Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
Section 915 — CARBON MONOXIDE (CO) DETECTION
2025 California Fire Code (Title 24, Part 9) · 2025 edition · updated 2026-07-29 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
915.1 General. ¶
Carbon monoxide (CO) detection shall be installed in new buildings in accordance with Section 915.1.1 through 915.7 . Carbon monoxide detection shall be installed in existing buildings in accordance with this section and Section 1103.9.
Pursuant to Health and Safety Code Section 17926, carbon monoxide detection shall be installed in all existing Group R buildings as required in this section.
Exception: Carbon monoxide detection is not required in Group S, Group F and Group U occupancies that are not normally occupied.
915.1.1 Where required. Carbon monoxide detection shall be installed in the locations specified in Section 915.2 where any of the following conditions exist.
- In buildings that contain a CO source.
- In buildings that contain or are supplied by a CO-producing forced-air furnace.
- In buildings with attached private garages.
- In buildings that have a CO-producing vehicle that is used within the building.
915.2 Locations. ¶
Carbon monoxide detection shall be installed in accordance with the manufacturer’s published instructions in the locations specified in Sections 915.2.1 through 915.2.3.
915.2.1 Dwelling units. Carbon monoxide detection shall be installed in dwelling units 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 CO source is located within a bedroom or its attached bathroom, carbon monoxide detection shall be installed within the bedroom.
915.2.2 Sleeping units. Carbon monoxide detection shall be installed in sleeping units.
Exception: Carbon monoxide detection shall be allowed to be installed outside of each separate sleeping area in the immediate vicinity of the sleeping unit where the sleeping unit or its attached bathroom does not contain a CO source and is not served by a CO-producing forced-air furnace.
915.2.3 Group E occupancies. A carbon monoxide system that uses carbon monoxide detectors shall be installed in Group E occupancies where classrooms include any of the conditions identified in Sections 915.1.2 through 915.1.6 . Alarm signals from carbon monoxide detectors shall be automatically transmitted to an on-site location that is staffed by school personnel.
Exception: Carbon monoxide alarm signals shall not be required to be automatically transmitted to an on-site location that is staffed by school personnel in Group E occupancies with an occupant load of 30 or less.
915.2.4 CO-producing forced-air furnace. Carbon monoxide detection complying with Item 2 of Section 915.1.1 shall be installed in all enclosed rooms and spaces served by a fuel-burning, forced-air furnace.
Exceptions:
- Where a carbon monoxide detector is provided in the first room or space served by each main duct leaving the furnace, and the carbon monoxide alarm signals are automatically transmitted to an approved location.
- Dwelling units that comply with Section 915.2.1.
915.2.5 Private garages. Carbon monoxide detection complying with Item 3 of Section 915.1.1 shall be installed within enclosed occupiable rooms or spaces that are contiguous to the attached private garage.
Exceptions:
- In buildings without communicating openings between the private garage and the building.
- In rooms or spaces located more than one story above or below a private garage.
- Where the private garage connects to the building through an open-ended corridor.
- An open parking garage complying with Section 406.5 of the California Building Code or an enclosed parking garage complying with Section 406.6 of the California Building Code shall not be considered a private garage.
- Dwelling units that comply with Section 915.2.1.
story above or below a private garage. 3. Where the private garage connects to the building through an open-ended corridor. 4. An open parking garage complying with Section 406.5 of the California Building Code or an enclosed parking garage complying with Section 406.6 of the California Building Code shall not be considered a private garage. 5. Dwelling units that comply with Section 915.2.1.
915.2.6 All other occupancies. For locations other than those specified in Sections 915.2.1 through 915.2.5, carbon monoxide detectors shall be installed on the ceiling of enclosed rooms or spaces containing CO-producing devices or served by a CO source forced-air furnace.
Exception: Where environmental conditions prohibit the installation of carbon monoxide detector in an enclosed room or space, carbon monoxide detectors shall be installed in an approved enclosed location contiguous with the room or space that contains a CO source.
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FIRE PROTECTION AND LIFE SAFETY SYSTEMS
915.3 Carbon monoxide detection. ¶
Carbon monoxide detection required by Sections 915.1 through 915.2.3 shall be provided by carbon monoxide alarms complying with Section 915.4 or carbon monoxide detection systems complying with Section 915.5.
