But when they used what would have been the equivalent of a real car, the fireproofing failed.

"It seems as if the fireproofing was not up to what it should have been."

Fireproofing of the hanging system must also be considered.

Perhaps not surprising, there is extensive evidence that the trade center's fireproofing was missing in places.

He ordered that the thickness of the fireproofing be increased to an inch and a half.

Metal-framed buildings were also particularly vulnerable to fire and required special fireproofing.

But according to the chairman of the company that made the fireproofing, a problem arose with the steel even before the building was constructed.

Engineers are still not sure whether the hot fires or the lack of fireproofing posed the greatest danger.

But it did acknowledge that problems with maintaining the fireproofing had plagued the structures.

Stripped of its fireproofing, a steel column heats up much more quickly in a fire.

More fireproofing was added after a fire in February 1975 that spread to six floors before being extinguished.

The impacts of the planes also knocked off at least some of the fireproofing.

Less intensive work involving fireproofing, the exterior facing and other details remained, the source said.

The recommendations on structural fireproofing in Corley's report were implemented throughout the industry.

The steel structure was protected by structural clay tile and concrete fireproofing.

It launched the craze for terra-cotta fireproofing of structural steel.

And they have disputed the assertion of some experts that the authority had failed to adequately maintain the fireproofing.

Second, the impact dislodged the fireproofing that was sprayed on the floors and the columns.

Mr. Morse said that despite his concerns about the fireproofing, he never imagined the buildings would collapse.

For years, Grace had weathered litigation from the old-style fireproofing laden with asbestos.

The piece of flooring with the half-inch coating of fireproofing failed.

Asbestos and silica exceeded the benchmarks in the fireproofing.

Astaneh also suggested that the fireproofing became dislodged during the initial aircraft impacts.

They will then vary parameters in the computer model, like better fireproofing or thicker columns, that might have extended how long the towers remained standing.

At the heart of that theory was the suspicion that perhaps no fireproofing, however formidable, could have been of much help in such a fire.