Co2 ppm query

[MtB]

Can we get this straight please? A conventional CO detector is triggered by hydrogen as well as CO?

 

Can anyone cite an authoritative reference for this please?

 

Thanks.

 

MtB

[Keeping Up]

I can't cite a reference, and I admit that I don't even know whether it's the hydrogen gas or the hydrogen sulphide (bad egg smell) gas that you get from a bad battery when it's gassing. But I do know that both CO detectors and LPG detectors will react to it (or maybe even one reacts to the hydrogen and one to the sulphide) because I've seen it on my own.

 

ETA it's not definitive but a report from the Fire Service in Ontario says:

 

"When charging lead acid batteries, hydrogen (H2) gas is produced. Hydrogen gas is a by-product from the electrolysis reaction (charging) of the lead acid battery. Hydrogen gas can interfere with the carbon monoxide detector's sensor. The carbon monoxide sensor is sensitive to and will respond to hydrogen gas at about a 10 to 15 % of it's actual concentration. If you find you are getting high carbon monoxide readings around battery charging operations do not be alarmed, but be cautious. The Lower Explosive Limit (LEL) for hydrogen is 4.0 % by volume (40,000 ppm by volume). If your carbon monoxide detector alerts, and you are charging a lead acid battery in the area, disconnect the battery charger and ventilate the space in order to dissipate the gas"

Edited December 15, 2013 by Keeping Up

[Arthur Brown]

CO always comes from burning, and there is always some CO among the CO2 in burner fumes. If there is no fire -stove, engine, cooking, water heater etc then there can be no CO or CO2

 

Yes we have seen on here several examples of batteries gassing to failure causing CO detectors to indicate falsely.

 

Probably a new battery will cause the CO indication to go away. I certainly wouldn't .want to go into the depths of winter with batteries that were basically dead.

[MtB]

Ok thanks Allan.

 

I ask because we gas bods get called out to investigate CO incidents. When a punter's CO alarm sounds and frightens them witless the official advice is call a gas bod like me to check out all the gas appliances. I have yet to detect CO in a home that has suffered a CO alarm incident, and often the only gas appliance is a room sealed boiler. Vanishingly unlikely to be issuing CO intermittently.

 

So I've had a weather eye open for some time now for other things that might trigger CO alarms. I'm wondering if they might be a source of hydrogen is some domestic homes causing them.

 

 

MtB

 

 

(Spellin mistakes edited out)

Edited December 15, 2013 by Mike the Boilerman

[Phil Ambrose]

Can we get this straight please? A conventional CO detector is triggered by hydrogen as well as CO?

 

Can anyone cite an authoritative reference for this please?

 

Thanks.

 

MtB

The instructions that came with mine states a variety of "fumes" that will make it react and advise that you should avoid if possible anything (unspecified)which could in extreme cases ruin the detector paint fumes are mentioned.

Phil

[Guest]

Can we get this straight please? A conventional CO detector is triggered by hydrogen as well as CO?

 

Can anyone cite an authoritative reference for this please?

 

Thanks.

 

 

MtB

I can't quote an authoritve source but have seen it mentioned on here a few times.

 

Besides it's clear the OP's batteries are goosed any way so they are not wasting any money changing them.

 

If it doesn't sort the high readings then it's summit else. The batteries causing it is a logical starting point.

[Keeping Up]

Ok thanks Allan.

 

I ask because we gas bods get called out to investigate CO incidents. When a punter's CO alarm sounds and frightens them witless the official advice os call a gas bod like me to check out all the gas appliances. I have yet to detect CO in a home that has suffered a CO alaram incident, and often to only gas appliance is a room sealed boiler. Vanishingly unlikely to be issuing CO intermittently.

 

So I've had a weather eye open for some time now for other things that might trigger CO alarms. I'm wondering if they might be a source of hydrogen is some domestic homes causing them.

MtB

 

Mike, see also my edit that we cross-posted on

[Phil Ambrose]

Just a thought, its quite possible that a variety of Hydrocarbons found in the home could be disruptive, quite possible even things like air fresheners

Phil

[Captain Fizz]

In the meantime, ventilate the engine room, leave a hatch open, hydrogen is lighter than air so should vent out of the compartment.

In the meantime, ventilate the engine room, leave a hatch open, hydrogen is lighter than air so should vent out of the compartment.

This will also help to prevent the possibility of an explosive atmosphere forming.

[MtB]

The instructions that came with mine states a variety of "fumes" that will make it react and advise that you should avoid if possible anything (unspecified)which could in extreme cases ruin the detector paint fumes are mentioned.

Phil

 

Thanks Phil, time I read an instruction leaflet again then! They never used to say that but once you think you know what it says, there is a tendency to stop reading the paperwork that comes with them.

 

MtB

[Paul C]

MIke, an affordable, normal household CO alarm doesn't actually measure the CO directly - to do this would require a gas chromotograph, which is a laboratory instrument costing many thousands of pounds. Instead, they'll use an easily measurable physical property of the gas, together with several assumptions about what the gas is likely to consist of (ie its mostly air with a small amount of combustion products). For example, refractive index of the sample gas. Hence any gases outside of the assumptions the manufacturer assumed, will be able to produce spurious results. Hydrogen, paint fumes, etc certainly fall outside of the assumed stuff the detector might 'sniff'.

