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Profile: National Institute of Standards and Technology (NIST)

National Institute of Standards and Technology (NIST) was a participant or observer in the following events:

The hole caused by the Flight 11 crash.The hole caused by the Flight 11 crash. [Source: Reuters]Flight 11 slams into the WTC North Tower (Building 1). Hijackers Mohamed Atta Waleed Alshehri, Wail Alshehri, Abdulaziz Alomari, and Satam Al Suqami presumably are killed instantly, and many more in the tower will die over the next few hours. Seismic records pinpoint the crash at 26 seconds after 8:46 a.m. [CNN, 9/12/2001; New York Times, 9/12/2001; North American Aerospace Defense Command, 9/18/2001; USA Today, 12/20/2001; Federal Emergency Management Agency, 5/1/2002, pp. 1-10; New York Times, 5/26/2002; USA Today, 8/13/2002; Associated Press, 8/21/2002; Newsday, 9/10/2002] The NIST report states the crash time to be 8:46:30. [National Institute of Standards and Technology, 9/2005, pp. 19] The 9/11 Commission Report states the crash time to be 8:46:40. [9/11 Commission, 7/24/2004, pp. 7] Investigators believe the plane still has about 10,000 gallons of fuel (see 8:57 a.m. September 11, 2001). [New York Times, 5/26/2002] The plane strikes the 93rd through 99th floors in the 110-story building. No one above the crash line survives; approximately 1,360 people die. Below the crash line, approximately 72 die and more than 4,000 survive. Both towers are slightly less than half full at the time of the attack, with between 5,000 to 7,000 people in each tower. This number is lower than expected. Many office workers have not yet shown up to work, and tourists to the observation deck opening at 9:30 A.M. have yet to arrive. [USA Today, 12/20/2001; National Institute of Standards and Technology, 9/2005, pp. 20-22] The impact severs some columns on the north side of the North Tower. Each tower is designed as a “tube-in-tube” structure and the steel columns which support its weight are arranged around the perimeter and in the core. The plane, which weighs 283,600 lb and is traveling at an estimated speed of around 430 mph (see October 2002-October 2005), severs 35 of the building’s 236 perimeter columns and damages another two. The damage to the South Tower’s perimeter will be similar (see 9:03 a.m. September 11, 2001). [National Institute of Standards and Technology, 9/2005, pp. 5-9, 20, 22] The perimeter columns bear about half of the tower’s weight, so this damage reduces its ability to bear gravity loads by about 7.5 percent. [National Institute of Standards and Technology, 9/2005, pp. 6] The actual damage to the 47 core columns is not known, as there are no photographs or videos of it, but there will be much speculation about this after 9/11. It will be suggested that some parts of the aircraft may have damaged the core even after crashing through the exterior wall. According to the National Institute of Standards and Technology (NIST): “Moving at 500 mph, an engine broke any exterior column it hit. If the engine missed the floor slab, the majority of the engine core remained intact and had enough residual momentum to sever a core column upon direct impact.” [National Institute of Standards and Technology, 9/2005, pp. 107] According to NIST’s base case computer model, three of the core columns are severed and another ten suffer some damage. [National Institute of Standards & Technology, 9/2005, pp. 189 pdf file] If this is accurate, it means that the impact damage to the core reduces the Tower’s strength by another approximately 7.5 percent, meaning that the building loses about 15 percent of its strength in total. This damage will be cited after 9/11 by NIST and others researchers as an event contributing to the building’s collapse (see October 23, 2002 and October 19, 2004). In addition, some of the fireproofing on the steel columns and trusses may be dislodged. The original fireproofing on the fire floors was mostly Blazeshield DC/F, but some of the fireproofing on the flooring has recently been upgraded to Blazeshield II, which is about 20 percent denser and 20 percent more adhesive. [National Institute of Standards & Technology, 9/2005, pp. xxxvi, 83 pdf file] Photographs and videos of the towers will not show the state of fireproofing inside the buildings, but NIST will estimate the damage to it using a computer model. Its severe case model (see (October 2002-October 2005)) will predict that 43 of the 47 core columns are stripped of their fireproofing on one or more floors and that fireproofing is stripped from trusses covering 60,000 ft2 of floor area, the equivalent of about one and a half floors. NIST will say that the loss of fireproofing is a major cause of the collapse (see April 5, 2005), but only performs 15 tests on fireproofing samples (see October 26, 2005). [National Institute of Standards and Technology, 9/2005, pp. 23] According to NIST, more fireproofing is stripped from the South Tower (see 9:03 a.m. September 11, 2001).

Entity Tags: Mohamed Atta, National Institute of Standards and Technology, Satam Al Suqami, Waleed Alshehri, Abdulaziz Alomari, World Trade Center, Wail Alshehri

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The jet fuel that spilled from Flight 11 when it hit the North Tower (see 8:46 a.m. September 11, 2001) has mostly burned up by this time. The National Institute of Standards and Technology (NIST), which investigates the collapses, will say “The initial jet fuel fires themselves lasted at most a few minutes.” [National Institute of Standards and Technology, 9/2005, pp. 183] Engineering professor Forman Williams will say the jet fuel “burned for maybe 10 minutes.” [Popular Mechanics, 3/2005] Flight 11, a Boeing 767, had a fuel capacity of 23,980 gallons, but was only carrying about 10,000 gallons when it hit the WTC. NIST will estimate that less than 1,500 gallons were consumed in a fireball inside the tower and a comparable amount was consumed in the fireballs outside the building. Therefore, approximately 7,000 gallons splashed onto the office furnishings and started fires on various floors. However, after the jet fuel is used up, office fires burn until the building collapses. NIST will calculate that there were about four pounds per square foot of combustibles in the office space, or about 60 tons per floor. Offices in the WTC actually have fewer combustibles than some other similar spaces due to the small number of interior walls and limited bookshelf space. NIST will later find that only three of sixteen perimeter columns it recovers reached a temperature of 250°C and neither of the two core columns it retrieves reached this temperature. NIST will also find that none of the samples it acquires reaches a temperature above 600°C (see August 27, 2003). Although steel does not melt until its temperature is about 1,600°C, it may begin to lose significant strength at over 500°C. [National Institute of Standards and Technology, 9/2005, pp. 20, 29, 24, 77] The jet fuel will also burn up in the South Tower about 10 minutes after it is hit (see 9:13 a.m. September 11, 2001).

Entity Tags: Forman Williams, World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Flight 175 hits the WTC South Tower. The picture was taken from a traffic helicopter.Flight 175 hits the WTC South Tower. The picture was taken from a traffic helicopter. [Source: WABC 7/ Salient Stills]Flight 175 hits the South Tower of the World Trade Center (Tower Two). Seismic records pinpoint the time at six seconds before 9:03 a.m. (rounded to 9:03 a.m.). Hijackers Marwan Alshehhi, Fayez Ahmed Banihammad, Mohand Alshehri, Hamza Alghamdi, and Ahmed Alghamdi presumably are killed instantly, and many more in the tower will die over the next few hours. [New York Times, 9/12/2001; CNN, 9/12/2001; CNN, 9/17/2001; North American Aerospace Defense Command, 9/18/2001; USA Today, 12/20/2001; Federal Emergency Management Agency, 5/1/2002, pp. 1-10; New York Times, 5/26/2002; Associated Press, 8/21/2002; USA Today, 9/2/2002] According to the NIST report, the crash time is 9:02:59. [National Institute of Standards and Technology, 9/2005, pp. 38] According to the 9/11 Commission Report, the crash time is 9:03:11. [9/11 Commission, 7/24/2004, pp. 8] Millions watch the crash live on television. The plane strikes the 77th through 85th floors in the 110-story building. Approximately 100 people are killed or injured in the initial impact; 600 people in the tower eventually die. The death toll is far lower than in the North Tower because about two-thirds of the South Tower’s occupants have evacuated the building in the 17 minutes since the first tower was struck. [USA Today, 12/20/2001; National Institute of Standards and Technology, 9/2005, pp. 5-9, 41] The combined death toll from the two towers is estimated at 2,819, not including the hijackers. [Associated Press, 8/21/2002] The impact severs some columns on the south side of the South Tower. Each of the Twin Towers is designed as a “tube-in-tube” structure and the steel columns which support its weight are arranged around the perimeter and in the core. The plane, which is traveling at an estimated speed of around 500 mph (see October 2002-October 2005), severs 33 of the building’s 236 perimeter columns and damages another one. [National Institute of Standards and Technology, 9/2005, pp. 39] The perimeter columns bear about half of the tower’s weight, so the damage to them reduces the tower’s ability to bear gravity loads by about 7.1 percent. [National Institute of Standards and Technology, 9/2005, pp. 6] The actual damage to the 47 core columns is not known, as there are no photographs or videos of it, but there will be much speculation about this after 9/11. It will be suggested that some parts of the aircraft may be able to damage the core even after crashing through the exterior wall (see 8:46 a.m. September 11, 2001). [National Institute of Standards and Technology, 9/2005, pp. 107] According to NIST’s base case model, five of the core columns are severed and another five suffer some damage. [National Institute of Standards & Technology, 9/2005, pp. 235 pdf file] This may reduce the tower’s ability to bear loads by a further approximately 8 percent, meaning that the aircraft impact accounted for a loss of about 15 percent of the building’s strength. This damage will be cited as an event contributing to the building’s collapse after 9/11 (see October 23, 2002 and October 19, 2004). NIST’s base case estimate of damage to the North Tower’s core will be similar, even though the aircraft impact there was dissimilar (see 8:46 a.m. September 11, 2001). Flight 11 hit the North Tower’s core head on, whereas Flight 175 only hits the corner of the South Tower’s core. [National Institute of Standards and Technology, 9/2005, pp. 20-23, 38-41] In addition, some of the fireproofing on the steel columns and trusses may be dislodged (see 8:46 a.m. September 11, 2001). [National Institute of Standards & Technology, 9/2005, pp. xxxvi, 83 pdf file] Photographs and videos of the towers will not show the state of fireproofing inside the buildings, but the National Institute of Standards and Technology (NIST) will try to estimate the damage to fireproofing using a series of computer models. Its severe case model (see (October 2002-October 2005)) will predict that 39 of the 47 core columns are stripped of their fireproofing on one or more floors and that fireproofing is stripped from trusses covering 80,000 ft2 of floor area, the equivalent of about two floors. NIST will say that the loss of fireproofing is a major cause of the collapse (see April 5, 2005), but only performs 15 tests on fireproofing samples (see October 26, 2005). [National Institute of Standards and Technology, 9/2005, pp. 41] According to NIST, less fireproofing is stripped from the North Tower (see 8:46 a.m. September 11, 2001).

