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Towers' Strength Not Tested for a Fire,
Investigators Find
May 8, 2003

New York Times

Federal investigators studying the collapse of the twin towers on Sept. 11, 2001, say they now believe that the Port Authority of New York and New Jersey, the government agency that built the towers, never performed the fundamental tests needed to determine how their innovative structures would perform in a fire.

The preliminary finding, if it holds up, will undermine decades of public assurances by the Port Authority that the twin towers met or exceeded the requirements of New York City's building code, and therefore would be structurally safe in a large fire. The codes are based on tests of each building component in furnaces that subject the structures, and the fireproofing insulation that protects them, to the harsh conditions of a major fire.

"At this point, we don't know why the tests were not done," said Dr. S. Shyam Sunder, who is leading the eight-month-old investigation at the Building and Fire Research Laboratory at the National Institute of Standards and Technology. But Dr. Sunder added, "To the best of our knowledge, they were not done."

The investigators took great care yesterday to say they were nowhere close to definitively determining how and why the towers collapsed after they were struck by hijacked airliners, and some experts have argued that the buildings were so badly wounded by the impact of the airliners that their ultimate demise was inevitable.

But investigators, speaking at a news conference near ground zero, said their findings about the fire tests were an important development in their examination of one theory for why the buildings collapsed when and how they did: that the huge fires set by burning jet fuel weakened the lightweight floors of the towers, and that the failure of at least several floors in each building set off a chain reaction culminating in the total collapse of the complex.

The investigators have said that it is unclear whether, even if the tests had been done and the building been found to have met standards, the lightweight floor structures, called trusses, and the fluffy fireproofing on them could have been expected to withstand the intense fires of Sept. 11. But the absence of the central tests has robbed them of the ability to even say whether the buildings performed as their designers had specified in their original plans and as the city's codes required of other buildings like them.

Yesterday, independent experts as well as relatives of those who died that day said they were dumbstruck or outraged that such prominent buildings – where fires had occurred more than once and that had been the target of a previous terrorist attack in 1993 – could have been first built and then maintained without such a basic test of its safety having been conducted.

A Port Authority spokesman, Greg Trevor, said yesterday that he did not have enough information to "definitively" comment on the question of whether the fire tests had been done. He added that the Port Authority had given to investigators all documents that it had been able to locate. The Port Authority has long maintained that it is not legally obligated to comply with the city and state's building codes, but has always insisted that it nonetheless did so in all its major construction, including the trade center.

"I would stress," Mr. Trevor added, "that none of the people who were involved in the making of those decisions at that time are currently working for the Port Authority."

One of those people, Guy Tozzoli, who oversaw all major aspects of the World Trade Center for the Port Authority at the time of its construction, said his memory was imperfect, but that he thought full-scale tests on the floors and their supports most likely had not been done.

"I don't remember that being done, to be honest with you," Mr. Tozzoli said. "I know there was testing of the fireproofing material. But you are asking a different question. Whether we built a truss and tested that? I'm inclined to say no."

Many yesterday found that startling, even unthinkable.

"How did they arrive at that decision that the floor system complied" with the building and fire codes, asked Dr. Glenn P. Corbett, a professor of fire science at the John Jay College of Criminal Justice. "The only way they can do that is go back to the tests."

Dr. Corbett is a member of the federal team's advisory committee, though he said he was speaking as an independent researcher.

Others were less measured. "It's horrific that they were allowed to do these 110-story, mammoth buildings without proper fireproofing," said Monica Gabrielle, co-chairwoman of the Skyscraper Safety Campaign, who lost her husband, Richard, in the collapse of the south tower. "How could they not have tested this to make sure those lives were safe?" Mrs. Gabrielle said.

The preliminary findings could affect everything from legal actions against the Port Authority to structural analyses of the disaster to historical assessments of how well the buildings protected their occupants against the 9/11 attack.

Marc S. Moller, a lawyer at Kreindler & Kreindler, which has brought a liability lawsuit against the Port Authority in connection with the 9/11 attack, said at least one of his firm's legal theories could be bolstered by the findings: that fireproofing in the towers was defective and so the buildings were not safe.

