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Information on Carbon Monoxide Alarms
Posted Date: 8/22/2011


Building & Safety


2010 California Building Code and  Title 24, California Administrative Code.

The California Residential Code requires the installation of carbon monoxide (CO) alarms in residential buildings to ensure that CO hazards do not go undetected and to reduce the risk and impact it has on occupants.


Section 315 of the California Residential Code requires that when a new dwelling unit is added, or the valuation of an addition, alteration or repair to Group R-3 Occupancies exceeds $1,000 and a permit is required, carbon monoxide alarms shall be installed in the following areas:

Outside of each separate dwelling unit sleeping area in the immediate vicinity of the bedroom(s).

On every level of a dwelling unit including basements.

In sleeping units that have attached garages or fuel-burning appliances installed.

Carbon monoxide alarms shall receive their primary power from the building wiring provided that such wiring is served from a commercial source and shall be equipped with a battery backup. Alarm wiring shall be connected to the permanent building wiring without a disconnecting switch other than as required for overcurrent protection, with the only exemption being in existing dwelling units, a carbon monoxide alarm is permitted to be solely battery operated where repairs or alterations do not result in the removal of wall and ceiling finishes or there is no access by means of attic, basement or crawl space.

Where more than one carbon monoxide alarm is required to be installed within an individual dwelling unit or within a sleeping unit the alarm shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms in the individual unit with the only exemption of interconnection is not required in existing dwelling units where repairs do not result in the removal of wall and ceiling finishes, there is no access by means of attic, basement or crawl space, and no previous method for interconnection existed.

All carbon monoxide alarms shall be listed in accordance with UL 2034 and installed in accordance with the current edition of NFPA 720.