BasqueArch
Graduate Poster
- Joined
- Jan 11, 2009
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Rust scale and rust on the WTC1,2 primed steel
Wrong.
The steel was primed and rusted.
http://www.fireengineering.com/articles/print/volume-155/issue-10/world-trade-center-disaster/volume-ii-the-ruins-and-the-rebirth/fireproofing-at-the-wtc-towers.html
Rust and rust scale on primed steel at the WTC1,2. From fireproofing inspections.
Originally Posted by C7
But this does point out that the hypothesis in the letter is dumb. There was no rust to flake and melt because the columns had a coat of primer to prevent that.
It takes a while for iron oxide to form in an appreciable amount. The amount of rust is minute when they primer.
There is no mention of primer in the letter. Whoever wrote it is uninformed and grasping at straws.
Wrong.
I inspected core columns up to the 78th floor but was unable to access them above that point. These inspections revealed that the bond of fireproofing on core columns had failed in many locations and the fireproofing was falling off the columns in floor-high sheets. Photo 3, taken in 1994, shows a core column from which the fireproofing had fallen off in a sheet that is several stories high. The red circle and date was the Port Authority's response to the missing fireproofing. This resulted because the steel had not been properly prepared at the time of the initial spray application. Rust scale had not been removed prior to applying the fireproofing. The fireproofing had adhered well to the rust scale, but the rust was coming loose from the steel (photo 4). of the rust, indicating that the rust existed at the time the fireproofing was applied.
The result was that the fireproofing adhered loosely to the columns and would fall off in large sheets. This defect was never corrected and still existed in June 2000 and probably at the time of the plane crashes. It is possible the fireproofing was missing from sections of columns on the impact floors or that some or all of the loosely adhered fireproofing fell off with the force of the impacts. This is a defect that would have been easily discovered by the ASTM adhesion and cohesion quality assurance test, had this standard existed at the time of construction......
Test conditions, however, do not match actual conditions in the field. Insulation adhesion may be ineffective because of rust. Frequently, insulation is applied to rusted metal that has not been properly treated before application; the insulation's consistency may vary; its application may be inconsistent; or it may be dislodged during original and new construction and maintenance.
The steel was primed and rusted.
http://www.fireengineering.com/articles/print/volume-155/issue-10/world-trade-center-disaster/volume-ii-the-ruins-and-the-rebirth/fireproofing-at-the-wtc-towers.html
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