Entity Tags: World Trade Center, Marwan Alshehhi, Fayez Ahmed Banihammad, Hamza Alghamdi, National Institute of Standards and Technology, Ahmed Alghamdi, Mohand Alshehri

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

In the lobby of the north WTC tower, just after the South Tower is hit, Fire Commissioner Thomas Von Essen speaks briefly to Fire Chief Ray Downey. According to Von Essen, Downey—who is a highly respected expert on building collapses—says to him, “You know, these buildings can collapse.” Von Essen later recalls, “He just said it in passing, not that these buildings will collapse in 40 minutes and we have to get everybody out of here, or not that they’ll collapse by tomorrow, or not that they necessarily will collapse at all. Just that they can collapse.” [Fink and Mathias, 2002, pp. 229; 9/11 Commission, 5/18/2004] But other firefighters do not appear to have shared this concern. According to the National Institute of Standards and Technology (NIST), the Fire Department command officers who are planning for operations inside the Twin Towers expect that there will “be localized collapse conditions on the damaged fire floors,” but do “not expect that there [will] be any massive collapse conditions or complete building collapse.” At the end of its three-year investigation of the WTC collapses, NIST will report, “No one interviewed indicated that they thought that the buildings would completely collapse.” [National Institute of Standards and Technology, 9/2005, pp. 72 and 75-76] In fact, Deputy Fire Commissioner Lynn Tierney will meet up with Downey and others—including Von Essen—slightly later, on the south lawn of the WTC complex, where a new command center is set up. At that time, according to Tierney, Downey will only be concerned that the 360-foot antenna atop the North Tower will fall, and “No one ever thought the towers were going to come down.” [Pittsburgh Tribune-Review, 9/11/2006] However, shortly before the first tower comes down, EMT Richard Zarrillo will be asked to relay a message to some senior firefighters that the mayor’s Office of Emergency Management “says the buildings are going to collapse” (see (Before 9:59 a.m.) September 11, 2001). And later in the day, Mayor Giuliani will recount that around the same time, he had been told “that the World Trade Center was going to collapse” (see (Before 9:59 a.m.) September 11, 2001). The 9/11 Commission will state, “The best estimate of one senior [fire] chief, provided to the chief of the department sometime between 9:25 and 9:45, was that there might be a danger of collapse [of the South Tower] in a few hours, and therefore units probably should not ascend above floors in the sixties.” The Commission does not state, however, whether this fire chief was referring to a total building collapse or just a localized collapse. [9/11 Commission, 5/19/2004] Ray Downey is killed when the second tower collapses at 10:28 a.m. [New York Times, 9/9/2005]

Entity Tags: Lynn Tierney, New York City Fire Department, Ray Downey, National Institute of Standards and Technology, Thomas Von Essen

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The jet fuel that spilled from Flight 175 when it hit the South Tower (see 9:03 a.m. September 11, 2001) has mostly burned up by this time. The National Institute of Standards and Technology (NIST), which later investigates the collapses, will say the “initial jet fuel fires themselves lasted at most a few minutes.” [National Institute of Standards and Technology, 9/2005, pp. 183] Engineering professor Forman Williams will say the jet fuel “burned for maybe 10 minutes.” [Popular Mechanics, 3/2005] Flight 175, a Boeing 767, had a capacity of 23,980 gallons, but was only carrying about 9,100 gallons of fuel when it hit the WTC. NIST will estimate that less than 1,500 gallons were consumed in a fireball inside the tower and 910 to 2,275 gallons were consumed in the fireballs outside the building. Approximately 6,100 gallons therefore splashed onto the office furnishings and started fires on various floors. However, after the jet fuel is used up, office fires burn until the building collapses. NIST will calculate that there were about four pounds per square foot of combustibles in the office space, or about 60 tons per floor. Offices in the WTC actually had fewer combustibles than other similar spaces due to the small number of interior walls and limited bookshelf space. NIST will later find that only three of sixteen perimeter columns it recovers reached a temperature of 250°C and neither of the two core columns it retrieves reached this temperature. NIST will also find that none of the samples it acquires reached a temperature above 600°C (see August 27, 2003). While steel does not melt until its temperature is about 1,600°C, it may begin to lose significant strength at over 500°C. [National Institute of Standards and Technology, 9/2005, pp. 29, 38, 42, 77] The jet fuel also burned up in the North Tower about 10 minutes after it was hit (see 8:57 a.m. September 11, 2001). When a group of firefighters reach the bottom impact floor in the South Tower just before collapse, they only find two isolated fires (see 9:52 a.m. September 11, 2001).

Entity Tags: World Trade Center, National Institute of Standards and Technology, Forman Williams

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The exterior wall on the east side of the World Trade Center’s South Tower apparently bows before the building collapses. The first inquiry into the collapse, by the Federal Emergency Management Agency and the American Society of Civil Engineers, states that the perimeter walls bow outward. “Expansion of floor slabs and framing results in outward deflection of columns and potential overload,” the investigation concludes. [Federal Emergency Management Agency, 5/1/2002, pp. 2-25] However, a subsequent report by the National Institute of Standards and Technology states that the east wall of the South Tower bows inward. In places the wall is said to bow inward by between seven and nine inches at floor 80, and NIST interprets this bowing to mean that the floors must be sagging. NIST will find that the sagging and bowing are two of the seven major factors that led to the collapse of each tower, as the bowing walls are no longer able to support their share of the buildings’ weight, causing the buildings to tilt and the upper sections to fall. [National Institute of Standards and Technology, 9/2005, pp. 43-46, 87] A wall in the North Tower also apparently bows before the building collapses (see 10:23 a.m. September 11, 2001).

Entity Tags: Federal Emergency Management Agency, World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The exterior wall on the south side of the World Trade Center’s North Tower apparently bows before the building collapses. The first inquiry into the collapse, by the Federal Emergency Management Agency and the American Society of Civil Engineers, states that the perimeter walls bow outward (see (9:21 a.m.-9:59 a.m. September 11, 2001)). However, a subsequent report by the National Institute of Standards and Technology states that the south wall of the North Tower bows inward. In places the wall is said to bow inward by approximately 55 inches at floor 97, and NIST interprets this bowing to mean that the floors must be sagging. NIST will find that the sagging and bowing are two of the seven major factors that led to the collapse of each tower, as the bowing walls are no longer able to support their share of the buildings’ weight, causing the buildings to tilt and the upper sections to fall. [National Institute of Standards and Technology, 9/2005, pp. 32-34, 87]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Damage to the southwest corner of WTC 7.Damage to the southwest corner of WTC 7. [Source: Arquelio Galarza]World Trade Center Building 7 (WTC 7) suffers some damage, caused by debris from the collapse of the north WTC tower, according to later official reports. [Federal Emergency Management Agency, 5/1/2002, pp. 5-16; National Institute of Standards and Technology, 11/2008, pp. 16]
WTC 7 Undamaged by South Tower Collapse - WTC 7 is a 47-story office building located 370 feet north of the North Tower (WTC 1). In the final report of its investigation into WTC 7’s collapse, published in November 2008 (see November 20, 2008), the National Institute of Standards and Technology (NIST) will state that although a few windows on the lower floors of WTC 7’s south face were broken when the South Tower (WTC 2) collapsed at 9:59 a.m. (see 9:59 a.m. September 11, 2001), “None of the large pieces of debris from WTC 2 hit WTC 7, because of the large distance between the two buildings,” and there is “no evidence of structural damage to WTC 7” as a result of the South Tower’s collapse.
Debris Reportedly Damages Exterior Columns - However, when the North Tower collapses (see 10:28 a.m. September 11, 2001), some fragments of debris are “forcibly ejected” from it, and travel “distances up to hundreds of meters.” According to NIST, pieces of this debris “hit WTC 7, severing six columns on floors 7 through 17 on the south face and one column on the west face near the southwest corner.” NIST will add that the debris also causes “structural damage between floor 44 and the roof,” and breaks a large number of windows on WTC 7’s south face.
Building Core Undamaged - However, NIST will state, based on “photographic evidence, witness accounts, and engineering judgment, it is likely that the structural damage (steel and floor slabs) did not penetrate beyond the perimeter of the building core. At the southwest corner, the structural damage extended only about one-third of the distance from the exterior wall to the building core.” NIST will comment, “Compared to the airplane impact damage to the WTC towers, there was relatively little damage to the interior of WTC 7.” There is also “no superficial or structural damage” to WTC 7’s north and east faces. And the sprayed fire resistive material that has been applied to the building’s steel columns, girders, and beams is only damaged in the “immediate vicinity of the WTC 1 debris impact.” NIST will admit, however, that there are “uncertainties” in its accounting of the events leading up to the collapse of WTC 7, because “the remains of all the WTC buildings were disposed of before Congressional action and funding was available for [its] investigation [of the WTC collapses] to begin” (see Shortly After September 11, 2001 and September 12-October 2001). [National Institute of Standards and Technology, 8/21/2008; National Institute of Standards and Technology, 11/2008, pp. 15-16]
FEMA Describes WTC 7 Damage - According to an earlier report on the collapse of WTC 7, published by the Federal Emergency Management Agency (FEMA) in May 2002 (see May 1, 2002), at that time, the “extent and severity of the resulting damage to WTC 7” when the North Tower collapses “are currently unknown.” But based on “photographic evidence and eyewitness accounts,” it is “assumed that the south side of the building was damaged to some degree.” FEMA’s report will state: “It does not appear that the collapse of WTC 1 affected the roof, or the east, west, and north elevations of WTC 7 in any significant way. However, there was damage to the southwest corner of WTC 7 at approximately floors 8 to 20, 24, 25, and 39 to 46.” The report will add: “According to firefighters’ eyewitness accounts from outside of the building, approximately floors 8-18 were damaged to some degree. Other eyewitness accounts relate that there was additional damage to the south elevation.” [Federal Emergency Management Agency, 5/1/2002, pp. 5-16, 5-20]
Structural Damage Not Responsible for Collapse - WTC 7 will collapse at 5:20 p.m. this afternoon (see (5:20 p.m.) September 11, 2001). [National Institute of Standards and Technology, 8/21/2008] However, NIST will conclude that the structural damage the building suffers plays no role in causing it to come down. NIST will state, “Other than initiating the fires in WTC 7, the damage from the debris from WTC 1 had little effect on initiating the collapse of WTC 7.” [National Institute of Standards and Technology, 11/2008, pp. xxxvii] WTC 7 suffers fires on some floors, which are reportedly initiated by debris from the collapse of the North Tower (see (10:28 a.m.-5:20 p.m.) September 11, 2001). According to NIST, it is these fires, “rather than the structural damage that resulted from the impacts” of debris, which “initiated the building’s collapse.” [National Institute of Standards and Technology, 8/21/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

