CRC · California Residential Code
When are combination smoke/CO alarms permitted and what listing/approval applies?
You can use a combination smoke/CO alarm instead of separate smoke and CO devices in California, but the unit must have the exact UL listings required for the job (UL 217 + UL 2034 for household alarms; UL 268 + UL 2075 when used in a detection system), be installed per the manufacturer’s listing and the CRC, be State Fire Marshal‑listed, and comply with interconnection and power rules where multiple alarms are required.
Last reviewed: July 6, 2026
What the code requires — plain English
- Combination carbon monoxide and smoke alarms are allowed as a direct substitute for required standalone carbon monoxide (CO) alarms and for required smoke alarms, provided the device carries the appropriate UL listings and State Fire Marshal approval. § R311.4 and § R310.5 / § R310.1.1 set this permission and the listing requirement.
- The code distinguishes two situations: simple household alarms (listed to UL standards for alarms) and devices used as part of a carbon monoxide detection system (which require different UL detector listings). See § R311.7.4 for detection systems.
The single most important rule: A combination smoke/CO device may be used in place of either required smoke alarms or CO alarms — but it must be listed to the UL standards required for the role it is filling and be approved/listed by the California State Fire Marshal.
Requirements in detail
Two different contexts — alarms vs. detectors/systems
- As a household alarm (installed per the smoke-alarm / CO‑alarm provisions), the device must be listed to both UL 217 (smoke alarm) and UL 2034 (CO alarm) and be State Fire Marshal listed/approved. § R310.1.1 and § R311.1.1.
- As a component of a carbon monoxide detection system (a system-level installation covered by NFPA 72 and the detection-system rules), combination detectors must be listed to UL 268 (smoke detector) and UL 2075 (gas/CO detector) and comply with State Fire Marshal listing/approval. § R311.7.1 and § R311.7.4.
Installation, power, and interconnection basics
- Devices must be installed in accordance with their listing and the manufacturer’s instructions (applies to both smoke and CO provisions). § R310.1.2 and § R311.1.2.
- Where more than one CO alarm is required in a dwelling, alarms must be interconnected so activation of one activates all (with listed wireless allowed). § R311.5. The parallel interconnection requirement for smoke alarms appears in § R310.4.
- CO alarms (including combination devices functioning as CO alarms) must receive primary power from the building wiring served from a commercial source with battery backup, except in limited circumstances (existing buildings, no commercial power, etc.). § R311.6.
Decision table — which listing applies
| Use / Question | Required listing(s) / approval | Code Reference |
|---|---|---|
| Replace a required CO alarm with a combination unit (household alarm) | UL 2034 (CO) and UL 217 (smoke); State Fire Marshal listing/approval | § R311.1.1 |
| Replace a required smoke alarm with a combination unit (household alarm) | UL 217 (smoke) and UL 2034 (CO); State Fire Marshal listing/approval | § R310.1.1 and § R310.5 |
| Use combination detectors as part of a CO detection system (system-level protection) | UL 268 (smoke detector) and UL 2075 (CO/gas detector); State Fire Marshal listing/approval; comply with NFPA 72 | § R311.7.1 and § R311.7.4 |
| Multiple required alarms in a dwelling — interconnection needed? | Yes — alarms must be interconnected (listed interconnect or listed wireless). Applies to both CO and smoke alarms. | § R311.5 and § R310.4 |
| State approval requirement | Devices must be California State Fire Marshal listed and approved per Title 19 for the purpose intended. | § R310.1.1 and § R311.1.1 |
Exceptions & special cases
- Existing dwellings (built before Jan 1, 2011) have limited exceptions to the wiring/power and interconnection requirements for CO alarms; battery-powered or plug‑in with battery backup may be allowed in those specific circumstances. See the power-source exceptions in § R311.6.
- Where a combination device is being used as part of a larger fire- or CO‑detection system, the UL listing requirement changes from UL 2034/UL 217 to the detector/system standards UL 2075/UL 268 as required by § R311.7.4. Do not mix system-detector listing rules with household-alarm rules; the code differentiates them.
If you need a determination for an unusual installation (e.g., multi-family covered by the Building/Fire Code system-level rules), consult the applicable Building or Fire Code sections because system/detection installations may be governed by those chapters (see CBC/FC cross-references).
