posted 08-07-2002 01:18 AM
t was well known that Number Seven WTC was the (well publicized and controversial) Emergency Command Center for NYC and thiese are just afew of the articles that I was able to find on the subject. The one major structural problem mentioned quite a few times besides the large amoount of diesel fuel that was stored there, there was also a "bridge-like transfer truss structure" that "allowed the building to be constructed above an already existing power substation." Truss construction of any type, metal or wood, is extremely dangerous in a fire situation.
Most new houses and commercial buildings are truss construction and have been known to rapidly collapse without warning when subjected to extreme temperatures.
I do think that it is quite possible, since there was a lot of controversy about the mayor having the 13 million dollar Emergency Command Center installed in 7 WTC, that it was purposely taken out. Also, fire crews, having limited resources, decided to abandon their efforts to extinguish the blaze which may have also been a contributing factor of the collapse.
March 2, 2002
Burning Diesel Is Cited in Fall of 3rd Tower
By JAMES GLANZ and ERIC LIPTON
Massive structural beams that functioned as a sort of bridge to hold up the 47-story skyscraper known as 7 World Trade Center were compromised in a disastrous blaze fed by diesel fuel, leading to the building's collapse on Sept. 11, investigators have concluded in a preliminary report.
The tower was set on fire by debris from the twin towers and burned for about seven hours before collapsing in the late afternoon under previously unexplained circumstances. The analysis of its collapse is one of the first detailed findings by a team of engineers organized by the Federal Emergency Management Agency and the American Society of Civil Engineers to understand the fate of all the buildings around the site.
As much as 42,000 gallons of diesel fuel was stored near ground level in the tower and ran in pipes up to smaller tanks and emergency generators for Mayor Rudolph W. Giuliani's command center, the Secret Service's office and other tenants.
Investigators have determined that the burning fuel apparently undermined what is known as a transfer truss. The trusses, a series of steel beams that allowed the skyscraper to be built atop multistory electricity transformers, were critical to the structural integrity of the building and ran near the smaller diesel tanks.
A failure of the same type of structural bridge contributed to the collapse of the Alfred P. Murrah Federal Building in Oklahoma City when it was bombed in 1995. Federal guidelines for public buildings, created in 1996, warned of the dangers of such trusses in terrorist attacks.
"It's certainly right in the vicinity where the columns go into this transfer system," said a person knowledgeable about the investigators' draft report on the World Trade Center. "The rest of the building is built on top of the bridge."
While 7 World Trade Center, which stood across Vesey Street just to the north of the twin towers, was not formally a federal building, it did house crucial government offices that included the city's nerve center for emergency response.
The investigators said that their conclusions, combined with other findings about the failure and collapse of 5 World Trade Center, could prompt serious changes in the codes used in building construction.
The findings are in a draft report that has already been circulated among government agencies, and are based on videos made on Sept. 11, witnesses' reports, interviews with firefighters, evidence from the debris pile and structural analysis. Team members, who described many of the findings, cautioned that the conclusions on the collapse of 7 World Trade Center could still be modified as reviews proceed.
But Irwin Cantor, one of the building's original structural engineers, who is now a consulting engineer and member of the City Planning Commission, said the diesel-related failure of transfer trusses was a reasonable explanation for the collapse.
He said he believed that diesel tanks were not envisioned in the original design of the building."It ended up with tenants who had diesels," Mr. Cantor said. "I know none of that was planned at the beginning."
According to floor plans submitted to the Port Authority of New York and New Jersey, which owns the land on which 7 World Trade sat, the building complied with city fire codes, said Frank Lombardi, the authority's chief engineer.
Those codes permit no more than one fuel tank with a capacity of 275 gallons or less on above-ground floors, he said.
Jerome M. Hauer, who was the director of Mayor Giuliani's Office of Emergency Management at the time the command center was opened at 7 World Trade, said several teams of engineers reviewed plans to open the office there. But no one ever mentioned any hazard associated with placing fuel tanks above ground, near a transfer truss, he said.
"There were a host of people who looked at this," said Mr. Hauer, who is now a managing director of the crisis and consequence group at Kroll Worldwide, a security consulting company based in New York. "We relied on their judgment."
Fire officials did at one point question the storage of large amounts of fuel well above the ground level, saying that one large tank for the mayor's command center, if ever compromised, might fuel a fire that would threaten the building.
