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London N. Breed, Mayor
City and County of San Francisco
Patrick O’Riordan, C.B.O., Director
Department of Building Inspection
INFORMATION SHEET
ES I SE EE]
No. FS-12
DATE : May 5, 2023
CATEGORY : Fire Safety
SUBJECT : Accessory Dwelling Units — Group R3 Occupancy Change, Sprinkler
Requirements, and Unit Separation Requirements
SRS RS NES EE EE ST TST]
PURPOSE : To clarify Group-R3 occupancy change triggers, sprinkler requirements, and unit
separation requirements when accessory dwelling units are added
REFERENCE’ :_ Current edition California Building Code (CBC), Section 310
California Government Code 65852.2, 65852.22
Information Sheet G-23
Accessory Dwelling Unit Handbook, prepared by California Department of Housing
and Community Development
DISCUSSION
Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs) must comply with all
applicable local building codes that apply to detached dwellings, including but not limited to unit
separation, independent heating system, and independent ingress/egress. The following exceptions
apply:
1. The addition of an ADU or JADU to a Group R3 occupancy, resulting in three total dwelling units,
is permitted to remain a Group R3 occupancy. (California Government Code 65852.2(a)(D)(viii))
2. Creation of an ADU, whether attached or detached, shall not require installation of fire sprinklers
in the new ADU or existing primary dwelling if none existed prior. (Government Code
65852.2(a)(D)(xii)) Exception: Where a fire sprinkler system is otherwise triggered in the code by
these alterations, such as vertical or horizontal additions, travel distance, new buildings, etc.
3. Where a JADU is created within existing conditioned space, then unit separation and independent
heating system is not required.
For additional information on ADUs and JADUs, see Information Sheet G-23 and
https://sfplanning.org/accessory-dwelling-units.
Note: This information sheet applies to permit applications with filing dates after January 1, 2023.
ond— STS /Z
Patrick O’Riordan, C.B.O., Director Date
Department of Building Inspection
Technical Services
49 South Van Ness Avenue, Suite 500 — San Francisco CA 94103
Office (628) 652-3720 — www.sfdbi.org