Common mistakes
- Assuming any combination device is acceptable: the device must carry the specific UL listings required for the role it fills — UL 217 + UL 2034 for household alarms, or UL 268 + UL 2075 for system detectors. Do not rely on a single UL listing unless it matches the code requirement. § R310.1.1, § R311.1.1, § R311.7.4.
- Forgetting State Fire Marshal listing: even properly UL‑listed products must be California State Fire Marshal listed/approved as required by the CRC. § R310.1.1 and § R311.1.1.
- Ignoring interconnection and power requirements: when multiple alarms are required, interconnection and permanent primary power rules apply unless a specific exception is met. § R311.5 and § R311.6.
Worked example
Scenario: Single-family dwelling, new construction, three required smoke alarms (one in each sleeping room), two required CO alarms (one outside sleeping area and one on each occupiable level). The designer wants to use combination smoke/CO alarms wherever possible.
Step-by-step:
- Because this is new construction, combination units are permitted to replace both required smoke and CO alarms — provided each combination unit is listed to UL 217 and UL 2034 and is State Fire Marshal listed. § R310.1.1 and § R311.1.1.
- Because more than one CO alarm is required in the dwelling, all CO-capable devices must be interconnected so one activation will sound all CO alarms (interconnection requirement for CO alarms). § R311.5. If using wired interconnect, wiring must be permanent and powered per § R311.6.
- Confirm each combination unit’s listing label: it must show both UL 217 and UL 2034 (household alarm case). If any detector is intended as part of a monitored detection system instead, different UL listings (UL 268 & UL 2075) would be required. § R311.7.4.
Result: Using combination units is allowed — but verify each unit’s UL 217 + UL 2034 markings and SFM listing, wire them for primary power with battery backup, and interconnect all required devices. § R310.1.1, § R311.1.1, § R311.5, § R311.6.
Related provisions
- § R310.1.1 — Listings for smoke alarms and combination smoke/CO alarms.
- § R310.4 — Interconnection requirement for smoke alarms.
- § R311.1.1 — Listings for CO alarms and combination CO/smoke alarms.
- § R311.4 — Permission to use combination alarms in lieu of CO alarms.
- § R311.5 — Interconnectivity requirement for CO alarms.
- § R311.6 — Power source requirements and exceptions for CO alarms.
- § R311.7.4 — Listing requirements for combination detectors when used in CO detection systems (UL 268 & UL 2075).
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 915.4.2 High relevance — show source text
Exceptions:
1. Where installed in buildings without commercial power, battery-powered carbon monoxide alarms shall be an acceptable alternative. 2. Carbon monoxide alarms in Group R occupancies shall be permitted to receive their primary power from other power sources recognized for use by NFPA 720. 3. Carbon monoxide alarms in Group R occupancies shall be permitted to be battery-powered or plug-in with a battery backup in existing buildings built prior to January 1, 2011, under any of the following conditions: 3.1. No construction is taking place. 3.2. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 3.3. 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. 3.4. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
915.4.2 Listings. Residential carbon monoxide alarms shall be listed in accordance with UL 2034.
No person shall install, market, distribute, offer for sale or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Marshal.
915.4.3 Combination alarms. Combination carbon monoxide/smoke alarms shall be an acceptable alternative to carbon monoxide alarms. Combination carbon monoxide/smoke alarms shall be listed in accordance with UL 217 and UL 2034. Combination carbon monoxide/smoke alarms shall comply with Section 915, and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
915.4.4 Interconnection. Where more than one carbon monoxide alarm is required to be installed within a dwelling unit or within a sleeping unit in Group R occupancies, the alarms shall be interconnected in a manner that activation of one alarm shall activate all of the alarms in the individual unit.
Exception : Interconnection is not required in existing buildings, built prior to January 1, 2011, under any of the following conditions: 1. Physical interconnection is not required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
2. No construction is taking place. 3. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 4. 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. 5. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
915.5 Carbon monoxide detection systems. Carbon monoxide detection systems shall be an acceptable alternative to carbon monoxide alarms and shall comply with Sections 915.5.1 through 915.5.3.
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CRC § 9-57 High relevance — show source text
which do_ not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
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[F] 915.4.2 Listings. Residential Carbon monoxide alarms shall be listed in accordance with UL 2034.
No person shall install, market, distribute, offer for sale, or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Marshal.
