CRC · California Residential Code

Where are smoke alarms required and how must they be installed?

Homes must have listed smoke alarms installed in every sleeping room, outside every sleeping area (in the immediate vicinity of bedrooms), and on every level including basements and habitable attics; install them exactly per the alarm’s listing and manufacturer’s instructions and follow the specific proximity and placement limits adopted by the CRC (see §§ R310.1.2, R310.2, and R310.3).

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Last reviewed: July 6, 2026

What the code requires — plain English

New and substantially altered dwelling units must have listed smoke alarms installed where people sleep, outside sleeping areas, and on every story (including basements and habitable attics). Installations must follow the alarm’s listing and the manufacturer’s instructions. See § R310.2, § R310.3, and § R310.1.2 for the requirements and installation authority.

Install a listed smoke alarm in every bedroom, outside the bedrooms near the sleeping area, and on every level of the home — and follow the manufacturer’s instructions exactly. (Key rule from the CRC.)

Requirements in detail

Short checklist (what to place where)

  • In each sleeping room. — § R310.3.
  • Outside each separate sleeping area in the immediate vicinity of the bedrooms (typically in the hallway serving the bedrooms). — § R310.3.
  • On each additional story of the dwelling unit, including basements and habitable attics (crawl spaces and uninhabitable attics excluded). — § R310.3.
  • Follow the alarm’s listing and the manufacturer’s installation instructions for exact placement, mounting surface, environmental limits, and wiring. — § R310.1.2.

Decision table — common decision dimensions

Decision dimension Typical values / threshold Code Reference
Required inside sleeping rooms? Yes — each sleeping room § R310.3
Required outside bedrooms? Yes — outside each separate sleeping area (immediate vicinity) § R310.3
Required on each story? Yes — each additional story, incl. basements & habitable attics § R310.3
Distance from bathroom door with tub/shower Not less than 3 feet (914 mm) horizontally, unless it prevents required placement § R310.3 (and R310.3.3 extract)
Cooking appliance exclusion Do not place within 10 ft (radial horizontal) of a fixed cooking appliance unless listed for proximity; other allowances for photoelectric/ionization with silencing are specified in NFPA extract NFPA extract adopted in § R310.3.3
Proximity to HVAC supply registers or ceiling fans Keep 36 in. (910 mm) horizontal distance from supply registers and ceiling-fan blades NFPA extract in § R310.3.3
Mounting surface limits Do not mount where ambient temps/humidity exceed manufacturer limits; avoid unfinished attics/garages (temps <40°F or >100°F) NFPA extract in § R310.3.3; installation authority § R310.1.2

Location specifics and mounting

  • Ceiling is the preferred location unless the manufacturer/listing directs otherwise; where ceilings are subject to large temperature swings (e.g., below unfinished attic) mount on an interior wall per NFPA guidance adopted by reference in § R310.3.3.
  • For stairways from basements, place the alarm on the basement ceiling near the stair entry so rising smoke can reach it. This and other detailed positioning rules are in the NFPA extract adopted by reference. § R310.3.3 (see NFPA extract).

Installation authority

  • The CRC requires alarms to be installed in accordance with their listing and the manufacturer’s instructions; follow both the UL/State Fire Marshal listing and manufacturer directions for mounting height, clearances, wiring, and environmental limits. § R310.1.2.

Exceptions & special cases

  • Existing dwelling units undergoing repairs/alterations that require a permit must be brought up to the new-dwelling smoke alarm locations — the unit must be equipped “as required for new dwellings.” § R310.2.2.
  • Crawl spaces and uninhabitable attics are excluded from the “each story” requirement; habitable attics and basements are included. § R310.3.
  • Specific proximity rules (kitchens, bathrooms, HVAC registers, ceiling fans, tray ceilings, stairs) are provided by the NFPA 72 extract adopted into § R310.3.3; consult those sub‑rules for nuisance-reduction and exact clearances.

If you need requirements about power source or interconnection for new construction: those topics are addressed in the California Fire/Building Code (for example, required primary power from building wiring and battery backup in new construction) rather than in the three CRC sections you asked about — see related provisions below for the specific code sections.

Common mistakes

  • Assuming “one alarm per floor is always enough.” The CRC requires alarms in every sleeping room and outside sleeping areas in addition to the per-story requirement — don’t skip bedroom alarms. § R310.3.
  • Mounting alarms too close to cooking appliances or bathrooms and causing nuisance alarms — observe the 10 ft / 20 ft cooking appliance radial exclusions and 3 ft bathroom rule in the NFPA extract adopted in § R310.3.3.
  • Ignoring manufacturer listing and instructions — CRC requires installation per the alarm’s listing and instructions (§ R310.1.2) so deviations can violate the code and void listing.

Worked example — small two-story house

Scenario: 1,200 ft² two-story single-family home with basement, two second-story bedrooms served by a bedroom hallway, an open-plan kitchen on the first floor, and a sleeping loft open to a living room.