World Trade Center Building 7 (WTC 7) suffers fires on several floors, some of which last until 5:20 p.m., when the building collapses. [National Institute of Standards and Technology, 8/21/2008] WTC 7 is a 47-story office building located just north of the Twin Towers. It is damaged when the north WTC tower (WTC 1) collapses at 10:28 a.m. (see 10:28 a.m. September 11, 2001). [National Institute of Standards and Technology, 11/2008, pp. 2, 16]
Fires Started by Collapse Debris - Two official reports on the collapse of WTC 7 will tentatively conclude that fires in this building are initiated by debris that is ejected when the North Tower collapses (see 10:28 a.m. September 11, 2001). In a 2002 report (see May 1, 2002), the Federal Emergency Management Agency (FEMA) will state, “It is likely that fires” in WTC 7 “started as a result of debris from the collapse of WTC 1.” [Federal Emergency Management Agency, 5/1/2002, pp. 5-20] In a 2008 report (see November 20, 2008), the National Institute of Standards and Technology (NIST) will state, “Most likely, the WTC 7 fires began as a result of burning debris from the collapse of WTC 1.” However, NIST will add, “visual evidence of fires in the building was not available until around noon.” [National Institute of Standards and Technology, 11/2008, pp. 18]
Fires Spread in WTC 7 - According to NIST, fires are ignited “on at least 10 floors” of WTC 7, but “only the fires on floors 7 through 9 and 11 through 13 grew and lasted until the time of the building collapse.” [National Institute of Standards and Technology, 11/2008, pp. xxxvi] NIST will state, “Early fires were seen on the southwest corner of floors 19, 22, 29, and 30 shortly after noon,” but “These were short-lived.” [National Institute of Standards and Technology, 11/2008, pp. 51] The fires on floors 7 to 9 and 11 to 13, however, “grew and spread, since they were not extinguished either by the automatic sprinkler system or by [the New York City Fire Department], because water was not available in WTC 7.” Fires are “generally concentrated on the east and north sides of the northeast region beginning at about 3 p.m. to 4 p.m.” [National Institute of Standards and Technology, 11/2008, pp. 21] The fires on floors 7 to 9 and 11 to 13 have “characteristics similar to those that have occurred previously in tall buildings,” according to NIST, and “Their growth and spread [are] consistent with ordinary building contents fires.” [National Institute of Standards and Technology, 11/2008, pp. xxxvi] These fires are “fed by combustibles (e.g., desks, chairs, papers, carpet) that were ordinary for commercial occupancies.” However, NIST will point out, there is “no evidence that the fires spread from floor to floor, except, perhaps, just prior to the collapse of the building.” [National Institute of Standards and Technology, 11/2008, pp. 51-52]
Limited Evidence Available - Both FEMA and NIST will admit that their accounts of the fires in WTC 7 are based upon imperfect evidence. In its report on the WTC collapses, published in May 2002, FEMA will note, “Currently, there is limited information about the ignition and development of fires at WTC 7.” [Federal Emergency Management Agency, 5/1/2002, pp. 5-20] In the final report of its investigation of the collapse of WTC 7, NIST will point out that “available images showing fires in WTC 7 did not allow the detailed description of fire spread that was possible for the WTC towers.” The report will add: “It must be kept in mind that [NIST’s] fire observations were based on images of the exterior faces, which provided little indication about the behavior of fires well removed from the exterior walls. It is likely that much of the burning took place beyond the views of the windows.” But, the report will state, “[T]here was sufficient information to derive general descriptions of fire ignition and spread on various floors of the building.” [National Institute of Standards and Technology, 11/2008, pp. 18]
NIST Blames Fires for Collapse - WTC 7 collapses at 5:20 p.m. this afternoon (see (5:20 p.m.) September 11, 2001). In late 2008, at the end of its investigation into WTC 7’s collapse, NIST will blame the fires WTC 7 suffers for causing its collapse (see August 21, 2008 and August 21, 2008). NIST will state: “The heat from the uncontrolled fires caused steel floor beams and girders to thermally expand, leading to a chain of events that caused a key structural column to fail. The failure of this structural column then initiated a fire-induced progressive collapse of the entire building.” [National Institute of Standards and Technology, 8/21/2008; National Institute of Standards and Technology, 11/2008, pp. xxxvi-xxxvii] However, critics will dispute this conclusion, instead blaming explosives for the collapse (see August 21, 2008). [New York Times, 8/21/2008] FEMA will offer no firm conclusions about the possible role fires play in causing WTC 7 to collapse. In its 2002 report it will state, “The specifics of the fires in WTC 7 and how they caused the building to collapse remain unknown at this time.” [Federal Emergency Management Agency, 5/1/2002, pp. 5-31]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Ronald Hamburger, a member of NIST’s WTC team and advocate of the ‘piledriver’ theory.Ronald Hamburger, a member of NIST’s WTC team and advocate of the ‘piledriver’ theory. [Source: National Council of Structural Engineers' Associations]After 9/11, the scientists investigating the WTC collapse give very different figures for the buildings’ weight. Some sources say that each building weighed 500,000 tons. For example, MIT professor Thomas Eager writes, “The total weight of each tower was about 500,000 t.” [Scientific American, 10/9/2001; Eagar and Musso, 12/2001; Frank Greening, 2/16/2006, pp. 23 pdf file; PBS, 8/2006] However, the National Institute of Standards and Technology (NIST) states that the buildings weighed only 250,000 tons each. [National Institute of Standards and Technology, 9/2005, pp. 32] One theory explaining the building’s total collapse is that the upper section acts as a “piledriver” and smashes through the floors below it. [BBC, 9/13/2001; Stanford Report, 12/5/2001] The heavier the upper block above the impact zone, the more likely it is to be able to destroy the other floors as it falls.

Entity Tags: World Trade Center, Thomas Eager, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Following the attacks, there is no agreement on the speed with which the Twin Towers of the World Trade Center collapsed on 9/11 (see 9:59 a.m. September 11, 2001 and 10:28 a.m. September 11, 2001). The 9/11 Commission says that the South Tower collapsed in “ten seconds” and the National Institute of Standards and Technology says that tops of the buildings came down “essentially in free fall.” [9/11 Commission, 7/24/2004, pp. 305; National Institute of Standards and Technology, 9/2005, pp. 146] In the dispute over the reason for the WTC’s collapse after 9/11, it is claimed that, if the towers fell in ten seconds, then this is evidence they were destroyed by explosives. For example, David Ray Griffin, a theologian and outspoken critic of commission’s report, writes, “For a 1,300-foot building, however, ten seconds is almost free-fall speed. But if each floor produced just a little resistance, so that breaking through each one took half a second, the collapse of all those floors—80 or 95 of them—would have taken 40 to 47 seconds. Can we really believe that the upper part of the buildings encountered virtually no resistance from the lower part?” [Griffin, 2004, pp. 16] But according to Canadian scientist Frank Greening, who studies the Twin Towers’ collapse, the freefall time would be about 9.6 seconds, and he calculates that it takes longer for the buildings to fall—twelve to thirteen and a half seconds—and states this does not indicate that explosives were used. [Canadian Broadcasting Corporation, 8/25/2005]

Entity Tags: World Trade Center, Frank Greening, National Institute of Standards and Technology, David Ray Griffin, 9/11 Commission

