In the wake of growing skepticism, the U.S. government is taking the unusual step of responding to conspiracy theories about the Sept. 11, 2001, destruction of the World Trade Center.
The National Institute of Standards and Technology, or NIST, headquartered in Gaithersberg, Md., investigated the causes of the collapse of the twin towers.
Yesterday NIST announced it had posted a "fact sheet" addressing alternative theories about the World Trade Center fires and collapse.
The government's response comes in response to accusations and suspicions of increasing numbers of Americans that the official explanation of the events of Sept. 11, 2001 � that 19 Muslim terrorists hijacked four U.S. jetliners and crashed them into the World Trade Center and Pentagon, with a fourth being downed in rural Pennsylvania � are wrong. In fact, a shocking new Scripps Howard poll shows a third of Americans believe the U.S. government was complicit in the Sept. 11 terror attacks.
On its website, the National Institute of Standards and Technology posed 14 questions regarding the 9/11 terror attacks and answered each in detail. For instance, one question asked:
Why did NIST not consider a "controlled demolition" hypothesis with matching computer modeling and explanation as it did for the "pancake theory" hypothesis? A key critique of NIST�s work lies in the complete lack of analysis supporting a "progressive collapse" after the point of collapse initiation and the lack of consideration given to a controlled demolition hypothesis.
Here's is the government's response:
NIST conducted an extremely thorough three-year investigation into what caused the WTC towers to collapse, as explained in NIST�s dedicated Web site. This included consideration of a number of hypotheses for the collapses of the towers.
Some 200 technical experts � including about 85 career NIST experts and 125 leading experts from the private sector and academia � 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 of the sequence of events that occurred from the moment the aircraft struck the towers until they began to collapse.
Based on this comprehensive investigation, NIST concluded that the WTC towers collapsed because: (1) the impact of the planes severed and damaged support columns, dislodged fireproofing insulation coating the steel floor trusses and steel columns, and widely dispersed jet fuel over multiple floors; and (2) the subsequent unusually large jet-fuel ignited multi-floor fires (which reached temperatures as high as 1,000 degrees Celsius) significantly weakened the floors and columns with dislodged fireproofing to the point where floors sagged and pulled inward on the perimeter columns. This led to the inward bowing of the perimeter columns and failure of the south face of WTC 1 and the east face of WTC 2, initiating the collapse of each of the towers. Both photographic and video evidence � as well as accounts from the New York Police Department aviation unit during a half-hour period prior to collapse � support this sequence for each tower.
NIST's findings do not support the "pancake theory" of collapse, which is premised on a progressive failure of the floor systems in the WTC towers (the composite floor system � that connected the core columns and the perimeter columns � consisted of a grid of steel "trusses" integrated with a concrete slab; see diagram below). Instead, the NIST investigation showed conclusively that the failure of the inwardly bowed perimeter columns initiated collapse and that the occurrence of this inward bowing required the sagging floors to remain connected to the columns and pull the columns inwards. Thus, the floors did not fail progressively to cause a pancaking phenomenon.
NIST's findings also do not support the "controlled demolition" theory since there is conclusive evidence that:
the collapse was initiated in the impact and fire floors of the WTC towers and nowhere else, and;
the time it took for the collapse to initiate (56 minutes for WTC 2 and 102 minutes for WTC 1) was dictated by (1) the extent of damage caused by the aircraft impact, and (2) the time it took for the fires to reach critical locations and weaken the structure to the point that the towers could not resist the tremendous energy released by the downward movement of the massive top section of the building at and above the fire and impact floors.
Video evidence also showed unambiguously that the collapse progressed from the top to the bottom, and there was no evidence (collected by NIST, or by the New York Police Department, the Port Authority Police Department or the Fire Department of New York) of any blast or explosions in the region below the impact and fire floors as the top building sections (including and above the 98th floor in WTC 1 and the 82nd floor in WTC 2) began their downward movement upon collapse initiation.
In summary, NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to Sept. 11, 2001. NIST also did not find any evidence that missiles were fired at or hit the towers. Instead, photographs and videos from several angles clearly show that the collapse initiated at the fire and impact floors and that the collapse progressed from the initiating floors downward until the dust clouds obscured the view.
Read More Here:NIST and the World Trade Center
Read The Fact Sheet Here:Federal Building and Fire Safety Investigation of the World Trade Center Disaster
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