Years ago I was driving along the freeway in LA around twilight time when I saw a skyscraper on fire. It was the First Interstate Bank building, tallest building in LA. (It had a big sign on top with the name of the building.)
https://en.wikipedia.org/wiki/First_Interstate_Tower_fire
Years later I saw a made-for-TV movie about it (starring Lee Majors, the Six Million Dollar Man).
Fire: Trapped on the 37th Floor (TV Movie 1991) - IMDb
I didn't watch the whole movie, just 15 minutes. What I saw was the part where the chief architectural engineer shows up and starts talking to the fire chief.
"How long has it been burning?"
"Four hours."
"You need to pull your men out in two hours."
"Who are you to tell me what to do?"
"I'm the chief architectural engineer on that building. I designed it to withstand 8 hours or fire, plus or minus two hours. After that, it will collapse and kill everyone inside."
"But that's a steel-framed building. That fire's not hot enough to melt steel. It's only 800 degrees. Steel melts at 2000 degrees.'
"Steel looses its strength at 800 degrees. When that happens, the floors above will collapse on to the weakened floors. It will hit with such momentum that the floor below it will collapse, then the one below that, all the way down to the bottom. The whole building will just pancake, like a controlled demolition."
"But don't they have concrete around those pillars?"
"Yes, enough to buy time. 8 hours, plus or minus two. You have two hours to put out that fire, or get your men out."
Of course this conversation could never have taken place in real life. That's because you can't get a job as a firefighter without going through the fire department's equivalent of police academy. Besides practicing on actual fires, you sit in a classroom with textbooks, etc. That's why every firefighter already knows about this stuff. The explanation was just for the average television viewer.
