alarm

Submitted: Thursday, Mar 23, 2017 at 15:01
ThreadID: 134527 Views:2058 Replies:8 FollowUps:12
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where is the best place to mount a carbon monoxide alarm in your caravan/camper up high, down low or does it not matter ,thanks for future replys barry
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Reply By: Shaker - Thursday, Mar 23, 2017 at 17:58

Thursday, Mar 23, 2017 at 17:58
I fitted one a while ago & found it quite confusing:
1. Is carbon monoxide heavier than air?
Carbon monoxide has a density that is about 97% that of air under normal room temperature. So, to answer the question, no, it is lighter than air. You would think, then, that it would rise. In real-world conditions, there are a lot of forces that cause the CO to mix rather completely into the air. Therefore, it will neither rise nor fall. What might be more important is the temperature of the gases it is part of. Since it is a combustion product, the hot exhaust gases that contain the CO will rise, but are soon mixed into the air you are breathing. If there is a source of CO present, such as a poorly-maintained stove, the CO level will highest close to the source, and decline with distance.

I found another reference that suggested 5 feet from the floor was the best position.

AnswerID: 609631

Follow Up By: garrycol - Thursday, Mar 23, 2017 at 18:01

Thursday, Mar 23, 2017 at 18:01
I would be mounting in accordance with the instructions that came with the unit.
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Reply By: Duncanm - Thursday, Mar 23, 2017 at 18:24

Thursday, Mar 23, 2017 at 18:24
My instructions say around shoulder height
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Follow Up By: Zippo - Thursday, Mar 23, 2017 at 18:44

Thursday, Mar 23, 2017 at 18:44
Those references to height (5ft/shoulder height) are simply to where your personal vapour/gas INLET is located - when vertical. If the sensor is to alert you while sleeping, I'd reckon something akin to your schnozzle height again would be appropriate. But as always, YMMV and RTFM.

(The density differences between CO and main air constituents O2 and N2 are insufficient to prevent fairly complete mixing - corresponding directly to their molecular weights 28 vs 32 vs 28 respectively.)
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Reply By: RMD - Thursday, Mar 23, 2017 at 18:56

Thursday, Mar 23, 2017 at 18:56
Many toxic gasses are heavier than air, LPG is, and in workshops where vehicles are running a deep pit contains exhaust gasses (NOx) which are heavier than air. That kills blokes who are in a deep pit. The gas may rise a bit when hot with convection but cooler they sink.

I have bought one and will install it about ankle height in the van, definitely below the mattress level.
If you don't hear from me anymore then I may have that wrong.
AnswerID: 609634

Follow Up By: mountainman - Thursday, Mar 23, 2017 at 19:12

Thursday, Mar 23, 2017 at 19:12
Yes.
Lowest to the ground is the best idea.
carbon monoxide will always go to the lowest place in a room.

Soo many farmers have died from generators when they work on a dam.
generator shuts down
they check on it and overcome with fumes and die.
just recently 3 from the one family died
working on a water tank.

mount your alarms below bed height.
as you want it to go off when your asleep
hopefully it wakes you up ! Within time
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Follow Up By: Shaker - Thursday, Mar 23, 2017 at 19:30

Thursday, Mar 23, 2017 at 19:30
I'm not trying to be pedantic, but they were working IN an enclosed water tank, with the generator in with them.

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Follow Up By: Member - peter_mc - Friday, Mar 24, 2017 at 09:40

Friday, Mar 24, 2017 at 09:40
Carbon dioxide is heavier than air - it will sink to the lowest part of the room

Carbon monoxide is slightly lighter than air - it is unlikely to sink to the lowest part. But as others have said, it's also unlikely to all be at the ceiling.
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Follow Up By: PhilD - Friday, Mar 24, 2017 at 21:22

Friday, Mar 24, 2017 at 21:22
Mine is about 450 mm from the floor.
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Reply By: Gundarooster - Friday, Mar 24, 2017 at 13:39

Friday, Mar 24, 2017 at 13:39
Why just CO rather than CO2 and or LPG?

What type is best and where do you get one?

Thanks
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Follow Up By: PhilD - Friday, Mar 24, 2017 at 21:23

Friday, Mar 24, 2017 at 21:23
Mine is Safe T Alert and I bought it online from the US.
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Reply By: Motherhen - Friday, Mar 24, 2017 at 23:20

Friday, Mar 24, 2017 at 23:20
Because it mixes with air and does not sink like carbon dioxide and LPG, around seated head height would be a good place. I note someone has said the instructions on theirs said should height (standing I presume).

Last winter I posted a My Blog on heating on the dangers of carbon monoxide. Worldwide, thousands of deaths each year are attributed to carbon monoxide poisoning.
Motherhen

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AnswerID: 609678

Follow Up By: Duncanm - Saturday, Mar 25, 2017 at 07:52

Saturday, Mar 25, 2017 at 07:52
Good point, yes my instructions said shoulder height when standing.

Thanks
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Reply By: Member - Andrew & Jen - Saturday, Mar 25, 2017 at 12:50

Saturday, Mar 25, 2017 at 12:50
My understanding is that the trigger point for the alarm is set well below the lethal concentration of CO. It should therefore give plenty of warning before you become drowsy / head-achy, etc and while you are still able to take the appropriate action.

Given that CO mixes with air, rather than building up near the floor or rising to the roof, the recommended height of near shoulder level would seem sensible.

We always sleep with the door vent and top vents open, thus reducing moisture levels and therefore condensation as well as reducing the chances of any buildup of harmful gases.

Cheers
Andrew
AnswerID: 609680

Reply By: The Bantam - Sunday, Mar 26, 2017 at 11:13

Sunday, Mar 26, 2017 at 11:13
consi the shoulder height instruction is probably in a situation where people are expected to be standing ...... think about how that works when sleeping.

where ever you have it, will be better than none

cheers
AnswerID: 609699

Follow Up By: Shaker - Sunday, Mar 26, 2017 at 11:21

Sunday, Mar 26, 2017 at 11:21
Maybe if you are sleeping you would be below the biggest concentration of the gas.

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Follow Up By: The Bantam - Sunday, Mar 26, 2017 at 18:00

Sunday, Mar 26, 2017 at 18:00
All the information I have from OH&S and the alarm industry says that carbon monoxide is not in theory or practice a gas that rises.

In fact it tends to remain in low voids and cavities

so a greater concentration of gas is unlikely to higher in the space.

cheers
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Follow Up By: Shaker - Sunday, Mar 26, 2017 at 18:20

Sunday, Mar 26, 2017 at 18:20
Surely the manufacturers of the alarms could be regarded as "the alarm industry", they seem to suggest siting their alarms at around 5 feet.

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Follow Up By: Colcam42 - Tuesday, Mar 28, 2017 at 14:07

Tuesday, Mar 28, 2017 at 14:07
The instructions that came with mine said to avoid the ceiling "dead-spot" and mount it at least 30cm below the ceiling.
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Reply By: Batt's - Sunday, Apr 02, 2017 at 20:29

Sunday, Apr 02, 2017 at 20:29
I had a van for a while but never heard about needing a CO alarm and would probably question as to why one is needed when there is always air flow able to get into the van via an external vent or vents in the door or behind the fridge which I believe the door vent should not be able to be closed I may be wrong..

I would be more inclined to install an LPG gas monitor in a van.
AnswerID: 609865

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