An
examination of the two opposing hypotheses for the destruction of World
Trade Center 7 rules out the official explanation of fire-induced
collapse.
According
to the National Institute of Standards and Technology (NIST), videos of
the collapse of the 47-story World Trade Center 7 on September 11, 2001
show the building succumbing to a fire-induced progressive collapse.
Many independent researchers and scientists, however, including over
1,400 professional architects and engineers who have signed a petition calling for a new investigation, disagree, pointing to evidence that it was deliberately brought down in a controlled demolition.
Despite
the dramatically different conclusions drawn, there does exist
widespread agreement on both sides on a number of important questions.
Proponents of both hypotheses agree that the damage to WTC 7 sustained
from the impact of debris from the collapse of the north tower (WTC 1)
was not an initiating or determinative factor in the collapse. Both
sides also agree that the system of transfer trusses and girders in the
building that allowed it to be constructed above the Consolidated Edison
New York electric power substation played no role in the collapse, that
hypothetical fuel oil fires from tanks stored in the building for
emergency generators was not a causal factor, and that the office fires
did not result in any significant loss of strength of the building’s
load-bearing steel columns.
While NIST
initially denied that the building achieved gravitational acceleration
during its collapse in its draft report for public comment, it was
forced to acknowledge that this was indeed the case in its final report
after high school physics teacher David Chandler submitted his own
analysis showing that the building collapsed at free-fall for
approximately 2.5 seconds, and that there was a sudden onset of
free-fall. According to NIST, the period of free-fall was 2.25 seconds.
To
illustrate, what this means is that for 8 stories, or more than 100
feet, the building fell at the same rate as would a bowling ball dropped
from the same height and falling through the air.
Proponents
of the controlled demolition hypothesis argue that elementary laws of
physics rule out the fire-induced collapse hypothesis. They point out,
for example, that the law of conservation of energy dictates that
free-fall means all of the building’s potential energy was converted to
kinetic energy, which means there was no energy remaining to do the work
of buckling the columns, as is required by NIST’s hypothesis. The
corollary is that there must have been some external source of energy
acting on the columns for this free-fall to have occurred.
NIST
argues in its final report that the rate of collapse was consistent
with its computer models. However, language that the collapse was
consistent with physical principles that existed in the draft report, in
which NIST denied free-fall, was removed from the final report, in
which free-fall is acknowledged.
Independent researchers
point to other evidence that NIST failed to account for in its
hypothesis, such as the presence of active thermitic material in the
dust from the collapses of the World Trade Center buildings, consistent
with nano-thermite. This material was found in four separate samples of
the dust collected from four separate locations following the collapses.
An international team of scientists issued a paper of their study of these red/gray chips found in the dust in the peer-reviewed Open Chemical Physics Journal in 2009, though to date, there remains a blackout on the topic in the mainstream U.S. media.
The
material found in the dust is not a naturally occurring substance, but a
manufactured material of highly advanced technology. The Lawrence
Livermore National Laboratory, working under the auspices of the U.S.
Department of Energy, has released a paper noting that by controlling
the composition of energetic materials at the nano-meter scale, a more
efficient chemical reaction can be produced, with applications for
making explosives. The thermite reaction is specifically cited as an
example. A publication of the U.S. Department of Defense has similarly
pointed out that energetic materials produced on the nanoscale, such
nano-thermite, has applications for “high-power, high-energy composite
explosives”.
The ability of thermite to
cut through steel has long been known. It involves a chemical reaction
between aluminum and iron oxide, which produces aluminum oxide and
molten iron. When sulfur is added to the thermite mixture, it is known
as thermate. Conventional thermite, however, is an incendiary, while
nano-thermite, or super thermite, results in a much more efficient
chemical reaction, with much more explosive results, as noted by the
Departments of Energy and Defense.
Also a
“signature” of the WTC dust is the presence of iron-rich micro-spheres,
which shows that the iron must have been molten prior to or during the
destruction of the World Trade Center buildings, with the surface
tension of the liquid forming a sphere before cooling and solidifying in
that shape. Yet NIST itself points out that fires did not burn at
anywhere near the temperature required to melt iron or steel. Such
spheres are a known byproduct, however, of the thermite reaction.
And
while NIST claims that no steel was recovered from WTC 7, it could not
have been unaware of a sample that was recovered and studied by a team
from the Worcester Polytechnic Institute. The steel had been severely
corroded, showing signs of intergranular melting and sulfidation, with a
“swiss cheese”-like appearance. The New York Times referred to
this piece of steel as “Perhaps the deepest mystery uncovered in the
investigation”, and the team’s findings and recommendations for further
study were published as Appendix C of the report of the Federal
Emergency Management Agency (FEMA). Although NIST was tasked with
carrying out the recommendations of the FEMA report, it ignored Appendix
C altogether and implicitly denied the very existence of this steel.
Dr.
Abolhassan Astaneh-Asl, a professor at the Department of Civil and
Environmental Engineering at the University of California, Berkeley, who
headed up a separate effort with funding from the National Science
Foundation to investigate the steel and recover important evidence, also
recovered a piece of steel from WTC 7. He described steel flanges that
“had been reduced from an inch thick to paper thin” to the New York Times. “Parts of the flat top of the I [of the “I-beam”], once five-eighths of an inch thick, had vaporized,” he observed.