Where to place alarms (apply § R310.3):

  • One alarm in each bedroom (2 alarms — each sleeping room). § R310.3(1).
  • One alarm outside the bedrooms in the hallway immediately serving the bedrooms (1 alarm). § R310.3(2).
  • One alarm on the first floor (one per story) — because the kitchen is on the first floor, do not place the first-floor alarm within the cooking appliance exclusion zone; use a photoelectric alarm or locate at least 10 ft away horizontally from the stove per § R310.3.3. § R310.3(3) and NFPA extract.
  • One alarm in the basement near the head of the stairs (1 alarm). § R310.3(3) and NFPA extract for stairways.
  • For the sleeping loft open to the living room, install an alarm within the room to which the loft is open, in the immediate vicinity of the loft. § R310.3(6).

Total alarms in this example: 6 (2 bedrooms + hallway + first floor + basement + loft location). Install each alarm per its listing/manufacturer instructions (mounting height, clearances). § R310.1.2.

Related provisions (other code sections to consult)

  • § R310.1.2 — Installation in accordance with listing and manufacturer’s instructions (controlling CRC installation authority).
  • § R310.2 — Where required; new construction and alterations.
  • § R310.3 — Location requirements (sleeping rooms, outside sleeping areas, per story, bath and loft rules).
  • § R310.3.3 — NFPA 72 extract with specific location clearances (cooking, bathrooms, HVAC registers, ceiling fans, tray ceilings, stairs).
  • § R310.4 — Interconnection requirements when more than one alarm is required in a dwelling unit (see CRC extract).
  • California Fire/Building Code § 907.2.11.6 — Power source and battery backup requirements for new construction (useful when planning new wiring).

Code references

Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:

  • CRC § 3.3 High relevance — show source text

    Exceptions: See Section R310.6.

    R310.3 Location. Smoke alarms shall be installed in the following locations:

    1. In each sleeping room.
    2. Outside each separate sleeping area in the immediate vicinity of the bedrooms.
    3. On each additional story of the dwelling unit, including basements and habitable attics and not including crawl spaces and uninhabitable attics. In dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.
    4. Not less than 3 feet (914 mm) horizontally from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by this section.
    5. In the hallway and in the room open to the hallway in dwelling units where the ceiling height of a room open to a hallway serving bedrooms exceeds that of the hallway by 24 inches (610 mm) or more.
    6. Within the room to which a sleeping loft is open, in the immediate vicinity of the sleeping loft.

    See Section R310.3.3 for specific location requirements.

    R310.3.1 Installation near cooking appliances. See Section R310.3.3 for specific location requirements.

    R310.3.2 Smoke alarms. Smoke alarms shall be tested and maintained in accordance with the manufacturer’s instructions. Smoke alarms that no longer function shall be replaced.

    R310.3.3 Specific location requirements. Extract from NFPA 72 Section 29.8.3.4 Specific Location Requirements.*

    This extract has been provided by NFPA as amended by the Office of the State Fire Marshal and adopted by reference as follows:

    NFPA 72 29.8.3.4 Specific location requirements. The installation of smoke alarms and smoke detectors shall comply with the following requirements: (1) Smoke alarms and smoke detectors shall not be located where ambient conditions, including humidity and temperature, are outside the limits specified by the manufacturer's published instructions. (2) Smoke alarms and smoke detectors shall not be located within unfinished attics or garages or in other spaces where tempera- tures can fall below 40ºF (4ºC) or exceed 100ºF (38ºC). (3) Where the mounting surface could become considerably warmer or cooler than the room, such as a poorly insulated ceiling below an unfinished attic or an exterior wall, smoke alarms and smoke detectors shall be mounted on an inside wall.

    (4) Smoke alarms or smoke detectors shall be installed a minimum of 20 feet horizontal distance from a permanently installed cooking appliance. Exception: Ionization smoke alarms with an alarm-silencing switch or Photoelectric smoke alarms shall be permitted to be installed 10 feet (3 m) or greater from a permanently installed cooking appliance. Photoelectric smoke alarms shall be permitted to be installed greater than 6 feet (1.8 m) from a permanently installed cook- ing appliance where the kitchen or cooking area and adjacent spaces have no clear interior partitions and the 10 ft distances

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  • CRC § 29.8.3.4 High relevance — show source text

    This extract has been provided by NFPA as amended by the Office of the State Fire Marshal and adopted by reference as follows:

    NFPA 72 29.8.3.4 Specific location requirements. The installation of smoke alarms and smoke detectors shall comply with the following requirements: (1) Smoke alarms and smoke detectors shall not be located where ambient conditions, including humidity and temperature, are outside the limits specified by the manufacturer's published instructions. (2) Smoke alarms and smoke detectors shall not be located within unfinished attics or garages or in other spaces where tempera- tures can fall below 40ºF (4ºC) or exceed 100ºF (38ºC). (3) Where the mounting surface could become considerably warmer or cooler than the room, such as a poorly insulated ceiling below an unfinished attic or an exterior wall, smoke alarms and smoke detectors shall be mounted on an inside wall.