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

A sample of WTC steel eroded and corroded due to eutectic formations.A sample of WTC steel eroded and corroded due to eutectic formations. [Source: FEMA]The Journal of the Minerals, Metals and Materials Society (JOM) reports that the examination of a beam from the remains of WTC Building 7—which collapsed late in the afternoon of 9/11 (see (5:20 p.m.) September 11, 2001)—has revealed “unexpected erosion” of the steel. The article states: “The formation of the eutectic mixture of iron oxide and iron sulfide lowers the temperature at which liquid can form in this steel. This strongly suggests that the temperatures in this region of the steel beam approached around 1,000°C, forming the eutectic liquid by a process similar to making a ‘blacksmith’s weld’ in a hand forge.” [Barnett, Biederman, and Sisson, 12/2001] The New York Times will call this “perhaps the deepest mystery uncovered in the investigation.” [New York Times, 2/2/2002] FEMA’s World Trade Center Building Performance Study, released in May 2002 (see May 1, 2002), will add that the same “unusual erosion patterns” have been observed in a sample of the remaining structural steel from one of the Twin Towers. It will state, “This sulfur-rich liquid penetrated preferentially down grain boundaries of the steel, severely weakening the beam and making it susceptible to erosion.” FEMA is unable to explain this phenomenon, saying, “The severe corrosion and subsequent erosion… are a very unusual event. No clear explanation for the source of the sulfur has been identified.… It is possible that this is the result of long-term heating in the ground following the collapse of the buildings. It is also possible that the phenomenon started prior to collapse and accelerated the weakening of the steel structure.” [Federal Emergency Management Agency, 5/1/2002, pp. C-1 - C-13] Despite FEMA’s call for further research, the National Institute of Standards and Technology (NIST) will make no mention of the eutectic formations in its final report into the WTC collapses, released in late 2005, following its three-year investigation. [National Institute of Standards and Technology, 9/2005, pp. 13]

Entity Tags: National Institute of Standards and Technology, World Trade Center, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST)—an agency of the US Commerce Department’s Technology Administration—announces details of its forthcoming investigation into the collapses of the World Trade Center Twin Towers and Building 7 on 9/11. The NIST investigation aims “to investigate the building construction, the materials used, and the technical conditions that contributed to the outcome of the World Trade Center (WTC) disaster.” It also aims to examine the activities of building occupants and emergency responders on 9/11, studying such issues as emergency communications within the WTC, the movement of people during the evacuations, and issues around persons with disabilities. Leading technical experts from industry, academia, and other laboratories, alongside NIST’s own expert staff, will participate in the investigation. Expert professionals from the private sector will also be involved. Glenn Corbett, a fire science professor at John Jay College, says, “This is going to be the most extensive building disaster investigation ever performed.” [Associated Press, 8/21/2002; National Institute of Standards and Technology, 8/21/2002; National Institute of Standards and Technology, 8/3/2005] The investigation is formally authorized in October 2002, when the National Construction Safety Team Act is signed into law. The act, which gives NIST authorization to investigate major building failures in the US, is written largely as a result of the World Trade Center collapses. [National Institute of Standards and Technology, 10/2/2002; New York Times, 5/8/2003] NIST’s investigation is originally proposed to last two years, with a budget of $16 million. [National Institute of Standards and Technology, 8/21/2002] However, it eventually will last three years, with its final report into the collapses of the Twin Towers being released in October 2005 (see October 26, 2005). A previous analysis of the WTC collapses conducted by FEMA and the American Society of Civil Engineers (ASCE) was completed earlier in 2002 (see May 1, 2002), but this had a budget of just $1.1 million. By the time NIST starts its investigation, much of the crucial steel debris from the WTC collapses has already been destroyed (see September 12-October 2001). They later refer to there being a “scarcity of physical evidence that is typically available in place for reconstruction of a disaster.” [National Institute of Standards and Technology, 9/2005, pp. xxxvi]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Glenn Corbett

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

One of the key variables in the computer simulations used by the National Institute of Standards and Technology (NIST) (see (October 2002-October 2005)) to explain the WTC collapses is the speed of the aircraft that hit the towers. However, there is no consensus on how fast the planes were traveling. The first estimate was contained in an initial research paper by engineers Zdenek Bazant and Yong Zhou, who stated that the planes were traveling at 342 miles per hour. [Bazant and Zhou, 1/2002 pdf file] However, the Federal Emergency Management Agency (FEMA) and American Society of Civil Engineers (ASCE) report said that the plane that hit the North Tower was traveling at 470 miles per hour, whereas the plane that hit the South Tower was traveling at 590 miles per hour (see May 1, 2002). [Federal Emergency Management Agency, 5/1/2002, pp. 31] NIST initially estimates speeds of 435 miles per hour for the plane that hit the North Tower and 497 miles per hour for the plane that hit the South Tower. These estimates closely match figures produced by the Massachusetts Institute of Technology, which finds speeds of 429 miles per hour and 503 miles per hour for the two planes. However, NIST is dissatisfied with these results and does a second study, which finds speeds of 466 and 545 miles per hour. It then uses speeds of 472 and 570 miles per hour in its severe case model, on which its final report is based. In this model, the simulation of the planes traveling faster means greater damage to the towers’ structure, making them more unstable. [Kausel, 5/2002 pdf file; National Institute of Standards & Technology, 9/2005, pp. 152-165 pdf file; National Institute of Standards and Technology, 9/2005, pp. 109]

Entity Tags: Zdenek Bazant, National Institute of Standards and Technology, World Trade Center, Yong Zhou, Massachusetts Institute of Technology, American Society of Civil Engineers, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

During the course of its three-year investigation of the World Trade Center collapses, the National Institute of Standards and Technology (NIST) performs computer simulations of the behavior of each WTC tower on 9/11. In its final report, released in October 2005 (see October 26, 2005), it will describe having determined which variables most affected the outcome of its various simulations. Then, “[f]or each of the most influential variables, a central or middle value and reasonable high and low values were identified.” However, “[u]pon a preliminary examination of the middle cases, it became clear that the towers would likely remain standing. The less severe cases were discarded after the aircraft impact results were compared to observed events. The middle cases… were discarded after the structural response analysis of major subsystems were compared to observed events.” Therefore, the “more severe case… was used for the global analysis of each tower.” But, to “the extent that the simulations deviated from the photographic evidence or eyewitness reports, the investigators adjusted the input, but only within the range of physical reality.” [National Institute of Standards and Technology, 9/2005, pp. 143-144]

Entity Tags: National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Insulated trusses in the World Trade Center.
Insulated trusses in the World Trade Center. [Source: Gilsanz Murray Steficek]At a press briefing in New York City, the National Institute of Standards and Technology (NIST) releases a 122-page progress report on its investigation into the WTC collapses. NIST began its study in August 2002 (see August 21, 2002). Investigators say they believe that the Port Authority of New York and New Jersey, who built the Twin Towers, failed to carry out vital tests to establish how the buildings would cope with a major fire. They have been unable to find evidence that tests were conducted on the fireproofing material used in the buildings. Their report also states that in 1969, builders directed contractors to coat the WTC floor supports with half an inch of spray-on fireproofing. In 1999, the Port Authority issued guidelines to triple the thickness of the fireproofing, and by 9/11, about 30 floors in the upper areas of the two towers had been upgraded. Almost all the floors in the impact zone of the North Tower had their fireproofing upgraded, while in the South Tower just the 78th floor—the lowest in its impact zone—had been upgraded. As the New York Times states, though, “investigators took great care… to say they were nowhere close to definitively determining how and why the towers collapsed after they were struck by hijacked airliners.” [National Institute of Standards and Technology, 5/2003, pp. 81 pdf file; National Institute of Standards and Technology, 5/7/2003; Guardian, 5/8/2003; New York Times, 5/8/2003]

Entity Tags: National Institute of Standards and Technology, Port Authority of New York and New Jersey, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

