711.2.3 Supporting Construction for Horizontal Assembly, R-2 above B

[DNW-KW]

2018 IBC: 3-story Type VB NFPA 13 sprinklered construction, level 1 ground floor is Group B with levels 2 and 3 Group R-2 above.

1. 711.2.3 Exception 2 - IF pursue mixed use nonseparated occupancies, will this exception 2 allow the horizontal assembly between B and R-2 not be rated? Exception allows for horizontal assemblies not rated where separating dwelling units as required by Section 420.3 - Section 420.3 requires horizontal separation between dwelling units and separating dwelling units from other contiguous occupancies. (Table 508.4 not applicable since nonseparated occupancies approach to mixed use.)
2. Supporting construction of 1-hr horizontal assembly:
   1. If horiz. assembly between B and R-2 is exempted from being rated (per #1 above), will supporting construction bearing walls below need to be 1-hr rated?
   2. Would supporting construction exterior bearing walls need to be rated from both sides, or at interior side only?
   3. What about supporting construction that is a bearing post within a shear wall? Would that entire shear wall need to be rated, or just post protected individually since it's the 'supporting construction'?
   4. Are openings allowed in the 'supporting construction' wall assemblies?
   5. Is the supporting construction allowed to have unprotected window and door openings (as long as meets Table 705.8 FSD max. openings size limitations)?

 

[RLGA]

You are still required to have the rated horizontal assembly. The exception just means that the construction supporting the horizontal assembly (i.e., columns and load-bearing walls) does not need to have the 1-hour rating.