[Phil Ambrose]

 

Thanks Phil, time I read an instruction leaflet again then! They never used to say that but once you think you know what it says, there is a tendency to stop reading the paperwork that comes with them.

 

MtB

Just for info Mike, my alarm is a Kidde.

Phil

[The Lockie]

Don't want to scaremonger here but gassing producing hydrogen sulphide can be lethal not just from the explosion risk.

 

It was recently the method of choice by which a poor lad (a chemistry undergraduate at Oxford) commuted suicide in a tent on Port Meadow.

 

Please keep the engine compartment permanently ventilated until this is sorted.

[Higgs]

This happened to me a while back. I googled for any light that could be thrown on the CO monitor reading 140 +. Given that there were no appliances on that produce CO and the readings raised significantly in the area of the batteries I felt sure it was not CO.

 

Googling led me to information to do with submarines and too long ago, I couldn't find it in a hurry now. But, the reading on the meter would relate to 1000's ppm of hydrogen. I think, basically, the batteries were cooking. And all of this could be happening at the back of the boat. Eventually setting the monitor off in the saloon, which is in the front part of the boat.

Edited December 15, 2013 by Higgs

[RichardN]

Can anyone cite an authoritative reference for this please?

 

From personal experience I know that my Drager 4 gas monitors have a CO sensor which is very sensitive to hydrogen, and that seems to be typical for most similar monitors in the £500 to £1000 range. This link takes to the web site for the current basic 4 gas monitor, there is a link to a sensor and portable instruments handbook which gives you levels, I think it shows 90ppm CO for 0.1% concentration of hydrogen, I have always meant to read all of their handbook as it is full of interesting information.

[Paul C]

Maybe its a blessing in disguise that the CO meter has inadvertently detected a build up of hydrogen in the engine compartment.

[mark99]

I remember telling my mate that it was probably hydrogen he was bleeding from his radiators (byproduct of corrosion) and told him to stick his lighter under the next one he bled - which he did and a flame shot out and caught his net curtains alight.

[PaddingtonBear]

Lounge?

[Swallowman]

CO meters? My experience with a BG man and his meter some years ago is not good.

He came to do a routine boiler service and told me that my 20 year old Potterton Netaheat was dangerous because the CO level around the casing where it was mounted on an outside garage wall was too high. Can't remember now what his figure actually was but it was below the level at which he told me he would condemn it and isolate it leaving us with no hot water or heating. I asked him when the meter was last calibrated and he just looked at me blankly. I then asked him what the ambient level was and again he looked at me blankly so we took his meter to the pavement and measured the CO level just after a local "hopper" bus went past. Lo and behold, the CO level was double the figure he measured in my garage so he went on his way with his employer £4,500 less well off! There is an incentive scheme for engineers (and I use the term loosely here) to persuade gullible customers they need a new boiler for which they get rewarded handsomely.

This happened before the huge rise in gas prices and we did have a new much more efficient boiler fitted but not by British Gas. Paid for itself in four years but i doubt the aluminium heat exchanger will last 20 years like the cast iron Potterton one!

Edited December 16, 2013 by Swallowman

[real_vibes]

Thanks again all for input and advice. Hugely useful. New batteries are en route!

[mango]

What about the BSS requirement for ventilation of batteries?

 

Non-sealed batteries give off an explosive mixture of hydrogen and oxygen when charging and all lead-acid batteries can produce these gases in substantial quantity if overcharged or a battery develops a fault. Richard? put some pictures showing the results of a battery explosion on this site in the past year or so.

 

When the engine is running, it will help prevent hydrogen from accumulating.

[Paul C]

What about the BSS requirement for ventilation of batteries?

 

Non-sealed batteries give off an explosive mixture of hydrogen and oxygen when charging and all lead-acid batteries can produce these gases in substantial quantity if overcharged or a battery develops a fault. Richard? put some pictures showing the results of a battery explosion on this site in the past year or so.

 

When the engine is running, it will help prevent hydrogen from accumulating.

 

I was wondering that too, but didn't want to tread on the toes of the many boaters with inadequate ventilation for their batteries, which are within the bodyshell in an engine compartment/engine room. Its an issue for themselves, and their BSS examiners, and I don't have or regularly use a trad stern boat.

[mango]

 

I was wondering that too, but didn't want to tread on the toes of the many boaters with inadequate ventilation for their batteries, which are within the bodyshell in an engine compartment/engine room. Its an issue for themselves, and their BSS examiners, and I don't have or regularly use a trad stern boat.

Many batteries are supplied with a tube and plastic connector that can be connected to one end of the case. The connector goes into one end of the casing and providing that the vent hole at the other end is plugged, the tubes can be linked to a vent outside the boat. That would I believe be a good way of ventilating batteries providing that the cases do not split or a filler plug has not been replaced.

[Alan de Enfield]

I know the subject is 'closed' but I thought the following may be of interest.

 

During my BSS the surveyor gave me a booklet produced by "The Council of Gas Detection & Environmental Monitoring" and called "Carbon Monoxide Safety On Boats" where it states

 

"A CO alarm can activate if it senses the explosive gas hydrogen:, eg from a boats batteries gassing off when under charge, perhaps indicating a charging problem"

 

It also suggests that the alarm should be covered or removed if using paints, solvents, degreasers or strong chemicals. It also suggests that the alarms should be removed from a 'winterised' boat as low temperatures may affect its sensor