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Carbon Monoxide detector location, where?

Posted: 13 Apr 2008, 11:07
by Smiler
Where is the best place to locate a Carbon Monoxide detector in my Autosleeper conversion please?

Posted: 13 Apr 2008, 19:24
by kevtherev
Carbon Monoxide is always lighter than air down to 32 degrees. Plus it come out of the appliance hot which would put it at the ceiling first. Warmest air in the roof space, therefore it would linger there the longest. What is often forgotten is that if CO is dumping into the van even greater amounts of CO2(Carbon Dioxide) are being emitted. Carbon Dioxide is 40% heavier than air and ends up on the floor rapidly. This could actually prevent CO from getting to an alarm if it is plugged in at a low wall outlet.

so high up then


and these are old draughty vans.. a good thing really for ventilation

Posted: 13 Apr 2008, 19:47
by kevtherev
more info on CO

Concentration of CO in the air Implications of Exposure

200 PPM Slight headache within 2-3 hours.
400 PPM Frontal headache within 1-2 hours, becoming widespread in 3 hours.
800 PPM Dizziness, nausea, convulsions within 45 minutes, insensible in 2 hours.
Source From: carbonmonoxidekills.com

Effects of Carbon Monoxide

The maximum level of Carbon Monoxide and Exposure Time that cannot be exceeded without risking illness to people with heart and lung diseases and pregnant women:
Concentration of CO in the air Time of intake before illness
87 PPM 15 min
52 PPM 30 min
26 PPM 1 hour
9 PPM 8 hours

Posted: 13 Apr 2008, 20:11
by Smiler
kevtherev wrote:
so high up then



Cheers :wink:

Posted: 14 Apr 2008, 03:38
by jpee
kevtherev wrote:more info on CO

Concentration of CO in the air Implications of Exposure

200 PPM Slight headache within 2-3 hours.
400 PPM Frontal headache within 1-2 hours, becoming widespread in 3 hours.
800 PPM Dizziness, nausea, convulsions within 45 minutes, insensible in 2 hours.
Source From: carbonmonoxidekills.com

Effects of Carbon Monoxide

The maximum level of Carbon Monoxide and Exposure Time that cannot be exceeded without risking illness to people with heart and lung diseases and pregnant women:
Concentration of CO in the air Time of intake before illness
87 PPM 15 min
52 PPM 30 min
26 PPM 1 hour
9 PPM 8 hours

i'll keep checking my watch and grab sampler then!!!!

Posted: 14 Apr 2008, 06:35
by Hacksawbob
CO is the same molecular weight as air regardless of air temperature, Unless the chemical composition changes with temperature then one molecule of CO is the same weight as another.
http://www.newton.dep.anl.gov/askasci/c ... m03609.htm
The source of the combustion and the air movements will be more of an effect than simple diffusion by brownian motion, ie a Propex blower for example moving air around the van. For a fridge, the heat rising from the flame in the first instance would drive it. As this temperature fell with no other air motion (ie on a still night) there would be no incentive to mix. So mixing would occur far more gradually. My sensor is as close to being at the same height as the top of the fridge, and coincidentally at the same height as the bed. If you mount it at the top of the van you potentially have to fill the van to a higher concentration before detection. Dont use the fridge at night would be one solution, or install two detectors.

Posted: 14 Apr 2008, 07:02
by T'Onion
mine is in the high top , about level with the vans tin roof ,and above the sliding door ,a few weeks ago it went off whilst we were camping in it , turned out to be the fridges vent that needed cleaning ,
thankfully it worked and thankfully we are all still here , also make sure that you check it everytime you use the van , batteries are cheap , a graveside isnt :(

Posted: 14 Apr 2008, 17:12
by kevtherev
sorry bob, but your wrong there CO is slightly lighter (your link says that too) than air and will diffuse upwards albeit slowly

Posted: 14 Apr 2008, 18:36
by gti mad man
sorry to hijack but i have a question
Been looking at the fireangel 828 the only one i can seem to find commonly available with a display but its not kite marked,the ones that are kite marked dont have a dispaly any thoughts????????

Posted: 14 Apr 2008, 19:10
by Hacksawbob
Taken from the above website

This molecular weight (of air) is more variable because several atmospheric gases such as H2O and CO2 have variable contributions. The molecular weight of CO is not significantly different than this number

In most common situations I would say it is the same weight as air.

Hi Kev, you haven't read my post, I didn't say that one was lighter than the other. The molecular weight of the molecule doesn't change with temperature which you stated in your first post. Unless there is some "deep chemistry" that I am unaware of the weight does not change with temperature at least not say between -50 and +50 degs C. I would be interested to know where you got 32 degs from. However the temperature MAY have an influence on the movement of the CO as a hot gas will rise.

Other factors such as the air movement outside and inside the van, the ambient air temperature, the location and size of the point of entry into the interior would have far more of an influence than the relatively insignificant differences in the weights of the gasses.

I realise this is a very real safety risk, so I'm not just gain saying you for the sake of it Kev. If there is something faulty in my logic then I would genuinely like to know.

I based my decision on where to mount my CO detector on an interview on the radio that the CO detector should be at the same height an close to the source, although this was relating to a house I believe it follows for a van.

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carbon monoxide detector

Posted: 14 Apr 2008, 19:16
by jaylo264
Where can I get one of these ? Guess we are lucky to have survived these last 10 years in the van-- like someone said , good job they are draughty .

Posted: 14 Apr 2008, 20:07
by Hacksawbob
B+Q DIY type places usually do them for about £15

Posted: 14 Apr 2008, 20:21
by kevtherev
When considering where to place a carbon monoxide detector, keep in mind that although carbon monoxide is roughly the same weight as air (carbon monoxide's specific gravity is 0.9657, as stated by the EPA; the National Resource Council lists the specific gravity of air as one), it may be contained in warm air coming from combustion appliances such as home heating equipment. If this is the case, carbon monoxide will rise with the warmer air.

hot gas rises..

hey Bob.. I could argue the toss all night .

at the end of the day installing a detector anywhere where you sleep is a good idea.

Posted: 14 Apr 2008, 21:15
by Smiler
Bloomin` `eck lads.............i`ll put it near where we sleep, thankyou for trying to help :wink:

Posted: 14 Apr 2008, 21:20
by T'Onion
hot gas rises..



at the end of the day installing a detector anywhere where you sleep is a good idea.

indeed , and my daughter sleeps above the height of the gas fridge/appliance so that is why mine is up there ...

As for where to get one ... Tesco's or most supermarkets .. read the instructions , and then follow how to test it .. using incense sticks :pimp or even block the vent up :shock: .. no dont do that :roll: