Conspiracy Theorists bring up the fact that the towers were the first steel high rises to fall from fire in history. The fact is the towers had other firsts that day they never seem to include.
There were a lot of firsts for the WTC. In all the history of high-rise fires, not one has ever been hit with a plane traveling 500 miles an hour and had its fire proofing removed from its trusses. In all the history of high-rise fires, not one has ever had its steel columns which hold lateral load sheared off by a 767. In all the history of high-rise fires, not one has ever been a building which had its vertical load bearing columns in its core removed by an airliner. For Building 7, in all the history of high-rise fires, not one has ever been left for 6-7 hours with its bottom floors on fire with structural damage from another building collapse. Not the Madrid/Windsor tower did not have almost 40 stories of load on its supports after being hit by another building which left a 20 story gash. The Madrid tower lost portions of its steel frame from the fire. Windsor's central core was steel reinforced concrete. In all the history of high-rise fires, not one has ever been without some fire fighters fighting the fires.
I could go on with the "Firsts" but you get the drift. The statement that the WTC buildings were the first high-rise buildings to collapse from fire is deceptive because it purposely doesn't take those factors into account.
Conspiracy sites point to the building falling straight down as proof the buildings were blown up. Even Professor Jones uses this in his paper as an indication of controlled demolition.
But Jones and others making this claim know very well that these buildings are not built like the towers. Most of the buildings they point to are steel reinforced concrete buildings or have steel reinforced concrete cores. Others are constructed with a steel web evenly distributed throughout the building. These buildings are not a "tube in a tube" design. The towers were steel without concrete. The towers perimeter steel walls were held in place by the trusses and those trusses were connected to the perimeter columns by small bolts. They also weren't hit by an airliner at 500 miles an hour. While it's true they were designed to withstand the impact of a smaller 707, they never factored in the removal of fire proofing or fuel in the wings.
"It is impressive that the World Trade Center towers held up as long as they did after being attacked at full speed by Boeing 767 jets, because they were only designed to withstand a crash from the largest plane at the time: the smaller, slower Boeing 707. And according to Robertson, the 707's fuel load was not even considered at the time. Engineers hope that answering the question of exactly why these towers collapsed will help engineers make even safer skyscrapers in the future. ASCE will file its final report soon, and NIST has been asked to conduct a much broader investigation into the buildings' collapse."
http://www.pbs.org/wgbh/nova/wtc/minu-trans.htmlBut it wasn't the impact which the NIST said brought the building down. That's a conspiracy theorist straw man. They show an interview with a construction manager who said the buildings steel skin should have held up by redistributing the load. He's right. This is EXACTLY what the NIST said happened. It wasn't the impact alone which the NIST said brought down the towers. It was a combination of factors. The only way conspiracy theorists can attack the report is by separating these factors and attacking them individually. It's like taking a car accident apart and saying the car shouldn't have skidded off the road because the factory said the car could grip up to .97 g's. While that might be true, the conditions on the road must be factored in. Was there rain, dirt, gravel, anything which could have contributed to the crash? Conspiracy theorists are engaged in deliberate disinformation when they talk about these factors in a vacuum. They KNOW these factors can't be separated.
The PBS special did a good job of explaining the difference between the towers construction and these other buildings conspiracy theorists like to point to. Most steel buildings have a web of steel like this...
The towers had most of the steel in this web on its skin to save office space. Like this...
Note: What's missing from the above photo are the core columns but they are not needed to show the difference in building construction. Conspiracy theorists will be quick to point out this photo doesn't show the core columns but this isn't here to show how many stick figures someone can create. It's here to show how the building had a vastly different design than the average building. If you're a conspiracy theorist just imagine your 47 box columns in the core. (The dark area in the center) The building will still be built differently, box columns in this image or not.
http://www.pbs.org/wgbh/nova/wtc/collapse.html The towers and building 7 were essentially bolted together like an erector set. No concrete was used to create a ridged block or protect the columns. The steel webbing was pushed to the outer walls.
A challenge to conspiracy theorists:
1) Find a steel frame building at least 40 stories high
2) Which takes up a whole city block
3) And is a "Tube in a tube" design
4) Which came off its core columns at the bottom floors (Earthquake, fire, whatever - WTC 7)
5) Which was struck by another building or airliner and had structural damage as a result.
6) And weakened by fire for over 6 hours
7) And had trusses that were bolted on with two 5/8" bolts.
And which, after all seven tests are met, the building does not fall down. Anyone dissecting this into 7 separate events is lying to you.
Anything less than meeting these seven tests is dishonest because it's not comparing apples with apples. Showing a much lighter 4, 5 or even 15 story building which doesn't even take up a city block, and has an old style steel web design leaves out the massive weight the 47 story WTC 7 had bearing down on its south face columns. Yes, this is "moving the bar", back to where it should have started.
It is an absurdity to expect these buildings to perform the same during a collapse. This is why it's the first time in history these buildings fell as they did. It's the first time in history buildings constructed like this collapsed.
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Update:
Conspiracy theorists say the Deutsche Bank fire is more proof that steel buildings do not collapse by fire. But once again they fail to compare apples with apples.
1) The building was NOT a tube in a tube design. It was a web design which disperses load more evenly.
2) The fires were on the upper floors. The fire affected steel did not have anywhere near the same weight on them as the WTC7.
3) The towers had it's fireproofing removed by the impact of the airliners. Not so for the Deutsche Bank.
4) The fires were being fought which is why 2 firemen died.
6) There was no Con Ed substation to build the core columns around as with the WTC 7.
7) Those steel beams already had floors removed above them. The steel started with a lighter load before the fire.
The Deutsche Bank did not have 6000 gal of oil stored in the building as WTC 7 did.
Those are just some reasons the events are very different.
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Contrary to popular belief September 11, 2001 was not the first time a steel framed building collapsed due to fire. Though the examples below are not high rise buildings, they make the point that fire alone can collapse a steel structure.
The McCormick Center in Chicago and the Sight and Sound Theater in Pennsylvania are examples of steel structures collapsing. The theater was fire protected using drywall and spray on material. A high rise in Philly didn't collapse after a long fire but firefighters evacuated the building when a pancake structural collapse was considered likely. Other steel-framed buildings partially collapsed due fires one after only 20 minutes.
The steel framed McCormick Center was at the time the World's largest exhibition center. It like the WTC used long steel trusses to create a large open space without columns. Those trusses were unprotected but of course much of the WTC lost it's fire protection due to the impacts.
"As an example of the damaging effect of fire on steel, in 1967, the original heavy steel-constructed McCormick Place exhibition hall in Chicago collapsed only 30 minutes after the start of a small electrical fire."
http://www.wconline.com/CDA/Archive/24ae78779d768010VgnVCM100000f932a8c0____
[Note this article has several comments from engineers who back the
WTC collapse theory.]
"The unprotected steel roof trusses failed early on in the fire"
http://www.chipublib.org/004chicago/disasters/mccormick_fire.html The McCormick Place fire "is significant because it illustrates the fact that steel-frame buildings can collapse as a result of exposure to fire. This is true for all types of construction materials, not only steel." wrote Robert Berhinig, associate manager of UL's Fire Protection Division and a registered professional engineer. He also discusses UL's steel fire certification much more knowledgably than Kevin Ryan. He is an example of one more highly qualified engineer who supports the collapse theory.
http://www.iaei.org/subscriber/magazine/02_d/berhinig.htm From the FEMA report of the theater fire, my comments in [ ]
www.interfire.org/res_file/pdf/Tr-097.pdf On the morning of January 28, 1997, in the Lancaster County, Pennsylvania township of Strasburg, a fire caused the collapse of the state-of-the-art, seven year old Sight and Sound Theater and resulted in structural damage to most of the connecting buildings.