    (4) Smoke alarms or smoke detectors shall be installed a minimum of 20 feet horizontal distance from a permanently installed cooking appliance. Exception: Ionization smoke alarms with an alarm-silencing switch or Photoelectric smoke alarms shall be permitted to be installed 10 feet (3 m) or greater from a permanently installed cooking appliance. Photoelectric smoke alarms shall be permitted to be installed greater than 6 feet (1.8 m) from a permanently installed cook- ing appliance where the kitchen or cooking area and adjacent spaces have no clear interior partitions and the 10 ft distances

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    would prohibit the placement of a smoke alarm or smoke detector required by other sections of the code. Smoke alarms listed for use in close proximity to a permanently installed cooking appliance. (5) Installation near bathrooms. Smoke alarms shall be installed not less than a 3 foot (0.91 m) horizontal distance from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by other sections of the code.

    (6) Smoke alarms and smoke detectors shall not be installed within a 36 in. (910 mm) horizontal path from the supply registers of a forced air heating or cooling system and shall be installed outside of the direct airflow from those registers. (7) Smoke alarms and smoke detectors shall not be installed within a 36 in. (910 mm) horizontal path from the tip of the blade of a ceiling-suspended (paddle) fan. (8) Where stairs lead to other occupied levels, a smoke alarm or smoke detector shall be located so that smoke rising in the stair- way cannot be prevented from reaching the smoke alarm or smoke detector by an intervening door or obstruction. (9) For stairways leading up from a basement, smoke alarms or smoke detectors shall be located on the basement ceiling near the entry to the stairs. (10) For tray-shaped ceilings (coffered ceilings), smoke alarms and smoke detectors shall be installed on the highest portion of the ceiling or on the sloped portion of the ceiling within 12 in. (300 mm) vertically down from the highest point. (11) Smoke alarms and detectors installed in rooms with joists or beams shall comply with the requirements of 17.7.3.2.4. (12) Heat alarms and detectors installed in rooms with joists or beams shall comply with the requirements of 17.6.3.

  • CRC § 907.2.11.2 High relevance — show source text

    [F] 907.2.11.2 Groups R-2, R-2.1, R-2.2, R-3, R-3.1, R-4 and R-4.1 . Single- or multiple-station smoke alarms shall be installed and maintained in Groups R-2, R-2.1, R-2.2, R-3, R-3.1 and R-4 regardless of occupant load at all of the following locations:

    1. On the ceiling or wall outside of each separate sleeping area in the immediate vicinity of bedrooms.
    2. In each room used for sleeping purposes.
    3. In each story within a dwelling unit, including basements but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level. 4. In a Group R-3.1 occupancies, in addition to the above, smoke alarms shall be provided throughout the habitable areas of the dwelling unit except kitchens. See Section 907.2.11.8 for specific location requirements. 907.2.11.2.1 Licensed Group R-2.1 occupancies. Licensed Group R-2.1 occupancies housing more than six nonambulatory, elderly clients shall be provided with an approved manual and automatic fire alarm system. Exceptions: Buildings housing nonambulatory clients on the first story only and which are protected throughout by the following: 1. An approved and supervised automatic sprinkler system, as specified in the California Fire Code Sections 903.3.1.1 or 903.3.1.2, which upon activation will initiate the fire alarm system to notify all occupants.

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    2. A manual fire alarm system. 3. Smoke alarms required by the California Fire Code Section 907.2.10.

    907.2.11.2.1.1 Smoke alarms. Single- and multiple-station smoke alarms shall be installed in accordance with California Fire Code Section 907.2.11.

    907.2.11.2.2 Group I-4 occupancies. Large family day-care homes shall be equipped with State Fire Marshal approved and listed single station residential type smoke alarms.

    907.2.11.2.3 Group R-3.1. In all facilities housing a bedridden client, smoke alarms shall receive their primary power from the build- ing wiring when such wiring is served from a commercial source and shall be equipped with a battery backup. Smoke alarms shall be electrically interconnected so as to cause all smoke alarms to sound a distinctive alarm signal upon actuation of any single smoke alarm. Such alarm signal shall be audible throughout the facility at a minimal level of 15 dB above ambient noise level. These devices need not be interconnected to any other fire alarm device, have a control unit, or be electrically supervised or provided with emer-

    gency power.

  • CRC § 3.8.2 High relevance — show source text
    1. The piping system is tested in accordance with the California Plumbing Code.

    R309.3.8.2 Final inspection. The following items shall be verified upon completion of the system:

    1. Sprinklers are not painted, damaged or otherwise hindered from operation.
    2. Where a pump is required to provide water to the system, the pump starts automatically upon system water demand.
    3. Pressure-reducing valves, water softeners, water filters or other impairments to water flow that were not part of the original design have not been installed.
    4. The sign or valve tag required by Section R309.3.7 is installed and the owner’s manual for the system is present.

    SECTION R310—SMOKE ALARMS

    R310.1 General. Smoke alarms shall comply with NFPA 72, Section R310 and the manufacturer’s installation instructions.

