlled demolitions and fire-induced failures.
As Table 1 illustrates, the corresponding features
of controlled demolition and fire-induced failure
are virtually the opposite of each other. Not every
controlled demolition exhibits all of the features of
controlled demolition listed in Table 1, nor does every
fire-induced failure exhibit all of the features of
fire-induced failure listed in Table 1. However, there
is very little crossover: When a building’s cause of
collapse is controlled demolition, the building exhibits
virtually none of the features of fire-induced
failure. Similarly, when a building suffers a fire-induced
failure, it exhibits virtually none of the key
features of controlled demolition (with the exception of the four smaller non-steel-framed buildings
that N.I.S.T’s 2002/2008 survey identified as having
suffered total collapse from fire).
Table 1:
The Features of Controlled Demolition
versus Fire-Induced Failure
CONTROLLED DEMOLITION The collapse is total, leaving virtually no parts of the
building standing.
The onset of collapse is always sudden.
The collapse lasts a matter of seconds.
The collapse typically starts at the base of the building,
though they can be engineered as top-down also.
The building descends symmetrically through what was the
path of greatest resistance, though asymmetrical collapses
are sometimes engineered on purpose.
The building typically descends to the ground at near
free-fall acceleration.
“Demolition squibs” (isolated explosive ejections) are visible
outside the main zone of destruction. Concrete and other materials are sometimes pulverized,
resulting in fine dust clouds.
The building’s steel structure is totally or mostly
dismembered.
FIRE-INDUCED FAILURE
The collapse is usually partial (always partial in the case of steel-framed buildings), leaving much of the building standing.
The onset of collapse is gradual, with visible building deformations appearing prior to the actual collapse.
The collapse takes place over many minutes or hours.
The collapse occurs randomly anywhere in the building.Collapse is always asymmetrical.
The descent of falling portions of the building is slowed or stopped by the lower sections of the building.
Explosions only occur at the location of fires, if at all.
Concrete and other materials are not pulverized. Most of the building’s remaining structure is left intact or in large sections.
The building’s steel structure is left mostly intact, even if heavily damaged.
If we look closely at the five buildings in N.I.S.T’s
survey that were over 20 stories or steel-framed or
both, and that suffered partial fire-induced collapse,
we find that none of them exhibited the features of
controlled demolition in Table 1 above.
■ One New York Plaza experienced local
connection failures resulting in filler beams
dropping onto their supporting girders on
two floors.
■ Alexis Nihon Plaza experienced a partial
collapse of its 11th floor, which was arrested
by the floor below it.
■ W.T.C 5 experienced partial collapses of four
floors and two bays.
■ The Jackson Street Apartments experienced
the partial collapse of a floor/ceiling
assembly.
■ C.E.S.P 2 experienced a substantial partial
collapse of its central core. The degree of
deformation prior to collapse is unknown.
Other than possibly experiencing little deformation
prior to collapse, C.E.S.P 2 exhibited no
other feature of controlled demolition.
In comparison, as we will discuss in the chapters
ahead, the destruction of W.T.C 7 exhibited all of the
features of controlled demolition listed in Table 1,
while W.T.C 1 and W.T.C 2 exhibited eight out of the
nine features listed in the table (the collapse W.T.C 1
and W.T.C 2 did not start at their bases).
What Is the Most Likely
Hypothesis?
We now have two main observations to help us establish
the most likely hypothesis for the destruction
of W.T.C 1, W.T.C 2, and W.T.C 7. First, the probability
of fire causing the total collapse of a steel-framed
high-rise building is exceedingly low. Such an event
has never occurred prior to or since September 11,
2001. On the other hand, every total collapse of a
steel-framed high-rise building in history has been
caused by controlled demolition. Second, fire-induced
failures exhibit virtually none of the features
of controlled demolition. Yet, as could be seen on
the day of September 11, 2001, the destruction of
W.T.C 1, W.T.C 2, and W.T.C 7 exhibited nearly all of the
features of controlled demolition and none of the
features of fire-induced failure.
If the destruction of W.T.C 1, W.T.C 2, and W.T.C 7 were
caused by fire, this would make them the first steel framed
high-rise buildings in history to suffer total
fire-induced collapse (combined with structural
damage from the airplane impacts in the case of
W.T.C 1 and W.T.C 2). They would also be the first
fire-induced collapses to exhibit nearly all of the
features of controlled demolition and none of the
features of fire-induced collapse. Edward Munyak,
a fire protection engineer, puts it this way: “Even
one progressive global collapse would have been
extraordinary. But to have three occur in one day
was just beyond comprehension.”
Let us revisit the principle introduced at the beginning
of this chapter:
“Unprecedented causes should not, without
good reasons, be posited to explain familiar
occurrences…. We properly assume, unless
there is extraordinary evidence to the contrary,
that each instance of a familiar occurrence
was produced by the same causal factors that
brought about the previous instances.”
Indeed, we can properly assume, based on the above
observations, that the most likely hypothesis for the
destruction of W.T.C 1, W.T.C 2, and W.T.C 7 is that it
was caused by controlled demolition. Only if there
is extraordinary evidence to the contrary should an
unprecedented cause be posited.
