Type V-N Rating on Zero Setback

I'm drawing a 3 story building that will be sprinklered (so we will be building it as Type V-N) and has Zero Setbacks in a downtown area. I've always assumed this will have to be a 4-hour separation from the adjacent buildings on either side, but when looking at CBC 2001, Table 5-A, B occupancy, Type V, it appears that we only need a 1-hour separation at exterior walls.

Is this really true, or am I missing a superceding code somewhere?
Original Post
Group B: ... Type V-N is limited to Two-stories per 2001 CBC Table 5B ... When building is equipped with fire sprinklers the number of stories may be increased to by one-story ... however ... In such case, sprinklers may NOT be used for an increase in allowable area, NOR substitution for one-hour construction throughout, ... NOR may building have an Atria per CBC 506 ... Otherwise Type V-1hour construction would be expected for a 3-story building of Type V construction per Table 5B

Exterior wall may be one-hour per Table 5A ... however ... Any individual structural member of the structural frame per Table 6A (i.e. steel column/beams) would need to be individually protected by one-hour assembly, or sprayed-on fire-proofing, within the one hour wall assembly per CBC 704.

The 2001 CBC code intends that the fire resistive protection for structural members be applied to the individual member. In other words, the code does "not" intend that the structural member be protected by a wall assembly. Thus structural frame members within a fire-resistive wall must be provided with individual protection. Review CBC 601.4 for description of structural frame.
quote:
Originally posted by Dave Robertson:
Group B: ... Type V-N is limited to Two-stories per 2001 CBC Table 5B ... When building is equipped with fire sprinklers the number of stories may be increased to by one-story ... however ... In such case, sprinklers may NOT be used for an increase in allowable area, NOR substitution for one-hour construction throughout, ... NOR may building have an Atria per CBC 506 ... Otherwise Type V-1hour construction would be expected for a 3-story building of Type V construction per Table 5B


I believe our total area will be less than 16,000 sf. From 5B, I can add a story using sprinklers and still stay non-rated by keeping under the 8,000sf x 2 per 504.2. Correct?

Thanks for pointing that out about the steel members also, I'll keep an eye out for that.
Group B: Per 2001 CBC Table 5A
Type V-N ... 1hour wall less than 20 feet
Type V-1hour ... 1hour wall

Group B: Type V-N Allowable area:
8000 basic X 100% stories = 16,000 sq.ft.

Group B: Table 5B Number of stories: V-N ... 2 to 3
Fire sprinklers used soley to increase the number of stories by one-story per CBC 506.

Group B: Maximum height: Table 5B
Type V-N: Maximum height 40 feet
quote:
Originally posted by rlga_AZ:
Geoff:

You need to look at Table 5-A. A 4-hour wall will be required if the separation distance is less than 5 feet.


I might still be missing it, but I read 5-A to be only 1 hour if it is B occupancy and Type V construction.
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