915.3.1 Alarm limitations. Carbon monoxide alarms shall only be installed in dwelling units and in sleeping units. They shall not be installed in locations where the code requires carbon monoxide detectors to be used.
915.3.2 Fire alarm system required. New buildings that are required by Section 907.2 to have a fire alarm system and by Section 915.2 to have carbon monoxide detectors shall be connected to the fire alarm system in accordance with NFPA 72.
915.3.3 Fire alarm systems not required. In new buildings that are not required by Section 907.2 to have a fire alarm system, carbon monoxide detection shall be provided by one of the following:
- Carbon monoxide detectors connected to an approved carbon monoxide detection system in accordance with NFPA 72.
- Carbon monoxide detectors connected to an approved combination system in accordance with NFPA 72.
- Carbon monoxide detectors connected to an approved fire alarm system in accordance with NFPA 72.
- Where approved by the fire code official, carbon monoxide alarms maintained in accordance with the manufacturer’s instructions.
915.3.4 Installation. Carbon monoxide detection shall be installed in accordance with NFPA 72 and the manufacturer’s instructions.
915.4 Carbon monoxide alarms. ¶
Carbon monoxide alarms shall comply with Sections 915.4.1 through 915.4.4.
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.
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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FIRE PROTECTION AND LIFE SAFETY SYSTEMS
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.
915.6.1 Enclosed parking garages. Carbon monoxide and nitrogen dioxide detectors installed in enclosed parking garages in accordance 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 720.
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Ask AI about this code▸ Contents — 2025 California Fire Code (Title 24, Part 9)
- Chapter 1 — ADMINISTRATION
- Chapter 2 — DEFINITIONS
- Chapter 3 — GENERAL REQUIREMENTS
- Chapter 4 — EMERGENCY PLANNING AND PREPAREDNESS
- Chapter 5 — FIRE SERVICE FEATURES
- Chapter 6 — BUILDING SERVICES AND SYSTEMS
- Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
- Chapter 8 — INTERIOR FINISH, DECORATIVE MATERIALS AND FURNISHI…
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▸ Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
Overview- Section 901 — GENERAL
- Section 902 — DEFINITIONS
- Section 903 — AUTOMATIC SPRINKLER SYSTEMS
- Section 904 — ALTERNATIVE AUTOMATIC FIRE-EXTINGUISHING SYSTEMS
- Section 905 — STANDPIPE SYSTEMS
- Section 906 — PORTABLE FIRE EXTINGUISHERS
- Section 907 — FIRE ALARM AND DETECTION SYSTEMS
- Section 908 — EMERGENCY ALARM SYSTEMS
- Section 909 — SMOKE CONTROL SYSTEMS
- Section 910 — SMOKE AND HEAT REMOVAL
- Section 911 — EXPLOSION CONTROL
- Section 912 — FIRE DEPARTMENT CONNECTIONS
- Section 913 — FIRE PUMPS
- Section 914 — FIRE PROTECTION BASED ON SPECIAL DETAILED REQUIR…
- Section 915 — CARBON MONOXIDE (CO) DETECTION
- Section 916 — GAS DETECTION SYSTEMS
- Section 917 — MASS NOTIFICATION SYSTEMS
- Chapter 10 — MEANS OF EGRESS
