California OSFM Clarifies Emergency Power Requirement for 120V Smoke Alarms with Integral Strobes (R-1 & R-2 Only)
Overview
The California Office of the State Fire Marshal (OSFM) has issued Code Interpretation 25-12, providing critical clarification on power supply requirements for 120-volt smoke alarms with integral strobe lights under the 2022 California Fire Code (CFC).
This interpretation has immediate design and construction implications for new residential projects, particularly Group R-1 and R-2 occupancies, and resolves long-standing confusion about whether internal battery backup alone is acceptable.
Spoiler alert: it is not.
What Triggered This Clarification?
Designers, contractors, and AHJs have questioned whether smoke alarms that include integral visual notification (strobes) could rely solely on internal battery backup during a power outage.
The OSFM was formally asked to interpret CFC Section 907.2.11.6, and the response was unambiguous.
Official OSFM Interpretation (Code Interpretation 25-12)
According to the OSFM:
Smoke alarms with integral strobes must be connected to an emergency electrical system when the strobe portion cannot be powered by the internal battery.
The Office further clarified that:
There are currently no listed smoke alarms where the battery backup is capable of powering the strobe
Strobes have significantly higher power demands than audible-only smoke alarms
Battery backup is therefore insufficient for visual notification appliances
This requirement is clearly stated in OSFM Code Interpretation 25-12, issued December 26, 2025
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| California OSFM Code Interpretation 25-12 requires smoke alarms with integral strobes in Group R-1 and R-2 occupancies to be powered by an emergency electrical system. |
Which Occupancies Are Affected?
This requirement applies only to the following occupancy groups:
Applies To:
Hotels
Motels
Boarding houses
Apartments
Condominiums
Dormitories
Assisted living (non-R-3.1)
Does NOT Apply To:
Group R-3 (single-family dwellings)
Commercial occupancies
Audible-only smoke alarms
Smoke alarms without integral strobes
Clarity here matters. This is not a blanket requirement across all residential buildings.
What “Emergency Power” Means in Practice
For applicable R-1 and R-2 projects:
The strobe portion of the smoke alarm must be supplied by emergency power
Acceptable sources include:
Legally required standby power systems
Emergency generators
Other code-compliant emergency electrical systems
Simply installing a 120VAC smoke alarm with battery backup is not compliant when a strobe is integrated
This has direct impact on:
Electrical design
Circuiting strategy
Panel schedules
Cost estimating
AHJ plan review approvals
Why the OSFM Took This Position
The OSFM explicitly stated that:
Battery technology cannot reliably support strobe operation
Visual notification is a life-safety feature, especially for the hearing-impaired
Emergency power ensures continuous visual alerting during outages
This interpretation reinforces accessibility and survivability objectives already embedded in the California Fire Code.
Key Takeaways for Designers & Contractors
Treat smoke alarms with integral strobes like notification appliances, not basic household alarms
Plan emergency power early in design for R-1 and R-2 projects
Expect AHJs to enforce this interpretation statewide
Do not assume battery backup satisfies strobe power requirements
Failing to account for this can result in plan check corrections, failed inspections, or costly redesigns.
Reference Document
CAL FIRE – Office of the State Fire Marshal
Code Interpretation 25-12
Issued December 26, 2025
2022 California Fire Code – Section 907.2.11.6
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