In the chapters ahead, we will examine whether that
extraordinary evidence to the contrary exists — or
not.
2
The Official
Investigations
This chapter provides a brief account of the investigations conducted by the
Federal Emergency Management Agency (F.E.M.A) and the National Institute of
Standards and Technology (N.I.S.T) with a focus on how their hypotheses were
developed over time. Toward the end are summaries of N.I.S.T’s final “probable
collapse sequences,” which are the sequences of events that N.I.S.T claims
led to the total collapse of the buildings. Whether the evidence supports the
scenarios put forth by N.I.S.T will be discussed in the following chapters.
In the last chapter, we established that the most
likely hypothesis for the destruction of W.T.C 1, W.T.C
2, and W.T.C 7 was that it was caused by controlled
demolition. Let us now consider a second principle
of the scientific method that is relevant in the early
stage of an investigation. David Ray Griffin describes
it as follows: “When there is a most likely explanation
for some phenomenon, the investigation should
begin with the hypothesis that this possible explanation
is indeed the correct one…. Doing otherwise
would suggest that the investigators’ work is being
determined by some extra-scientific motive, rather
than the simple desire to discover the truth.”(1)
With that principle in mind, we will now examine
whether investigators started with or ever considered
the most likely hypothesis.
The FEMA Building
Performance Study
“‘It appeared to me that charges had been placed in
the building,’ said Mr. Hamburger, chief structural
engineer for A.B.S Consulting in Oakland, Calif. Upon
learning that no bombs had been detonated, ‘I was
very surprised.’”
This quote from Ronald
Hamburger appeared in
The Wall Street Journal on
September 19, 2001. By
that time, Hamburger was
one of a team of engineers
that had been assembled
by the American Society
of Civil Engineers (A.S.C.E)
and that would be given
authority under F.E.M.A
to investigate the World
Trade Center destruction.
He would also be named
“Chapter Leader” for the
chapter on W.T.C 1 and W.T.C
2 in F.E.M.A’s final report.
How did Ronald Hamburger
learn that “no bombs
had been detonated?” F.E.M.A’s investigators were
not granted access to the site until the week of
October 7. Thus, neither he nor anyone else had
conducted forensic analysis of the debris, nor had
they interviewed eyewitnesses. From a scientific
perspective, there was no basis for dis-confirming his initial hypothesis.
The likely answer is that between September 11 and
the time that he was interviewed, the government and
the media had put forth an account of the day’s events
that was incompatible with his original assessment
that the buildings had been brought down with explosives.
Certainly, it would seem highly unlikely that
Al-Qaeda could have gained access to the buildings
and rigged them to be demolished without being detected.
Therefore, as Hamburger essentially stated,
he ruled out his initial hypothesis when he “learned”
to his surprise that the official account did not include
explosives being used to bring down the buildings.
Ronald Hamburger was not the only expert to rule
out this initial hypothesis. On September 11, Van
Romero, an explosives expert at New Mexico Tech,
told the Albuquerque Journal, “The collapse of the
buildings was ‘too methodical’ to be the chance
result of airplanes colliding with the structures….
‘My opinion is, based on the videotapes, that after
the airplanes hit the World Trade Center there were
some explosive devices inside the buildings that
caused the towers to collapse.’” By September 21,
Romero changed his opinion after “conversations
with structural engineers,” telling his local newspaper,
“Certainly, the fire is what caused the building
to fail.”
COMMON
MISUNDERSTANDINGS
“The Towers were a raging inferno.”
According to the NIST report: “At
any given location, the duration and
temperatures near 1,000°C, was
about 15 to 20 min. The rest of the
time, the temperatures were near
500°C or below…. The initial jet fuel
fires themselves lasted at most a few
minutes.”
“The fires melted the steel.”
Although some experts initially claimed
that fires had melted the steel, the
hypotheses put forward by FEMA and
NIST never involved the steel becoming
hot enough to melt. According to NIST,
the highest air temperatures reached
were 1,000°C (1,832°F), while steel
melts at about 1,500°C (2,732°F).
Whatever causes experts like Hamburger and Romero
might have initially suspected, within a week after
September 11 there was no longer any question that
fires had been the ultimate reason for the buildings’
demise. Even the precise mechanisms that triggered
the collapses were agreed upon, according to engineer
R. Shankar Nair, who would be a contributor to
the F.E.M.A investigation. “Already there is near-consensus
as to the sequence of events that led to the
collapse of the World Trade Center,” he told the
Chicago Tribune on September 19.
At least that was the case for W.T.C 1 and W.T.C 2. W.T.C
7’s collapse, on the other hand, investigators were at
a loss to explain. “Engineers and other experts, who
quickly came to understand how hurtling airplanes
and jet fuel had helped bring down the main towers,
were for weeks still stunned by what happened to 7
World Trade Center,” The New York Times reported
on November 29. “We know what happened at 1 and
2, but why did 7 come down?” said William Baker, a
member of the F.E.M.A team.
