Submitted by dingustotalicus t3_ya5lxo in DIY
hicow t1_itayua2 wrote
Reply to comment by slothlovereddit in Pilot light playing hard to get by dingustotalicus
Shouldn't CO detectors be low on the walls, being CO's heavier than air?
Silenthitm4n t1_itb6zu4 wrote
No. It’s slightly lighter than air but the difference is so small height makes no difference.
It’s recommended that they are installed at least 6” below ceiling level and above any doors or windows due to air flow.
HolycommentMattman t1_itbt4sh wrote
Check your exact model. Each one have different specifications. The truth is that CO detection has improved considerably in the last 30 years, and the sensors no longer work by "soaking in" X amount of CO, so many are perfectly fine being installed on the ceilling.
I know I installed brand new detectors, and they detected output of CO by our old furnace. Forced air is pretty turbulent, so it's not like all the CO is just gonna flow consistently to one place. Think of it like having a pitcher of oil and water perfectly separated. Pouring it into a new container will not maintain that perfect separation. Same thing for air, but the effect is even more pronounced.
And CO is lighter than air, so you would expect it to rise eventually anyway.
JeansAndAPolo t1_itbpvia wrote
I've usually seen them mounted about eye level on the wall. I think the idea is that the density is close enough that elevation isn't necessary. And having them at eye level makes it easier and more likely to regularly change the batteries.
PlasmaSheep t1_itck7bc wrote
Yeah, I usually just let my smoke alarms beep every 30 seconds for weeks until they die rather than just change the batteries.
Elk-Tamer t1_itbaoim wrote
If you think about it, and that's a huge simplification, the weight of the elements is like this: C<N<O. Now, our air consists primarily of N2 and O2. CO consists of one of the lighter atoms and one of the heavier atoms. The average weight is around the level of N2, but lighter than O2. Meaning, it's generally lighter that our air, but only to a small extent.
So in general, CO detectors can be near the ceiling, but they don't have to be. Someone once told me to hang them in the height of the average breather in the house. But definitively not near ground level.
hicow t1_itbgr7r wrote
I think I was thinking of radon
MooseBoys t1_itc1e0p wrote
Crucially, the difference in density is small enough that diffusion forces dominate at room temperature. The only issue with placement is ensuring the detector is in an area where the air can easily diffuse to. E.g. don’t put it in a closet, behind a dresser, or in a highly concave corner. These positions will eventually detect CO, but due to the room geometry it may take significantly longer which can easily mean the difference between life and death.
Nordalin t1_itbgt3o wrote
CO2 is heavier than O2, CO is lighter!
Carbon only has 3/4 the weight of oxygen, as it has only 12 protons+neutrons, and oxygen has 16 of them.
cocacola999 t1_itb6llm wrote
Oh that makes sense and makes me nervous about my combo that is mounted on the ceiling above the stairs
Silenthitm4n t1_itb708l wrote
No. It’s slightly lighter than air but the difference is so small height makes no difference.
It’s recommended that they are installed at least 6” below ceiling level and above any doors or windows due to air flow.
[deleted] t1_itb343c wrote
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pain-butnogain t1_itbaird wrote
i think those low placed alarms are for unburnt gas
Murky_Macropod t1_itbdef6 wrote
Yeah we have them on sailing yachts for propane leaks — particularly important as they have nowhere to ‘drain’ to on a boat.
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