The following requirements for carbon monoxide alarms are being considered regarding existing dwellings.

R315.2  Where required in existing dwellings.  Where work requiring a permit occurs in existing dwellings that have attached garages or in existing dwellings or sleeping units within which fuel-burning appliances exist, carbon monoxide alarms, carbon monoxide detectors , combination smoke/carbon monoxide alarms or combination smoke/carbon monoxide detectors shall be provided in accordance with Section R315.1.  Carbon monoxide alarms, carbon monoxide detectors, combination smoke/carbon monoxide alarms or combination smoke/carbon monoxide detectors shall only be required in the specific dwelling unit for which the permit was obtained.

 R315.3  Alarm requirements.  Single- and multiple station carbon monoxide alarms shall be listed as complying with the requirements of UL 2034 for equipment performance and carbon monoxide detectors shall be listed as complying with the requirements of UL 2075 for equipment performance.  Carbon monoxide alarms and carbon monoxide detectors shall be installed in accordance with this code.  The current edition of NFPA 720 for “Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment” and the manufacturer’s installation instructions.  Other carbon monoxide alarms and detection devices as recognized in NFPA 720 are also acceptable.

Carbon monoxide alarms, carbon monoxide detectors, combination smoke/carbon monoxide alarms or combination smoke/carbon monoxide detectors required by Sections R315.1 and R315.2 shall be installed in the following locations:

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

On every level of a dwelling unit, including basements.