Carbon Monoxide Sensors

Voyager00 · Veteran Member

Carbon Monoxide Sensors

JCT · Veteran Member

I have my carbon monoxide sensor at the highest point available, which is also the position of the smoke detector.

Both are side by side, which by coincidence is above the gas detector, which is obviously at floor level.

Better to be safe than sorry.

Footprints · Senior Member

I would have thought that as carbon monoxide is heavier than air the sensor should be low down in sleeping or at least seating area mounted high would probably be a case of sensor activating too late. You are possibly dead. Allen

Olley46 · Guru

My post was giving the wrong information so I have given it the flick.

Lance C

-- Edited by Olley46 on Friday 24th of July 2015 05:16:52 PM

-- Edited by Olley46 on Friday 24th of July 2015 08:20:05 PM

D and D · Guru

Carbon Monoxide is lighter and less dense than air meaning it will rise not fall. Placing CO monitors at the highest point is therefore more appropriate than placing them at the lowest point. See en.wikipedia.org/wiki/Carbon_monoxide for more info.

Regards

Dave

Voyager00 · Veteran Member

Thank you all for your advice.

D and D , how is your BT50 travelling ? Any problems ? We're heading off with ours towing a 20' off rorder.

jade46 · Senior Member

Which could just mean the CO has suffocated you lying in bed, lets say 600mm from the floor before it reaches the sensor mounted high in the van say 2000mm high? Just a thought

rainy1850 · Senior Member

Where do you get the sensors

Phil C · Guru

BTW to the new folks on our forum, welcome.

We have our CO alarm nice and high, the battery gets checked every quarter the same time as the smoke alarm and LPG alarm.

rainy I got mine from ebay (feebay)

Cheers

rainy1850 · Senior Member

Thanks. Will have a look. We use a gas heater in the annexe to warm up but turn it off before going to bed.

JCT · Veteran Member

Further to my previous reply and further searches on the web may I add the following.

The only units which can give off carbon monoxide, in my motorhome, are the gas hob and grill and also the gas hot water boiler.

Carbon monoxide and air are, I understand, are virtually the same density.

As my units all give of heat it is suggested that the combined hot/warm air/carbon monoxide will rise.

Based on this information and my previous understanding I will be leaving my carbon monoxide sensor in the high spot where I originally placed it and in a similar position as to where I have placed similar for many years in my various homes, RV and boat.

This is just my decision and I respectfully suggest everyone to decide according to their own units and their own research.

Stay safe whatever you decide.

dorian · Guru

The instructions for a Delta CO alarm ($14 from Aldi) recommend installing it "on the wall at eye-level (1.5m) and at least 30cm from adjoining walls or ceiling".

"If free-standing, the unit should be placed no more than 1 metre from the ground (to avoid permanent damage in case accidently knocked)."

"Do not wall-mount within 30cm of the ceiling as this is a 'dead air' space."

In fact the Aldi unit looks identical to this 7DCO Kidde alarm:
http://www.kiddesafetyeurope.co.uk/Documents/2530-7202-02_7CO(Caravans).pdf

See the installation instructions in the above PDF.

As for the density of CO compared to air, I can still remember my high school chemistry.

atomic mass of carbon / oxygen / nitrogen / argon = 12 /16 / 14 / 40 amu

http://www.google.com.au/search?q=atomic+mass+of+carbon

According to Wikipedia ...

"By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases."

https://en.wikipedia.org/wiki/Atmosphere_of_Earth

The molecular formulae are CO / O2 / N2 / Ar.

The atomic mass of CO = 12 + 16 = 28

The atomic mass of air = (14 x 2) x 78.09% + (16 x 2) x 20.95% + 40 x 0.93% = 28.94

So CO is slightly less dense than air (28 versus 28.9).

dorian · Guru

At the risk of labouring this question, consider that an oxygen molecule has an atomic mass of 32 whereas a nitrogen molecule has an atomic mass of 28. Does this mean that oxygen sits on the floor and nitrogen rises to the ceiling? Should we lie on the floor to get oxygen enriched air? Moreover, carbon monoxide has the same atomic mass as nitrogen.