    R310.1.1 Listings. Smoke alarms shall be listed and labeled in accordance with UL 217. Combination smoke and carbon monoxide alarms shall be listed and labeled in accordance with UL 217 and UL 2034. Systems and components shall be California State Fire Marshal listed and approved in accordance with California Code of Regulations, Title 19, Division 1 for the purpose for which they are installed.

    R310.1.2 Installation. Smoke alarms and combination smoke and carbon monoxide alarms shall be installed in accordance with their listing and the manufacturer’s instructions.

    R310.2 Where required. Smoke alarms shall be provided in accordance with this section.

    R310.2.1 New construction. Smoke alarms shall be provided in dwelling units.

    R310.2.2 Alterations, repairs and additions. Where alterations, repairs or additions requiring a permit occur, the individual dwelling unit shall be equipped with smoke alarms located as required for new dwellings.

    Exceptions: See Section R310.6.

    R310.3 Location. Smoke alarms shall be installed in the following locations:

    1. In each sleeping room.
    2. Outside each separate sleeping area in the immediate vicinity of the bedrooms.
    3. On each additional story of the dwelling unit, including basements and habitable attics and not including crawl spaces and uninhabitable attics. In dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.
    4. Not less than 3 feet (914 mm) horizontally from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by this section.
    5. In the hallway and in the room open to the hallway in dwelling units where the ceiling height of a room open to a hallway serving bedrooms exceeds that of the hallway by 24 inches (610 mm) or more.
    6. Within the room to which a sleeping loft is open, in the immediate vicinity of the sleeping loft.

    See Section R310.3.3 for specific location requirements.

    R310.3.1 Installation near cooking appliances. See Section R310.3.3 for specific location requirements.

    R310.3.2 Smoke alarms. Smoke alarms shall be tested and maintained in accordance with the manufacturer’s instructions. Smoke alarms that no longer function shall be replaced.

    R310.3.3 Specific location requirements. Extract from NFPA 72 Section 29.8.3.4 Specific Location Requirements.*

  • CRC § 907.2.11.1 High relevance — show source text

    907.2.11.1 Group R-1. Single- or multiple-station smoke alarms shall be installed in all of the following locations in Group R-1:

    1. In sleeping areas.
    2. In every room in the path of the means of egress from the sleeping area to the door leading from the sleeping unit.
    3. In each story within the sleeping unit, including basements. For sleeping units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level. See Section 907.2.10.8 for specific location requirements. 907.2.11.2 Groups R-2, R-2.1, R-2.2, R-3, R-3.1 and R-4 and I-1. Single- or multiple-station smoke alarms shall be installed and maintained in Groups R-2, R-2.1, R-2.2, R-3, R-3.1 and R-4 regardless of occupant load at all of the following locations:
    4. On the ceiling or wall outside of each separate sleeping area in the immediate vicinity of bedrooms.
    5. In each room used for sleeping purposes.
    6. In each story within a dwelling unit, including basements but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level. 4. In a Group R-3.1 occupancies, in addition to the above, smoke alarms shall be provided throughout the habitable areas of the dwelling unit except kitchens. See Section 907.2.10.8 for specific location requirements. 907.2.11.2.1 Licensed Group R-2.1 occupancies. Licensed Group R-2.1 occupancies housing more than six nonambulatory, elderly clients shall be provided with an approved manual and automatic fire alarm system. Exceptions: Buildings housing nonambulatory clients on the first story only and which are protected throughout by the following: 1. An approved and supervised automatic sprinkler system, as specified in Sections 903.3.1.1 or 903.3.1.2, which upon activation will initiate the fire alarm system to notify all occupants. 2. A manual fire alarm system. 3. Smoke alarms required by Section 907.2.11.

    907.2.11.2.1.1 Smoke alarms. Single- and multiple-station smoke alarms shall be installed in accordance with Section 907.2.11.

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    907.2.11.2.2 Group I-4 occupancies. Large family day-care homes shall be equipped with State Fire Marshal approved and listed single station residential type smoke alarms.

  • CRC § 0.91 High relevance — show source text

    would prohibit the placement of a smoke alarm or smoke detector required by other sections of the code. Smoke alarms listed for use in close proximity to a permanently installed cooking appliance. (5) Installation near bathrooms. Smoke alarms shall be installed not less than a 3 foot (0.91 m) horizontal distance from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by other sections of the code.

    (6) Smoke alarms and smoke detectors shall not be installed within a 36 in. (910 mm) horizontal path from the supply registers of a forced air heating or cooling system and shall be installed outside of the direct airflow from those registers. (7) Smoke alarms and smoke detectors shall not be installed within a 36 in. (910 mm) horizontal path from the tip of the blade of a ceiling-suspended (paddle) fan. (8) Where stairs lead to other occupied levels, a smoke alarm or smoke detector shall be located so that smoke rising in the stair- way cannot be prevented from reaching the smoke alarm or smoke detector by an intervening door or obstruction. (9) For stairways leading up from a basement, smoke alarms or smoke detectors shall be located on the basement ceiling near the entry to the stairs. (10) For tray-shaped ceilings (coffered ceilings), smoke alarms and smoke detectors shall be installed on the highest portion of the ceiling or on the sloped portion of the ceiling within 12 in. (300 mm) vertically down from the highest point. (11) Smoke alarms and detectors installed in rooms with joists or beams shall comply with the requirements of 17.7.3.2.4. (12) Heat alarms and detectors installed in rooms with joists or beams shall comply with the requirements of 17.6.3.

