Building Code Guides (BCGs) and Building Official Determinations (BODs) provide answers about the application of building codes and outline optional alternates. BODs are typically smaller in scope and address simpler questions. Code Guides provide a comprehensive alternative to a complicated set of code requirements.
BOD 24-01: R-4 Relative Hazard Classification
QUESTION: Since Table 24.85-A was developed before R-4 occupancies were added to the building code, which Relative Hazard Classification is appropriate?
Due to the number of occupants and nature of occupants, R-4 occupancy is considered more hazardous than R-3 (typically one and two-family residential dwellings) but less hazardous than I-1 occupancy (which includes assisted living facilities with more than 16 occupants). R-4 occupancies are assigned to Relative Hazard Classification 4.
| Relative Hazard Classification | OSSC Occupancy Classification | Seismic Improvement Standard |
|---|---|---|
| 6 (Highest) | A, E, I-2, I-3, H-1, H-2, H-3, H-4, H-5 | OSSC or ASCE 41-BPON |
| 5 | R-1, SR, I-1, I-4 | |
| 4 | R-2, R-4 | ASCE 41-BPOE |
| 3 | B, M | |
| 2 | F-1, F-2, S-1, S-2 | |
| 1 (Lowest) | R-3, U |
HISTORY: Implemented January 12, 2024.
DOWNLOAD a copy of this Building Official Determination:
Questions? Free 15-Minute Appointments for Permit, Code, and Zoning Questions