The standard time for evacuating an aircraft that has to be demonstrated for certification purposes is 90 seconds with only half of the exits usable. It general

The standard time for evacuating an aircraft that has to be demonstrated for certification purposes is 90 seconds with only half of the exits usable. It generally helps that the fire is (at least initially) outside the cabin most of the time. But yes, I wouldn't bet on conditions in the plane staying survivable for 90 seconds in all cases.