CO/Smoke Detectors

SIKSUKR · 04-12-2013, 08:01 AM

CO is definately not heavier but in fact slightly than the air we breath.the difference is so small (maybe 8%) that most likely it will mix in all levels if even small air movement is present.I looked at First Response detecters and their manual does not specify mounting height,just location.

DickR · 04-12-2013, 10:13 AM

Just to quantify things, the molecular weights of nitrogen, oxygen, of the blend we call "air," carbon monoxide, and pure propane are:

N2 28.014
O2 31.999
air 28.951
CO 28.010
C3H8 44.097

So, CO is almost exactly the same weight as nitrogen, and one can conclude that molecular diffusion keeps the molecules well mixed, without stratification. Propane is sufficiently heavier that it can stratify, although given time it will diffuse into the bulk air.

GsChinadoll · 04-12-2013, 11:50 AM

All I know is with a house ten years old and the wired in smoke detectors on their last legs, it is an expensive proposition to buy all new ones. I understand that we need them but things are very tight right now. It just never ends does it?

jrc · 04-12-2013, 12:30 PM

I think ToW is thinking about CO2 (carbon dioxide), which is heavier than air. There are lots of stories about dry ice fumes pooling up and causing lack of oxygen.

CO is carbon monoxide and it comes from burning stuff. House furnaces and engine exhaust are the most common sources of CO danger. Being a weekend boat resident, we always hear the stories about boaters killed by CO. I keep my CO detector near my head since that's where I breath.

04-12-2013, 08:01 AM	#1
SIKSUKR Senior Member Join Date: Apr 2004 Posts: 5,075 Thanks: 215 Thanked 903 Times in 509 Posts	CO is definately not heavier but in fact slightly than the air we breath.the difference is so small (maybe 8%) that most likely it will mix in all levels if even small air movement is present.I looked at First Response detecters and their manual does not specify mounting height,just location. __________________ SIKSUKR

04-12-2013, 11:50 AM	#3
GsChinadoll Senior Member Join Date: Apr 2010 Location: Northern MA & Moultonboro Posts: 54 Thanks: 339 Thanked 15 Times in 7 Posts	Replacing All I know is with a house ten years old and the wired in smoke detectors on their last legs, it is an expensive proposition to buy all new ones. I understand that we need them but things are very tight right now. It just never ends does it? __________________ Don't let people drive you crazy when you know it's within walking distance.

04-12-2013, 10:13 AM	#2
DickR Senior Member Join Date: Apr 2008 Location: Moultonborough Posts: 758 Thanks: 4 Thanked 260 Times in 172 Posts	Just to quantify things, the molecular weights of nitrogen, oxygen, of the blend we call "air," carbon monoxide, and pure propane are: N2 28.014 O2 31.999 air 28.951 CO 28.010 C3H8 44.097 So, CO is almost exactly the same weight as nitrogen, and one can conclude that molecular diffusion keeps the molecules well mixed, without stratification. Propane is sufficiently heavier that it can stratify, although given time it will diffuse into the bulk air.

04-12-2013, 12:30 PM	#4
jrc Senior Member Join Date: Apr 2004 Location: NH Posts: 2,689 Thanks: 33 Thanked 439 Times in 249 Posts	I think ToW is thinking about CO2 (carbon dioxide), which is heavier than air. There are lots of stories about dry ice fumes pooling up and causing lack of oxygen. CO is carbon monoxide and it comes from burning stuff. House furnaces and engine exhaust are the most common sources of CO danger. Being a weekend boat resident, we always hear the stories about boaters killed by CO. I keep my CO detector near my head since that's where I breath.