I attended a fire safety luncheon yesterday, specifically regarding fire rated glass technology which is improving. Someone asked a question if say 2 hour rated glazing (Very expensive $200/sf and 3 inches thick, it's amazing stuff, actually it's a ceramic. Many new government buildings are using it. It can burn on one side for hours and you can put your hand on the other side which remains cool.) had been used,would it have made a difference in the WTC. The speaker who was there to sell his product said no.
Even if you had a 4 hour rating, I still think both towers would have eventually collapsed as it is impossible to fight a fire that big in that tall a building. Whether or not asbestos was used is a moot question. Perhaps more people might have escaped, but I think the buildings still would have failed. That's why 7 WTC came down. An uncontrolled fire burning for several hours will collapse a steel building. Buildings are simply not designed to withstand fires of that magnitude and modern aircraft impacts.
The authorities should concentrate on keeping from aircraft being used as guided missiles, and improving evacuation routes in buildings. I think you may see new rules calling for better protection of stairwells using solid CMU walls instead of fire rated sheetrock. There will also be more attention paid to the weakest link in steel construction. At the WTC attention is focused on the clips connecting the floor trusses to the perimieter columns, likely the point of failure for most of the trusses. You will also see engineering design focus on redundant structure. 7 WTC and the OKC buildings collapsed after key structural members were destroyed resulting in catostrophic failure. On the other hand the WTC stood up after having gaping holes punched in it because it in fact had redundant structure. What brought down the towers was a combination of fire, damage, and increased stresses as floors failed in the fire, trusses separated from the walls, and perimeter columns eventually buckled under the weight.
Thank you for the info - very infomative, you are obviously very knowledgeable.