"It remains for us to prove our allegations," Mr. Moller said. "The NIST study suggests that we are on the right track."

He added that for now, about 450 people had joined the lawsuit, but that "the litigation option becomes more viable as more becomes known about design deficiencies in the buildings."

By law, the institute's findings cannot be used directly in lawsuits or other actions to recover damages. In the briefing, Dr. Sunder described a variety of other findings in what has become a wide-ranging investigation. He highlighted new evidence appearing to support the theory that the lightweight trusses played some role in the collapse. Dr. Sunder showed a high-resolution photograph of the east face of the south tower, 12 minutes before it collapsed. The picture revealed what appeared to be a floor truss sagging deeply, like a clothesline overloaded with wet clothing.

Heat-softened steel would be expected to sag in just such a way. The south tower was the first to collapse, and an earlier study determined that the deadly sequence started on the east face near the 83rd floor, where the sagging truss was.

Dr. Sunder also said that 37 pieces of steel from near the impact zones of the airplanes had been recovered from scrapyards and other sources. In a vivid illustration of how images of 9/11 have advanced the work, he showed how a sophisticated electronic analysis of videos that were shot by a photographer, Scott Meyers, revealed the structural convulsions of the south tower just after it was hit.

The analysis, revolving around a kind of wavy moiré pattern that came and went in the computerized images, showed that the building shuddered, swayed and convulsed for more than four minutes after the strike.

The investigative team is appealing to the public for additional video images. In particular, the team says it is lacking clear views of the south face of 7 World Trade Center, a 47-story skyscraper that collapsed later in the day on Sept. 11.

The standards institute received formal federal authority to investigate building disasters in October 2002 when the National Construction Safety Team Act was signed into law. The act was written largely as a result of the collapse of the towers.

Yesterday's briefing covered a 122-page progress report on the trade center investigation.

In it, investigators have included evidence that confusion, ambiguity and uncertainty surrounded the question of the complex's fire safety protection almost from the start of its design and construction.

In May 1963, more than five years before steel construction for the trade center began, the Port Authority ordered its engineers to comply with the New York City building code. The engineers decided early on that they were obligated to show that the steel and fireproofing could withstand at least three hours of intense fire without failing.

But by early 1969, after construction began, one of the trade center's architects, Emery Roth & Sons, complained that the Port Authority had arbitrarily changed their guidelines for establishing how much and what kind of fireproofing was required to ensure the complex's safety.

"We cannot be expected to accept responsibility for specifications which have been revised in such a manner," the architect wrote.

Then, in a mysterious communication a few months later, the Port Authority wrote to Louis DiBono, president of the company that was applying the fireproofing, to say that it should be applied to a thickness of one-half inch on the floor trusses.

Dr. Sunder said today that "we are unable to determine the technical basis" for choosing half an inch of fireproofing. He said no records had turned up to indicate that the trusses were subjected to any standard furnace tests at all with the fireproofing in place.

The confusion continued in 1975, several years after the towers had opened, when a sizable fire spread from the 9th to the 19th floor of the north tower. The fire caused buckling of some parts of the trusses on those floors. An engineering firm called in to assess the fire damage concluded that only fire testing and analysis by fire experts could determine if the floor systems were safe.

But again, there is no indication the tests were ever done.

The same engineers concluded that the fireproofing specifications – requiring half an inch of fireproofing – might simply have been read out of a fireproofing manufacturer's product catalog. But the federal investigative team determined that the truss systems, new in their day, were not included in those catalogs when the decisions were made.

A Port Authority engineer named Frank Lombardi finally did discover that the fireproofing was inadequate in the mid-1990's.

He ordered that the thickness of the fireproofing be increased to an inch and a half. And about 30 floors in the upper reaches of the two towers – including virtually all the floors in the impact zone of the north tower – had been at least partly upgraded at the time of the attack.


© Copyright 2003 New York Times

Sally Regenhard,

P. O. Box 70
Woodlawn Station
Bronx, NY 10470

Monica Gabrielle,

P. O. Box 70
Woodlawn Station
Bronx, NY 10470