[F] 915.4.3 Combination alarms. Combination carbon monoxide/smoke alarms shall be an acceptable alternative to carbon monoxide alarms. Combination carbon monoxide/smoke alarms shall be listed in accordance with UL 217 and UL 2034.
Combination carbon monoxide/smoke alarms shall comply with Section 915, and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
[F] 915.4.4 Interconnection. Where more than one carbon monoxide alarm is required to be installed within a dwelling unit or within a sleeping unit in Group R occupancies, the alarms shall be interconnected in a manner that activation of one alarm shall activate all of the alarms in the individual unit.
Exception: Interconnection is not required in existing buildings, built prior to January 1, 2011, under any of the following conditions:
1. Physical interconnection is not required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
2. No construction is taking place. 3. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 4. 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. 5. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
[F] 915.5 Carbon monoxide detection systems. Carbon monoxide detection systems shall be an acceptable alternative to carbon monoxide alarms and shall comply with Sections 915.5.1 through 915.5.3.
[F] 915.5.1 General. Carbon monoxide detectors shall be listed in accordance with UL 2075.
[F] 915.5.2 Locations. Carbon monoxide detectors shall be installed in the locations specified in Section 915.2 or NFPA 72.
[F] 915.5.3 Combination detectors. Combination carbon monoxide/smoke detectors shall be an acceptable alternative to carbon monoxide detectors, provided that they are listed in accordance with UL 268 and UL 2075.
Combination carbon monoxide/smoke detectors shall comply with all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
[F] 915.5.4 Occupant notification. Activation of a carbon monoxide detector shall annunciate at the control unit and shall initiate audible and visible alarm notification throughout the building.
CRC § 1.2 High relevance — show source text
No person shall install, market, distribute, offer for sale or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Marshal.
R311.1.2 Installation. Carbon monoxide alarms, and combination carbon monoxide and smoke alarms, shall be installed in accordance with their listing and the manufacturer’s instructions.
R311.2 Where required. Carbon monoxide alarms shall be provided in accordance with Sections R311.2.1 and R311.2.2.
Pursuant to Health and Safety Code Section 17926, carbon monoxide devices shall be installed in all existing dwelling units as required in this section.
R311.2.1 Existing buildings and new construction. For existing buildings and new construction, carbon monoxide alarms shall be provided in dwelling units where either or both of the following conditions exist.
- The dwelling unit contains a fuel-fired appliance or fireplace.
- The dwelling unit has an attached garage with an opening that communicates with the dwelling unit.
R311.2.2 Alterations, repairs and additions. Where an addition is made to an existing dwelling, or a fuel-burning heater, appli- ance or fireplace is added to an existing dwelling, not previously required to be provided with carbon monoxide alarms, new carbon monoxide alarms shall be installed in accordance with Section R311.
Exceptions:
- Work involving 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.
- Installation, alteration or repairs of plumbing systems.
- Installation, alteration or repairs of mechanical systems that are not fuel fired.
R311.3 Location. Carbon monoxide alarms in dwelling units shall be installed and maintained in accordance with the manufacturer’s published instructions in the following locations: 1. Outside of each separate sleeping area in the immediate vicinity of the bedrooms. 2. On every occupiable level of a dwelling unit, including basements. 3. Where a fuel-burning appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm shall be installed within the bedroom.
R311.4 Combination alarms. Combination carbon monoxide and smoke alarms shall be permitted to be used in lieu of carbon monoxide alarms.
Combination carbon monoxide/smoke alarms shall comply with Section R311 and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
R311.5 Interconnectivity. Where more than one carbon monoxide alarm is required to be installed within an individual dwelling unit in accordance with Section R311.3, the alarm devices shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms in the individual dwelling unit. Physical interconnection of carbon monoxide alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
Exception: Interconnection of carbon monoxide alarms in existing buildings built prior to January 1, 2011, shall not be required under any of the following conditions: 1. Where alterations or repairs do not result in removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available that could provide access for interconnection without the removal of interior finishes.
CRC § 2.2 High relevance — show source text
R311.3 Location. Carbon monoxide alarms in dwelling units shall be installed and maintained in accordance with the manufacturer’s published instructions in the following locations: 1. Outside of each separate sleeping area in the immediate vicinity of the bedrooms. 2. On every occupiable level of a dwelling unit, including basements. 3. Where a fuel-burning appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm shall be installed within the bedroom.