The Sept. 11 draft report also has photographs and a description of debris collected from a previously undisclosed, multistory collapse within 5 World Trade Center, a nine-story office building that also burned on Sept. 11 but largely remained standing.
The team has found that one specific type of bolted connection, called a column tree connection, that joined floor-support beams, failed in the heat of the fires, causing the four- story collapse in the part of 5 World Trade at the corner of Vesey and Church Streets.
Although no one died as a result of the collapses in 5 and 7 World Trade Centers, since both stood long enough to be evacuated, the team's findings are likely to lead to recommended changes in the way public and government buildings are constructed, much the way similar studies did after the Northridge earthquake near Los Angeles in 1994 and the Oklahoma City bombing.
The team is still deliberating on how tightly it can pin down the precise train of events that led to the collapse of the twin towers themselves. But until now, the collapse of 7 World Trade has stood as one of the outstanding mysteries of the Sept. 11 attack, since before then, no modern, steel-reinforced high-rise in the United States had ever collapsed in a fire.
High-rise buildings are designed to be able to survive a fire, even if the fire has to burn itself out.
The strategy is to ensure that the steel support structures are strong enough or protected well enough from fire that they do not give way in the time it takes for everything inside an office building, like furniture, to burn.
In major high-rise fires elsewhere in the country, such as the 1 Meridian Plaza fire in Philadelphia in 1991 and the First Interstate Bank fire in Los Angeles in 1988, this approach has worked. The 1 Meridian fire burned for 19 hours, leaping from floor to floor and burning out as combustible materials were used up. But the fires at 7 World Trade Center raged mainly on lower floors and never burned out, and in the chaos of Sept. 11, the Fire Department eventually decided to stop fighting the blazes.
http://www.nytimes.com/2002/03/02/nyregion/02TOWE.html
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Web posted Sunday, March 3, 2002
Report: Fuel fire collapsed 7 WTC building
The Associated Press
NEW YORK (AP) -- Investigators believe a fire fed by diesel fuel stored in 7 World Trade Center may have led to the building's collapse, according to a published report.
The fire, which was ignited by falling debris from the burning twin towers, raged for about seven hours before the 47-story building collapsed on Sept. 11.
According to a preliminary report, the fire may have caused a group of steel beams that supported the skyscraper -- called "transfer trusses" -- to fail, The New York Times reported Saturday.The findings were detailed in a preliminary report by a team of engineers organized by the Federal Emergency Management Agency and the American Society of Civil Engineers.
The report was based on video footage, debris, structural analysis and interviews with firefighters and witnesses. Researchers cautioned that the conclusions could be modified as the investigation continues.
The office tower, which stood across Vesey Street just north of the World Trade Center, housed former Mayor Giuliani's emergency command center and other government agencies, including offices for the Secret Service. The bridge-like transfer truss structure allowed the building to be constructed above an already existing power substation.
The diesel fuel that investigators believe may have fed the fire was stored in large tanks near ground level and in smaller tanks and emergency generators for the command center, the Secret Service and other tenants, The Times said.
Irwin Cantor, one of the building's original structural engineers, said the report's findings provided a reasonable explanation for the collapse. He said he did not think the diesel fuel tanks were included in the building's original design.
"It ended up with tenants who had diesels," Cantor told The Times. "I know none of that was planned at the beginning."But Frank Lombardi, the chief engineer for the Port Authority, which owns the property that the tower was built on, told The Times that according to floor plans, the building complied with city fire codes.
Jerome Hauer, who was the director of Giuliani's office of Emergency Management when the emergency command center opened, said several engineers had reviewed the plans. "There were lots of people that looked at this," Hauer told The Times. "We relied on their judgment."
The failure of a structural feature similar to the transfer trusses at 7 World Trade Center contributed to the collapse of the Alfred P. Murrah Federal Building in Oklahoma City, The Times said.
Federal guidelines for public buildings created after the Oklahoma City bombing warned of the dangers of similar trusses in terrorist attacks, the newspaper said.
http://www.hollandsentinel.com/stories/030302/new_030302042.shtml
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November 29, 2001
Engineers Suspect Diesel Fuel in Collapse of 7 World Trade Center
By JAMES GLANZ
Almost lost in the chaos of the collapse of the World Trade Center is a mystery that under normal circumstances would probably have captured the attention of the city and the world. That mystery is the collapse of a nearby 47-story, two-million-square-foot building seven hours after flaming debris from the towers rained down on it, igniting what became an out-of-control fire.
