Re: Insulation
Insulation only slows down the transfer of heat; it doesn't prevent it.
There was a highrise fire in Philly eleven years ago, without jet-fuel accelerant and with code-compliant fireproofing - but no sprinklers, unfortunately - which still burned hot enough to deform the steel structure of the 'fire floors'. After much litigation and cost analysis, the building was dismantled.
If it had had a few more floors stacked above it, it might've collapsed, too.
Oh, yeah - the Philadelphia Building Code was updated, too, and the loopholes which allowed that building to be built without sprinklers were eliminated, and existing buildings were required to retrofit.