occupancy category iii per ibc 2006, table 1604.5

huangyhg

occupancy category iii per ibc 2006, table 1604.5
ibc states for occupancy category iii that covered structures whose primary occupancy is public assembly with a capacity greater than 300 persons.
base on what the commentary states, if you exceed 300 persons yet the building's primary occupancy is not governed by public assembly (say residential governs) you can fall back to category ii.  
now say you have a restaurant and the occupancy load is 2450 while the remaining occupants are condos (residential).  the total building load is 4999 (2549 residential at 51%).  this makes the primary occupancy residential thus you fall under category ii.
any thoughts?

check out our whitepaper library.
is the separation between the occupancies a fire wall?  if so, then each can be considered a separate building and the a-2 would be iii, and the r-2 ii.
  
don phillips
i would think a firewall is included.  where in the code does it specifically say to consider them as separate buildings?
tia

don't you also have a change in the importance factors.  i would stay with cat 3
cut the restaurant loose structurally is the only way i can see designing for a lower i.  
it a renovation on a multi story building so there no opportunity to separate the structural systems.  my gut tells me to stay with category iii as well but i need to prove it in the code and currently the way ibc 2006 has changed this statement i'm struggling to find the exception to the rule.  it's interesting how fema 450 retains this statement but asce 7-05 chose not to.

asce 7-05 states "the classification for each independent structural system of a multiple-use building or other structure shall be that of the highest usage group in any part of the building or other structure that is dependent on that basic structural system."
seems pretty clear you have to go with worst case, occupancy category iii.

i like what your saying but how would this govern over ibc section 508 for mixed use occupancy?
705.1 general. each portion of a building separated by one or more fire walls that comply with the provisions of this section shall be considered a separate building. the extent and location of such fire walls shall provide a complete separation. where a fire wall also separates occupancies that are required to be separated by a fire barrier wall, the most restrictive requirements of each separation shall apply.
  
don phillips
bingo!  thank you don for the late night tip and to everyone else.