With fire-induced failure as its only hypothesis, the
F.E.M.A investigation proceeded for the next several
months with significant constraints. As New York
Times reporters James Glanz and Eric Lipton wrote:
The investigation was financed and given
its authority by F.E.M.A, with which lead investigator
Gene Corley’s team had a shaky
relationship from the start. For months after
September 11, the investigators…were unable
to persuade F.E.M.A to obtain basic data like
detailed blueprints of the buildings that collapsed.
Bureaucratic restrictions often kept
the engineers from interviewing witnesses to
the disaster, making forensic inspections at
ground zero, or getting crucial information like
recorded distress calls from people trapped in
the buildings. For reasons that would remain
known only to F.E.M.A, the agency refused to let
the team appeal to the public for photographs
and videos of the towers that could help with
the investigation.(2)
Most detrimental to the team’s ability to conduct
forensic analysis was the City’s recycling of the
buildings’ steel, which continued despite requests
from the investigators — and outcry among the victims’
families and the fire safety community — for
the steel to be saved.(3) Although investigators were
eventually granted access to the scrap yards, nearly
all of the steel, including most of the steel from the
upper floors of W.T.C 1 and W.T.C 2, was destroyed
before it could be inspected.(4) [The only crime scene in history where evidence was destroyed and law enforcement did not ask why D.C.]
F.E.M.A released its report, titled World Trade Center
Building Performance Study: Data Collection, Preliminary
Observations, and Recommendations, on
May 1, 2002. As implied in the title, the report did
not attempt to provide a definitive explanation for
the destruction of each building. Instead, it posited
scenarios in general terms while recommending
further investigation to definitively determine the
exact causes.
This PBS NOVA animation attempts to illustrate the “pancake theory.”
F.E.M.A’s scenario for W.T.C 1 and W.T.C 2 — which reflected
common thinking at that time but was later
ruled out by N.I.S.T — is what became known as the
“pancake theory.” According to this hypothesis, the
fires caused the floor trusses to lose their rigidity
and sag. As a result of the sagging, the column-to-truss
connections failed and the floors collapsed
onto the floors below them. This precipitated “an
immediate progressive series of floor failures,”
which left behind “tall freestanding portions of the
exterior wall and possibly central core columns.”
F.E.M.A then stated, “As the unsupported height
of these freestanding exterior wall elements increased,
they buckled at the bolted column splice
connections, and also collapsed. Perimeter walls
of the building seem to have peeled off and fallen
directly away from the building face, while portions
of the core fell in a somewhat random manner.”
F.E.M.A also claimed that the upper sections of the
buildings then acted as pile drivers, causing “a wide
range of failures in the floors directly at and below
the aircraft impact zone,” which progressed all the
way down to the base of the buildings.
Regarding W.T.C 7, F.E.M.A reported that there was “no
clear evidence of where or on which floor the initiating
failure occurred,” but it put forward a number
of “potential scenarios” involving fires on various
floors on the east side of the building. Noting that
those areas contained “little if any fuel” that would
be required to feed fires hot enough and long-lasting
enough to weaken the structure, the report
suggested “a hypothesis based on potential rather
than demonstrated fact” that diesel fuel from the
buildings’ emergency generators was the source
of fire. Like the “pancake theory,” this hypothesis
reflected common thinking at the time but was later
ruled out by N.I.S.T. Toward the end of the report,
however, F.E.M.A observed:
The specifics of the fires in W.T.C 7 and how they
caused the building to collapse remain unknown
at this time. Although the total diesel fuel on the
premises contained massive potential energy,
the best hypothesis has only a low probability
of occurrence.
Thus, rather than pursuing the most likely hypothesis
for W.T.C 7’s destruction, F.E.M.A posited a hypothesis
that it found no evidence for; that involved an
unprecedented cause; and that it acknowledged
had “only a low probability of occurrence.”
Although a new agency was assuming the task of investigating the World Trade Center destruction, a number of key members of the F.E.M.A Building Performance Study would come to have principal roles in the N.I.S.T investigation. Some of them included:
■ Therese McAllister and John Gross, who became Co-Project Leaders of the most important part of the N.I.S.T investigation, “Structural Fire Response and Collapse Analysis.” McAllister had been the editor of the F.E.M.A Building Performance Study and the Chapter Leader of the report’s introduction. Gross had been a contributing author to the introduction.
■ Ronald Hamburger, whose firm was awarded the most important contract related to W.T.C 1 and W.T.C 2: a study of the thermal-structural response of the buildings to the fires.Hamburger had been the Chapter Leader of F.E.M.A’s chapter on W.T.C 1 and W.T.C 2. As discussed above, Hamburger initially thought that “charges had been placed in the building” but apparently ruled out this hypothesis when he learned it was not compatible with the official account.
■ Ramon Gilsanz, whose firm was awarded the most important contract related to W.T.C 7: the development of structural models and collapse hypotheses for W.T.C 7. Gilsanz had been the Chapter Leader of F.E.M.A’s chapter on W.T.C 7.
