Carbon Monoxide Detectors
Hardwired CO detectors installed on every floor and near any fireplace.
Spec
Applies uniformly from Certified upward.
Scope
Carbon-monoxide detection throughout the dwelling.
Requirements
- 01.
Install UL-certified CO detectors on every floor of the dwelling.
- 02.
Place a CO detector within 10 feet of every bedroom door.
- 03.
Place a CO detector within 10 feet of every fireplace and combustion appliance.
- 04.
Detectors must be hardwired with battery backup (not battery-only).
Documentation
Evidence the inspector / Institute will need.
- 01.
Floor-plan markup showing CO-detector locations.
- 02.
Photos of installed detectors (showing the UL listing label).
Guidance
Combination vs dedicated detectors
Combination smoke + CO detectors satisfy this requirement. Standalone CO detectors are also fine. The key is coverage per the placement rules above. Replace all detectors every 10 years (per UL 2034 sensor lifespan) — most current models have a built-in end-of-life chirp.
Note
Low-level CO detectors (sensitive to 10-30 ppm) provide a much earlier warning than standard UL-listed units, which only alarm at 70+ ppm sustained for over an hour. Not required by this standard, but recommended for households with children, pregnant occupants, or anyone with heart/respiratory issues.