23 Sep
2018
23 Sep
'18
11:13 a.m.
The 3 hr rating is for the *FIRE PROTECTION material* coating the columns, not the columns themselves, let alone the whole building, like peter wrongly assumes.
What do you think the fire protection material is for?
If it rated for three hours, this implies that the columns will cease to be protected after three hours.
Actually, the 3 hours figure is according to some 'standard', some 'parameters', some 'temperatures' and bla bla bla - a set of conditions which you don't know if they existed.
None of which changes the fact the building was designed to withstand three hours of uncontrolled fire - not seven hours of uncontrolled fire, hence could be expected to collapse in much the way it did collapse.