CO from S/F stoves?

[AlanH]

There has been a lot said about the dangers of CO escaping from solid fuel stoves but I don'r really understand why.

Many houses had (and some still do have) open fires. How come this is not a problem there?

 

We, like thousands of others, have a gas fired coal effect open fire. It never sets off the CO alarm. So why is the stove so dangerous?

Edited November 25, 2010 by AlanH

[carlt]

House chimneys are (usually) much higher, improving draw so pulling all the fumes out of the room.

 

Many SF burners' installation instructions demand a stack height that is impractical, in a cruising boat.

 

If house chimneys are not swept, regularly, and there is inadequate ventilation, there is still a CO risk.

[Rob@BSSOffice]

There has been a lot said about the dangers of CO escaping from solid fuel stoves but I don'r really understand why.

Many houses had (and some still do have) open fires. How come this is not a problem there?

 

Why do think it is not a problem on land? It is a problem. Stoves installed in houses where the works are subject to building certificates must be installed by HETAS registered installers, certificated and as from October 1st this year, there must be a CO alarm installed.

 

Any carbon fuelled engine or appliance has the potential to produce CO on land or water.

 

Regards

Rob

[Proper Job]

CO (1 molecule of carbon and 1 molecule of oxygen) is formed as a result of poor/incomplete combustion. When a carbon based fuel is burnt cleanly it produces CO2 (1 molecule of carbon and 2 molecules of oxygen).

 

The problem with stoves is that they are often 'damped down'. As a result, there is insufficient oxygen and a surplus of fuel and the generation of CO instead of CO2 as a product of combustion.

 

Your gas fired coal effect fire reduces the fuel (gas) when you turn it down, hence the reduced risk (but still there) of the production of CO.

 

With a solid fuel stove, to turn it down, you reduce the oxygen and hence the almost certain production of CO. That's why you must ensure that a SF stove has no leaks and your flue/chimney is kept clear.

 

And fit a CO alarm!

Edited November 25, 2010 by Proper Job

[DaveC]

Should a CO alarm be fitted at ceiling height or at floor level? The instructions with the one I bought didn't give that information.

 

Dave

[MoominPapa]

Should a CO alarm be fitted at ceiling height or at floor level? The instructions with the one I bought didn't give that information.

 

Dave

The density of CO is similar to that of air, so it won't stratify under normal conditions. I installed the CO alarm on the ceiling on the grounds that CO will be hot as it leaves the stove so convection will make it go upwards first. Our CO alarm is combined with a smoke alarm and they are installed high for the same reason.

 

 

MP.

Edited November 25, 2010 by MoominPapa

[Timleech]

A few weeks ago we'd had the squirrel stove in one house room (2-storey chimney) burning very slowly quite happily for several days, with smokeless eggs, to air the room. Suddenly one evening the CO alarm (in another room) went bananas. There were some funny atmospheric conditions, possibly a local temperature inversion, and the fire had started burning 'backwards', with cold air coming down the chimney.

I ended up having to remove all the burning coals from the fire to fix it. I'm fairly sure that if the fire had been running above tickover, so that the chimney was warmer, the problem wouldn't have arisen. If that can happen with a 2-storey chimney, I expect it's much more likely with a short boat flue.

 

Tim

[canaldrifter]

I'm surprised that flu extensions are not use more when boats are moored, thus increasing draw. Even a few feet could make a lot of difference.

 

Tone

[Proper Job]

The density of CO is similar to that of air, so it won't stratify under normal conditions. I installed the CO alarm on the ceiling on the grounds that CO will be hot as it leaves the stove so convection will make it go upwards first. Our CO alarm is combined with a smoke alarm and they are installed high for the same reason.

 

 

MP.

CO is very slightly lighter than air, but as MP says, consider it the same as. I have mine fitted to the side about 4" down from the roof.

[Dekazer]

The destructions with our CO alarm said that it should be nearer floor than ceiling. I figured that a sensible place would be about the same height as our heads when we are in bed - also the height of our heads when we're in our chairs watching telly. I reckoned that whether the CO was rising or sinking it was probably best that we heard the alarm when it reached our breathing tubes. It still gives me the heeby jeebies so maybe I should just buy another!

 

(And at least our smoke alarm gets tested regularly - at least once a week we cook sausages or bacon or something that sets it off )

[Paul Evans]

And at least our smoke alarm gets tested regularly - at least once a week we cook sausages or bacon or something that sets it off

 

If you turned the smoke alarm off and burned the sausages and bacon properly, you might get to test your CO alarm!

[nb Innisfree]

CO is very slightly lighter than air, but as MP says, consider it the same as. I have mine fitted to the side about 4" down from the roof.

 

Not sure if CO behaves the same but smoke doesn't penetrate the corner formed by a wall and ceiling, smoke alarms need to be away from this preferably in the centre of the ceiling, that's where we have both our smoke and CO alarms.

[Québec]

I'm surprised that flu extensions are not use more when boats are moored, thus increasing draw. Even a few feet could make a lot of difference.

 

Tone

 

Funny you should say that. We're seriously considering getting a much taller chimney for when we are moored, and especially for when it's really cold - like now!

[Odana]

Agree with Dekazer - I have one at mattress height in the bedroom (though under the gunwales is probably not ideal, it does stop me knocking it off as I walk past). And another middling height opposite the fire. Two alarms of different brands (inc one where I can check the numbers on a digital readout) makes me feel more comfortable, especially as I lost an uncle to an unventilated shower and nearly lost two other close relatives to a blocked boiler flue. Sometimes a touch of paranoia is no bad thing.

[blackrose]

Funny you should say that. We're seriously considering getting a much taller chimney for when we are moored, and especially for when it's really cold - like now!

 

Tall single-wall chimneys are more subject to problems of condensing flue gasses due to cold outside temperatures than short chimneys, which can result in a poor draw up the flue. For this reason if you want a tall chimney (greater than about 1m), the use of stainless insulated flue is advised.

[canaldrifter]

Tall single-wall chimneys are more subject to problems of condensing flue gasses due to cold outside temperatures than short chimneys, which can result in a poor draw up the flue. For this reason if you want a tall chimney (greater than about 1m), the use of stainless insulated flue is advised.

 

Absolutely, also double walling helps.

 

Tone

[carlt]

Tall single-wall chimneys are more subject to problems of condensing flue gasses due to cold outside temperatures than short chimneys, which can result in a poor draw up the flue. For this reason if you want a tall chimney (greater than about 1m), the use of stainless insulated flue is advised.

I never had any trouble with my 6' tall, single skin, galvanised stack.

 

Always drew well, only needed sweeping at the start and finish of winter and no tar drips.

[cariad]

we have both fire and c02 alarms fitted on ceiling and have experienced both going off due to leaving fire door open too long ( waiting for glass to cool before cleaning) and of course bacon, sausages etc. happier knowing that they both work.