In its final plan, released in August 2002, N.I.S.T acknowledged that fire had never caused the total collapse of a high-rise building prior to September 11, 2001. Nonetheless, it pursued its hypothesis confidently, even going so far as to declare it as fact: “The W.T.C Towers and W.T.C 7 are the only known cases of total structural collapse in high-rise buildings where fire played a role.”
N.I.S.T’s first progress report in December 2002 did not discuss hypotheses in any detail. In May 2003, it released a second progress report, which laid out three leading hypotheses for the destruction of W.T.C 1 and W.T.C 2. One was F.E.M.A’s “pancake theory” involving the failure of floor connections. Another suggested that the floor connections held strong, which then allowed the sagging floors to pull the exterior columns inward until they buckled. This would become the main initiating mechanism in N.I.S.T’s probable collapse sequence (see Table 2). The third hypothesis posited direct fire-induced column failure. The May 2003 progress report, however, did not explore hypotheses for the destruction of W.T.C 7.
N.I.S.T’s working hypothesis for the destruction of W.T.C 7 was further elaborated in a Popular Mechanics article from March 2005, which said: “N.I.S.T researchers now support the working hypothesis that W.T.C 7 was far more compromised by debris than the F.E.M.A report indicated.... N.I.S.T investigators believe a combination of intense fire and severe structural damage contributed to the collapse.”
In April 2005, N.I.S.T announced that its technical work was nearly finished and that a draft report on W.T.C 1 and W.T.C 2 would be released for public comment in June 2005, followed by the final report in September 2005. N.I.S.T also announced for the first time that its report on W.T.C 7 would be released as a supplement to the other report, with a draft report due in October 2005 and the final report slated for December 2005. This schedule for the W.T.C 7 report was repeated at a public briefing on June 23, 2005. In its April 2005 progress report, N.I.S.T addressed the subject of the controlled demolition hypothesis for the first time — but only in relation to W.T.C 7: “N.I.S.T has seen no evidence that the collapse of W.T.C 7 was caused by bombs, missiles, or controlled demolition.” N.I.S.T did not describe what methods it used to search for evidence of controlled demolition. Whether it conducted an adequate search for such evidence will be discussed in later chapters.
Then, in September 2005, at a three-day technical conference where N.I.S.T released its final report on W.T.C 1 and W.T.C 2 (see Table 2 for a summary of N.I.S.T’s final probable collapse sequence), it announced that its report on W.T.C 7 would be further postponed, with the technical work being completed in January 2006, the draft report for public comment scheduled for May 2006, and the final report finished in June 2006.
STEP 1: Structural Damage from Airplane
Impact
The impact of the airplane severed 35 exterior columns
and six core columns in W.T.C 1. An additional two exterior
columns and three core columns were heavily damaged.
In W.T.C 2, the impact of the airplane severed 33 exterior
columns and 10 core columns. An additional exterior
column and core column were heavily damaged.
STEP 2: Redistribution of Loads The damage to exterior columns caused their loads to be redistributed mostly to the columns next to the impact zones. Damage to the core columns was distributed mostly to the core columns next to them that were still intact, and to a lesser extent to the exterior columns via the hat truss and floor systems. Additional loading redistribution occurred as some core columns were weakened and thus shortened, redistributing loads to the exterior columns. Loads increased by up to 25% in some areas and decreased by up to 20% in other areas.
STEP 3: Dislodging of Fireproofing The sprayed-on fireproofing was completely dislodged on all sides of some exterior columns, trusses, core beams, and all the gypsum board was knocked off some core columns over a wide area of multiple floors. According to N.I.S.T, the dislodging of fireproofing was necessary for the collapses to have occurred: “The towers likely would not have collapsed under the combined effects of aircraft impact and the subsequent multi-floor fires... if the insulation had not been widely dislodged or had been only minimally dislodged by aircraft impact.”
STEP 4: Sagging of Thermally Weakened Floors Pulled Exterior Columns Inward Heated floors began to sag and pull the exterior columns inward, though in some areas the floor connections failed rather than pulling on the exterior columns. In W.T.C 1, sagging of floors and inward bowing of exterior columns occurred on the south side from the 95th to the 99th floors. In W.T.C 2, sagging of floors and inward bowing of exterior columns occurred on the east side of the building from the 79th to the 83rd floors.
STEP 5: Exterior Columns Buckled, Causing Instability to Spread The bowed exterior columns buckled. Their gravity loads were transferred to the adjacent exterior columns, but those columns quickly became overloaded as well. In W.T.C 1, the south wall failed. In W.T.C 2, the east wall failed.
STEP 6: Global Collapse Ensued The portions of the buildings above where the failures occurred tilted in the direction of the failed walls, accompanied by a downward movement. The stories below the level of collapse initiation provided little resistance to the falling upper sections.
But N.I.S.T ended up significantly extending that timeline. A report that in June 2005 was set for release by the end of that year would end up being released almost three years later. In a March 2006 New York Magazine interview, N.I.S.T lead investigator Dr. Shyam Sunder provided some possible insight into why the report was delayed so long. When asked about W.T.C 7, Dr. Sunder said that N.I.S.T had some “preliminary hypotheses,” then added, “But truthfully, I don’t really know. We’ve had trouble getting a handle on building No. 7.” This was three and a half years into N.I.S.T’s W.T.C investigation.