At the end of a two-day meeting to discuss the progress of their investigation of the WTC collapses on 9/11, National Institute of Standards and Technology (NIST) investigators say that early tests on steel beams recovered from the World Trade Center showed they met or were stronger than design requirements. NIST has collected 236 pieces of steel from the wreckage of the towers. Tests have found that the steel beams exceeded requirements to bear 36,000 pounds per square inch, and were often capable of bearing around 42,000 pounds per square inch. Lead investigator Shyam Sunder says that if further testing corroborates these findings, this will rule out weak steel as a factor in the collapses. [National Institute of Standards and Technology, 8/26/2003; Associated Press, 8/28/2003] The final report of the NIST investigation, released in 2005, will corroborate this finding: “Overall, approximately 87 percent of all perimeter and core column steel tested exceeded the required minimum yield strengths specified in design documents. Test data for the remaining samples were below specifications, but were within the expected variability and did not affect the safety of the towers on September 11, 2001.” It also will point out: “Of the more than 170 areas examined on 16 perimeter column panels, only three columns had evidence that the steel reached temperatures above 250°C.… Only two core column specimens had sufficient paint remaining to make such an analysis, and their temperatures did not reach 250°C.… Using metallographic analysis, NIST determined that there was no evidence that any of the samples had reached temperatures above 600 °C.” [National Institute of Standards and Technology, 9/2005, pp. 89-90]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST) issues a progress report on its investigation into the World Trade Center collapses. Since 2002, NIST has been investigating the collapses of the Twin Towers and WTC Building 7 (see August 21, 2002). The progress report includes its “working hypothesis” for the collapse of WTC 7. This was a 47-story building, located about 350 feet from the north side of WTC 1, which collapsed completely at around 5:20 in the afternoon of 9/11. The report claims that “fire appears to have played a key role” in the collapse, though it points out, “No fire was observed or reported in the afternoon on floors 1-5, 10, or above Floor 13.” It also says, “there may have been some physical damage on the south side of the building.” NIST summarizes its working hypothesis of the WTC 7 collapse as follows:
bullet “An initial local failure at the lower floors (below Floor 13) of the building due to fire and/or debris induced structural damage of a critical column (the initiating event), which supported a large span floor bay with an area of about 2,000 square feet.”
bullet “Vertical progression of the initial local failure up to the east penthouse, as large floor bays were unable to redistribute the loads, bringing down the interior structure below the east penthouse.”
bullet “Horizontal progression of the failure across the lower floors… triggered by damage due to the vertical failure, resulting in the disproportionate collapse of the entire structure.”
NIST claims this hypothesis “is consistent with all evidence currently held by NIST, including photographs and videos, eyewitness accounts and emergency communication records,” but says it “will be revised and updated as results of ongoing, more comprehensive analyses become available.” [National Institute of Standards and Technology, 6/2004, pp. L1, L3, L17, L34, L38, L51-L52 pdf file; National Institute of Standards and Technology, 6/18/2004] NIST will release its final reports on the collapses of the Twin Towers in October 2005 (see October 26, 2005). As of mid-2007, it has yet to release a final report on the collapse of WTC 7. In early 2006, Dr. S. Shyam Sunder, who is the lead investigator for NIST’s WTC investigation, will admit, “truthfully, I don’t really know” what caused WTC 7 to collapse. He will add, “We’ve had trouble getting a handle on building no. 7” (see March 20, 2006). [New York Magazine, 3/20/2006] An earlier report on the WTC collapses, released by the Federal Emergency Management Agency (FEMA) in May 2002, had been inconclusive on what caused WTC 7 to collapse, and stated that “Further research, investigation, and analyses” were necessary (see May 1, 2002). [Federal Emergency Management Agency, 5/1/2002, pp. 5-31]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Shyam Sunder.Shyam Sunder. [Source: NIST]The National Institute of Standards and Technology (NIST) releases nearly 500 pages of documents, detailing the latest findings of its investigation of the WTC collapses on 9/11. These include its hypotheses for the collapse sequences of each of the Twin Towers; details of their analysis of interviews with nearly 1,200 building occupants, emergency responders, and victims’ relatives; and information from their analysis of the emergency response and evacuation procedures. Their investigation into the collapses is based upon an analysis of thousands of photos and videos, examination of many of the elements used to construct the towers, and computer-enhanced modeling of the plane impacts and the spreading of the fires. Their hypothesis is that the towers collapsed ultimately due to the fires they suffered: As the fires burned, the buildings’ steel core columns buckled and shortened. This shifted more load to the buildings’ perimeter columns, which were already affected by the heat of the fires, and caused them to give way under the increased stress. Investigators have conducted a test with a reconstructed section of the WTC floor, and found that the original fireproofing was sufficient to meet the New York City building code. They say that had a typical office fire occurred in the towers, without the structural damage and the loss of some fireproofing caused by the plane impacts, it is likely the buildings would have remained standing. Lead investigator Dr. Shyam Sunder says, “The buildings performed as they should have in the airplane impact and extreme fires to which they were subjected. There is nothing there that stands out as abnormal.” NIST’s theories of why the WTC buildings collapsed conflict with an earlier investigation by FEMA, which claimed the collapse of the North Tower had begun in its core, rather than its perimeter columns (see May 1, 2002). [National Institute of Standards and Technology, 10/19/2004; New York Times, 10/20/2004]

Entity Tags: Shyam Sunder, National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Kevin Ryan.Kevin Ryan. [Source: Public domain]Kevin Ryan, the laboratory director at Environmental Health Laboratories Inc., which is a subsidiary of Underwriters Laboratories Inc., writes an e-mail to the National Institute of Standards and Technology (NIST)—the agency currently investigating the WTC collapses—in which he challenges the official theory regarding the WTC collapses. According to Ryan, Underwriters Laboratories Inc. was the company that certified the steel components used in the construction of the World Trade Center, and it had been agreed that the samples it certified met all requirements. His e-mail states, “This story just does not add up. If steel from [the Twin Towers] did soften or melt, I’m sure we can all agree that this was certainly not due to jet fuel fires of any kind, let alone the briefly burning fires in those towers.” His e-mail is published on the Internet, and generates interest on many websites. Days later, Kevin Ryan is fired because, according to a company spokesman, he “expressed his own opinions as though they were institutional opinions and beliefs” of Underwriters Laboratories. According to Underwriters Laboratories, “there is no evidence” that any firm tested the materials used to build the towers. They also say that Ryan was not involved in any way with their fire protection division, which had conducted testing at NIST’s request. [South Bend Tribune, 11/22/2004]

Entity Tags: National Institute of Standards and Technology, Underwriters Laboratories Inc., Kevin Ryan, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST), which is conducting an investigation into the WTC collapses on 9/11, releases three new reports. Investigators say that the Twin Towers would probably have remained standing if the fireproofing material that surrounded the buildings’ structural steel had not been stripped away when the planes hit. Their report states that “[t]he jet fuel, which ignited the fires, was mostly consumed within the first few minutes after impact. The fires that burned for almost the entire time that the buildings remained standing were due mainly to burning building contents and, to a lesser extent, aircraft contents, not jet fuel.” However, they claim, without the loss of fireproofing during the planes’ impacts, the heat from the fires would have been insufficient to cause the buildings to collapse. They say that although the architects had in 1964 tested the impact of a Boeing 707 airplane crashing into the 80th floor of one of the towers, they never envisioned the intense fires that ensued. NIST also reports that the time taken by survivors from the North Tower to descend a flight of stairs was about double the slowest evacuation speed estimated in a standard fire engineering text. They state: “approximately 87 percent of the WTC tower occupants, including more than 99 percent below the floors of impact, were able to evacuate successfully.” However, they say, if each tower had been full when they were hit, as many as 14,000 people could have died. [National Institute of Standards and Technology, 4/5/2005; Associated Press, 4/5/2005; New York Times, 4/5/2005; Associated Press, 4/6/2005]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Based upon its three-year investigation of the WTC collapses, the National Institute of Standards and Technology (NIST) calls for changes in the planning, construction, and operation of skyscrapers. NIST releases 43 draft reports, totaling about 10,000 pages, for public comments. These include 25 pages of recommendations, intended to learn from 9/11 and make building occupants and emergency responders safer in any future disasters. NIST’s inquiry has been conducted by more than 200 technical experts and contractors, and had two main parts: to look at the causes of the collapses and to identify weaknesses in building codes. Their recommendations include specific improvements to building standards, codes and practices; changes to evacuation and emergency response procedures; and research to help prevent future building failures. NIST does not have the authority to change building codes, but hopes to influence the policies of local authorities. The cost of implementing their recommended changes would add an estimated extra 2 to 5 percent to the development costs of buildings. Some are critical of their recommendations. Structural engineer Jon Magnusson, whose firm is the descendant of the company that designed the Twin Towers, says, “They are leading the public down the wrong path. They are saying we are going to fix the codes in order to deal with Sept. 11th. The physics say that you can’t do that.” [New York Times, 6/22/2005; National Institute of Standards and Technology, 6/23/2005; Associated Press, 6/24/2005] The New York Times points out that between 1989 and 1999, only five civilians had been killed in some 6,900 reported high-rise office building fires within the US. [New York Times, 6/24/2005] NIST will release its final report on the Twin Towers collapses four months later (see October 26, 2005).

Entity Tags: National Institute of Standards and Technology, World Trade Center, Jon Magnusson

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Both towers of the World Trade Center tilted to one side before beginning to fall on 9/11 (see 9:59 a.m. September 11, 2001 and 10:28 a.m. September 11, 2001). The National Institute of Standards and Technology, which investigated the collapses (see August 21, 2002), states that the South Tower, which was hit on its south side, tilted about 7-8 degrees to the east and 3-4 degrees to the south, and the North Tower, which was hit on its north side, tilted about 8 degrees to the south, before starting to fall. [National Institute of Standards and Technology, 9/2005, pp. 300, 308 pdf file] However, these findings are criticized by Canadian scientist Frank Greening. After examining photo and video evidence, Greening says that the South Tower tilted by no more than two degrees and the North Tower by no more than three degrees before collapse initiation. Greening also says that the tilt angles NIST gives cannot correspond to the downward movement of the towers’ walls NIST claims before they started to fall, and points out that the tilt angles NIST uses are inconsistent throughout its reports. Though Greening agrees with NIST that the towers were destroyed by the plane impacts and fire damage, he concludes that its computer model is “highly inaccurate and therefore of no value in explaining the demise of the Twin Towers.” [Greening, 11/2005 pdf file] Greening is a leading figure in the post-9/11 dispute over why the WTC collapsed and publishes a series of papers dealing with various aspects of the Twin Towers’ collapse. For example, a CBC documentary uses Greening for analysis of the WTC’s fall. [Canadian Broadcasting Corporation, 8/25/2005]

Entity Tags: World Trade Center, Frank Greening, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The British publication New Civil Engineer reports that, despite calls from leading structural and fire engineers, WTC collapse investigators with the National Institute of Standards and Technology (NIST) are refusing to show computer visualizations of the Twin Towers’ collapses. Despite having shown detailed computer generated visualizations of the plane impacts and the development of fires in the WTC at a recent conference, it showed no visualizations of the actual collapse mechanisms of the towers. Colin Bailey, a professor of structural engineering at the University of Manchester, complains, “NIST should really show the visualisations; otherwise the opportunity to correlate them back to the video evidence and identify any errors in the modelling will be lost.” A leading US structural engineer says that NIST’s “global structural model” is less sophisticated than its plane impact and fire models: “The software used has been pushed to new limits, and there have been a lot of simplifications, extrapolations and judgement calls.” [New Civil Engineer, 10/6/2005]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Colin Bailey