Engineers and other experts, who quickly came to understand how hurtling airplanes and burning jet fuel had helped bring down the main towers, were for weeks still stunned by what had happened to 7 World Trade Center.
That building had housed, among other things, the mayor's emergency command bunker. It tumbled to its knees shortly after 5:20 on the ugly evening of Sept. 11.
The building had suffered mightily from the fire that raged in it, and it had been wounded by the flying beams falling off the towers. But experts said no building like it, a modern, steel-reinforced high-rise, had ever collapsed because of an uncontrolled fire, and engineers have been trying to figure out exactly what happened and whether they should be worried about other buildings like it around the country.
As engineers and scientists struggle to explain the collapse of 7 World Trade Center, they have begun considering whether a type of fuel that was inside the building all along created intensely hot fires like those in the towers: diesel fuel, thousands of gallons of it, intended to run electricity generators in a power failure.
One tank holding 6,000 gallons of fuel was in the building to provide power to the command bunker on the 23rd floor. Another set of four tanks holding as much as 36,000 gallons were just below ground on the building's southwest side for generators that served some of the other tenants.
Engineers and other experts have already uncovered evidence at the collapse site suggesting that some type of fuel played a significant role in the building's demise, but they expect to spend months piecing together the picture of what remains a disturbing puzzle.
"Even though Building 7 didn't get much attention in the media immediately, within the structural engineering community, it's considered to be much more important to understand," said William F. Baker, a partner in charge of structural engineering at the architectural firm Skidmore, Owings & Merrill. "They say, `We know what happened at 1 and 2, but why did 7 come down?' "
Engineers said that here and across the country, diesel-powered generators are used in buildings like hospitals and trading houses, where avoiding power outages is crucial. Partly for that reason, Jonathan Barnett said, a definitive answer to the question of what happened in 7 World Trade Center is perhaps the most important question facing investigators.
"It's just like when you investigate a plane crash," said Dr. Barnett, a professor of fire protection engineering at the Worcester Polytechnic Institute. "If we find a weakness in the building or a deficiency in the building that causes that collapse, we then want to find that weakness in other buildings and fix it."
In many ways, 7 World Trade Center, built and owned by Silverstein Properties, was structurally similar to its towering cousins across Vesey Street to the south. The weight of the building was supported by a relatively tight cluster of steel columns around the center of each floor and a palisade of columns around the outside, in the building's facade.
Sprayed on the steel, almost like imitation snow in holiday decorations, was a layer of fireproofing material, generally less than an inch thick. Although the fireproofing was intended to withstand ordinary fires for at least two hours, experts said buildings the size of 7 World Trade Center that are treated with such coatings have never collapsed in a fire of any duration.
Most of three other buildings in the complex, 4, 5 and 6 World Trade, stood despite suffering damage of all kinds, including fire.
Still, experts concede, in a hellish day, 7 World Trade might have sustained structural injuries never envisioned in fire codes.That day began with flaming pieces of steel and aluminum and, horribly, human bodies raining around the building.
With the collapse of both towers by 10:30 a.m., larger pieces of the twin towers had smashed parts of 7 World Trade and set whole clusters of floors ablaze. An hour later, the Fire Department was forced to abandon its last efforts to save the building as it burned like a giant torch. It fell in the late afternoon, hampering rescue efforts and hurling its beams into the ground like red-hot spears.
Within the building, the diesel tanks were surrounded by fireproofed enclosures. But some experts said that like the jet fuel in the twin towers, the diesel fuel could have played a role in the collapse of 7 World Trade.
"If the enclosures were damaged, then yes, this would be enough fuel to explain why the building collapsed," Dr. Barnett said.
Dr. Barnett and Mr. Baker are part of an assessment team organized by the American Society of Civil Engineers and the Federal Emergency Management Agency to examine the performance of several buildings during the attacks.
If further studies of the debris confirm the findings of extremely high temperature, Dr. Barnett said, "the smoking gun would be the fuel."
Others experts agreed that the diesel fuel could have speeded the collapse, but said the building might have met the same fate simply because of how long it burned.
"The fuel absolutely could be a factor," said Silvian Marcus, executive vice president for the Cantor Seinuk Group and a structural engineer involved in the original design of the building, which was completed in 1987. But he added, "The tanks may have accelerated the collapse, but did not cause the collapse."
Because of those doubts, engineers hold open the possibility that the collapse had other explanations, like damage caused by falling debris or another source of heat.