    R310.4 Interconnection. Where more than one smoke alarm is required to be installed within an individual dwelling or sleeping unit, the smoke alarms shall be interconnected in such a manner that the activation of one alarm will activate all of the alarms in the individ- ual unit. The alarm shall be clearly audible in all bedrooms over background noise levels with all intervening doors closed.

    Exceptions: 1. Interconnection is not required in buildings that are not undergoing alterations, repairs or construction of any kind. 2. Smoke alarms in existing areas are not required to be interconnected where alterations or repairs do not result in the removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available which could provide access for interconnection without the removal of interior finishes. 3. Smoke alarms are not required to be interconnected where repairs or alterations are limited to the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck. 4. Smoke alarms are not required to be interconnected when work is limited to the installation, alteration or repairs of plumb- ing or mechanical systems or the installation, alteration or repair of electrical systems which do not result in the removal of interior wall or ceiling finishes exposing the structure.

    R310.5 Combination alarms. Combination smoke and carbon monoxide alarms shall be permitted to be used in lieu of smoke alarms. Systems and components shall be California State Fire Marshal listed and approved in accordance with California Code of Regu- lations, Title 19, Division 1 for the purpose for which they are installed.

  • CRC § 3.8.1 High relevance — show source text

    R309.3.8.1 Preconcealment inspection. The following items shall be verified prior to the concealment of any automatic sprinkler system piping:

    1. Sprinklers are installed in all areas as required by Section R309.3.1.1.
    2. Where sprinkler water spray patterns are obstructed by construction features, luminaires or ceiling fans, additional sprinklers are installed as required by Section R309.3.2.4.2.
    3. Sprinklers are the correct temperature rating and are installed at or beyond the required separation distances from heat sources as required by Sections R309.3.2.1 and R309.3.2.2 .
    4. The pipe size equals or exceeds the size used in applying Tables R309.3.6.2 (4) through R309.3.6.2 (9) or, if the piping system was hydraulically calculated in accordance with Section R309.3.6.1, the size used in the hydraulic calculation.
    5. The pipe length does not exceed the length permitted by Tables R309.3.6.2 (4) through R309.3.6.2 (9) or, if the piping system was hydraulically calculated in accordance with Section R309.3.6.1, pipe lengths and fittings do not exceed those used in the hydraulic calculation.

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    1. Nonmetallic piping that conveys water to sprinklers is listed for use with fire sprinklers.

    2. Piping is supported in accordance with the pipe manufacturer’s and sprinkler manufacturer’s installation instructions.

    3. The piping system is tested in accordance with the California Plumbing Code.

    R309.3.8.2 Final inspection. The following items shall be verified upon completion of the system:

    1. Sprinklers are not painted, damaged or otherwise hindered from operation.
    2. Where a pump is required to provide water to the system, the pump starts automatically upon system water demand.
    3. Pressure-reducing valves, water softeners, water filters or other impairments to water flow that were not part of the original design have not been installed.
    4. The sign or valve tag required by Section R309.3.7 is installed and the owner’s manual for the system is present.

    SECTION R310—SMOKE ALARMS

    R310.1 General. Smoke alarms shall comply with NFPA 72, Section R310 and the manufacturer’s installation instructions.

    R310.1.1 Listings. Smoke alarms shall be listed and labeled in accordance with UL 217. Combination smoke and carbon monoxide alarms shall be listed and labeled in accordance with UL 217 and UL 2034. Systems and components shall be California State Fire Marshal listed and approved in accordance with California Code of Regulations, Title 19, Division 1 for the purpose for which they are installed.

    R310.1.2 Installation. Smoke alarms and combination smoke and carbon monoxide alarms shall be installed in accordance with their listing and the manufacturer’s instructions.

    R310.2 Where required. Smoke alarms shall be provided in accordance with this section.

    R310.2.1 New construction. Smoke alarms shall be provided in dwelling units.

  • CRC § 907.2.11.7 High relevance — show source text

    [F] 907.2.11.7 Smoke detection system. Smoke detectors listed in accordance with UL 268 and provided as part of the building fire alarm system shall be an acceptable alternative to single- and multiple-station smoke alarms and shall comply with the following:

    1. The fire alarm system shall comply with all applicable requirements in Section 907.
    2. Activation of a smoke detector in a dwelling unit or sleeping unit shall initiate alarm notification in the dwelling unit or sleeping unit in accordance with Section 907.5.2.
    3. Activation of a smoke detector in a dwelling unit or sleeping unit shall not activate alarm notification appliances outside of the dwelling unit or sleeping unit, provided that a supervisory signal is generated and monitored in accordance with Section 907.6.6.