That same month, N.I.S.T awarded a new contract to Applied Research Associates for the job of determining the location and cause of the initiating event and the subsequent series of failures that led to the total collapse of W.T.C 7. The contract was appended in August 2006 to include the task of determining if any “hypothetical blast event or events” contributed to the destruction of W.T.C 7. As we will see in Chapter 6, N.I.S.T would use the analysis performed under this contract in its attempt to disprove the hypothesis of controlled demolition.
In August 2008, the draft for public comment was finally released. That November, the final report was published. Diesel fuel fires and structural damage were no longer hypothesized to have contributed to the collapse. Instead, normal office fires were said to be the sole cause, making it “the first known instance of the total collapse of a tall building primarily due to fires.”
STEP 1: Debris from W.T.C 1 Ignited Fires Falling debris from W.T.C 1, which collapsed at 10:28 AM, ignited fires on at least 10 different floors between Floors 7 and 30.
STEP 2: Fire Spread Because water was not available in W.T.C 7, as a result of the water main being broken when W.T.C 1 collapsed, the automatic sprinkler system and the firefighters were unable to suppress the fires. Fires on Floors 7 to 9 and 11 to 13 spread over the course of several hours.
STEP 3: Thermal Expansion of Beams The fires heated steel floor beams in affected areas to temperatures up to 700°C (1,292°F), causing them to thermally expand and damaging the floor framing on several floors.
STEP 4: Girder Walk-off On the northeast corner of the building below the 13th floor, thermally expanding beams below Floor 13 pushed a critical girder (girder A2001) off of its seat at core corner Column 79. This thermal expansion occurred at temperatures at or below approximately 400°C (750°F), which is “hundreds of degrees below those typically considered in design practice for establishing structural fire resistance ratings.”
STEP 5: Cascade of Floor Failures The unsupported girder, along with other local fire-induced damage, caused Floor 13 to collapse. This caused a cascade of floor failures down to Floor 5.
STEP 6A: Buckling of Column 79 Due to the cascade of floors, Column 79 was left laterally unsupported over nine floors, causing the column to buckle eastward between Floors 5 and 14. As Column 79 buckled, its upper section dropped, causing the kink and subsequent fall of the east penthouse observed in videos.
STEP 6B: Buckling of Columns 80 and 81 The cascading failures of the lower floors surrounding Column 79 led to increased unsupported length in Columns 80 and 81, as well as debris falling onto them and loads being redistributed to them, causing them to buckle.
STEP 7: Propagation of Internal Column and Floor Failures All of the floor connections to Columns 79, 80, and 81 as well as the connections to the exterior columns failed, causing all the floors on the east side of the building to fall and leaving the exterior facade on the east quarter of W.T.C 7 a hollow shell. The interior column failures then progressed westward, with each north-south line of three core columns buckling in succession as a result of the loss of lateral support from floor system failures plus forces exerted by falling debris plus and the redistribution of loads from buckled columns. This sequence led to the drop of the screen wall and west penthouse.
STEP 8: Failure of the Exterior Columns With loads redistributed to the exterior columns, the exterior columns buckled between Floors 7 and 14, causing the entire visible section of the building to drop uniformly as a unit, as observed in the videos.
next
The Destruction of W.T.C 1 and W.T.C 2
footnotes
Introduction
1. Public opinion polls by Scripps Survey Research Center, Angus Reid, and You Gov have found 63 to 77 percent of Americans believe the destruction of W.T.C 1 and W.T.C 2 was caused by airplane impacts and fires. http://www.aei.org/wp-content/uploads/2013/11/-public-opinion-on-conspiracy-theories_181649218739.pdf and http://rethink911.org/ docs/ReThink911_YouGov_Poll_Results_Summary. pdf.
2. The above-referenced public opinion polls found 13 to 16 percent of Americans believe the destruction of W.T.C 1 and W.T.C 2 was caused by controlled demolition.
3. As of the publication of this booklet, 2,353 verified architects and engineers have signed the Architects & Engineers for 9/11 Truth petition calling for a new investigation into the destruction of W.T.C 1, W.T.C 2, and W.T.C 7.
Chapter 1
1. Griffin, David Ray: The Mysterious Collapse of World Trade Center 7 (2009), p. 23.
2. N.I.S.T: Analysis of Needs and Existing Capabilities for Full-Scale Fire Resistance Testing (October 2008).
Chapter 2
1. Griffin, p. 20.
2. Glanz, James and Lipton, Eric: City in the Sky: The Rise and Fall of the World Trade Center (2003), p. 330.
3. Ibid., pp. 330–332.
4. U.S. House of Representatives Committee on Science: Hearing: The Investigation of the World Trade Center Collapse: Findings, Recommendations, and Next Steps (May 1, 2002), p. 27.
