Carbon monoxide detector

[JJWalecka]

Carbon monoxide is heavier than Nitrogen and Oxygen, but lighter than Carbon Dioxide.

It's almost always the product of combustion, so it's going to be hot and lighter than air most of the time. Carbon monoxide, at room temperature, collects near the floor. But also readily mixes with air.

Would the ceiling mounting of a carbon monoxide detector be a hazard?

JJ

 

[Lcdrwalker]

I'm not aware of any code that governs the placement of a co2 detector. I have a combo smoke/ co2 detector in my basement. Follow mfg. suggestions that should have come with the unit.

 

[bphgravity]

If adopted by your state and/or local jurisdiction, the NFPA 720 covers the installation of CO Alarms. There is also some nice commentary in the Annexes that address these same questions.

 

[JJWalecka]

I have been searching NFPA 720 and the archives…

NFPA720 mentioned following the manufacturer instructions

Stickboy1375 posted
“Homeowners should remember not to install carbon monoxide detectors directly above or beside fuel-burning appliances, as appliances may emit a small amount of carbon monoxide upon start-up. A detector should not be placed within fifteen feet of heating or cooking appliances or in or near very humid areas such as bathrooms.

Thank you for your time

JJ

 

[wwhitney]

Carbon monoxide is heavier than Nitrogen and Oxygen, but lighter than Carbon Dioxide.

Carbon monoxide (molecular weight 14) is the same weight (roughly) as diatomic nitrogen (molecular weight 14), and both of them are lighter than diatomic oxygen (molecular weight 16). But as far as I know the oxygen and nitrogen in the air are evenly mixed, so I believe the carbon monoxide will mix evenly, too. This is all at constant temperature--hot combustion gasses will be less dense.

Cheers, Wayne

 

[DUCKMAN]

Ceiling Mount CO

Ceiling Mount CO

I have a completely unscientific Carbon monoxide test to report on. I have a recently completed a log cabin. The cabin has propane lights, refridgerator, hot water and stove. I have several different types of detectors installed in the cabin. When the lights are not properly adjusted, they produce CO in excess levels. There has been a bit of a learning curve in getting them properly adjusted. SO, I have had numerous CO alarm trips. The first device to sound is always the combo smoke/CO unit mounted on the ceiling. Although the gas may have the same weight as air (ish) I am guessing that the CO is warmer, contributing to its bouyancy. Maybe, I am the one full of hot air, but often the ceiling unit will sound, and 5-10 minutes later the downstairs wall unit will sound (eye level mounting).

 

[bphgravity]

I think you pretty much are seeing the theory of how CO flows as it is released as a product of combustion. I've heard it desribed as "thermal plume".

 

[bphgravity]

Research the term "Coanda Effect" and "Buoyant Thermal Plume".

I feel these two issues, while typically related to kitchen exhaust hoods, also demonstrates how smoke and CO flows thru a dwelling.

 

[JJWalecka]

Thank you very much for the info.

JJ

 

[stickboy1375]

Carbon monoxide is heavier than Nitrogen and Oxygen, but lighter than Carbon Dioxide.

It's almost always the product of combustion, so it's going to be hot and lighter than air most of the time. Carbon monoxide, at room temperature, collects near the floor. But also readily mixes with air.

Would the ceiling mounting of a carbon monoxide detector be a hazard?

JJ

Actually Carbon monoxide has a specific gravity of 0.9667, air is 1.000 so IMO, it does not matter where the detection device is located. I would go by the manufactures directions.