    907.2.11.8 Specific location requirements.

    Extract from NFPA 72 Section 29.11.3.4 Specific Location Requirements*.

    This extract has been provided by NFPA for the Office of the State Fire Marshal adoption by reference as follows:

    29.11.3.4 Specific location requirements. The installation of smoke alarms and smoke detectors shall comply with the following requirements: (1) Smoke alarms and smoke detectors shall not be located where ambient conditions, including humidity and temperature, are outside the limits specified by the manufacturer's published instructions. (2) Smoke alarms and smoke detectors shall not be located within unfinished attics or garages or in other spaces where temperatures can fall below 40ºF (4ºC) or exceed 100ºF (38ºC). (3) Where the mounting surface could become considerably warmer or cooler than the room, such as a poorly insulated ceil- ing below an unfinished attic or an exterior wall, smoke alarms and smoke detectors shall be mounted on an inside wall. (4) Smoke alarms and smoke detectors shall not be installed within an area of exclusion determined by a 10-foot (3.0 m) radial distance along a horizontal flow path from a stationary or fixed cooking appliance, unless listed for installation in close proximity to cooking appliances. Smoke alarms and smoke detectors installed between 10 feet (3.0 m) and 20 feet (6.1 m) along a horizontal flow path from a stationary or fixed appliance shall be equipped with an alarm-silencing means or use photoelectric detection.

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    (5) Smoke alarms or smoke detectors that use photoelectric detection shall be permitted for installation at a radial distance greater than 6 feet (1.8 m) from any stationary or fixed cooking appliance when both of the following conditions are met: (a) The kitchen or cooking area and adjacent spaces have no clear partitions or headers. (b) The 10-foot (3.0 m) area of exclusion would prohibit the placement of a smoke alarm or smoke detector required by other sections of this code. (6) Effective January 1, 2022, smoke alarms and smoke detectors installed between 6 feet (1.8 m) and 20 feet (6.1 m) along a horizontal flow path from a stationary or fixed cooking appliance shall be listed for resistance to common nuisance sources from cooking. (7) Smoke alarms and smoke detectors shall not be installed within a 36-inch (910 mm) horizontal path from a door to a _bathroom containing a shower or tub unless listed for installation in close proximity to such locations.

  • CRC § 907.2.11.2.6 High relevance — show source text

    907.2.11.2.6 Group R-4. A manual fire alarm system that activates the occupant notification system in accordance with Section 907.5 shall be installed in Group R-4 occupancies housing nonambulatory clients.

    [F] 907.2.11.3 Installation near cooking appliances. See Section 907.2.11.8.

    [F] 907.2.11.4 Installation near bathrooms. See Section 907.2.11.8.

    [F] 907.2.11.5 Interconnection. Where more than one smoke alarm is required to be installed within an individual dwelling unit or sleeping unit in Group R occupancies, the smoke alarms shall be interconnected in such a manner that the activation of one alarm will activate all of the alarms in the individual unit. Physical interconnection of smoke alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm. The alarm shall be clearly audible in all bedrooms over background noise levels with all intervening doors closed.

    [F] 907.2.11.6 Power source. In new construction, and in newly classified Group R-3.1 occupancies, required smoke alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and shall be equipped with a battery backup. Smoke alarms with integral strobes that are not equipped with battery backup shall be connected to an emergency electrical system in accordance with Section 2702. Smoke alarms shall emit a signal when the batteries are low. Wiring shall be permanent and without a disconnecting switch other than as required for overcurrent protection.

    Exception: Smoke alarms are not required to be equipped with battery backup where they are connected to an emergency electrical system that complies with Section 2702.

    [F] 907.2.11.7 Smoke detection system. Smoke detectors listed in accordance with UL 268 and provided as part of the building fire alarm system shall be an acceptable alternative to single- and multiple-station smoke alarms and shall comply with the following:

    1. The fire alarm system shall comply with all applicable requirements in Section 907.
    2. Activation of a smoke detector in a dwelling unit or sleeping unit shall initiate alarm notification in the dwelling unit or sleeping unit in accordance with Section 907.5.2.
    3. Activation of a smoke detector in a dwelling unit or sleeping unit shall not activate alarm notification appliances outside of the dwelling unit or sleeping unit, provided that a supervisory signal is generated and monitored in accordance with Section 907.6.6.

    907.2.11.8 Specific location requirements.

    Extract from NFPA 72 Section 29.11.3.4 Specific Location Requirements*.

    This extract has been provided by NFPA for the Office of the State Fire Marshal adoption by reference as follows:

    29.11.3.4 Specific location requirements. The installation of smoke alarms and smoke detectors shall comply with the following requirements: (1) Smoke alarms and smoke detectors shall not be located where ambient conditions, including humidity and temperature, are outside the limits specified by the manufacturer's published instructions. (2) Smoke alarms and smoke detectors shall not be located within unfinished attics or garages or in other spaces where temperatures can fall below 40ºF (4ºC) or exceed 100ºF (38ºC). (3) Where the mounting surface could become considerably warmer or cooler than the room, such as a poorly insulated ceil- _ing below an unfinished attic or an exterior wall, smoke alarms and smoke detectors shall be mounted on an inside wall.

