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Chapter 3 — BUILDING PLANNING

Section R315

California Residential Code (Title 24, Part 2.5) · 2019 edition · updated 2026-09-12 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

R315.1 General.

Carbon monoxide alarms shall comply with Section R315.

R315.1.1 Listings. Carbon monoxide alarms shall be listed in accordance with UL 2034. Combination carbon monoxide and smoke alarms shall be listed in accordance with UL 2034 and UL 217.

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 Mar- shal.

R315.2 Where required.

Carbon monoxide alarms shall be provided in accordance with Sections R315.2.1 and R315.2.2.

Pursuant to Health and Safety Code Section 17926, car- bon monoxide devices shall be installed in all existing dwell- ing units as required in this section.

R315.2.1 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.

  1. The dwelling unit contains a fuel-fired appliance or fireplace.

  2. The dwelling unit has an attached garage with an opening that communicates with the dwelling unit.

R315.2.2 Alterations, repairs and additions. Where an addition is made to an existing dwelling, or a fuel-burning heater, appliance, or fireplace is added to an existing dwelling, not previously required to be provided with car- bon monoxide alarms, new carbon monoxide alarms shall be installed in accordance with Section R315.

Exceptions:

  1. 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.

  2. Installation, alteration or repairs of plumbing or mechanical systems.

Copyright © 2019 ICC. ALL RIGHTS RESERVED. Accessed by Kevin Day (kevin.day@dgs.ca.gov), (California Building Standards Commission) Order Number #100735044 on Jul 24, 2019 03:54 PM (PDT) pursuant to License Agreement with ICC. No further reproduction or distribution authorized. Single user only, copying and networking prohibited. ANY UNAUTHORIZED REPRODUCTION OR DISTRIBUTION IS A VIOLATION OF THE FEDERAL COPYRIGHT ACT AND THE LICENSE AGREEMENT, AND SUBJECT TO CIVIL AND CRIMINAL PENALTIES THEREUNDER.

100735044

BUILDING PLANNING

R315.3 Location.

Carbon monoxide alarms in dwelling units shall be installed and maintained in accordance with the manufacturer’s published instructions in the following loca- tions:

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.

R315.4 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 com- ply with Section R315 and all requirements for listing and approval by the Office of the State Fire Marshal for smoke alarms.

R315.5 Interconnectivity.

Where more than one carbon monoxide alarm is required to be installed within an individual dwelling unit in accordance with Section R315.3, 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 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 sur- faces 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.

R315.6 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:

  1. 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 R315.2.2 shall be permitted to be battery powered.

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 720.

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 exte- rior 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 electri- cal 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.

R315.7 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 R315.7.1 through R315.7.4.

R315.7.1 General. Household carbon monoxide detection systems shall comply with NFPA 720. Carbon monoxide detectors shall be listed in accordance with UL 2075.

R315.7.2 Location. Carbon monoxide detectors shall be installed and maintained in the locations specified in Section R315.3 or NFPA 720.

R315.7.3 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.

R315.7.4 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 2075 and UL 268.

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.

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▸Contents — California Residential Code (Title 24, Part 2.5)
California Residential Code (Title 24, Part 2.5)
  1. Chapter 2 — DEFINITIONS AND ABBREVIATIONS
  2. Chapter 1 — SCOPE AND APPLICATION
  3. ▸Chapter 3 — BUILDING PLANNING
    Overview
    1. Section R300
    2. Section R301
    3. Section R302
    4. Section R303
    5. Section R304
    6. Section R305
    7. Section R306
    8. Section R307
    9. Section R308
    10. Section R309
    11. Section R310
    12. Section R311
    13. Section R312
    14. Section R313
    15. Section R314
    16. Section R315
    17. Section R316
    18. Section R317
    19. Section R318
    20. Section R319
    21. Section R320
    22. Section R321
    23. Section R322
    24. Section R323
    25. Section 324
    26. Section R325
    27. Section R334
    28. Section R335
    29. Section R326
    30. Section R327
    31. Section R336
    32. Section R337
    33. Section R337.1
    34. Section R337.2
    35. Section R337.3
    36. Section R337.4
    37. Section R337.5
    38. Section R337.6
    39. Section R337.7
    40. Section R337.8
    41. Section R337.9
    42. Section R337.10
    43. Section R340
    44. Section R338
  4. Chapter 4 — FOUNDATIONS
  5. Chapter 5 — FLOORS
  6. Chapter 6 — WALL CONSTRUCTION
  7. Chapter 7 — WALL COVERING
  8. Chapter 8 — ROOF-CEILING CONSTRUCTION
  9. Chapter 9 — ROOF ASSEMBLIES
  10. Chapter 10 — CHIMNEYS AND FIREPLACES
  11. Chapter 44 — REFERENCED STANDARDS
  12. Appendix F — RADON CONTROL METHODS
  13. Appendix H — PATIO COVERS
  14. Appendix I — PRIVATE SEWAGE DISPOSAL
  15. Appendix J — EXISTING BUILDINGS AND STRUCTURES
  16. Appendix K — SOUND TRANSMISSION
  17. Appendix L — PERMIT FEES
  18. Appendix O — AUTOMATIC VEHICULAR GATES
  19. Appendix Q — TINY HOUSES
  20. Appendix R — LIGHT STRAW-CLAY CONSTRUCTION
  21. Appendix S — STRAWBALE CONSTRUCTION
  22. Appendix T — SOLAR-READY PROVISIONS—DETACHED ONE- AND
  23. Appendix V — SWIMMING POOL SAFETY ACT
  24. Appendix W — AREAS PROTECTED BY THE FACILITIES
  25. Appendix X — EMERGENCY HOUSING

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