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Carbon Monoxide Detectors
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Cal Fire
Frequently Asked Questions (FAQ) on
Carbon Monoxide (CO) Devices

CAL FIRE and the Office of the State Fire Marshal have created these frequently asked questions (FAQ) on carbon monoxide devices for the citizens of California to provide information on this important matter.


1. What is Senate Bill 183 (SB183)?


2. What is carbon monoxide and where can I go to receive further information on carbon monoxide?

Carbon monoxide is a colorless, odorless gas that is produced from heaters, fireplaces, furnaces, and many types of appliances and cooking devices. It can also be produced from vehicles that are idling. For more information, please see http://www.fire.ca.gov/communications/communications_firesafety_carbonmonoxide.php

3. What is the definition of a dwelling unit?


4. Does a duplex qualify as a single family dwelling?

By definition, a duplex is not considered a single-family dwelling.

5. Are apartments with attached garages with no direct access to the apartment and no fossil fuel appliances required to have a CO alarm?

Yes. The law requires that CO alarms be installed in multi-unit occupancies if there is fossil fuel burning appliances or attached garages. There isn’t an exception for dwellings without direct access from the garage to the living area, as CO from the garage can travel through openings and ventilation systems entering into the living space.

6. If there is a two story apartment building equipped with electric appliances and the building has a common hallway having fossil fuel central heat, is a CO alarm required and where?

Yes. The law requires that CO alarms be installed when fossil fuel appliances are used. Since common areas and hallways leading to the living units can produce CO, which could enter the living units by ventilation systems, an alarm would be located within the living unit.

7. What is the difference between a carbon monoxide alarm and a carbon monoxide detector?

A carbon monoxide alarm is a stand-alone unit that is tested to Underwriters Laboratory (UL) Standard 2034 and has its own built-in power supply and audible device. These units are typically installed in your single family dwelling. A carbon monoxide detector is a system unit which is tested to UL Standard 2075, is designed to be used with a fire alarm system, and receives its power from the fire alarm panel.

8. How many types of CO devices are available?

There are two types of devices available. There are carbon monoxide alarms (CSFM category # 5276) and carbon monoxide detectors (CSFM category # 5278).


Yes. SB183 prohibits the marketing, distribution, or sale of devices unless it is approved and listed by the State Fire Marshal.

10. Where can I find a list of CSFM-listed carbon monoxide devices?

Where does one obtain a full listing copy of a California State Fire Marshal (CSFM)-listed CO device?

a) Click this URL link, http://osfm.fire.ca.gov/strucfireengineer/pdf/bml/List_CSFM_Approved.pdf and click the desired listing’s listing number URL link, which will open up a pdf document of the full listing.-or-b) To locate up-to-date listings, go to http://osfm.fire.ca.gov/licensinglistings/licenselisting_bml_searchcotest.php and search by CSFM category or Company (Manufacturer).



12. Is there a plan for a 10 year battery combination smoke/CO alarm?

At this time, CAL FIRE/Office of the State Fire Marshal is not aware of any requirement for a 10-year life battery for CO alarms. However, if the device is a combination battery operated (primary power source) smoke/CO alarm, commencing January 1, 2014, in order for the State Fire Marshal to approve and list the device, the device must display the date of manufacture, provide a place where the date of installation can be written, incorporate a hush feature, incorporate an end-of-life feature providing notice that the device needs to be replaced, and contain a non-replaceable, non-removable battery that is capable of powering the smoke alarm for a minimum of 10 years as required per Senate Bill 1394 recently chaptered into law.

Effective date

13. What is the effective date for installing a CO device?

For a single-family dwelling having fossil fuel burning appliances and/or attached garages, the effective date is July 1, 2011.For all other dwelling units having fossil fuel burning appliances and/or attached garages, the effective date is Jan. 1, 2013.For hotels and motels having fossil fuel burning appliances and/or attached garages, the effective date is Jan. 1, 2016.


14. Where should CO devices be installed in homes?

CO devices should be installed outside each sleeping areas of the home, including the basement. The manufacturer’s installation instruction should also be followed.

15. Are CO devices that are required by SB183 to be installed in each room?

No. They are required by SB183 to be installed outside of each sleeping area. For maximum protection against CO gas, it is recommended that a CO device be installed in each sleeping room.

16. At what height/location should a CO device be mounted?

According to the National Fire Protection Association (NFPA) 720, the location for effective performance is not generally dependent on mounting height. The density of carbon monoxide is similar to that of air at room temperature, and carbon monoxide generally mixes readily with air. The manufacturer’s installation instruction should also be followed.

17. Can I replace my existing smoke detector with a carbon monoxide device?



18. Who is responsible for enforcing the CO installation requirements?

CAL FIRE/Office of the State Fire Marshal approved and listed the CO alarms but enforcement of the requirement could fall upon the “Enforcing Agency” as designated by statue or regulations. Normally, a typical enforcing agency is your local fire and/or building department.

19. How do enforcing agencies gain entry into private single-family residence to enforce the requirements?

California Building Code, Chapter 2 and Health and Safety Code, Section 17920 provide a definition that states, “…diligent effort to secure compliance, including review of plans and permit applications, response to complaints, citation of violations, and other legal process. Except as otherwise provided in this part, “enforcement” may, but need not, include inspections of existing buildings on which no complaint or permit application has been filed, and effort to secure compliance as to these buildings”. As always, it is advisable that enforcing agencies consult with their legal counsel regarding the enforcement of these provisions on existing single-family residence.

20. Who can we contact for additional information?

For other questions, contact your local enforcing agencies, such as local building and fire departments. Regulation information is available on the California Department of Housing and Community Development website at http://www.hcd.ca.gov/.
Information on the hazards of carbon monoxide is available from the California Department of Public Health website at http://www.cdph.ca.gov/Pages/DEFAULT.aspx.