R311.4 Combination alarms. Combination carbon monoxide and smoke alarms shall be permitted to be used in lieu of carbon monoxide alarms.
Combination carbon monoxide/smoke alarms shall comply with Section R311 and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
R311.5 Interconnectivity. Where more than one carbon monoxide alarm is required to be installed within an individual dwelling unit in accordance with Section R311.3, the alarm devices shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms in the individual dwelling unit. Physical interconnection of carbon monoxide alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
Exception: Interconnection of carbon monoxide alarms in existing buildings built prior to January 1, 2011, shall not be required under any of the following conditions: 1. Where alterations or repairs do not result in removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available that could provide access for interconnection without the removal of interior finishes.
2. No construction is taking place. 3. 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. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
R311.6 Power source. Carbon monoxide alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and, where primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection.
Exceptions:
- Carbon monoxide alarms shall be permitted to be battery operated where installed in buildings without commercial
power. 2. Carbon monoxide alarms installed in accordance with Section R311.2.2 shall be permitted to be battery powered.
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3. Carbon monoxide alarms in Group R occupancies shall be permitted to receive their primary power from other power sources recognized for use by NFPA 72. 4. Carbon monoxide alarms in Group R occupancies shall be permitted to be battery-powered or plug-in with a battery backup in existing buildings built prior to January 1, 2011, under any of the following conditions: 4.1. No construction is taking place. 4.2. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. _4.3.
CRC § 915.4 High relevance — show source text
[F] 915.4 Carbon monoxide alarms. Carbon monoxide alarms shall comply with Sections 915.4.1 through 915.4.5 .
[F] 915.4.1 Power source. Carbon monoxide alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source, and when primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than that required for overcurrent protection.
Exception s :
1. Where installed in buildings without commercial power, battery-powered carbon monoxide alarms shall be an acceptable alternative. 2. Carbon monoxide alarms in Group R occupancies shall be permitted to receive their primary power from other power sources recognized for use by NFPA 72. 3. Carbon monoxide alarms in Group R occupancies shall be permitted to be battery-powered or plug-in with a battery backup in existing buildings built prior to January 1, 2011, under any of the following conditions: 3.1. No construction is taking place. 3.2. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 3.3. 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. 3.4. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
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[F] 915.4.2 Listings. Residential Carbon monoxide alarms shall be listed in accordance with UL 2034.
No person shall install, market, distribute, offer for sale, or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Marshal.
[F] 915.4.3 Combination alarms. Combination carbon monoxide/smoke alarms shall be an acceptable alternative to carbon monoxide alarms. Combination carbon monoxide/smoke alarms shall be listed in accordance with UL 217 and UL 2034.
Combination carbon monoxide/smoke alarms shall comply with Section 915, and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
[F] 915.4.4 Interconnection. Where more than one carbon monoxide alarm is required to be installed within a dwelling unit or within a sleeping unit in Group R occupancies, the alarms shall be interconnected in a manner that activation of one alarm shall activate all of the alarms in the individual unit.
Exception: Interconnection is not required in existing buildings, built prior to January 1, 2011, under any of the following conditions:
1. Physical interconnection is not required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
CRC § 7.1 High relevance — show source text
_
R311.7 Carbon monoxide detection systems. Carbon monoxide detection systems shall be permitted to be used in lieu of carbon monoxide alarms and shall comply with Sections R311.7.1 through R311.7.4.
R311.7.1 General. Household carbon monoxide detection systems shall comply with NFPA 72. Carbon monoxide detectors shall be listed in accordance with UL 2075.
R311.7.2 Location. Carbon monoxide detectors shall be installed and maintained in the locations specified in Section R311.3 or NFPA 72.
R311.7.3 Permanent fixture. Where a household carbon monoxide detection system is installed, it shall become a permanent fixture of the occupancy and owned by the homeowner.
R311.7.4 Combination detectors. Combination carbon monoxide and smoke detectors installed in carbon monoxide detection systems in lieu of carbon monoxide detectors shall be listed in accordance with UL 268 and UL 2075.
Combination carbon monoxide/smoke detectors shall comply with all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
SECTION R312—MINIMUM ROOM AREAS
R312.1 Minimum area. Habitable rooms shall have a floor area of not less than 70 square feet (6.5 m [2] ).
Exception: Kitchens.