The theater was a total loss, valued at over $15 million.
pg 6/74
The theater was built of steel rigid frame construction to allow for the large open space of the auditorium, unobstructed by columns... The interior finish in the auditorium was drywall.
The stage storage area, prop assembly building, and prop maintenance building were protected with a sprayed-on fire resistant coating on all structural steel. The plans called for the coating to meet a two-hour fire resistance assembly rating. The sprayed-on coating, which was susceptible to damage from the movement of theater equipment, was protected by attaching plywood coverings on the columns to a height of eight feet.
The walls of the storage area beneath the stage were layered drywall to provide a two-hour fire protection rating for the mezzanine offices [the WTC used drywall as fire protection in the central core] , and sprayed-on fire-resistant coatings on the structural
steel columns and ceiling bar joists supporting the stage floor.
pg 15/74
The two theater employees told the State Police Fire Investigator that when they first discovered the fire they noticed that the sprayed-on fire proofing had been knocked off the underside of the stage floor bar joists and support steel. The fire proofing was hanging on the wire mesh used to hold the coating to the overhead. The investigation revealed that the construction company's removal of the stage floor covering down to the corrugated decking involved striking the floor hard enough to knock off the sprayed-on protection, exposing the structural steel and bar-joists in the storage area. [The theater's spray-on fireproofing was newer and more modern than at the WTC, The theater was only seven years old. If striking the floor during renovations was enough to dislodge it imagine the impact of a 767]
pg 16/74
Temperatures of 1000° F can cause buckling and temperatures of 1500° F can cause steel to lose strength and collapse. When the heat and hot gases reached the stage ceiling they extended horizontally into the auditorium, causing the roof to fail all the way to the lobby fire wall. The fire also extended horizontally from the stage to the elevated hallway, causing the structural steel to fail and buckle in the prop assembly and prop maintenance buildings
pg 17/74
Once the heat of the fire caused the structural steel to fail in the storage area (aided by the damage to the sprayed-on fire protection during renovation), interior firefighting became too hazardous to continue. The truck crews ventilating the roof noted metal
discoloration and buckling steel.
pg. 21/74
The two hour fire resistance-rated assembly in the storage area beneath the stage was damaged during the stage floor renovation, leaving the structural members unprotected from the ensuing fire.
pg. 26/74
Buildings constructed of steel should, in effect, be considered unprotected and capable of collapse from fire in as few as ten minutes. Fire resistant coatings sprayed onto structural steel are susceptible to damage from construction work.
The impact of fire and heat on structural steel members warrant extreme caution by firefighters.
pg. 36/74
Unless the steel members are cooled with high-volume hose streams, the fire's heat can rapidly cause steel to lose its strength and contribute to building collapse.
pg. 37/74
Other Fires
In February 1991, a fire broke out in One Meridian Plaza - a 38 story office building in Philadelphia. The building was built during the same period as the WTC and had spray-on fire protection on its steel frame. Despite not suffering impact damage, authorities were worried it might collapse.
"All interior firefighting efforts were halted after almost 11 hours of uninterrupted fire in the building. Consultation with a structural engineer and structural damage observed by units operating in the building led to the belief that there was a
possibility of a pancake structural collapse of the fire damaged
floors."
http://www.usfa.fema.gov/downloads/txt/publications/tr-049.txt About 2 years later, the NYFD was concerned that a steel framed building that partially collapsed during after a gas explosion might collapse entirely due to the resulting fire.
http://www.usfa.fema.gov/downloads/pdf/publications/TR-068.pdf Part of a floor of an unprotected steel frame building collapsed in Brackenridge, Pennsylvania on, December 20, 1991, Killing 4 volunteer firemen
http://www.usfa.fema.gov/downloads/pdf/publications/TR-061.pdf Part of the roof of a steel framed school in Virginia collapsed about 20 minutes after fire broke out
http://www.usfa.fema.gov/downloads/pdf/publications/tr-135.pdf
