I earned a degree in fire science in Honolulu Hawaii well before 9/11. Honolulu has its fair share of high rises, so we studied all kinds of fires including tall structures. The program included a building construction class, of which the primary focus was learning to recognize when a structure was at risk of collapse. If there is one thing that I recall about my studies of building construction and collapse, it is that buildings of all types and sizes can and will collapse from structural damage caused by fire. Its not a matter of can a tall building collapse from fire, its when it will collapse and can the fire be put out before it get close to that point. Direct fire impingement on steel structural members can cause collapse in as little time as 15 minutes. Structural steel is coated with fire protective foam to help prevent the steel from reaching temperatures where it can become soft in a fire. This foam, however, can deteriorate or break off over time or burn away in a fire. It would be insane to build skyscrapers the way we do today without fire sprinkler systems, without them skyscraper collapse would not be all that uncommon (except that we probably wouldn’t build them anymore in the first place). Fire officers are trained to recognize and predict building collapse; it is usually the biggest concern at any structure fire. The fire officers at the WTC should have pulled their crews long before the towers fell; the towers lasted longer than should have been expected. Building seven was in serious threat of collapse; the integrity of the foam insulation and sprinkler systems had to be considered. Building seven had also withstood the force of debris from the two massive towers collapsing near it. The New York Fire Department had just had the greatest reminder in our history of how costly building collapse can be. They didn’t want to, and didn’t need to, risk any more lives unnecessarily.
Quite often, clearing out and letting a building fall is by far the safest thing to do.
After reading portions of this thread I did a search and found a few articles that make similar claims; that something fishy happened with building seven. I also found that many New York Firefighters and other “experts’ were surprised that the twin towers collapsed from fire and suspect otherwise. I’m baffled that their studies differed so much from mine. Just because no major skyscraper had collapsed from fire, does not mean that it is not very possible. Countless smaller steel buildings have collapsed from fire. Several tests have been conducted that show that steel beams can give way in as little as 15 minutes of direct fire impingement. When I turned on the TV on 9/11 and saw towers burning, I expected them to fall. They actually lasted a bit longer than I expected. Once again, I was trained to expect severely burned buildings to fall.
I read the FEMA report on building seven and find it to be a reasonable account.
The articles that contradicted the FEMA report contain many ideas that are borderline silly.
eskimo
