WTC 7 was a controlled demolition

The collapse of WTC 7 was analyzed by a large team of qualified engineers under the direction of the National Institute of Standards and Technology. The team comprised over 200 engineers, more than half from outside the government. The report is given at http://wtc.nist.gov.... The collapse sequence is described starting on page 21. It is surprisingly mundane, and, incidentally, quite different from the mechanisms causing the collapse of WTC 1 & 2. Debris from the fall of WTC 1 & 2 damaged seven exterior columns of the south and west faces of WTC 7, and started fires interior fires. The fuel within WTC 7 was equivalent to 32 kg of paper per square meter. The sprinkler system failed in the building due to failure of the water supply, and due to the same lack of water, the Fire Department could not extinguish the fire. The intense fire caused the heated steel to expand, which placed stress on adjacent columns. "In this case, the floor beams on the east side of the building expanded enough that they pushed the girder spanning between columns 79 and 44 to the west on the 13th floor. . . . Many of these floors had already been partially weakened by the fires in the vicinity of column 79. This left column 79 with insufficient lateral support, and as a consequence, the column buckled eastward, becoming the initial local failure for collapse initiation." The report shows that the timing and pattern of the collapse were consistent with all of the observed data. Detailed computer simulation verifies the analysis. Moreover, several hypotheses involving explosives were tested and found to be inconsistent ith observations. Explosives would have made shock waves much larger that actually observed and would have blown out windows inconsistent with that observed. Structure Magazine reported the detailed analysis of the WTC 7 collapse. "A collapse mechanism analysis performed for the removal of column 79 produced a deformed shape with kink in the roof of the east penthouse, as captured in actual videos and photos taken that day." http://www.structuremag.org... The esolution is wrong because it is inconsistent with competent analysis and the observed facts. It is not credible to suppose that 200+ highly qualified engineers form diverse organization would participate in a conspiracy to cover up the murder of 3000 citizens, and even less conceivable that none would ever recant in the passing years. Pro claims that there are ten characteristics of controlled demolition that match WTC 7. The supposed characteristics of controlled demolition that Pro cites do not derive from any true authority on such demolition, but as far as I can track down, from a retired professor of religion. In any case, some of items on the list [3.5.7,9,10] are not characteristic of controlled demolitions and the rest are characteristic of any building collapse. One of the established characteristics of controlled demolition missing from the list is that the building requires elaborate preparation, exposing steel columns and wiring up detonators. Yet none of 4000 people working in WTC 7 saw any preparation. How was that accomplished? Note that thermite is not an explosive. Thermite burns, but it does not explode. It is not used in controlled demolition because its ignition is too unreliable and it melts steel too slowly to be controllable. Hence, if thermite were used as claimed by Pro, then the citing of explosions is wrong. 1. Sudden onset is consistent with virtually all mechanisms of building collapse. Skyline Towers in Virginia collapsed suddenly due to improper construction techniques. http://en.wikipedia.org... The Sampoong Department Store in Korea collapsed due to dragging a heavy air conditioner over a column. http://en.wikipedia.org... 2. Straight down symmetrical collapse is due to gravity. All large buildings will fall straight down because the structure cannot resist the force. Small reinforced concrete buildings may tip over because of the relatively low mass relative to the strength of the structure. 3. The columns did not collapse simultaneously, but rather within about a few seconds as shown to be consistent with the NIST simulations. The building collapse began internally before the outside showed collapse. Videos show the east penthouse moving before the exterior collapse. See the Structure Magazine article. 4. Controlled demolitions do not use explosives on the upper floors, only near the base. Consequently, the rate at which the building falls will be the same regardless of whether it is a controlled demolition or not. Under the forces of collapse, the steel fails quickly by brittle fracture. 5. Pro supposes that thermite or shaped charges were placed at a predetermined length on every piece of steel in the building to cut in into pieces. This would require exposing the steel, placing charges, and wiring it all up. this could not conceivably be accomplished without the 4000 occupants noticing, therefore it didn't happen. The metal breaks from the forces of collapse. It is not a part of controlled demolitions. 6. Why would conspirators want to minimize damage to adjacent buildings? In any case, all the WTC buildings were severely damaged. What controlled demolition experts worry about is shattered glass and flying debris. http://en.wikipedia.org... 7. People heard loud noises. There is no evidence they were by explosive charges. A likely cause is from transformer vaults in the building. http://www.debunking911.com... Note the testing of the hypothesis in the NIST report, cited previously. 8. Every large building collapse produces clouds of pulverized concrete from the force of the descending structure. In a controlled demolition, the energy in the explosives is tiny compared to the energy in the building, so in controlled demolitions the explosives have nothing to do with the dust cloud. The energy in one of the WTC towers was equivalent to the energy in 5000 tons of TNT. WTC 7 was about half the height, so it probably had the equivalent eergy of about 2500 tons of TNT. If you drop a bowling ball on your foot, the potential energy of the ball held in your hand is converted to kinetic energy as it falls. The same principle applies on a large scale to building collapse. Dr. Frank Greening has done the detailed calculation for the WTC http://www.911myths.com... 9. There were pools of molten metal several weeks after the collapse the WTC buildings. Thermite can melt metal, but the liquid metal solidifies again very quickly, which is why thermite is used for welding. No method, neither using thermite nor anything else, that will keep metal liquid for weeks with one shot. There had to be heat continually applied over the long period of time. The explanation is a natural furnace effect in the debris piles whereby combustibles continued to supply high heat. "NIST concluded that the source of the molten material was aluminum alloys from the aircraft,...Pure liquid aluminum would be expected to appear silvery. However, the molten metal was very likely mixed with large amounts of hot, partially burned, solid organic materials ... which can display an orange glow," http://wtc.nist.gov... 10. Thermite is aluminum and iron oxide. With an aluminum plane, cladding, and furnishings and with steel beams, it is likely that the oxides would appear in the dust. Conspiracy theorists have no interest in any explanation that does not fit their theory, of course, so they do not consider the possibility of it being a natural product. The WTC collapse is well explained by real engineering. The ad hoc theories by rambling amateurs are self-contradictory and do not fit the facts.