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POL Government Elected Officials Auditor Griffin-Valade Charter, Code & Policies City Code & Charter Online Code & Charter Title 24 Building Regulat Chapter 24.85 Seismic Design Requirements for Existing Buildings
24.85.040 Change of Occupancy or Use.

(Amended by Ordinance Nos. 169905, 170997 and 178831, effective November 20, 2004.) The following table shall be used to classify the relative hazard of all building occupancies:
 
 TABLE 24.85-A
 Relative
Hazard Classification
 OSSC Occupancy Classification
 Seismic
Improvement
Standard
 5 (Highest)
 A, E, I-2, I-3, H-1, H-2, H-3, H-4, H-5
 OSSC
 4
 R-1, R-2, SR, I-1, I-4
OSSC
 3
 B,M
 ASCE 31
 2
 F-1, F-2, S-1, S-2
ASCE 31
 1 (Lowest)
 R-3, U
ASCE 31
 
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 31 improvement standard shall 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 5
 More than 1/3 of area or
 150 and above
 ASCE 31
 1, 2, and 3
 More than 1/3 of area or
 150 and above
OSSC
 4 and 5
 
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 31 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 shall 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 shall be improved such that the entire building conforms to the ASCE 31 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, shall be improved such that the entire building conforms to the ASCE 31 improvement standard.
D. Occupancy Change to Essential Facilities. All structures which are being converted to essential facilities, as defined in the OSSC, shall comply with current state code seismic requirements, regardless of other requirements in this section.

Title 24 Building Regulat
Chapter 24.10 Administration and Enforcement
Chapter 24.15 Definitions
Chapter 24.20 Special Inspections
Chapter 24.25 Movings of Buildings
Chapter 24.30 Home Occupations
Chapter 24.35 Historical Buildings
Chapter 24.40 Use of and Projections Over Public Streets and Property
Chapter 24.45 Parking and Driveway Surfaces
Chapter 24.50 Flood Hazard Areas
Chapter 24.51 Wildfire Hazard Zones
Chapter 24.55 Building Demolition
Chapter 24.60 Fences
Chapter 24.65 Sidewalk Vault Openings
Chapter 24.70 Clearing, Grading and Erosion Control
Chapter 24.75 Uniform Building Address System
Chapter 24.80 (Repealed)
Chapter 24.85 Seismic Design Requirements for Existing Buildings
Chapter 24.90 Manufactured Dwelling Installation and Accessory Structures, Manufactured Dwelling Parks, Recreation Parks, Recreational Park Trailer Installation and Accessory Structures
Chapter 24.95 (Repealed)