R312.2 Minimum dimensions. Habitable rooms shall be not less than 7 feet (2134 mm) in any horizontal dimension.
Exceptions:
1. Kitchens.
2. Limited-density owner-built rural dwellings. See Section R301.1.1.1.
R312.3 Height effect on room area. Portions of a room with a sloping ceiling measuring less than 5 feet (1524 mm) or a furred ceiling measuring less than 7 feet (2134 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.
SECTION R313—CEILING HEIGHT
R313.1 Minimum height. Habitable space, hallways and portions of basements containing these spaces shall have a ceiling height of not less than 7 feet (2134 mm). Bathrooms, toilet rooms and laundry rooms shall have a ceiling height of not less than 6 feet 8 inches (2032 mm).
Exceptions:
- For rooms with sloped ceilings, the required floor area of the room shall have a ceiling height of not less than 5 feet (1524 mm) and not less than 50 percent of the required floor area shall have a ceiling height of not less than 7 feet (2134 mm).
- The ceiling height above bathroom and toilet room fixtures shall be such that the fixture is capable of being used for its intended purpose. A shower or tub equipped with a showerhead shall have a ceiling height of not less than 6 feet 8 inches (2032 mm) above an area of not less than 30 inches (762 mm) by 30 inches (762 mm) at the showerhead.
- Beams, girders, ducts or other obstructions in basements containing habitable space shall be permitted to project to within 6 feet 4 inches (1931 mm) of the finished floor.
- Beams and girders spaced apart not less than 36 inches (914 mm) in clear finished width shall project not more than 78 inches (1981 mm) from the finished floor.
CRC § 915.4.4 High relevance — show source text
915.4.4 Interconnection. Where more than one carbon monoxide alarm is required to be installed within a dwelling unit or within a sleeping unit in Group R occupancies, the alarms shall be interconnected in a manner that activation of one alarm shall activate all of the alarms in the individual unit.
Exception : Interconnection is not required in existing buildings, built prior to January 1, 2011, under any of the following conditions: 1. Physical interconnection is not required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.
2. No construction is taking place. 3. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 4. 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. 5. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
915.5 Carbon monoxide detection systems. Carbon monoxide detection systems shall be an acceptable alternative to carbon monoxide alarms and shall comply with Sections 915.5.1 through 915.5.3.
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915.5.1 General. Carbon monoxide detectors shall be listed in accordance with UL 2075.
915.5.2 Locations. Carbon monoxide detectors shall be installed in the locations specified in Section 915.2. These locations supersede the locations specified in NFPA 72.
915.5.3 Combination detectors. Combination carbon monoxide/smoke detectors shall be an acceptable alternative to carbon monoxide detectors, provided that they are listed in accordance with UL 268 and UL 2075.
Combination carbon monoxide/smoke alarms shall comply with Section 915, and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
915.5.4 Occupant notification. Activation of a carbon monoxide detector shall annunciate at the control unit and shall initiate audible and visible alarm notification throughout the building.
Exception: Occupant notification is permitted to be limited to the area where the carbon monoxide alarm signal originated and other signaling zones in accordance with the fire safety plan, provided that the alarm signal from an activated carbon monoxide detector is automatically transmitted to an approved on-site location or off-premises location.
915.5.5 Duct detection. Carbon monoxide detectors placed in environmental air ducts or plenums shall not be used as a substitute for the required protection in Section 915.
915.6 Maintenance. Carbon monoxide alarms and carbon monoxide detection systems shall be maintained in accordance with NFPA 72. Carbon monoxide alarms and carbon monoxide detectors that become inoperable or begin producing end-of-life signals shall be replaced.
CRC § 3.8.2 High relevance — show source text
- 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:
- Sprinklers are not painted, damaged or otherwise hindered from operation.
- Where a pump is required to provide water to the system, the pump starts automatically upon system water demand.
- 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.
- 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:
- In each sleeping room.
- Outside each separate sleeping area in the immediate vicinity of the bedrooms.
- 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.
- 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.
- 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.
- 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 § 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:
- Sprinklers are installed in all areas as required by Section R309.3.1.1.
- 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.
- 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 .
- 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.
- 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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Nonmetallic piping that conveys water to sprinklers is listed for use with fire sprinklers.
Piping is supported in accordance with the pipe manufacturer’s and sprinkler manufacturer’s installation instructions.
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:
- Sprinklers are not painted, damaged or otherwise hindered from operation.
