The two major factors in the collapse itself were the fires and the lack of fire proofing around the trusses and some columns. With fire proofing, the steel was rated for 2 hours of continuous fire. Without it, that time is cut dramatically.
Construction.com
The below test results are used by conspiracy theorists to suggest the collapse couldn't have happened because, if you note the test under "Failure to support load" there are three asterisks (***) which indicates that failure did not occur. What they don't stress is the fact that all four tests have fire proofing on the trusses. Note the fire rating with 1/2 inch spray on fire proofing is 45 minutes. Some trusses and columns in the towers impact zone had none.
http://www.nist.gov/public_affairs/facts...
An incredibly detailed account of the fires can be found here
http://wtc.nist.gov/NISTNCSTAR1-5A_chap_... (56 megs)
--------------------------------------...
Update:
One of the BIG lies in the "truth" movement is that UL certifies steel. An ex-employee named Kevin Ryan, who worked as a water tester at UL, said "The buildings should have easily withstood the thermal stress caused by pools of burning jet fuel." He says he knows this because UL certified steel components of the World Trade Center and that someone from the company who was connected with the UL testing told him this fact.
Now for some facts the "truth" movement doesn't tell you.
UL doesn't certify steel components like a steel truss or column. They certify assemblies. That means they certified the total assembly, all put together. They also didn't replicate the impact levels. They replicated a floor system with fireproofing as it would have been before the impact. They also tested it with various fireproofing thicknesses. (See above UL test results) The test trusses were physically undamaged and had intact fireproofing for the purpose of standard rating. What this means is that Mr. Ryan doesn't even know what his former employer does, much less what it did during the World Trade Center investigation. Maybe that's why they fired him...
The other lie in the "truth" movement is the characterization of what the NIST said was the cause of the collapse.
1) The NIST NEVER said burning jet fuel was the cause of the collapse
2) If the assembly stayed together, it only SUPPORTS the NIST hypothesis that the trusses pulled the columns in.
3) The UL test caused the test trusses to sag even with fireproofing
NIST Tests Provide Fire Resistance Data on World Trade Center Floor Systems
National Institute of Standards & Technology
Aug 27, 2004 10:14 AM
The Commerce Department鈥檚 National Institute of Standards and Technology today reported that results from a series of four fire resistance tests conducted this month on composite concrete-steel trussed floor systems typical of those used in the World Trade Center towers showed that the test structures were able to withstand standard fire conditions for between one and two hours. The tests are part of NIST鈥檚 building and fire safety investigation of the WTC disaster on Sept. 11, 2001.
The 1968 New York City building code 鈥?the code that the towers were intended but not required to meet when they were built 鈥?required a two-hour fire rating for the floor system.
Shyam Sunder, lead investigator of the NIST WTC investigation, explained that the four laboratory tests provide only a means for evaluating the relative fire resistance rating of the floor systems under standard fire conditions and according to accepted test procedures. Sunder cautioned, 鈥淭hese tests alone cannot be used to determine the actual performance of the floor systems in the collapse of the WTC towers. However, they are already providing valuable insight into the role that the floors may have played in causing the inward bowing of the perimeter columns minutes before both buildings collapsed.鈥?br>
鈥淭he fire conditions in the towers on 9-11 were far more extreme than those to which floor systems in standard U.S. fire rating tests are subjected,鈥?Sunder said to a group that gathered to watch yesterday鈥檚 final test at Underwriters Laboratories (UL) in Northbrook, Ill. 鈥淥ur investigation鈥檚 final assessment of how the floor system performed in the WTC fires also must consider factors such as the combustible fuel load of the hijacked jets, the extent and number of floors involved, the rate of the fire spread across and between floors, ventilation conditions, and the impact of the aircraft-damaged towers鈥?ability to resist the fire,鈥?Sunder said.
All four WTC floor system fire tests used the standard procedure known as ASTM E119 for rating the fire resistance of a building structural unit such as a floor system, column or beam under prescribed conditions. The tests were conducted as part of a NIST contract at two separate UL fire test laboratories to take advantage of the different capabilities available at these facilities.
The first two tests, conducted earlier this month at the UL facility in Toronto, Canada, looked at the fire performance of 11-meter (35-foot) floor systems coated with a near-uniform 19-millimeter-thick (0.75-inch) layer of fireproofing material. This is representative of the span size and as-applied average fireproofing thickness of the floor systems in the WTC towers.
http://firechief.com/news/nist-tests-wtc...
Kevin Ryan is the editor of the "scholars" Journal of 911 Studies and one of the "peers" who review their so called "peer" reviewed papers.