  • CRC § 18001.8. High relevance — show source text

    (5) A fire alarm system with smoke detectors installed in accordance with the State Fire Marshal’s regulations may be installed in lieu of smoke alarms required pursuant to paragraph (1) or (2) of this subdivision, or paragraph (3) of subdivision (d).

    (b) “Dwelling units intended for human occupancy,” as used in this section, includes a duplex, lodging house, apartment complex, hotel, motel, condominium, stock cooperative, time-share project or dwelling unit of a multiple-unit dwelling complex. For the purpose of this part, “dwelling units intended for human occupancy” does not include manufactured homes as defined in Section 18007, mobilehomes as defined in Section 18008, and commercial coaches as defined in Section 18001.8.

    (c) A high-rise structure, as defined in subdivision (b) of Section 13210 and regulated by Chapter 3 (commencing with Section 13210), and which is used for purposes other than as dwelling units intended for human occupancy, is exempt from the require- ments of this section.

    (d) (1) The owner shall be responsible for testing and maintaining alarms in hotels, motels, lodging houses, apartment complexes and other multiple-dwelling complexes in which units are neither rented nor leased.

    (2) The owner of a hotel, motel, lodging house, apartment complex or other multiple-dwelling complex in which units are rented or leased, and commencing January 1, 2014, the owner of a single-family dwelling that is rented or leased, shall be responsible for testing and maintaining alarms required by this section as follows:

    (A) An owner or the owner’s agent may enter any dwelling unit, efficiency dwelling unit, guest room and suite owned by the owner for the purpose of installing, repairing, testing and maintaining single station smoke alarms required by this section. Except in cases of emergency, the owner or owner’s agent shall give the tenants of each such unit, room or suite reasonable notice in writing of the intention to enter and shall enter only during normal business hours. Twenty-four hours shall be presumed to be reasonable notice in absence of evidence to the contrary.

    (B) At the time that a new tenancy is created, the owner shall ensure that smoke alarms are operable. The tenant shall be responsible for notifying the manager or owner if the tenant becomes aware of an inoperable smoke alarm within his or

    2025 CALIFORNIA FIRE CODE 11-11

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    CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS

    her unit. The owner or authorized agent shall correct any reported deficiencies in the smoke alarm and shall not be in violation of this section for a deficient smoke alarm when he or she has not received notice of the deficiency.

    (3) On or before January 1, 2016, the owner of a dwelling unit intended for human occupancy in which one or more units is rented or leased shall install additional smoke alarms, as needed, to ensure that smoke alarms are located in compliance with current building standards. Existing alarms need not be replaced unless the alarm is inoperable. New smoke alarms installed in compliance with current building standards may be battery operated provided the alarms have been approved by the State Fire Marshal for sale in the state. This paragraph shall not apply to fire alarm systems with smoke detectors, fire alarm devices that connect to a panel, or other devices that use a low-power radio frequency wireless communication signal.

    (e) A violation of this section is an infraction punishable by a maximum fine of two hundred dollars ($200) for each offense.

  • CRC § 907.2.11.6 High relevance — show source text

    907.2.11.6 Power source. In new construction, and in newly classified Group R-3.1 occupancies, required smoke alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and shall be equipped with a battery backup. Smoke alarms with integral strobes that are not equipped with battery back-up shall be connected to an emergency electrical system in accordance with Section 1203. Smoke alarms shall emit a signal when the batteries are low. Wiring shall be permanent and without a disconnecting switch other than as required for overcurrent protection.

    Exception: Smoke alarms are not required to be equipped with battery backup where they are connected to an emergency electrical system that complies with Section 603.

    907.2.11.7 Smoke detection system. Smoke detectors listed in accordance with UL 268 and provided as part of the building fire alarm system shall be an acceptable alternative to single- and multiple-station smoke alarms and shall comply with the following:

    1. The fire alarm system shall comply with all applicable requirements in Section 907.
    2. Activation of a smoke detector in a dwelling unit or sleeping unit shall initiate alarm notification in the dwelling unit or sleeping unit in accordance with Section 907.5.2.
    3. Activation of a smoke detector in a dwelling unit or sleeping unit shall not activate alarm notification appliances outside of the dwelling unit or sleeping unit, provided that a supervisory signal is generated and monitored in accordance with Section 907.6.6.

    907.2.11.8 Specific location requirements.

    Extract from NFPA 72 Section 29.11.3.4 Specific Location Requirements*.

    This extract has been provided by NFPA for the Office of the State Fire Marshal adoption by reference as follows:

    29.11.3.4 Specific location requirements. The installation of smoke alarms and smoke detectors shall comply with the follow- ing requirements:

    (1) Smoke alarms and smoke detectors shall not be located where ambient conditions, including humidity and temperature, are outside the limits specified by the manufacturer's published instructions.