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

National Institute of Standards and Technology (NIST) releases a 12-page appendix to its final reports on the WTC collapses (see October 26, 2005) detailing tests it conducted on samples of the type of fireproofing used in the WTC. An earlier NIST report had concluded that loss of fireproofing was a major factor in the collapses (see April 5, 2005). The appendix was not included in earlier drafts of the report (see June 23, 2005) [National Institute of Standards and Technology, 6/23/2005 pdf file; National Institute of Standards & Technology, 9/2005, pp. 263-274 pdf file; National Institute of Standards and Technology, 9/2005, pp. 149] NIST conducted a series of fifteen tests. In the tests projectiles were fired at fireproofing mounted on 12 inch x 12 inch plates, and steel bars with a one inch diameter. The fireproofing used in the tests was Blazeshield DC/F, one of the two grades of fireproofing used on the impact floors. In thirteen of the tests the projectiles were buckshot, which was fired at the steel samples from a modified shotgun at a distance of 29.5 ft. The other two tests used steel bolts and hexagon nuts, fired with less velocity and at closer range. According to NIST, “The test results support the assumption that, within the debris field created by the aircraft impact into WTC 1 and WTC 2, the SFRM [i.e., fireproofing] used for thermal insulation of structural members was damaged and dislodged.” [National Institute of Standards & Technology, 9/2005, pp. 83, 263-274 pdf file]

Entity Tags: National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

James Quintiere.James Quintiere. [Source: University of Maryland]During a House Science Committee hearing on the key findings and recommendations of the National Institute of Standard and Technology (NIST) investigation into World Trade Center collapse, a fire expert raises several concerns. James Quintiere is a professor of fire protection engineering at the University of Maryland, with over 35 years of experience in fire research. He’d worked in the fire program at NIST for 19 years, and is a former chair of the International Association for Fire Safety Science, which is the principal world forum for fire research. In his statement presented at the hearing, Quintiere lists several specific concerns that he’d submitted to NIST, but which were never acknowledged or answered. These include:
bullet “Why were not alternative collapse hypotheses investigated and discussed as NIST had stated repeatedly that they would do?”
bullet “Spoliation of a fire scene is a basis for destroying a legal case in an investigation. Most of the steel [from the WTC] was discarded.… A careful reading of the NIST report shows that they have no evidence that the temperatures they predict as necessary for failure are corroborated by findings of the little steel debris they have.”
bullet “NIST used computer models that they said have never been used in such an application before and are the state of the art.… But the validation of these modeling results is in question.”
bullet “The critical collapse of WTC 7 is relegated to a secondary role.… Why has NIST dragged on this important investigation?”
Quintiere also complains, “In my opinion, the WTC investigation by NIST falls short of expectations by not definitively finding cause, by not sufficiently linking recommendations of specificity to cause, by not fully invoking all of their authority to seek facts in the investigation, and by the guidance of government lawyers to deter rather than develop fact finding.” [US Congress. House. Committee on Science, 10/26/2005]

Entity Tags: World Trade Center, James Quintiere, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The 43 NIST reports ran to over 10,000 pages.The 43 NIST reports ran to over 10,000 pages. [Source: NIST]The National Institute of Standards and Technology (NIST) issues the final report of its three-year, $16 million study into the WTC collapses on 9/11. NIST has produced over 10,000 pages of findings, and its report includes 30 recommendations for improving building safety, such as having wider stairwells and structurally hardened elevators for use in emergencies. The recommendations are mostly the same as those outlined in an earlier draft of the report (see June 23, 2005). [Engineering News-Record, 10/27/2005; New York Times, 10/27/2005] NIST has made some amendments and clarifications, though, based upon nearly 500 comments received during a six-week public review period. [National Institute of Standards and Technology, 10/26/2005] NIST’s theory about what caused the Twin Towers to collapse remains the same as that described in its previously released findings (see October 19, 2004). However, the NIST’s account only examines events up to the initiation of each collapse; the investigation “does not actually include the structural behavior of the tower after the conditions for collapse initiation were reached and collapse became inevitable.” [National Institute of Standards and Technology, 9/2005, pp. 82] NIST makes no mention of molten metal found at the collapse site in the weeks and months after 9/11, which has been described in numerous reports (see September 12, 2001-February 2002). The “NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down by controlled demolition using explosives planted prior to September 11, 2001.” [National Institute of Standards and Technology, 9/2005, pp. 146] Members of Congress are critical of NIST’s recommendations, saying they are not detailed enough, or adequately documented, to be rapidly incorporated into standard building code publications. [New York Times, 10/27/2005] According to Glenn Corbett, a technical adviser to NIST and fire science professor at John Jay College, NIST is not aggressive enough to carry out major forensic investigations. He says, “Instead of a gumshoe inquiry that left no stone unturned, I believe the investigations were treated more like research projects in which they waited for information to flow to them.” [Associated Press, 10/26/2005; US Congress, 10/26/2005 pdf file] NIST will release its final report on the collapse of Building 7 of the WTC separately, at a later date. [National Institute of Standards and Technology, 9/2005, pp. xiii]

Entity Tags: World Trade Center, Glenn Corbett, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Dr. S. Shyam Sunder, head of the National Institute of Standards and Technology government investigation into the collapse of the World Trade Center building, is asked about the collapse of WTC Building 7. Sunder says that he hopes to release something about that by the end of 2006. He adds, NIST did have some “preliminary hypotheses… We are studying the horizontal movement east to west, internal to the structure, on the fifth to seventh floors.… But truthfully, I don’t really know. We’ve had trouble getting a handle on building No. 7.” [New York Magazine, 3/20/2006]

Entity Tags: Shyam Sunder, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

One of the ‘puffs of smoke’ observed during the Twin Towers collapses.One of the ‘puffs of smoke’ observed during the Twin Towers collapses. [Source: Richard Lethin]The National Institute of Standards and Technology (NIST) issues a seven-page fact sheet to counter alternative theories about the WTC collapses. NIST conducted a three-year study of the collapses, and concluded they were caused by the damage when the planes hit combined with the effects of the ensuing fires. However, many people—what the New York Times calls an “angry minority”—believe there was US government complicity in 9/11, and a recent poll (see July 6-24, 2006) found 16 percent of Americans believe the WTC towers were brought down with explosives. [National Institute of Standards and Technology, 8/31/2006; New York Times, 9/2/2006; Reuters, 9/2/2006] The fact sheet responds to 14 “Frequently Asked Questions.” Some of its key points include the following:
bullet Regarding whether NIST considered a controlled demolition hypothesis: “NIST found no corroborating evidence for alternative hypotheses suggesting that the WTC towers were brought down… using explosives… 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.” However, it admits, “NIST did not test for the residue” of explosives in the remaining steel from the towers.
bullet Its explanation for puffs of smoke seen coming from each tower as it collapsed: “[T]he falling mass of the building compressed the air ahead of it—much like the action of a piston—forcing smoke and debris out the windows as the stories below failed sequentially.”
bullet Its explanation for a stream of yellow molten metal that poured down the side of the South Tower shortly before it collapsed (see (9:50 a.m.) September 11, 2001). NIST previously claimed it was aluminum, but this should not have been yellow in color: “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.”
bullet Regarding reports of molten steel in the wreckage at Ground Zero (see September 12, 2001-February 2002): “Any molten steel in the wreckage was more likely due to the high temperature resulting from long exposure to combustion within the pile than to short exposure to fires or explosions while the buildings were standing.”
bullet Regarding the collapse of WTC 7 (see (5:20 p.m.) September 11, 2001): “While NIST has found no evidence of a blast or controlled demolition event, NIST would like to determine the magnitude of hypothetical blast scenarios that could have led to the structural failure of one or more critical elements.” [National Institute of Standards and Technology, 8/30/2006] In response to the fact sheet, Kevin Ryan, the coeditor of the online Journal of 9/11 Studies, says, “The list of answers NIST has provided is generating more questions, and more skepticism, than ever before.” He says, “NIST is a group of government scientists whose leaders are Bush appointees, and therefore their report is not likely to veer from the political story.” [New York Times, 9/2/2006; Reuters, 9/2/2006]

Entity Tags: National Institute of Standards and Technology, Kevin Ryan

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

In a reply to criticisms of its World Trade Center investigation, the National Institute of Standards and Technology (NIST) admits that it is unable to fully explain the total collapse of the Twin Towers on 9/11. NIST’s letter is a response to a “request for correction” letter sent to it five months earlier by Bob McIlvaine and Bill Doyle, who both lost family members on 9/11, along with scientists Kevin Ryan and Steven E. Jones, architect Richard Gage, and the group Scholars for 9/11 Truth and Justice. This letter made several assertions about NIST’s final reports of its WTC investigation, and suggested they had violated the Data Quality Act and NIST’s information quality standards. NIST’s reply denies the requests for corrections. However, it also mentions, “[W]e are unable to provide a full explanation of the total collapse” of the World Trade Center. [National Institute of Standards and Technology, 9/27/2007 pdf file] In its final report on the Twin Towers collapses, released in October 2005, NIST admitted that its investigation did “not actually include the structural behavior of the tower after the conditions for collapse initiation were reached and collapse became inevitable” (see October 26, 2005). [National Institute of Standards and Technology, 9/2005, pp. 82]