--------------------------------------...
Since we are on the subject of fire proofing, let me touch on something which keeps being repeated by the so called "scholars". They keep suggesting that lease owner Larry Silverstein had a very good reason to blow up the towers.
Fetzer: My impression has been that there were a couple of problems with the towers and it may have been that they were chronic problems. One of course was that it was laden with asbestos and that any proposal to remove that asbestos which was used as a coating on the steel as I understand it would have been a gargantuan task at incredible expense. Can anyone imagine for example of constructing scaffolding around a 110 story building? And second of all that there were difficulties with occupancy that Larry Silverstein wasn鈥檛 getting a full return on his investment from the ordinary use of the buildings, because a tremendous large numbers of offices were unoccupied. Whole floors and sections of the buildings.
The fact is that asbestos in the towers was limited to floors only up to the 38th floor of WTC 1 and it was encapsulated. There was no asbestos in WTC2 .
"Several materials were considered for the sprayed thermal insulation. The exterior columns required insulation not only for fire protection but also to control column temperatures under service conditions. Alcoa recommended for the exterior columns the use of a sprayed material produced by U.S. Mineral Products, Co. known as BLAZE-SHIELD Type D. The same material was eventually selected for the floor trusses and core beams and columns. This product, however, contained asbestos fibers. On April 13, 1970, New York City issued restrictions on the application of sprayed thermal insulation containing asbestos. The use of BLAZE-SHIELD Type D was discontinued in 1970 at the 38th floor of WTC 1. The asbestos-containing material was subsequently encapsulated with a sprayed material that provided a hard coating. A green dye was added to the encapsulating material so that the asbestos containing SFRM could be identified. Thermal protection of the remaining floors of WTC 1 and all of WTC 2 was carried out using BLAZE-SHIELD Type DC/F, a product that contained mineral wool (glassy fibers) in place of the crystalline asbestos fibers. On the basis of tests, it was reported that the thermal properties of BLAZE-SHIELD Type DC/F were equal to or "slightly better" than those of BLAZE-SHIELD Type D"
NIST NCSTAR 1-6A
So much for asbestos, now what about the occupancy...
May 31, 1998
As the market for office space in midtown has tightened and rental rates increased, tenants have been looking to downtown as a cheaper alternative. Over the last year, those seeking large blocks of space have been finding them at the trade center, which had many vacancies as a result of the 1993 terrorist bombing and the shrinkage of the financial industry in the early part of the decade.
''In January 1997 we had about an 80 percent occupancy rate,'' said Cherrie Nanninga, director of real estate for the Port Authority of New York and New Jersey, which owns the complex. Twenty percent of 10.5 million square feet of space is 2.1 million, which would be a substantial building by itself.
But as a result of the last year's work, Ms. Nanninga, said the complex is over 90 percent occupied and expects to it reach the 95 percent mark by the end of the year. That, she said, would be about as full as the center is likely to get, since there is almost always someone moving in or out. ''Ninety-seven percent occupancy would be full,'' said Ms. Nanninga, whose name is pronounced NAN-in-gay.
Downtown; At the World Trade Center, Things Are Looking Up
February 12, 2001
As Real Estate Director, a position Mrs. Nanninga has held since 1996, the occupancy rate at the trade center has risen from 78 percent to a healthy 98 percent, retail soared in the trade center's mall, and available office space in the Newark Legal Center has nearly been filled.
Today, only about 250,000 of the 10.4 million square feet of office space in the trade center remains vacant. And the legal center has an occupancy rate of over 99 percent.
http://www.panynj.gov/AboutthePortAuthor...
PressRelease/index.php?id=61
So much for the "difficulties with occupancy".
http://www.911myths.com/html/windfall.ht...
This is yet another example of what the "scholars" want to spend millions investigating. I don't want my child paying one cent just because these "scholars" do sloppy research or have hidden political agendas. Because with the 8.4 trillion national debt, the millions they want spent will be paid by our children. It's cheaper to just send me a thank you at debunk911@hotmail.com. :)
One more thing, if making money off the murder of 3000 people mean you committed the murder, does that also mean losing money off the murder of 3000 people mean you're innocent? Sources: http://www.debunking911.com Wow, impressive 3 Nice job! ya put those liberals down!! When those buildings were built, the biggest airplane was probly a 727 maybe 737. The fire proffing was designed to withstand that much damage in the event of one hitting them. 757/767 hit the World Trade Centers and those were much bigger than the ones intended in the event of an accident. Its amazing that the building actually lasted as long as they did. |