    (2) Smoke alarms and smoke detectors shall not be located within unfinished attics or garages or in other spaces where temperatures can fall below 40ºF (4ºC) or exceed 100ºF (38ºC).

    (3) Where the mounting surface could become considerably warmer or cooler than the room, such as a poorly insulated ceil- ing below an unfinished attic or an exterior wall, smoke alarms and smoke detectors shall be mounted on an inside wall.

    (4) Smoke alarms and smoke detectors shall not be installed within an area of exclusion determined by a 10-foot (3.0 m) radial distance along a horizontal flow path from a stationary or fixed cooking appliance, unless listed for installation in close proximity to cooking appliances. Smoke alarms and smoke detectors installed between 10 feet (3.0 m) and 20 feet (6.1 m) along a horizontal flow path from a stationary or fixed appliance shall be equipped with an alarm-silencing means or use photoelectric detection.

    (5) Smoke alarms or smoke detectors that use photoelectric detection shall be permitted for installation at a radial distance greater than 6 feet (1.8 m) from any stationary or fixed cooking appliance when both of the following conditions are met: (a) The kitchen or cooking area and adjacent spaces have no clear partitions or headers.

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    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

  • CRC § 9-31 High relevance — show source text

    2025 CALIFORNIA BUILDING CODE 9-31

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    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

    2. A manual fire alarm system. 3. Smoke alarms required by the California Fire Code Section 907.2.10.

    907.2.11.2.1.1 Smoke alarms. Single- and multiple-station smoke alarms shall be installed in accordance with California Fire Code Section 907.2.11.

    907.2.11.2.2 Group I-4 occupancies. Large family day-care homes shall be equipped with State Fire Marshal approved and listed single station residential type smoke alarms.

    907.2.11.2.3 Group R-3.1. In all facilities housing a bedridden client, smoke alarms shall receive their primary power from the build- ing wiring when such wiring is served from a commercial source and shall be equipped with a battery backup. Smoke alarms shall be electrically interconnected so as to cause all smoke alarms to sound a distinctive alarm signal upon actuation of any single smoke alarm. Such alarm signal shall be audible throughout the facility at a minimal level of 15 dB above ambient noise level. These devices need not be interconnected to any other fire alarm device, have a control unit, or be electrically supervised or provided with emer-

    gency power.

    907.2.11.2.4 Smoke alarms. Smoke alarms shall be tested and maintained in accordance with the manufacturer's instructions. Smoke alarms that no longer function shall be replaced.

    907.2.11.2.5 Existing Group R occupancies. See the California Residential Code for existing Group R-3 occupancies or Chapter 11 of the California Fire Code for all other existing Group R occupancies.

    907.2.11.2.6 Group R-4. A manual fire alarm system that activates the occupant notification system in accordance with Section 907.5 shall be installed in Group R-4 occupancies housing nonambulatory clients.

    [F] 907.2.11.3 Installation near cooking appliances. See Section 907.2.11.8.

    [F] 907.2.11.4 Installation near bathrooms. See Section 907.2.11.8.

    [F] 907.2.11.5 Interconnection. Where more than one smoke alarm is required to be installed within an individual dwelling unit or sleeping unit in Group R occupancies, the smoke alarms shall be interconnected in such a manner that the activation of one alarm will activate all of the alarms in the individual unit. Physical interconnection of smoke alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm. The alarm shall be clearly audible in all bedrooms over background noise levels with all intervening doors closed.

    [F] 907.2.11.6 Power source. In new construction, and in newly classified Group R-3.1 occupancies, required smoke alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and shall be equipped with a battery backup. Smoke alarms with integral strobes that are not equipped with battery backup shall be connected to an emergency electrical system in accordance with Section 2702. Smoke alarms shall emit a signal when the batteries are low. Wiring shall be permanent and without a disconnecting switch other than as required for overcurrent protection.

Frequently asked questions

Do smoke alarms have to be interconnected?

Yes — when more than one smoke alarm is required in a dwelling unit they must be interconnected so activation of one alarm will sound them all, unless an exception applies (see § R310.4).

Can I use a combination smoke/CO alarm to satisfy the smoke alarm requirement?

Yes — combination smoke and carbon monoxide alarms are permitted in lieu of standalone smoke alarms if they are listed for both functions and installed per their listing and instructions (§ R310.1.1 and § R310.1.2).

How close can a smoke alarm be to a bathroom or kitchen?

Do not place within 3 feet (914 mm) horizontally from the door/opening of a bathroom containing a tub/shower unless it prevents required placement; for cooking appliances follow the NFPA extract (typical exclusion is 10 ft radial horizontal unless the alarm is listed for proximity or meets photoelectric/silencing conditions). See § R310.3 and § R310.3.3.

Must new-construction alarms be hardwired or battery operated?

The CRC requires installation per listing and manufacturer instructions (§ R310.1.2). Power-source specifics for new construction (primary power from building wiring with battery backup) are addressed in the California Fire/Building Code (for example § 907.2.11.6). If you need the exact wiring rule for new construction, consult that section.

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California Residential Code