- Chapter 11 — CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS
- Chapter 12 — ENERGY SYSTEMS
- Chapter 20 — AVIATION FACILITIES
- Chapter 21 — DRY CLEANING
- Chapter 22 — COMBUSTIBLE DUST-PRODUCING OPERATIONS
- Chapter 23 — MOTOR FUEL-DISPENSING FACILITIES AND REPAIR GARAGES
- Chapter 24 — FLAMMABLE FINISHES
- Chapter 25 — FRUIT AND CROP RIPENING
- Chapter 26 — FUMIGATION AND INSECTICIDAL FOGGING
- Chapter 27 — SEMICONDUCTOR FABRICATION FACILITIES
- Chapter 28 — LUMBER YARDS AND AGRO-INDUSTRIAL, SOLID BIOMASS A…
- Chapter 29 — MANUFACTURE OF ORGANIC COATINGS
- Chapter 30 — INDUSTRIAL OVENS
- Chapter 31 — TENTS, TEMPORARY SPECIAL EVENT STRUCTURES AND OTH…
- Chapter 32 — HIGH-PILED COMBUSTIBLE STORAGE
- Chapter 33 — FIRE SAFETY DURING CONSTRUCTION AND DEMOLITION
- Chapter 34 — TIRE REBUILDING AND TIRE STORAGE
- Chapter 35 — WELDING AND OTHER HOT WORK
- Chapter 36 — MARINAS
- Chapter 37 — COMBUSTIBLE FIBERS
- Chapter 38 — RESERVED
- Chapter 39 — PROCESSING AND EXTRACTION FACILITIES
- Chapter 40 — STORAGE OF DISTILLED SPIRITS AND WINES
- Chapter 41 — TEMPORARY HEATING AND COOKING OPERATIONS
- Chapter 48 — MOTION PICTURE AND TELEVISION PRODUCTION STUDIO S…
- Chapter 49 — REQUIREMENTS FOR WILDLAND-URBAN INTERFACE FIRE AR…
- Chapter 50 — HAZARDOUS MATERIALS—GENERAL PROVISIONS
- Chapter 51 — AEROSOLS
- Chapter 52 — RESERVED
- Chapter 53 — COMPRESSED GASES
- Chapter 54 — CORROSIVE MATERIALS
- Chapter 55 — CRYOGENIC FLUIDS
- Chapter 56 — EXPLOSIVES AND FIREWORKS
- Chapter 57 — FLAMMABLE AND COMBUSTIBLE LIQUIDS
- Chapter 58 — FLAMMABLE GASES AND FLAMMABLE CRYOGENIC FLUIDS
- Chapter 59 — FLAMMABLE SOLIDS
- Chapter 60 — HIGHLY TOXIC AND TOXIC MATERIALS
- Chapter 61 — LIQUEFIED PETROLEUM GASES
- Chapter 62 — ORGANIC PEROXIDES
- Chapter 63 — OXIDIZERS, OXIDIZING GASES AND OXIDIZING CRYOGENI…
- Chapter 64 — PYROPHORIC MATERIALS
- Chapter 65 — PYROXYLIN (CELLULOSE NITRATE) PLASTICS
- Chapter 66 — UNSTABLE (REACTIVE) MATERIALS
- Chapter 67 — WATER-REACTIVE SOLIDS AND LIQUIDS
- Chapter 80 — REFERENCED STANDARDS
- Appendix Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON US…
- Appendix A — BOARD OF APPEALS
- Appendix B — FIRE-FLOW REQUIREMENTS FOR BUILDINGS
- Appendix BB — FIRE-FLOW REQUIREMENTS FOR BUILDINGS
- Appendix C — FIRE HYDRANT LOCATIONS AND DISTRIBUTION
- Appendix CC — FIRE HYDRANT LOCATIONS AND DISTRIBUTION
- Appendix D — FIRE APPARATUS ACCESS ROADS
- Appendix E — HAZARD CATEGORIES
- Appendix F — HAZARD RANKING
- Appendix G — CRYOGENIC FLUIDS—WEIGHT AND VOLUME EQUIVALENTS
- Appendix H — HAZARDOUS MATERIALS MANAGEMENT PLANS AND HAZARDOU…
- Appendix I — FIRE PROTECTION SYSTEMS—NONCOMPLIANT CONDITIONS
- Appendix J — BUILDING INFORMATION SIGN
- Appendix K — CONSTRUCTION REQUIREMENTS FOR EXISTING AMBULATORY…
- Appendix L — REQUIREMENTS FOR FIREFIGHTER AIR REPLENISHMENT SY…
- Appendix M — HIGH-RISE BUILDINGS—RETROACTIVE AUTOMATIC SPRINKL…
- Appendix N — INDOOR TRADE SHOWS AND EXHIBITIONS
- Appendix O — VALET TRASH AND RECYCLING COLLECTION IN GROUP R-2…
- Appendix P — TEMPORARY HAUNTED HOUSES, GHOST WALKS AND SIMILAR…
- Appendix Q — COMMUNITY WILDLAND-URBAN INTERFACE (WUI) FIRE HAZ…