The
reason so little steel was recovered from WTC 7 is that it was quickly
destroyed after having been removed from the site during the search and
rescue operations. Engineers across the country were outraged by the
destruction, prompting Bill Manning, editor-in-chief of Fire Engineering magazine, to write an editorial lambasting the official investigation under FEMA as “a half-baked farce”.
In
stark contrast, in testimony at the Hearing Before the Committee on
Science in the U.S. House of Representatives, the head of the FEMA
investigation, Dr. Gene Corley, expressed little concern about the
destruction of evidence and denied that it hampered the investigation.
Corley’s
insouciance about the destruction was further contrasted by Manning’s
prescient conclusion that “if they continue in such fashion, the
investigation into the World Trade Center fire and collapse will amount
to paper- and computer-generated hypotheticals.” Indeed, the NIST report
itself observes that its WTC 7 investigation was conducted with no
physical evidence, and its hypothesis relied entirely upon computer
models.
While the removal of debris from
the site of the World Trade Center disaster, or Ground Zero, was normal
and necessary, the destruction of evidence from a crime scene is a
felony offense under U.S. law. Yet no government or law enforcement
agency has sought to hold anyone accountable for the destruction of the
steel and other evidence from the WTC.
Another
unsolved mystery about the collapse is the prolonged fires that burned
under the rubble for months afterward, despite a number of rainfalls and
the round-the-clock efforts of firefighters to extinguish them. Many
credible witnesses, including scientists and engineers, reported seeing
molten iron or steel at the site.
When
asked about this phenomenon, NIST investigator Dr. John Gross responded
by denying not only that there was molten iron or steel, but that he
had even heard any such reports. Yet one witness who described seeing
“hot spots of molten metal” at Ground Zero was Mark Loizeaux, president
of Controlled Demolitions, Inc., who was contracted to remove debris
from the site and was also a consultant for the NIST report. Dr.
Astaneh-Asl was also among those testified to having seen “melting of
girders”.
While the official response to
this and other testimonial evidence is to dismiss it, proponents of the
alternative hypothesis have suggested the possibility that ongoing
chemical reactions from the use of thermitic materials might help to
explain why the fires could have burned for so long, despite several
rainfalls and firefighters’ best efforts, and how such temperatures
could have occurred in the oxygen-starved environment under the rubble.
There
are other holes in NIST’s hypothesis apart from its failure to account
for the physical and testimonial evidence. It requires, for example,
that fires were raging in the northeast area on the 12th floor, and it
input data assuming this scenario into its simulations. Yet the NIST
report itself states that fires only burned in any given area for 20-30
minutes before moving on, and NIST extensively documents the fires from
photographic and video evidence, showing that the fire had burned
through this area and already moved on, burning towards the west end of
the floor at the time of the collapse at 5:20 pm.
Apart
from the unscientific approach of inputting data according to an
assumption contradicted by their own evidence, NIST also assumed its own
worst-case scenario for maximum fire temperature and duration, and
carried only that scenario forward into its final computer analyses.
NIST has also refused to release its computer data for others to verify
and reproduce their results — a remarkable rejection of the scientific
method for an agency claiming to have used science to prove the
fire-induced collapse hypothesis.
Ph.D.
chemist F. R. Greening, who does not accept the controlled demolition
hypothesis and has debated it with its proponents, stated in comments on
the NIST draft report, “The main problem with the NIST fire simulation
appears to be the calculated duration of the fire on the 12th
and 13th floors of WTC 7…. In view of the fact that NIST appears to have
overestimated the intensity and duration of the fires in WTC 7,
particularly on floors 12 and 13, it follows that the heating of the
structural steel is also overestimated in the WTC 7 Draft Report. This
is fatal to the overall validity of NIST’s collapse initiation
hypothesis….”
The NIST hypothesis is
that fires on the 12th floor caused thermal expansion of 13th floor
beams in the northeast of the building. As a result of this thermal
expansion, shear studs, which make the beams composite with the metal
decking and concrete floor slab above, failed. The expanding beams then
pushed a girder spanning between the core and perimeter columns, causing
its welds and connections to fail and the girder to rock off its seat
where it was attached to the northeastern-most core column, number 79.
This failure resulted in the local collapse of the 13th floor. The
floors below, where beams were also weakened due to heat from the fires,
could not sustain the impact, and so a cascading series of floor
failures resulted. Column 79, unsupported laterally over nine stories,
buckled. Column failure then progressed through the core, from east to
west, and, as load was transferred to the perimeter columns, the entire
building began to move downward as a single unit.
This
is what one may witness in videos of the collapse of WTC 7, according
to NIST. The FEMA report noted that the building “imploded”, and NIST
lead investigator Dr. Shyam Sunder stated that because the core failed
first, due to fire, followed by the perimeter columns, “you get the
impression it was like a controlled demolition”.
Many
architects, engineers, scientists, firefighters, scholars, and other
groups of independent researchers calling for a new investigation argue
that the alternative hypothesis better explains all the available
evidence. They offer a perhaps simpler explanation for what one
witnesses in videos of the collapse: it appears to be a controlled demolition because it was.
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