5. At the 2015 Annual Business Meeting of the American Institute of Architects (A.I.A), during debate on a proposed resolution calling for the A.I.A to officially support a new investigation of the collapse of W.T.C 7, Anthony Schirripa, F.A.I.A, former president of the New York A.I.A Chapter, stated: “[W.T.C 7] collapsed because of a raging fire caused by 6,000-plus gallons of diesel fuel that fed the New York City Emergency Response Center. You need to admit that to yourselves.”
6. At the above-referenced 2015 A.I.A Annual Business Meeting, Donald King, F.A.I.A, a member of the A.I.A Strategic Council, stated: “The collapse of that building, according to the report, was caused by massive, intensive fire and the collision of debris from the collapse of World Trade Center Building, or Tower 1…. It was extreme fire and structural damage that caused the collapse.”
7. Ibid.
The N.I.S.T Investigation
Amid a growing sense that the F.E.M.A Building
Performance Study was insufficient for the task of
conducting a full-scale investigation, N.I.S.T began
planning its own investigation in October 2001 to
eventually succeed F.E.M.A’s. The N.I.S.T investigation
was announced on August 21, 2002, and was scheduled
to take 24 months. Although a new agency was assuming the task of investigating the World Trade Center destruction, a number of key members of the F.E.M.A Building Performance Study would come to have principal roles in the N.I.S.T investigation. Some of them included:
■ Therese McAllister and John Gross, who became Co-Project Leaders of the most important part of the N.I.S.T investigation, “Structural Fire Response and Collapse Analysis.” McAllister had been the editor of the F.E.M.A Building Performance Study and the Chapter Leader of the report’s introduction. Gross had been a contributing author to the introduction.
■ Ronald Hamburger, whose firm was awarded the most important contract related to W.T.C 1 and W.T.C 2: a study of the thermal-structural response of the buildings to the fires.Hamburger had been the Chapter Leader of F.E.M.A’s chapter on W.T.C 1 and W.T.C 2. As discussed above, Hamburger initially thought that “charges had been placed in the building” but apparently ruled out this hypothesis when he learned it was not compatible with the official account.
■ Ramon Gilsanz, whose firm was awarded the most important contract related to W.T.C 7: the development of structural models and collapse hypotheses for W.T.C 7. Gilsanz had been the Chapter Leader of F.E.M.A’s chapter on W.T.C 7.
In its final plan, released in August 2002, N.I.S.T acknowledged that fire had never caused the total collapse of a high-rise building prior to September 11, 2001. Nonetheless, it pursued its hypothesis confidently, even going so far as to declare it as fact: “The W.T.C Towers and W.T.C 7 are the only known cases of total structural collapse in high-rise buildings where fire played a role.”
N.I.S.T’s first progress report in December 2002 did not discuss hypotheses in any detail. In May 2003, it released a second progress report, which laid out three leading hypotheses for the destruction of W.T.C 1 and W.T.C 2. One was F.E.M.A’s “pancake theory” involving the failure of floor connections. Another suggested that the floor connections held strong, which then allowed the sagging floors to pull the exterior columns inward until they buckled. This would become the main initiating mechanism in N.I.S.T’s probable collapse sequence (see Table 2). The third hypothesis posited direct fire-induced column failure. The May 2003 progress report, however, did not explore hypotheses for the destruction of W.T.C 7.
COMMON
MISUNDERSTANDINGS
“W.T.C 7 collapsed because of the diesel
fuel fires.” 5
Although this was a leading hypothesis
for several years, F.E.M.A and N.I.S.T
found no evidence to support it and
N.I.S.T eventually ruled it out, stating,
“Diesel fuel fires did not play a role in
the collapse of W.T.C 7.”
“W.T.C 7 collapsed because of a massive,
extremely hot fire. It was a raging inferno.” 6
N.I.S.T concluded that the fires in W.T.C
7 were not unusual or extreme. In
its final report it stated: “The fires
in W.T.C 7 were similar to those that
have occurred in several tall buildings
where automatic sprinklers did not
function or were not present.” The
thermal expansion of beams that
initiated the collapse occurred “at
temperatures hundreds of degrees
below those typically considered
in design practice for establishing
structural fire resistance ratings.
In June 2004, N.I.S.T released a third, much more extensive
progress report containing interim findings
and a working hypothesis for the destruction of W.T.C
1 and W.T.C 2 — and this time W.T.C 7. Although the
working hypothesis for W.T.C 1 and W.T.C 2 described
the overall sequence of events from airplane impact
to collapse initiation in relatively clear steps,
N.I.S.T did not settle on an initiating mechanism or
on a location in either building where it might have
occurred. In regards to W.T.C 7, N.I.S.T suggested
that an initial local failure somewhere below Floor
13, caused by fire and/or structural damage, triggered
a column failure and subsequent vertical
progression of failures up to the east penthouse.
The resulting damage, N.I.S.T hypothesized, set off a
horizontal progression of failures across the lower
floors, resulting in disproportionate collapse of the
entire building. N.I.S.T’s working hypothesis for the destruction of W.T.C 7 was further elaborated in a Popular Mechanics article from March 2005, which said: “N.I.S.T researchers now support the working hypothesis that W.T.C 7 was far more compromised by debris than the F.E.M.A report indicated.... N.I.S.T investigators believe a combination of intense fire and severe structural damage contributed to the collapse.”