Entity Tags: National Institute of Standards and Technology, World Trade Center

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST) publishes a fact sheet responding to 14 “frequently asked questions” about its investigation into the collapse of the Twin Towers on September 11. Some of the key questions and answers are as follows:
bullet Regarding the question, “Why was the collapse of WTC 1 and 2 not arrested by the intact structure below the floors where columns first began to buckle?” NIST replies, “The vertical capacity of the connections supporting an intact floor below the level of collapse was adequate to carry the load of 11 additional floors if the load was applied gradually and 6 additional floors if the load was applied suddenly (as was the case).” As the number of floors above the points where the collapses initiated exceeded six (12 in the case of the North Tower, 29 for the South), NIST says, “[T]he floors below the level of collapse initiation were unable to resist the suddenly applied gravitational load from the upper floors of the buildings.”
bullet In answer to the question of “Why was physical evidence not collected immediately following the collapse of the WTC towers,” NIST says, “In the initial days and weeks following the WTC disaster, the emphasis was on rescue and later on recovery, necessitating the removal of steel and disturbing the collapse site.” It adds, “NIST did not receive the legal authority to collect and preserve physical evidence from a disaster/failure site until the National Construction Safety Team Act became law in October 2002.” The decision to rapidly scrap the remaining steel from the WTC was made shortly after 9/11 (see Shortly After September 11, 2001), but the destruction of this steel was strongly protested by some within the engineering and firefighting communities (see December 25, 2001 and January 4, 2002).
bullet In response to a question about why it did not use its subpoena authority during its investigation, NIST states that its “experience during the investigation was that it was able to obtain all essential documentary and visual evidence without the need to invoke subpoena authority.”
bullet In answer to the question, “Why didn’t NIST fully model the collapse initiation and propagation of WTC towers?” NIST says, “Once the collapse had begun, the propagation of the collapse was readily explained without the same complexity of modeling” as was used to determine the sequence of events leading up to the collapse initiation.
bullet During its investigation, NIST had selected several variables for its computer simulations, and then experimented with different possible values (see (October 2002-October 2005)). But it has been asked: “Why didn’t NIST consider the ‘base’ and ‘less severe’ cases throughout its analysis of the WTC towers? What was the technical basis for selecting only the ‘more severe’ case for its analyses?” Its answer is that, “Of the three [possible values], the more severe case resulted in the closest agreement with the visual and physical evidence.” [National Institute of Standards and Technology, 12/14/2007]
NIST published its final report on the Twin Towers collapse in October 2005 (see October 26, 2005). It released an earlier fact sheet answering previous “frequently asked questions” in August 2006 (see August 30, 2006). [National Institute of Standards and Technology, 8/30/2006]

Entity Tags: National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

For the first time, a scientific journal publishes a letter by scientists who think the World Trade Center buildings were destroyed by explosives, rather than impact damage and fire. The letter, cautiously entitled “Fourteen Points of Agreement with Official Government Reports on the World Trade Center Destruction,” is published in the Open Civil Engineering Journal. The lead author is Steven E. Jones, a physicist formerly at Brigham Young University. The abstract says: “Reports by FEMA and NIST lay out the official account of the destruction of the World Trade Center on 9/11/2001. In this Letter, we wish to set a foundation for productive discussion and understanding by focusing on those areas where we find common ground with FEMA and NIST, while at the same time countering several popular myths about the WTC collapses.” [Open Civil Engineering Journal, 4/8/2008; Deseret News, 5/3/2008] However, unlike the vast majority of journals, the Open Civil Engineering Journal charges authors to publish their articles or letters in it. [Open Civil Engineering Journal, 2007]

Entity Tags: National Institute of Standards and Technology, Steven E. Jones, Federal Emergency Management Agency

Timeline Tags: Complete 911 Timeline

The National Institute of Standards and Technology (NIST) releases a draft version of the final report of its investigation of the collapse of World Trade Center Building 7, the 47-story skyscraper which collapsed late in the afternoon of 9/11 (see (5:20 p.m.) September 11, 2001). [National Institute of Standards and Technology, 8/21/2008] The report describes NIST’s conclusions on how fires that followed the impact of debris from the north WTC tower’s collapse resulted in the eventual collapse of WTC 7. It evaluates the emergency response and building evacuation procedures, and provides 13 recommendations for construction of buildings in the future, and improved procedures and practices. [National Institute of Standards and Technology, 8/2008, pp. xiii pdf file] Some of the report’s key findings are:
bullet NIST describes its theory of what caused WTC 7 to collapse: “The probable collapse sequence… was initiated by the buckling of a critical interior column.… This column had become unsupported over nine stories after initial local fire-induced damage led to a cascade of local floor failures. The buckling of this column led to a vertical progression of floor failures up to the roof and to the buckling of adjacent interior columns to the south of the critical column. An east-to-west horizontal progression of interior column buckling followed, due to loss of lateral support to adjacent columns, forces exerted by falling debris, and load redistribution from other buckled columns. The exterior columns then buckled as the failed building core moved downward, redistributing its loads to the exterior columns. Global collapse occurred as the entire building above the buckled region moved downward as a single unit.” [National Institute of Standards and Technology, 8/2008, pp. xxxii pdf file]
bullet The collapse of WTC 7 “represents the first known instance of the total collapse of a tall building primarily due to fires. The collapse could not have been prevented without controlling the fires before most of the combustible building contents were consumed.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet The fires in WTC 7 “were ignited as a result of the impact of debris from the collapse of WTC 1, which was approximately 370 ft to the south.… The fires were ignited on at least 10 floors; however, only the fires on floors 7 through 9 and 11 through 13 grew and lasted until the time of the building collapse.” [National Institute of Standards and Technology, 8/2008, pp. xxxi-xxxii pdf file]
bullet “Even without the initial structural damage caused by debris impact from the collapse of WTC 1, WTC 7 would have collapsed from fires having the same characteristics as those experienced on September 11, 2001.” [National Institute of Standards and Technology, 8/2008, pp. 44 pdf file]
bullet “Had a water supply for the automatic sprinkler system been available and had the sprinkler system operated as designed, it is likely that fires in WTC 7 would have been controlled and the collapse prevented.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet Other skyscrapers had previously survived comparable fires. “The fires in WTC 7 were similar to those that have occurred previously in several tall buildings (One New York Plaza, 1970, First Interstate Bank, 1988, and One Meridian Plaza, 1991) where the automatic sprinklers did not function or were not present. However, because of differences between their structural designs and that of WTC 7, these three buildings did not collapse.” [National Institute of Standards and Technology, 8/2008, pp. 43 pdf file]
bullet NIST found that “temperatures did not exceed 300°C in the core or perimeter columns in WTC 7,” including the three interior columns that NIST says were the first to buckle in the collapse. “None of these columns were significantly weakened by elevated temperatures.” [National Institute of Standards and Technology, 8/2008, pp. 49-50 pdf file]
bullet NIST says it found “no evidence to suggest that WTC 7 was not designed in a manner generally consistent with applicable building codes and standards.” [National Institute of Standards and Technology, 8/2008, pp. 53 pdf file]
bullet The report concludes that neither explosives nor fuel oil fires fed by diesel tanks in WTC 7 played any role in the collapse (see August 21, 2008 and August 21, 2008). [National Institute of Standards and Technology, 8/2008, pp. 44-45 pdf file]
bullet However, the report points out that WTC 7 “and the records kept within it were destroyed, and the remains of all the WTC buildings were disposed of before congressional action and funding was available for this investigation to begin. As a result, there are some facts that could not be discerned, and thus there are uncertainties in this accounting. Nonetheless, NIST was able to gather sufficient evidence and documentation to conduct a full investigation upon which to reach firm findings and recommendations.” [National Institute of Standards and Technology, 8/2008, pp. xxxi pdf file]
NIST released a progress report in June 2004, which had included its “working hypothesis” at that time for the collapse of WTC 7 (see June 18, 2004). [National Institute of Standards and Technology, 6/18/2004] After suggestions are made by members of the public in response to the current draft report, NIST will release the finished version of the report in November 2008, which includes the same major findings and recommendations as the draft version (see November 20, 2008). [National Institute of Standards and Technology, 11/20/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

The National Institute of Standards and Technology (NIST) publicly rejects the theory that diesel fuel tanks installed in World Trade Center Building 7 played any role in the 47-story tower’s collapse, late in the afternoon of 9/11. This is clearly set out in a question-and-answer factsheet published on this day, together with an announcement of NIST’s draft report on the building’s collapse (see August 21, 2008 and August 21, 2008). The factsheet asks, “Did fuel oil systems in WTC 7 contribute to its collapse?” The answer is “No…. The worst-case scenarios associated with fires… could not have been sustained long enough, could not have generated sufficient heat to weaken critical interior columns, and/or would have produced large amounts of visible smoke from the lower floors, which were not observed.” [National Institute of Standards and Technology, 8/21/2008; New York Times, 8/21/2008] These findings are echoed in the draft version of its final report on the collapse. [National Institute of Standards and Technology, 8/2008, pp. xxxii pdf file] WTC 7 had three emergency power systems, all of which ran on diesel fuel. The systems contained two 12,000 gallon fuel tanks and two 6,000 gallon tanks located beneath the building’s loading docks, and another 6,000 gallon tank on its first floor. There were also 275 gallon tanks on the fifth, seventh, and eighth floors, and a 50 gallon tank on the ninth floor. [National Institute of Standards and Technology, 8/21/2008] It has previously been suggested that diesel stored in these tanks might have contributed to fires that led to WTC 7’s collapse (see March 2, 2002). [New York Times, 3/2/2002] This possibility was proposed in the final report of the Federal Emergency Management Agency (FEMA) investigation of the WTC collapses, published in May 2002 (see May 1, 2002). [Federal Emergency Management Agency, 5/1/2002, pp. 5-28 - 5-29] But in his summary of the findings of NIST’s three-year study of WTC 7, lead investigator Shyam Sunder says the building’s collapse was “not due to fires from the substantial amount of diesel fuel stored in the building.” [National Institute of Standards and Technology, 8/21/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Shyam Sunder

