The Believing Brain - Michael Shermer [116]
Let’s begin with this issue of the melting temperature of steel. According to 911research.wtc7.net, steel melts at a temperature of 2,777 degrees Fahrenheit (other sources put it at 2,750), but jet fuel burns at only 1,517 degrees Fahrenheit. No melted steel, no collapsed towers.4 Wrong. In an article in the Journal of the Minerals, Metals, and Materials Society, MIT engineering professor Dr. Thomas Eager explains why: steel loses 50 percent of its strength at 1,200 degrees Fahrenheit; the 90,000 liters of jet fuel ignited other combustible materials such as rugs, curtains, furniture, and paper, which continued burning after the jet fuel was exhausted, raising temperatures above 1,400 degrees Fahrenheit and spreading the fire throughout the building; temperature differentials of hundreds of degrees across single steel horizontal trusses caused them to sag, straining and then breaking the angle clips that held them to the vertical columns; once one truss failed, others failed, and when one floor collapsed (along with the ten stories above it) onto the next floor below, that floor then gave way, creating a pancaking effect that triggered the 500,000-ton building to collapse.
Conspiracists also argue that if the buildings had collapsed due to the impact of the planes, they should have fallen over on their sides. This is also wrong. With 95 percent of each building consisting of empty space (these were office buildings after all), they could only have collapsed straight down—there simply isn’t enough structural support integrity to take an entire building down in one piece.
The truthers also claim—in direct contradiction of the above claim—that the buildings fell straight down into their own footprint, which, they say, could have happened only if they had been deliberately brought down by explosive charges carefully and deliberately set ahead of time. Not true. The buildings did not fall down perfectly straight. Their collapse began on the side where the planes impacted, and so were tilted slightly toward that weakened collapse point, which you can clearly see in the numerous videos of the collapsing buildings.
Another conspiracy claim is that the buildings fell from the top down, precisely in the manner that controlled demolition buildings collapse. False. Controlled demolitions are done from the bottom up, not the top down. If you search “building demolition” on YouTube you will find hundreds of video clips of buildings collapsing by controlled demolition. I could not find one that collapsed from the top down, as did the World Trade Center buildings. Instead, you see what demolition experts tell us is how it is done: the charges are set to explode from the bottom up.
For our special 9/11 issue of Skeptic we consulted a demolition expert named Brent Blanchard, who is director of field operations for Protec Documentation Services, a company that documents the work of building demolition contractors. Since the rise in popularity of 9/11 conspiracy theories, he, too, has been inundated with requests to explain why the buildings appeared to have “collapsed as if by a controlled demolition.”5 Blanchard and his team of experts at Protec have worked with all major American demolition companies and many foreign ones to study the controlled demolition of more than one thousand of the largest and tallest buildings around the world. Their duties include engineering studies, structural analysis, vibration/air overpressure monitoring, and photographic services. On September 11, 2001, Protec had portable field seismic monitoring systems operating at other sites in Manhattan and Brooklyn. Demolition specialists were hired to clean up Ground Zero and remove the remaining damaged structures, and these experts called on Blanchard’s company to document both