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RE: 3rd floor in UBC97

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IBC does not seem to address this based on the story designation. It is addresses it based on the space and building as a whole. 1015 limits the number of exits from any space (floor) by the occupant load and travel distance. If you have less than 10 occupants (2000 sq. ft.) and travel no more than 75 feet to get to the outside you are OK with one exit. 1019 limits the number of buildings with one exit and it gives a blanket approval for one exit in any R3 (dwelling) building. So, unless you have very large floor area (more than 2000 square feet) and the travel distance from 3rd floor to the outside is greater than 75 feet you should be OK with one exit. Of course, I am a new 2006 IBC user and may be missing something.


Ben Yousefi, S.E., C.B.O

Assistant Building Officer

Santa Monica, CA


(310) 458-2201 x 5025


From: Truitt Vance [mailto:Truitt(--nospam--at)]
Sent: Monday, September 24, 2007 2:38 PM
To: seaint(--nospam--at)
Subject: 3rd floor in UBC97


I know this is an architectural question but you guys are smart so I am sure I will get an answer...


The UBC97 allows 3rd floors (residential occupancy, carriage or townhome style, attached multifamily units) up to 500 square feet, and then requires a second egress to grade separated by more than half the distance of the hypotenuse of the building.  However, if you can make the second level qualify as the “story, first” (as defined in section 220) you can “work around” this requirement by designing the site to have retaining on at least half the perimeter of the building over four feet.


My big concern is if there is a similar rule/exception in the IBC06 that will allow me to get third stories over 500 square feet using a similar configuration.   Does anyone know if this 500 sq ft limitation even exists in third stories under the IBC?  If it does, is there a way to design the buildings with a larger third story and not have a second means of egress?

This reason this is important is I am trying to get con docs in on a 12 unit, 2 building project, and if I am not able to submit before December 31 it will be reviewed under the IBC, and I have not yet had time to really look into that, just hoping to get it done under the old code because I know there are other little things changing also.




Truitt Vance