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

NIST lead investigator Shyam Sunder answering questions about NIST’s three-year study of the collapse of WTC 7.NIST lead investigator Shyam Sunder answering questions about NIST’s three-year study of the collapse of WTC 7. [Source: Don Berkemeyer / National Institute of Standards and Technology]The National Institute of Standards and Technology (NIST) announces the findings of its study of the collapse of World Trade Center Building 7, and says the 47-story tower fell late in the afternoon of 9/11 primarily due to fires. [National Institute of Standards and Technology, 8/21/2008; National Institute of Standards and Technology, 8/21/2008] NIST releases its findings as part of a 915-page report, which is the result of three years’ work by over 50 federal investigators and a dozen contractors (see August 21, 2008). [New York Times, 8/21/2008]
Collapse Is 'No Longer a Mystery' - In a news conference at NIST’s headquarters in Gaithersburg, Maryland, lead investigator Shyam Sunder admits: “[W]e knew from the beginning of our study that understanding what happened to Building 7 on 9/11 would be difficult. It did not fit any textbook description that you could readily point to and say, yes, that’s why the building failed.” But, he says, “[T]he reason for the collapse of World Trade Center 7 is no longer a mystery.” [National Institute of Standards and Technology, 8/21/2008; New York Times, 8/21/2008]
'New Phenomenon' Caused Collapse - Sunder says the “critical factor” that initiated the collapse was “thermal expansion of long-span floor systems located in the east side of the building,” and adds that NIST’s study “has identified thermal expansion as a new phenomenon that can cause structural collapse. For the first time we have shown that fire can induce a progressive collapse.”
Collapse Sequence - Sunder describes the sequence of events NIST believes led to the collapse of WTC 7. He says debris from the collapse of the north WTC tower “started fires on at least 10 floors of the building. The fires burned out of control on six of these 10 floors for about seven hours. The city water main had been cut by the collapse of the two WTC towers, so the sprinklers in Building 7 did not function for much of the bottom half of the building.” He continues: “Fires on floors 7 through 9 and 11 through 13 were particularly severe.… Eventually, a girder on floor 13 lost its connection to a critical interior column.” Floor 13 collapsed, beginning a cascade of floor failures down to the fifth floor. “With the support of these floors gone, column 79 buckled, which initiated the fire-induced progressive collapse of the building.… This in turn caused the failure of nearby columns 80 and 81 and floor failures up to the roof line.… As the roof line begins to fall adjacent columns buckle as well. In quick succession, the remaining interior columns failed from east to west across WTC 7, until the entire core began moving downward. Finally, the remaining outer shell or façade of the building fell.”
NIST Created 'Virtual WTC 7' Model - Sunder says that NIST reached its conclusions about the collapse “by reconstructing the entire building, beam by beam, column by column, connection by connection into a computer model, a virtual WTC 7 building. We then filled that virtual building with as much detail as possible about exactly what types of furnishings were on each floor. Then we set fire to those virtual offices on the floors where video and other visual evidence told us the fires burned.” The investigators “used a well-validated computer program developed at NIST, for studying the growth and spread of fires, to calculate temperatures throughout the building.… And we used well-established data on the properties of structural steel, the sprayed fire resistive material or fireproofing, and other building materials to determine how those temperatures affected the structure.”
Explosives Not Used - Sunder says that the investigators “did not find any evidence that explosives were used to bring the building down” (see August 21, 2008), nor was the collapse “due to fires from the substantial amount of diesel fuel stored in the building” (see August 21, 2008). NIST commenced its investigation of the WTC collapses in 2002 (see August 21, 2002) and issued its findings on the collapses of the Twin Towers in October 2005 (see October 26, 2005). Since then it has been focused on WTC 7. [Government Computer News, 8/21/2008; National Institute of Standards and Technology, 8/21/2008]
Final Report to Be Released - After suggestions are made by members of the public in response to its current report, NIST will release a finished version of the same report in November 2008, thereby completing its WTC investigation (see November 20, 2008). [National Institute of Standards and Technology, 11/20/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology, Shyam Sunder

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

After the National Institute of Standards and Technology (NIST) announces the results of its investigation into the collapse of World Trade Center Building 7, some critics dispute its explanation for the collapse and question its apparent debunking of claims that explosives were used to demolish the building. The 47-story tower collapsed late in the afternoon of 9/11, even though no plane hit it (see (5:20 p.m.) September 11, 2001). Some have argued that fire and the falling debris from the Twin Towers’ collapses should not have brought down such a large steel and concrete structure. [Associated Press, 8/21/2008]
NIST Lacks 'the Expertise on Explosives' - James Quintiere, a professor of fire protection engineering at the University of Maryland who previously worked as the chief of NIST’s fire science and engineering division, says that NIST does not “have the expertise on explosives, so I don’t know how they came to that conclusion,” that explosives did not cause the collapse. However, Quintiere says he never personally believed explosives were involved. [Los Angeles Times, 8/22/2008] Richard Gage, a California architect and leader of a group called Architects and Engineers for 9/11 Truth, complains, “How much longer do we have to endure the cover-up of how Building 7 was destroyed?” The New York Times points out that “the collapse of 7 World Trade Center—home at the time to branch offices of the Central Intelligence Agency, the Secret Service, and the Giuliani administration’s emergency operations center—is cited in hundreds of Web sites and books as perhaps the most compelling evidence that an insider secretly planted explosives, intentionally destroying the tower.” [New York Times, 8/21/2008]
NIST Presentation - At a presentation of its findings earlier in the day, NIST announced that, in its three-year study of the collapse, it found no evidence showing explosives were used to bring the building down. [National Institute of Standards and Technology, 8/21/2008; National Institute of Standards and Technology, 8/21/2008] During his summary of the findings of NIST’s WTC 7 investigation (see August 21, 2008), lead investigator Shyam Sunder said, “We did not find any evidence that explosives were used to bring the building down.” [National Institute of Standards and Technology, 8/21/2008]
'No Witness Reports' of Loud Explosions - In the draft version of its final report on the collapse, which is released on this day (see August 21, 2008), NIST explains: “Blast from the smallest charge capable of failing a critical column… would have resulted in a sound level of 130 dB to 140 dB at a distance of at least half a mile if unobstructed by surrounding buildings.… This sound level is consistent with standing next to a jet plane engine and more than ten times louder than being in front of the speakers at a rock concert. There were no witness reports of such a loud noise, nor was such a noise heard on the audio tracks of video recordings of the WTC 7 collapse.” [National Institute of Standards and Technology, 8/2008, pp. 44-45 pdf file]
NIST Rules out Thermite - Skeptics have argued that an incendiary material called thermite was used to bring down WTC 7 (see August 4, 2008), and this would not necessarily have created such a loud explosive boom. [New York Times, 8/21/2008] But in a fact sheet published on this day, NIST responds: “To apply thermite to a large steel column, approximately 0.13 lb of thermite would be needed to heat and melt each pound of steel. For a steel column that weighs approximately 1,000 lbs. per foot, at least 100 lbs. of thermite would need to be placed around the column, ignited, and remain in contact with the vertical steel surface as the thermite reaction took place. This is for one column… presumably, more than one column would have been prepared with thermite, if this approach were to be used. It is unlikely that 100 lbs. of thermite, or more, could have been carried into WTC 7 and placed around columns without being detected, either prior to Sept. 11 or during that day.” [National Institute of Standards and Technology, 8/21/2008] Sunder says that investigators therefore decided not to use their computer model to evaluate whether a thermite-fueled fire might have brought down WTC 7. Pointing to the omission, one skeptic says, “It is very difficult to find what you are not looking for.” [New York Times, 8/21/2008] In a 2006 fact sheet, NIST in fact admitted it “did not test for the residue” of explosives or thermite in the remaining structural steel from the WTC collapses (see August 30, 2006). [National Institute of Standards and Technology, 8/30/2006] And, as the New York Times notes, “Adding to the suspicion is the fact that in the rush to clean up the site, almost all of the steel remains of the tower were disposed of, leaving investigators in later years with little forensic evidence” (see Shortly After September 11, 2001 and September 12-October 2001). [New York Times, 8/21/2008]
Extensive Preparations for Demolition - NIST’s new fact sheet also points out: “For [WTC 7] to have been prepared for intentional demolition, walls and/or column enclosures and fireproofing would have to be removed and replaced without being detected. Preparing a column includes steps such as cutting sections with torches, which produces noxious and odorous fumes. Intentional demolition usually requires applying explosive charges to most, if not all, interior columns, not just one or a limited set of columns in a building.” [National Institute of Standards and Technology, 8/21/2008]

Entity Tags: Richard Gage, National Institute of Standards and Technology, Shyam Sunder, World Trade Center, James Quintiere

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

NIST’s ‘Final Report on the Collapse of World Trade Center Building 7.’NIST’s ‘Final Report on the Collapse of World Trade Center Building 7.’ [Source: National Institute of Standards and Technology.]The National Institute of Standards and Technology (NIST) releases the final report of its three-year investigation of the collapse of World Trade Center Building 7, the 47-story skyscraper which collapsed late in the afternoon of 9/11 (see (5:20 p.m.) September 11, 2001). This is the completed version of the report, and comes three months after a draft version was released for public comment (see August 21, 2008). NIST states that the new report “is strengthened by clarifications and supplemental text suggested by organizations and individuals worldwide in response to the draft WTC 7 report.” NIST conducted an additional computer analysis in response to comments from the building community, and made several minor amendments to the report. But, it says, “the revisions did not alter the investigation team’s major findings and recommendations, which include identification of fire as the primary cause for the building’s failure.” With the release of this report, NIST has completed its six-year investigation of the World Trade Center collapses, which it commenced in August 2002 (see August 21, 2002). The final report of its investigation of the Twin Towers’ collapses was published in October 2005 (see October 26, 2005). [National Institute of Standards and Technology, 11/20/2008; Occupational Health and Safety, 11/25/2008]

Entity Tags: World Trade Center, National Institute of Standards and Technology

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

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