Skip to content

Chapter 5A — PRESCRIPTIVE COMPLIANCE METHOD

Section 501A — GENERAL

2025 California Existing Building Code (Title 24, Part 10) · 2025 edition · updated 2026-07-29 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

501 A .1 Scope. The provisions of this chapter shall control the alteration, addition and change of occupancy of existing buildings and structures. The provisions of this chapter shall apply to existing structures for applications listed in Section 1.10.1 [OSHPD 1] regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development (OSHPD).

501 A .1.1 Compliance with other methods. Alterations, additions and changes of occupancy to existing buildings and structures shall comply with the provisions of this chapter or with one of the methods or procedures provided in Section 301 A .3.

501 A .2 Fire-resistance ratings. Fire-resistance ratings shall comply with the California Building Standards Code.

501A.3 Prescriptive compliance provisions.

Alterations, additions and changes of occupancy to the following categories of existing buildings and structures shall comply with the provisions of this section.

501A.3.1 Prescriptive compliance provisions for SPC-4D using the California Building Code, 1980 (CBC 1980). Nonconforming buildings shall satisfy the following requirements: 1. The California Building Code, 1980 (CBC 1980), as used in this chapter, consists of the Uniform Building Code, 1979 (UBC 1979) along with requirements contained in: a) California Code of Regulations, Title 24- Building Standards, dated February 2, 1980 (Revision record for Register 80, No. 5). b) California Code of Regulations, Title 22 – Social Security, dated October 13, 1979 (Revision Record for Register 79, No 41). c) California Code of Regulations, Title 17 – Public Health, dated October 13, 1979 (Revision Record for Register 79, No 41-B). 2. All existing structural elements of Seismic Force Resisting System (SFRS) shall satisfy the detailing requirements in the CBC 1980 or demonstrate that the level of seismic performance is equivalent to that given in the CBC 1980, as determined by the building official. 3. A continuous load path or paths with adequate strength and stiffness to transfer all the forces from the point of origin to final point of resistance shall be justified by analysis. 4. Site data report in accordance with the CBC 1980 shall establish that seismically induced differential settlement does not exceed 1in 40.

5. Adjacent buildings shall satisfy the SPC building separation requirements in accordance with the California Administrative Code, Chapter 6 Section 3.4. 6. The addition of new structural elements or strengthening of existing structural elements for retrofit of nonconforming build- ings to SPC-4D shall comply with the following: a) The seismic demand (forces or displacements) shall be in accordance with the CBC 1980; b) Capacity, detailing and connections for new structural elements shall satisfy the requirements in the CBC 2025 for new construction; and c) The strengthening of existing structural elements shall use capacities determined in accordance with the CBC 2025 for new construction consistent with the detailing and connections used in the strengthened member. 7. All construction, quality assurance and quality control shall be in accordance with the new construction provisions of CBC 2025.

e CBC 2025 for_ new construction; and c) The strengthening of existing structural elements shall use capacities determined in accordance with the CBC 2025 for new construction consistent with the detailing and connections used in the strengthened member. 7. All construction, quality assurance and quality control shall be in accordance with the new construction provisions of CBC 2025.

8. Elements not part of the Seismic Force-Resisting System (SFRS), including those identified in the California Administrative Code Chapter 6, Article 10, shall be evaluated using seismic forces and the requirements of the CBC 1980. 9. Any column or wall that forms part of two or more intersecting SFRS and is subjected to axial load due to seismic forces acting along either principal plan axis equaling or exceeding 20 percent of the axial design strength of the column or wall shall be evaluated for the most critical load effect due to application of seismic force in any direction. The most critical load effect may be deemed to be satisfied if members and their foundations are evaluated for 100 percent of the forces for one direction plus 30 percent of the forces for the perpendicular direction, whereby the combination produces the maximum effect. Exceptions: The following buildings (with structural irregularities or unusual configuration/system) shall not be eligible for the SPC-4D upgrade using the prescriptive provisions in this section: 1. Buildings with prohibited irregularities in accordance with California Building Code 2022 Section 1617A.1.10.

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

PRESCRIPTIVE COMPLIANCE METHOD

2. Buildings taller than 5 stories or 65' height above the base having horizontal or vertical irregularities in accordance with ASCE 7-10 Tables 12.3-1 Items #1a, 1b and 3 or 12.3-2 Items #1a, 1b, 5a and 5b.

3. Buildings with unusual configuration or structural system, as determined by the building official.

501A.3.2 Prescriptive compliance provisions for SPC-4D using the new building design requirements of this code. Structures satisfying the requirements of the California Building Code for new general acute care hospital buildings design shall be deemed to satisfy the SPC-4D requirements of Table 2.5.3, Chapter 6 of the California Administrative Code.

All existing structural elements of a Seismic Force-Resisting System (SFRS) shall satisfy the detailing requirements of the California Building Code for new construction or demonstrate that the level of seismic performance is equivalent, as determined by the building official. A demonstration of equivalence shall consider the regularity, overstrength, redundancy and ductility of the structure.

Elements not part of the Seismic Force-Resisting System (SFRS), including those identified in the California Administrative Code Chapter 6, Article 10, shall be evaluated using seismic forces and the requirements of this code for new general acute care hospital buildings.

501A.3.3 Prescriptive compliance provisions for NPC 2, NPC 3, NPC 4 or NPC 4D and NPC 5.

501A.3.3.1 Supports and attachments of nonstructural components, except those listed in Section 501A.3.3.2 below, in buildings in seismic performance categories SPC 1 or SPC 2 with a performance level of NPC 3 or higher, and SPC 3, SPC 4 or SPC-4D, shall be permitted to comply with the provisions of Section 1630B of the 1998 California Building Code using an importance factor I p =1.5. The capacity of welds, anchors and fasteners shall be determined in accordance with requirements of the California Building Code for new construction.

501A.3.3.2 Supports and attachments for systems listed under NPC-2 and NPC-5 (excluding those specifically listed for NPC-3 and NPC-4 or NPC-4D) in the California Administrative Code, Chapter 6, Table 11.1 shall satisfy the requirements of the California Build- ing Code for new construction and Section 501A.3.3.1 above shall not be applicable.

501A.3.3.3 For NPC 3 and NPC 4 or NPC 4D in SPC 2, SPC 3, SPC 4 or SPC-4D buildings, the adequacy and design of nonstructural component or equipment supports and attachments may extend only to the connection of the component or equipment to the support when the total reaction at the point of support (including the application of F p ) is less than or equal to the following limits: 1. 250 pounds for components or equipment attached to light frame walls. For the purposes of this requirement, the sum of the absolute value of all reactions due to component loads on a single stud shall not exceed 250 pounds. 2. 1,000 pounds for components or equipment attached to roofs or walls of reinforced concrete or masonry construction. 3. 2,000 pounds for components or equipment attached to floors or slabs-on-grade.

Exception: If the anchorage or bracing is configured in a manner that results in significant torsion on a supporting structural element, the effects of the nonstructural reaction force on the structural element shall be considered in the anchorage design.

501 A . 4 Health care facilities. In Group I-2 facilities, ambulatory care facilities and outpatient clinics, any altered or added portion of an existing electrical or medical gas systems shall be required to meet installation and equipment requirements in NFPA 99.

Get a plain-English answer with a citation back to this text.

Ask AI about this code
Contents — 2025 California Existing Building Code (Title 24, Part 10)

GoCodebook provides public access, search, citation, multilingual explanation, and practical interpretation of legally adopted building regulations. It is not a substitute for the official ICC or California code publications.