The fuel tanks were not the only highly flammable materials in the building. But while some engineers have speculated that a high-pressure gas main ruptured and caught fire, there was none in the area, said David Davidowitz, vice president of gas engineering at Consolidated Edison.
The building was served only by a four-inch, low-pressure line for the building's cafeteria, Mr. Davidowitz said.
The mayor's command bunker, built in 1998, included electrical generators on the seventh floor, where there was a small fuel tank, said Jerome M. Hauer, director of the mayor's Office of Emergency Management from 1996 to 2000. That tank was fed by a tank containing thousands of gallons of diesel fuel on a lower floor, he said.
Francis E. McCarton, a spokesman for the emergency management office, confirmed that assessment. "We did have a diesel tank in the facility," he said. "Yes, it was used for our generating system." The manager of the building when it collapsed, Walter Weems, said the larger tank sat on a steel-and-concrete pedestal on the second floor and held 6,000 gallons of diesel fuel.
He said an even larger cache, four tanks containing a total of 36,000 gallons of diesel fuel, sat just below ground level in the loading dock near the southwest corner of the building.
"I'm sure that with enough heat it would have burned," Mr. Hauer said of the diesel. "The question is whether the collapse caused the tank to rupture, or whether the material hitting the building caused the tank to rupture and enhance the fire."
Falling debris also caused major structural damage to the building, which soon began burning on multiple floors, said Francis X. Gribbon, a spokesman for the Fire Department.
By 11:30 a.m., the fire commander in charge of that area, Assistant Chief Frank Fellini, ordered firefighters away from it for safety reasons.
A combination of an uncontrolled fire and the structural damage might have been able to bring the building down, some engineers said. But that would not explain steel members in the debris pile that appear to have been partly evaporated in extraordinarily high temperatures, Dr. Barnett said.
"Any structure anywhere in the world, if you put it in these conditions, it will not stand," Mr. Marcus said. "The buildings are not designed to be a torch."
http://www.wirednewyork.com/wtc/7wtc/default.htm
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Diesel Fire Led To WTC Collapse
NEW YORK, New York (AP) -- Investigators believe a fire fed by diesel fuel stored in 7 World Trade Center may have led to the building's collapse, according to a published report. The fire, which was ignited by falling debris from the burning twin towers, raged for about seven hours before the 47-story building collapsed on Sept. 11.
According to a preliminary report, the fire may have caused a group of steel beams that supported the skyscraper - called ``transfer trusses'' - to fail, The New York Times reported Saturday.
The findings were detailed in a preliminary report by a team of engineers organized by the Federal Emergency Management Agency and the American Society of Civil Engineers.
The report was based on video footage, debris, structural analysis and interviews with firefighters and witnesses. Researchers cautioned that the conclusions could be modified as the investigation continues. The office tower, which stood across Vesey Street just north of the World Trade Center, housed former Mayor Giuliani's emergency command center and other government agencies, including offices for the Secret Service. The bridge-like transfer truss structure allowed the building to be constructed above an already existing power substation. The diesel fuel that investigators believe may have fed the fire was stored in large tanks near ground level and in smaller tanks and emergency generators for the command center, the Secret Service and other tenants,
The Times said.
Irwin Cantor, one of the building's original structural engineers, said the report's findings provided a reasonable explanation for the collapse. He said he did not think the diesel fuel tanks were included in the building's original design. ``It ended up with tenants who had diesels,'' Cantor told The Times. ``I know none of that was planned at the beginning.''
But Frank Lombardi, the chief engineer for the Port Authority, which owns the property that the tower was built on, told The Times that according to floor plans, the building complied with city fire codes.
Jerome Hauer, who was the director of Giuliani's office of Emergency Management when the emergency command center opened, said several engineers had reviewed the plans. ``There were lots of people that looked at this,'' Hauer told The Times. ``We relied on their judgment.'' The failure of a structural feature similar to the transfer trusses at 7 World Trade Center contributed to the collapse of the Alfred P. Murrah Federal Building in Oklahoma City, The Times said.
Federal guidelines for public buildings created after the Oklahoma City bombing warned of the dangers of similar trusses in terrorist attacks, the newspaper said.
http://www.firehouse.com/news/2002/3/4_APwtcdiesel.html
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Here's one article that mentioned the possibility of a conspiracy involved with the 7 WTC collapse.
http://www.baltech.org/lederman/giuliani-wtc-collapse-3-01-02.html