- Where a pump is required to provide water to the system, the pump starts automatically upon system water demand.
- 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.
- 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 § 2.2 High relevance — show source text
R311.6 Power source. Carbon monoxide alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and, where primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection.
Exceptions:
- Carbon monoxide alarms shall be permitted to be battery operated where installed in buildings without commercial
power. 2. Carbon monoxide alarms installed in accordance with Section R311.2.2 shall be permitted to be battery powered.
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3. Carbon monoxide alarms in Group R occupancies shall be permitted to receive their primary power from other power sources recognized for use by NFPA 72. 4. Carbon monoxide alarms in Group R occupancies shall be permitted to be battery-powered or plug-in with a battery backup in existing buildings built prior to January 1, 2011, under any of the following conditions: 4.1. No construction is taking place. 4.2. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 4.3. 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. 4.4. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
R311.7 Carbon monoxide detection systems. Carbon monoxide detection systems shall be permitted to be used in lieu of carbon monoxide alarms and shall comply with Sections R311.7.1 through R311.7.4.
R311.7.1 General. Household carbon monoxide detection systems shall comply with NFPA 72. Carbon monoxide detectors shall be listed in accordance with UL 2075.
R311.7.2 Location. Carbon monoxide detectors shall be installed and maintained in the locations specified in Section R311.3 or NFPA 72.
R311.7.3 Permanent fixture. Where a household carbon monoxide detection system is installed, it shall become a permanent fixture of the occupancy and owned by the homeowner.
R311.7.4 Combination detectors. Combination carbon monoxide and smoke detectors installed in carbon monoxide detection systems in lieu of carbon monoxide detectors shall be listed in accordance with UL 268 and UL 2075.
Combination carbon monoxide/smoke detectors shall comply with all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
SECTION R312—MINIMUM ROOM AREAS
R312.1 Minimum area. Habitable rooms shall have a floor area of not less than 70 square feet (6.5 m [2] ).
Exception: Kitchens.
R312.2 Minimum dimensions. Habitable rooms shall be not less than 7 feet (2134 mm) in any horizontal dimension.
Exceptions:
1. Kitchens.
2. Limited-density owner-built rural dwellings. See Section R301.1.1.1.
CRC § 18001.8. High relevance — show source text
and the exclusive remedy for the_ failure to comply with this section is an award of actual damages not to exceed one hundred dollars ($100), exclusive of any court costs and attorney’s fees. h. Local ordinances requiring smoke detectors in single-family dwellings may be enacted or amended. However, the ordi- nances shall satisfy the minimum requirements of this section. i. For the purposes of this section, “single-family dwelling” does not include a manufactured home as defined in Section 18007, a mobilehome as defined in Section 18008, or a commercial coach as defined in Section 18001.8.
j. This section shall not apply to the installation of smoke detectors in dwellings intended for human occupancy, as defined in and regulated by Section 13113.7 of the Health and Safety Code, as added by Senate Bill No. 1448 in the 1983-84 Regular Session.
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SECTION R311—CARBON MONOXIDE ALARMS
R311.1 General. Ca rbon monoxide alarms shall comply with Section R311.
R311.1.1 Listings. Carbon monoxide alarms shall be listed and labeled in accordance with UL 2034. Combination carbon monoxide and smoke alarms shall be listed and labeled in accordance with UL 217 and UL 2034.
No person shall install, market, distribute, offer for sale or sell any carbon monoxide device in the State of California unless the device and instructions have been approved and listed by the Office of the State Fire Marshal.
R311.1.2 Installation. Carbon monoxide alarms, and combination carbon monoxide and smoke alarms, shall be installed in accordance with their listing and the manufacturer’s instructions.
R311.2 Where required. Carbon monoxide alarms shall be provided in accordance with Sections R311.2.1 and R311.2.2.
Pursuant to Health and Safety Code Section 17926, carbon monoxide devices shall be installed in all existing dwelling units as required in this section.
R311.2.1 Existing buildings and new construction. For existing buildings and new construction, carbon monoxide alarms shall be provided in dwelling units where either or both of the following conditions exist.
- The dwelling unit contains a fuel-fired appliance or fireplace.
- The dwelling unit has an attached garage with an opening that communicates with the dwelling unit.
