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OT: Carbon Monoxide Alarm....
matt.c - 31/1/10 at 08:22 PM

As part of my DIY weekend i have bought a Kidde Night Hawk Carbon Monoxide Alarm. In the fitting instructions it tells you "mount it on a wall 3 feet from the floor"

I have a small child who loves to pull things of walls like the alarm!! So it not a good idea to put where it said. Also at that height i would look bl**dy stupid plus would prob be knocked of the wall buy a loose arm or something.

How important is it to fit it 3 feet above floor height? Cant i mount it like the fire alarm on the seeling?

Any experts about?

tomprescott - 31/1/10 at 08:25 PM

Or even on the ceiling? I think they need to be quite close to possible sources, we have one that stays in a socket and on the instructions says to put it as close to source as possible and if the plug isn't close enough, to get an extension!

[Edited on 31/1/10 by tomprescott]

matt.c - 31/1/10 at 08:32 PM

My one says not to put it any closer that 2 metres from the gas fire.

speedyxjs - 31/1/10 at 08:39 PM

We have one on the ceiling and one about 6ft up a wall.

blakep82 - 31/1/10 at 08:45 PM

well, carbon monoxide is heavier than air i believe, so i think the idea is that if it's 3ft from the gound, you can still breath standing up ok to get out, but if you put it on the ceiling, i guess by the time it reaches the alarm, its kinda too late

also, i've heard that there is a particular model of plane (can't remember if its a boeing or airbus) that the air is so thin, that basically there isn't any air at floor level. don't let your kids sleep under the seats thats nothing to do with CO though...

searching the internet, i've found as many answers saying CO is heavier than air as i've found for it being lighter...

probably best to do what they advise i'd think.

[Edited on 31/1/10 by blakep82]

wicket - 31/1/10 at 09:57 PM

Just fitted one of these, see pages 5&6 for position details

http://www.fireangeldirect.co.uk/files/CO-9B-Manual.pdf

tomprescott - 31/1/10 at 10:10 PM

I guess following manufacturer advice is the best option and hope your kid(s) leave it one piece. I think (but not sure) that CO poisoning can be cumulative - as in a little over a long time is as bad as a lot at once and that it never leaves your system, so having an alarm too high/low is better than not having one at all!

907 - 31/1/10 at 11:19 PM

I'm no chemist, or doctor, but as I understand it this is the way it goes.

One atom of carbon isn't very happy attached to one atom of oxygen, i.e. CO.
(It's a bit like a British football supporter with an empty glass. )

CO needs another atom of oxygen to become a stable substance, i.e. CO2.
(Full glass = happy bunny )

CO formed in say a flame "robs" the oxygen from the surrounding air, so it's lack of oxygen in the air
that is the danger, and causes drowsiness, sleep, then death.

The killer second stage, as if the first wasn't bad enough, is that if CO is breathed into the lungs it
then gets its extra oxygen from your blood stream, and your brain dead in minutes.

Like I say, I'm no expert. Just my 2p.

Cheers
Paul G

Fozzie - 31/1/10 at 11:43 PM

Kidde recommend at least 1.5 meters (4feet 11 inches) from the floor as a 'rough' guide.
Eye level (to the lights) is optimum......

HTH Fozzie

[Edited on 31-1-10 by Fozzie]

Breaker - 1/2/10 at 12:09 AM

quote:
Originally posted by 907
I'm no chemist, or doctor, but as I understand it this is the way it goes.

One atom of carbon isn't very happy attached to one atom of oxygen, i.e. CO.
(It's a bit like a British football supporter with an empty glass. )

CO needs another atom of oxygen to become a stable substance, i.e. CO2.
(Full glass = happy bunny )

CO formed in say a flame "robs" the oxygen from the surrounding air, so it's lack of oxygen in the air
that is the danger, and causes drowsiness, sleep, then death.

The killer second stage, as if the first wasn't bad enough, is that if CO is breathed into the lungs it
then gets its extra oxygen from your blood stream, and your brain dead in minutes.

Like I say, I'm no expert. Just my 2p.

Cheers
Paul G


That's not completely correct.

First of all: if you burn something you need O2 (oxygen). If you supply enough oxygen to your 'burning process' this will result in heat and the production of C02 (carbon dioxide). If your burning process is not supplied with sufficient O2, this will result in the production of CO instead of CO2. Once CO is formed, it will not take up other oxygen to get to CO2; it will stay as it is.

Why is CO so deadly ?
Our red blood cells have the ability to bond with oxygen (O2) while breathing. This oxygen is then transported through your body and supplied to your organs. When the oxygen arrives at an organ, the oxygen will disconnect from the red blood cells so oxygen is supplied to this organ. The red blood cell is pumped back to your lungs to pick up new oxygen and so on and so on....
But!!! Carbon monoxide (CO) also has the ability to bond with your red blood cells but because of the physical properties of this molecule, it will not disconnect any more from the red blood cells. So your blood keeps on bonding with CO and looses the ability to take up O2. If no O2 goes to your organs....you die !

Where to put the alarm:
First look at the molar mass (specific weight of a molecule) of CO: 28.010 grams/mol.
O2 (oxygen) : 31.9988 grams/mol.

So you see CO is lighter then oxygen, but not by much. So theoretically you should put the alarm on the ceiling, but most fireplaces are on the ground. If your bed is close to the ground and your heater is not working properly (producing CO), this CO is moving up very slowly (especially if there is low air movement for example while you are sleeping). It's possible when the CO finally reaches your alarm on the ceiling, you will already be dead. So keep the alarm closer to the floor.

Just my 2 cents

907 - 1/2/10 at 08:35 AM

I stand corrected then.

I remembered that from my college days, a while ago now.
The lecture that day was "The products of the the Oxy Acetylene Flame".
He touched on the safety aspects of using it in confined spaces, so my info was not from a medical source.

Sorry

Paul G