Building Occupancy Category - Code Clarification

[cmbyrd77]

I have a bit of a quandary. I am doing a roof framing evaluation for a client that wants to install solar panels. Currently I am determining the design the loads on the existing structure. The project is for a small college and the facility that I am looking at is large and therefore probably has a capacity of over 500, bumping it up to a Occupancy Category III. However, with that being said, the portion I am looking at is a small bumpout that only houses a couple small classrooms, with much less than 500 occupants, putting it into a Occupancy Category II. I am curious to see what some of my other fellow professional's opinions are on this subject. Thank you for the help.

 

[jayrod12]

Is the portion you are looking at considered a completely separate compartment, i.e. it's own fire compartment?

I've heard of people using different classifications for different segments of a large facility when each segment was it's own fire compartment.

Don't ask for proof though. Never done it myself, just an old wives tale.

 

[cmbyrd77]

There is a CMU wall between the bump-out and the remaining portion of the facility, but I doubt it is a true fire wall. Especially because the joists are bearing on it.

 

[wannabeSE]

Unless the area is structurally separated, the worst occupancy category applies to the entire structure. If a structure with higher occupancy category has exiting or other life safety systems that pass through a structure with a lower occupancy category, both structures need to be designed with the higher occupancy category. For code reference, see ASCE 7-05 section 1.5.1 or 2009 IBC section 1604.5.1(for risk categories see ASCE7-10 section 1.5.2 or 2012 IBC section 1604.5.1).