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City and County of San Francisco Edwin M. Lee, Mayor
Department of Building Inspection Tom C. Hui, S.E., C.B.O., Director
INFORMATION SHEET
NO. FS-05
DATE September 30, 2015
CATEGORY Fire Safety
SUBJECT Sprinkler Systems Requirements for Addition or Legalization of
Dwelling Unit
PURPOSE The purpose of this Information Sheet is to clarify the sprinkler systems
requirements for addition or legalization of dwelling unit.
REFERENCE 2013 San Francisco Building Code
Ordinance No. 43-14
Ordinance No. 49-14
Ordinance No. 30-15
DISCUSSION The requirements for sprinkler systems for addition or legalization of dwelling unit.
A. When the occupancy is changed from Group R3 to Group R2 by adding or legalizing a dwelling unit,
resulting in a building not more than 3 stories and within existing building envelope:
1. If the added or legalized dwelling unit is on the first floor,
(i) Sprinklers will be required on the entire first level designed per designated hazard
classification (NFPA 13R and NFPA 13); and,
(ii) For building more than 2 stories, the first floor shall be separated from the upper floor
by 1-hour fire rated construction applied on the affected side.
2. If the added or legalized dwelling unit is not located on the first floors,
(i) Sprinklers will be required for the added or legalized dwelling unit and the egress path
of the unit; and,
(ii) For buildings more than 2 stories, the first floor shall be separated from the upper floor
by 1-hour fire rated construction applied on the affected side.
B. When the occupancy is changed from Group R3 to Group R2 by adding or legalizing a dwelling unit,
resulting in a building more than 3 stories:
1. If building envelope is changed (excluding exterior egress), the entire building needs to be fully
sprinklered.
2. If story count is increased to 4 stories within existing envelope, entire building shall be
sprinklered.
3. If story count is not changed and within existing envelope, sprinklers will be required for the
added or legalized dwelling unit and the egress path of that unit.
TECHNICAL SERVICES DIVISION
1660 Mission Street - San Francisco CA 94103
Office (415) 558-6205 - FAX (415) 558-6401
Website: www.sfdbi.org
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INFORMATION SHEET FS-05
C. When a dwelling unit is added or legalized in a Group R2 building within existing building envelope,
sprinklers will only be required for the added or legalized dwelling unit and the egress path of that unit.
D. In an existing 3- or 4-story building or building which is increased to resulting in 3- or 4-story, the
ground floor ceiling may be upgraded to 1-hour rated construction in lieu of upgrading to 1-hour rated
building.
E. This Information Sheet is applicable to any of the following:
1. Ordinance No. 43-14: Legalization of Dwelling Units Installed Without A Permit
2. Ordinance No. 49-14: Construction of In-Law Units in Existing Residential Buildings of Auxiliary
Structures on the Same Lot; Rent Control
3. Ordinance No. 30-15: Adding Dwelling Units to Existing Buildings Undergoing Seismic
Retrofitting
OTHER CONDITIONS:
Other conditions will be evaluated on a case-by-case basis by the Supervisor or Manager.
Pre-application meeting or approval of AB-005 is required.
1<:/1(~!15
Daniel de Cossio Date
Fire Marshal & Assistant Deputy Chief
San Francisco Fire Department
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Tom C. Hui, S.E, C.B.O. ~
Director
Department of Building Inspection
This Information Sheet is subject to modification at any time. For the most current version, visit our
website at http://www.sfdbi.or(l
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