"Gerald Henriksen"

It was pointed out in one of the shows about the collapse that the
stairwells in a modern building would likely have survived (as they
are typically in a concrete shell in the centre of the bulding)
whereas the stairs in the wtc were only protected using fireproof
building materials.

AIUI, two layers of "firestop" drywall.


--
Cheers
Roger T.

Home of the Great Eastern Railway
http://www.highspeedplus.com/~rogertra/