City Code Section
- The following table is used to classify the relative hazard of all building occupancies:
| TABLE 24.85-A | ||
| 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 | ASCE 41-BPOE |
| 3 | B, M | |
| 2 | F-1, F-2, S-1, S-2 | |
| 1 (Lowest) | R-3, U | |
- A. Occupancy change to a higher relative hazard classification. An occupancy change to a higher relative hazard classification will require seismic improvements based upon the factors of changes in the net floor area and the occupant load increases as indicated in Table 24.85-B below. All improvements to either the OSSC or ASCE 41 improvement standard must be made such that the entire building conforms to the appropriate standard indicated in Table 24.85-B.
| TABLE 24.85-B | ||||
| Percentage of Building Net Floor Area Changed | - | Occupant Load Increase | Required Improvement Standard | Relative Hazard Classification |
| 1/3 of area or less | and | Less than 150 | None | 1 through 6 |
| More than 1/3 of area | or | 150 and above | ASCE 41-BPOE | 1, 2, 3 and 4 |
| More than 1/3 of area | or | 150 and above | OSSC or ASCE 41-BPON | 5 and 6 |
- Multiple occupancy changes to a single building may be made under this Section without triggering a seismic upgrade provided the cumulative changes do not exceed 1/3 of the building net floor area or add more than 149 occupants with respect to the legal building occupancy as of October 1, 2004.
- B. Occupancy change to same or lower relative hazard classification. An occupancy change to the same or a lower relative hazard classification or a change in use within any occupancy classification will require seismic improvements using either the OSSC or ASCE 41 improvement standard, as identified in Table 24.85-A above, where the change results in an increase in occupant load of more than 149 people as defined by the OSSC. Where seismic improvement is required, the entire building must be improved to conform to the appropriate improvement standard identified in Table 24.85-A.
- Multiple occupancy changes to a single building may be made under this Section without triggering a seismic upgrade provided the cumulative changes do not result in the addition of more than 149 occupants with respect to the legal building occupancy as of October 1, 2004.
- C. Occupancy change to live work space. Any building occupancy classified as relative hazard category 1, 2, or 3 may undergo a change of occupancy to live/work space provided that:
- 1. The building must be improved such that the entire building conforms to the ASCE 41-BPOE improvement standard; and
- 2. The building meets the fire and life safety standards of either the FLEx Guide or the current OSSC.
- 3. Any unreinforced masonry bearing wall building converted to live/work space, regardless of construction costs, must be improved such that the entire building conforms to the ASCE 41-BPOE improvement standard.
- D. Occupancy change to essential facilities. All structures that are being converted to essential facilities, as defined in the OSSC, must comply with current state code seismic requirements or ASCE 41-BPON improvement standard, regardless of other requirements in this Section.