Carbon monoxide detectors locations | Code requirements

The installation of the carbon monoxide detector still a bit confusing for homeowners and even some contractors.

Explaining in detail the locations requirements for the smoke detectors according to the most recent international and California residential building codes and NFPA 72 in new and existing residential properties.

What is the carbon monoxide detector?

A device with an integral sensor to detect carbon monoxide gas and transmit an alarm signal to a connected alarm control unit according to the International Residential Code and California residential code.

When a carbon monoxide detector is required inside a house?

It is required when one of the following conditions occur (R315.2).

  • The dwelling unit contains a fuel-fired appliance (Gas appliances) such as wall heater, stove, water heater, HVAC or fireplace.
  • The dwelling unit has an attached garage with a common door or/ and a window between the garage and house.

Carbon monoxide detectors locations – Code requirements

Carbon monoxide device in the residential properties shall be installed in the following locations (R315.3),

  1. Outside of each separate sleeping area (bedroom), if a hallway connecting a group of a bedrooms, only one carbon monoxide alarm is required in hallway.
  2. On every level of a dwelling unit, including basements.
  3. Where gas appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm shall be installed within the bedroom.

When Carbon monoxide detectors required to be battery operated VS hard wired?

Carbon Monoxide detectors are permitted to be battery operated or plug-in with battery back up if the following conditions occur (R 315.6),

  • No construction, just updating or adding the carbon monoxide within the dwelling unit.
  • Interior remodeling of the house without removing drywall, unless there is an access to the attic, crawl space or basement which could provide access for the house wiring without removing drywall.
  • Where construction are limited to the exterior of the residential property, such as the reroofing or replacing siding, or the addition or replacement of windows or doors.
  • Construction is limited to the installation, alteration or repairs of plumbing or mechanical systems or the installation, alteration or repair of electrical systems without removing drywall.

If any other type of constructions were not previously listed above, carbon monoxide detector shall be hard wired, equipped with a battery backup and connected to the smoke alarms system.

Related: Smoke alarms approved locations

Carbon monoxide interconnections

Carbon monoxide detector shall be interconnected when its required to be hard wired according to the residential code. Which means when one goes off the rest of the carbon monoxide detectors within the same house shall go off as well. (R315.5).

Combination of smoke alarm and carbon monoxide

Combination of smoke alarm and carbon monoxide can be used instead of carbon monoxide detector. It shall comply with the same requirements for the carbon monoxide detector.(R315.7.4).

Reference Codes – International Residential Code – California Residential Code