This question concerns smoke/CO detector placement within a bedroom (the code is pretty clear regarding outside-of-bathroom & distance-from-kitchen-appliances).

Given a 12x10ft bedroom, with the entrance being on one of the 10ft sides, and a detector being placed either on the ceiling or wall more than 4" but less than 12" from the ceiling, my question is as follows:

Is there any specific place in the bedroom that a smoke/CO detector cannot be placed, outside of the above mentioned "dead air" zone?

I.e. does the IRC consider any non-dead-air detector location on the ceiling / wall acceptable as long as it's not too close to potential appliances, bathrooms, lights, fans, AC/heating units, furnaces, etc?

I believe it does, but I thought I'd check with some more knowledgeable folks.

Ideally the center of a bedrooms' ceiling would be the preferred location, but it's not an option given the timeframe and amount of work to get there, so it may end up on a wall 10ft of the way across the room opposite a door, and I want to make sure that's not prohibited by code.

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    I'm not familiar with IRC regs, but here is installation guidelines for Edwards Fire Safety (UTC/Kidde) for Fire Alarm Systems. Smoke detectors and Fire alarm systems are not technically the same but may give some guidelines. The two biggest issues I ran into doing commercial installations of FA Systems were beams (greater than 8 in.) and clearance from diffusers (3 ft.). CO detectors may differ from smoke, clearly read installation instructions that come with product. edwards-signals.com/files/… Jul 23, 2021 at 15:42
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    FA System smoke detector coverage was center of 30'x30' square (actually a 21' radius), 10x12 would fit completely in one quarter of 30x30 square (and have corner to corner measurement of 15.6', less than 21 '), so it would seem you would be good to go. Jul 23, 2021 at 15:55
  • Much appreciated. I was looking for similar coverage data for Kidde and couldn't find any but i'll keep looking.
    – sil80
    Jul 24, 2021 at 5:21
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1 Answer 1


I would follow NFPA guidlines regarding smoke detectors and keep it at least 3 ft away from HVAC registers. In a room that small, any location would be fine. Unlike smoke, CO doesn't spread in plumes - it disperses evenly like air since it has the same density as air. It is NOT heavier than air. Mount it higher up a wall or on the ceiling, following the dead space parameters.

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