[reed13k]

an excellent paper on the subject:

http://iafss.org/publications/fss/8/211/view

key point on page 2: Proof stress and tensile strength at 600°C are 0.3-0.4 times those at room temperature.

[JockoManning]

Thanks. Have it open to scan before sleep. At least it’s trying to open.

[JockoManning]

That link won’t open in FireFox. may try Chrome

[Swordmaker]

key point on page 2: Proof stress and tensile strength at 600°C are 0.3-0.4 times those at room temperature.

ThanQ.

Add in that after finishing the 37th floor (IIRC) of building one, the Port Authority in a cost cutting measure, and because the management could not conceive of the need for its protection, discontinued the application of thesprayed-on fire insulation coating on the steel and concrete on all further construction. This coating was intended by the architect and engineers to prevent for a time the heating of the steel until a fire could be extinguished. Without it, no prevention was present.