In April 2005, N.I.S.T announced that its technical work was nearly finished and that a draft report on W.T.C 1 and W.T.C 2 would be released for public comment in June 2005, followed by the final report in September 2005. N.I.S.T also announced for the first time that its report on W.T.C 7 would be released as a supplement to the other report, with a draft report due in October 2005 and the final report slated for December 2005. This schedule for the W.T.C 7 report was repeated at a public briefing on June 23, 2005. In its April 2005 progress report, N.I.S.T addressed the subject of the controlled demolition hypothesis for the first time — but only in relation to W.T.C 7: “N.I.S.T has seen no evidence that the collapse of W.T.C 7 was caused by bombs, missiles, or controlled demolition.” N.I.S.T did not describe what methods it used to search for evidence of controlled demolition. Whether it conducted an adequate search for such evidence will be discussed in later chapters.
Then, in September 2005, at a three-day technical conference where N.I.S.T released its final report on W.T.C 1 and W.T.C 2 (see Table 2 for a summary of N.I.S.T’s final probable collapse sequence), it announced that its report on W.T.C 7 would be further postponed, with the technical work being completed in January 2006, the draft report for public comment scheduled for May 2006, and the final report finished in June 2006.
Table 2:
Summary of N.I.S.T’s Probable Collapse
Sequence for W.T.C 1 and W.T.C 2
STEP 2: Redistribution of Loads The damage to exterior columns caused their loads to be redistributed mostly to the columns next to the impact zones. Damage to the core columns was distributed mostly to the core columns next to them that were still intact, and to a lesser extent to the exterior columns via the hat truss and floor systems. Additional loading redistribution occurred as some core columns were weakened and thus shortened, redistributing loads to the exterior columns. Loads increased by up to 25% in some areas and decreased by up to 20% in other areas.
STEP 3: Dislodging of Fireproofing The sprayed-on fireproofing was completely dislodged on all sides of some exterior columns, trusses, core beams, and all the gypsum board was knocked off some core columns over a wide area of multiple floors. According to N.I.S.T, the dislodging of fireproofing was necessary for the collapses to have occurred: “The towers likely would not have collapsed under the combined effects of aircraft impact and the subsequent multi-floor fires... if the insulation had not been widely dislodged or had been only minimally dislodged by aircraft impact.”
STEP 4: Sagging of Thermally Weakened Floors Pulled Exterior Columns Inward Heated floors began to sag and pull the exterior columns inward, though in some areas the floor connections failed rather than pulling on the exterior columns. In W.T.C 1, sagging of floors and inward bowing of exterior columns occurred on the south side from the 95th to the 99th floors. In W.T.C 2, sagging of floors and inward bowing of exterior columns occurred on the east side of the building from the 79th to the 83rd floors.
STEP 5: Exterior Columns Buckled, Causing Instability to Spread The bowed exterior columns buckled. Their gravity loads were transferred to the adjacent exterior columns, but those columns quickly became overloaded as well. In W.T.C 1, the south wall failed. In W.T.C 2, the east wall failed.
STEP 6: Global Collapse Ensued The portions of the buildings above where the failures occurred tilted in the direction of the failed walls, accompanied by a downward movement. The stories below the level of collapse initiation provided little resistance to the falling upper sections.
But N.I.S.T ended up significantly extending that timeline. A report that in June 2005 was set for release by the end of that year would end up being released almost three years later. In a March 2006 New York Magazine interview, N.I.S.T lead investigator Dr. Shyam Sunder provided some possible insight into why the report was delayed so long. When asked about W.T.C 7, Dr. Sunder said that N.I.S.T had some “preliminary hypotheses,” then added, “But truthfully, I don’t really know. We’ve had trouble getting a handle on building No. 7.” This was three and a half years into N.I.S.T’s W.T.C investigation.
That same month, N.I.S.T awarded a new contract to Applied Research Associates for the job of determining the location and cause of the initiating event and the subsequent series of failures that led to the total collapse of W.T.C 7. The contract was appended in August 2006 to include the task of determining if any “hypothetical blast event or events” contributed to the destruction of W.T.C 7. As we will see in Chapter 6, N.I.S.T would use the analysis performed under this contract in its attempt to disprove the hypothesis of controlled demolition.
In August 2008, the draft for public comment was finally released. That November, the final report was published. Diesel fuel fires and structural damage were no longer hypothesized to have contributed to the collapse. Instead, normal office fires were said to be the sole cause, making it “the first known instance of the total collapse of a tall building primarily due to fires.”
A floor plan of W.T.C 1. Rather than a conventional
design where the support columns are arranged
in a grid, the designers concentrated all of the
columns at the center and the perimeter, creating
a central core and an outer shell connected by
horizontal floor trusses spanning from the center
to the perimeter
W.T.C 1 during construction
A floor plan of W.T.C 7. According to N.I.S.T,
Column 79 on the northeast side was the first
column to fail.
