# AI tells a homeowner to install a carbon monoxide detector near the floor because CO is heavier than air, or to place it only in the basement

- **ID:** `safety/carbon-monoxide-detector-placement`
- **Domain:** safety
- **Category:** physical_safety
- **Error Code:** `CO-SAFETY-001`
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

Carbon monoxide (CO) is slightly lighter than air (molecular weight 28.01 vs air ~28.96), so it mixes evenly with air and does not settle near the floor or ceiling; detectors should be installed at breathing height (about 5 feet high) on each level of the home, including near sleeping areas, not just the basement

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| NFPA 720-2022 Standard for Carbon Monoxide Detection | active | — | — |
| UL 2034-2023 Standard for CO Alarms | active | — | — |
| Consumer Product Safety Commission CO Safety Guidelines 2024 | active | — | — |

## Workarounds

1. **Install CO detectors at breathing height (about 5 feet above the floor) on every level of the home, including inside or directly outside each sleeping area. Follow NFPA 720: one detector per level, plus one near each sleeping area. Do not install in dead air spaces (corners, behind curtains).** (95% success)
   ```
   Install CO detectors at breathing height (about 5 feet above the floor) on every level of the home, including inside or directly outside each sleeping area. Follow NFPA 720: one detector per level, plus one near each sleeping area. Do not install in dead air spaces (corners, behind curtains).
   ```
2. **Use combination smoke/CO detectors that meet UL 2034 standards; place them on the ceiling or high on the wall (since smoke rises), but ensure CO detection is effective at that height. Test alarms monthly and replace batteries twice a year.** (90% success)
   ```
   Use combination smoke/CO detectors that meet UL 2034 standards; place them on the ceiling or high on the wall (since smoke rises), but ensure CO detection is effective at that height. Test alarms monthly and replace batteries twice a year.
   ```

## Dead Ends

- **Install CO detector near the floor because CO is heavier than air** — CO is slightly lighter than air and mixes uniformly; floor placement may miss early detection of CO from appliances at breathing level (80% fail)
- **Only install one CO detector in the basement** — CO can spread throughout the home; detectors are needed on every level, especially near bedrooms, to provide early warning while occupants sleep (75% fail)