NIST Responds to 9/11 Truthers
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm
Answers to Frequently Asked Questions
Some GOOD STUFF!!!:
From video evidence, significant portions of the cores of both buildings (roughly 60 stories of WTC 1 and 40 stories of WTC 2) are known to have stood 15 to 25 seconds after collapse initiation before they, too, began to collapse. Neither the duration of the seismic records nor video evidence (due to obstruction of view caused by debris clouds) are reliable indicators of the total time it took for each building to collapse completely.
UL did not certify any steel as suggested. In fact, in U.S. practice, steel is not certified at all; rather structural assemblies are tested for their fire resistance rating in accordance with a standard procedure such as ASTM E 119 (see NCSTAR 1-6B). That the steel was “certified ... to 2000 degrees Fahrenheit for six hours” is simply not true.
9. If thick black smoke is characteristic of an oxygen-starved, lower temperature, less intense fire, why was thick black smoke exiting the WTC towers when the fires inside were supposed to be extremely hot?
Nearly all indoor large fires, including those of the principal combustibles in the WTC towers, produce large quantities of optically thick, dark smoke. This is because, at the locations where the actual burning is taking place, the oxygen is severely depleted and the combustibles are not completely oxidized to colorless carbon dioxide and water.
The visible part of fire smoke consists of small soot particles whose formation is favored by the incomplete combustion associated with oxygen-depleted burning. Once formed, the soot from the tower fires was rapidly pushed away from the fires into less hot regions of the building or directly to broken windows and breaks in the building exterior. At these lower temperatures, the soot could no longer burn away. Thus, people saw the thick dark smoke characteristic of burning under oxygen-depleted conditions.
11. Why do some photographs show a yellow stream of molten metal pouring down the side of WTC2 that NIST claims was aluminum from the crashed plane although aluminum burns with a white glow?
NIST reported (NCSTAR 1-5A) that just before 9:52 a.m., a bright spot appeared at the top of a window on the 80th floor of WTC 2, four windows removed from the east edge on the north face, followed by the flow of a glowing liquid. This flow lasted approximately four seconds before subsiding. Many such liquid flows were observed from near this location in the seven minutes leading up to the collapse of this tower. There is no evidence of similar molten liquid pouring out from another location in WTC 2 or from anywhere within WTC 1.
Photographs, and NIST simulations of the aircraft impact, show large piles of debris in the 80th and 81st floors of WTC 2 near the site where the glowing liquid eventually appeared. Much of this debris came from the aircraft itself and from the office furnishings that the aircraft pushed forward as it tunneled to this far end of the building. Large fires developed on these piles shortly after the aircraft impact and continued to burn in the area until the tower collapsed.
NIST concluded that the source of the molten material was aluminum alloys from the aircraft, since these are known to melt between 475 degrees Celsius and 640 degrees Celsius (depending on the particular alloy), well below the expected temperatures (about 1,000 degrees Celsius) in the vicinity of the fires. Aluminum is not expected to ignite at normal fire temperatures and there is no visual indication that the material flowing from the tower was burning.
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 (e.g., furniture, carpets, partitions and computers) which can display an orange glow, much like logs burning in a fireplace. The apparent color also would have been affected by slag formation on the surface.
Why? Was he flicking his lighter in a celebratory gesture, or something?