A view of the 47-story W.T.C
7 from the viewing area of
W.T.C 2.
Table 3:
Summary of N.I.S.T’s Probable Collapse
Sequence for W.T.C 7
STEP 1: Debris from W.T.C 1 Ignited Fires Falling debris from W.T.C 1, which collapsed at 10:28 AM, ignited fires on at least 10 different floors between Floors 7 and 30.
STEP 2: Fire Spread Because water was not available in W.T.C 7, as a result of the water main being broken when W.T.C 1 collapsed, the automatic sprinkler system and the firefighters were unable to suppress the fires. Fires on Floors 7 to 9 and 11 to 13 spread over the course of several hours.
STEP 3: Thermal Expansion of Beams The fires heated steel floor beams in affected areas to temperatures up to 700°C (1,292°F), causing them to thermally expand and damaging the floor framing on several floors.
STEP 4: Girder Walk-off On the northeast corner of the building below the 13th floor, thermally expanding beams below Floor 13 pushed a critical girder (girder A2001) off of its seat at core corner Column 79. This thermal expansion occurred at temperatures at or below approximately 400°C (750°F), which is “hundreds of degrees below those typically considered in design practice for establishing structural fire resistance ratings.”
STEP 5: Cascade of Floor Failures The unsupported girder, along with other local fire-induced damage, caused Floor 13 to collapse. This caused a cascade of floor failures down to Floor 5.
STEP 6A: Buckling of Column 79 Due to the cascade of floors, Column 79 was left laterally unsupported over nine floors, causing the column to buckle eastward between Floors 5 and 14. As Column 79 buckled, its upper section dropped, causing the kink and subsequent fall of the east penthouse observed in videos.
STEP 6B: Buckling of Columns 80 and 81 The cascading failures of the lower floors surrounding Column 79 led to increased unsupported length in Columns 80 and 81, as well as debris falling onto them and loads being redistributed to them, causing them to buckle.
STEP 7: Propagation of Internal Column and Floor Failures All of the floor connections to Columns 79, 80, and 81 as well as the connections to the exterior columns failed, causing all the floors on the east side of the building to fall and leaving the exterior facade on the east quarter of W.T.C 7 a hollow shell. The interior column failures then progressed westward, with each north-south line of three core columns buckling in succession as a result of the loss of lateral support from floor system failures plus forces exerted by falling debris plus and the redistribution of loads from buckled columns. This sequence led to the drop of the screen wall and west penthouse.
STEP 8: Failure of the Exterior Columns With loads redistributed to the exterior columns, the exterior columns buckled between Floors 7 and 14, causing the entire visible section of the building to drop uniformly as a unit, as observed in the videos.
next
The Destruction of W.T.C 1 and W.T.C 2
footnotes
Introduction
1. Public opinion polls by Scripps Survey Research Center, Angus Reid, and You Gov have found 63 to 77 percent of Americans believe the destruction of W.T.C 1 and W.T.C 2 was caused by airplane impacts and fires. http://www.aei.org/wp-content/uploads/2013/11/-public-opinion-on-conspiracy-theories_181649218739.pdf and http://rethink911.org/ docs/ReThink911_YouGov_Poll_Results_Summary. pdf.
2. The above-referenced public opinion polls found 13 to 16 percent of Americans believe the destruction of W.T.C 1 and W.T.C 2 was caused by controlled demolition.
3. As of the publication of this booklet, 2,353 verified architects and engineers have signed the Architects & Engineers for 9/11 Truth petition calling for a new investigation into the destruction of W.T.C 1, W.T.C 2, and W.T.C 7.
Chapter 1
1. Griffin, David Ray: The Mysterious Collapse of World Trade Center 7 (2009), p. 23.
2. N.I.S.T: Analysis of Needs and Existing Capabilities for Full-Scale Fire Resistance Testing (October 2008).
Chapter 2
1. Griffin, p. 20.
2. Glanz, James and Lipton, Eric: City in the Sky: The Rise and Fall of the World Trade Center (2003), p. 330.
3. Ibid., pp. 330–332.
4. U.S. House of Representatives Committee on Science: Hearing: The Investigation of the World Trade Center Collapse: Findings, Recommendations, and Next Steps (May 1, 2002), p. 27.
5. At the 2015 Annual Business Meeting of the American Institute of Architects (A.I.A), during debate on a proposed resolution calling for the A.I.A to officially support a new investigation of the collapse of W.T.C 7, Anthony Schirripa, F.A.I.A, former president of the New York A.I.A Chapter, stated: “[W.T.C 7] collapsed because of a raging fire caused by 6,000-plus gallons of diesel fuel that fed the New York City Emergency Response Center. You need to admit that to yourselves.”
6. At the above-referenced 2015 A.I.A Annual Business Meeting, Donald King, F.A.I.A, a member of the A.I.A Strategic Council, stated: “The collapse of that building, according to the report, was caused by massive, intensive fire and the collision of debris from the collapse of World Trade Center Building, or Tower 1…. It was extreme fire and structural damage that caused the collapse.”
7. Ibid.
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