CHAPTER 9 Flashcards
When a wood joist supported system is exposed to fire, the roof deck will
Soften prior to joist failure
To determine the collapse risk 3 facts must be known about the roof
1) Type of roof support system
2) How are the joists connected to the supporting wall
3) Is there a built up structure above the roof supports (raised or inverted roof, etc)
An unrestrained beam and a fire cut beam will fail in
Similar manner
In brick cavity construction wood beams may
Continue to provide support even if the center is weakened by fire
Most H type apartment buildings have their roof joists
Simply resting on masonry
Corbel shelf construction is an example of
An unrestrained roof beam
Examples of shaped steel
Bar joist truss C beams Fluted floor decking Hollow tube steel decking Steel partition wall studs
Steel does not
Melt during a fire.
Requires more than 2,400 degrees to melt steel, rarely reached at structural fires
Most H type apartment roof joists are
Resting on a corbel shelf
Unrestrained beam