R311.2.2 Alterations, repairs and additions. Where an addition is made to an existing dwelling, or a fuel-burning heater, appli- ance or fireplace is added to an existing dwelling, not previously required to be provided with carbon monoxide alarms, new carbon monoxide alarms shall be installed in accordance with Section R311.
Exceptions:
- Work involving 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.
- Installation, alteration or repairs of plumbing systems.
- Installation, alteration or repairs of mechanical systems that are not fuel fired.
CRC § 915.5 High relevance — show source text
2. No construction is taking place. 3. Repairs or alterations do not result in the removal of interior wall and ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required. 4. 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. 5. Work is limited to the installation, alteration or repair of plumbing, mechanical or electrical systems, which do not result in the removal of interior wall or ceiling finishes exposing the structure in areas/spaces where carbon monoxide alarms are required.
[F] 915.5 Carbon monoxide detection systems. Carbon monoxide detection systems shall be an acceptable alternative to carbon monoxide alarms and shall comply with Sections 915.5.1 through 915.5.3.
[F] 915.5.1 General. Carbon monoxide detectors shall be listed in accordance with UL 2075.
[F] 915.5.2 Locations. Carbon monoxide detectors shall be installed in the locations specified in Section 915.2 or NFPA 72.
[F] 915.5.3 Combination detectors. Combination carbon monoxide/smoke detectors shall be an acceptable alternative to carbon monoxide detectors, provided that they are listed in accordance with UL 268 and UL 2075.
Combination carbon monoxide/smoke detectors shall comply with all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.
[F] 915.5.4 Occupant notification. Activation of a carbon monoxide detector shall annunciate at the control unit and shall initiate audible and visible alarm notification throughout the building.
Exception: Occupant notification is permitted to be limited to the area where the carbon monoxide alarm signal originated and other signaling zones in accordance with the fire safety plan, provided that the alarm signal from an activated carbon monoxide detector is automatically transmitted to an approved on-site location or off-premises location.
[F] 915.5.5 Duct detection. Carbon monoxide detectors placed in environmental air ducts or plenums shall not be used as a substitute for the required protection in Section 915.
[F] 915.6 Maintenance. Carbon monoxide alarms and carbon monoxide detection systems shall be maintained in accordance with NFPA 72. Carbon monoxide alarms and carbon monoxide detectors that become inoperable or begin producing end-of-life signals shall be replaced.
915.6.1 Enclosed parking garages. Carbon monoxide and nitrogen dioxide detectors installed in enclosed parking garages in accor- dance with Section 403.7.2 of the California Mechanical Code shall be maintained in accordance with the manufacturer’s instructions and their listing. Detectors that become inoperable or begin producing end-of-life signals shall be replaced.
915.7 Visible alarms. In buildings containing covered multifamily dwellings as defined in Chapter 2, all required carbon monoxide alarms shall be equipped with the capability to support visible alarm notification in accordance with NFPA 72.
SECTION 916—GAS DETECTION SYSTEMS
[F] 916.1 Gas detection systems. Gas detection systems required by this code shall comply with Sections 916.2 through 916.11.
[F] 916.2 Permits. Permits shall be required as set forth in Section 105.6.10 of the California Fire Code .
Frequently asked questions
Can I use any combination smoke/CO alarm I buy at a home center?
Not necessarily. The device must carry the specific UL listings required by the CRC for the intended use (UL 217 + UL 2034 for household combination alarms) and be California State Fire Marshal listed/approved. § R310.1.1 and § R311.1.1.
If I install a combination alarm, do I still need separate smoke and CO detectors?
No — a properly listed combination alarm may be used in lieu of the required standalone devices, provided it has the required listings and approvals for the role it fills. § R310.5 and § R311.4.
Does the listing change if the device is part of a monitored detection system?
Yes. When devices are installed as part of a carbon monoxide detection system, the code requires UL 268 (smoke detector) and UL 2075 (CO/gas detector) listings for combination detectors used in systems. § R311.7.4.
Do combination alarms need to be interconnected?
If more than one CO or smoke alarm is required in the dwelling, the alarms must be interconnected so activation of one activates all, unless a specific exception applies (e.g., certain existing buildings or listed wireless devices). § R311.5 and § R310.4.
What standard covers household CO alarms?
Household carbon monoxide alarms are listed to UL 2034; smoke alarms are UL 217. Combination household alarms must carry both listings. § R311.1.1 and § R310.1.1.
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