No, the documentary was a BBC one.
As Helen said, it was open-plan to a fault, with lightweight floors held up on trusses. The towers collapsed because of the trusses which held the floors up being vulnerable to heat. They also, willy-nilly, provided a good deal of the buildings' rigidity. The construction method was used because it enabled the buildings to go up at the rate of nearly two floors a month.
When the fire warped and melted the floor trusses, the floors began to collapse, one on to the other, until the sheer weight of falling floors began to smash through floors unaffected by the heat. Once the floors collapsed, the buildings' rigidity was compromised and the rest of the collapse was just a matter of time, and not very much of it at that as we saw.
What they should have done - and I understand that it was accepted as best practice even at the time - was to make every tenth floor rigid, i.e. girder rather than truss-based. If they had done that, it appears, the towers wouldn't have collapsed.
I work in a building with trussed floors. Do you?
OP
