Carbon Monoxide Fatalies

[dor]

 

Last Friday my boat had it's BSS inspection (it passed – which was no big surprise being all diesel) and I had arranged for the examiner to do a pre-test on a newly purchased narrowboat on the adjacent pontoon. The girl who had recently bought the boat had had various items of work carried out by a boatyard, including the installation of a solid fuel stove, which had not so far been lit (thank God).

 

When I saw the installation my first reaction was that the single walled flue was too small and that as it was routed within 1 1/2" of a wooden window pelmet, where it went through the roof, it would be a BSS fail.

 

On measuring the flue (nominally 4") and comparing it with the manufacturers' spec (6") I did the maths to discover that the specified flue would have had exactly 2 1/4 times the cross sectional area of the installed flue – i.e. I was looking at a flue that was "2 1/4 times too small"!

 

I contacted the manufacturers' (sending them some pics) and their response was that the installation was dangerous and should not, on any account, be lit. They recommended that the flue be twin walled; routed away from the combustible pelmet and that the DEFRA plate should be fitted (it was not as I'd pointed out to them). This prevents the secondary air damper from being fully closed, so pretty much shutting off the draft up the chimney: a double CO whammy!

 

The combination of a seriously reduced flue diameter and the ability of the user to fully close the secondary air damper would,under certain atmospheric conditions, have resulted in the stove producing copious quantities of CO.

 

I let the examiner (an extremely experienced, conscientious and competent man) inspect the stove without letting on that I'd already had a dialogue with the manufacturer and it was passed without comment. I queried the proximity of the wooden pelmet to the flue and his response was that, although it was bad practice, there was no sign of discolouration of the wood it passed so close to. I pointed out that as the stove had never been lit there were unlikely to be any such signs!

 

I then told him that he was actually looking at a 'killer installation', condemned by the manufacturer. I made it clear that I was not getting at him as it would be unreasonable to expect him to know the flue spec for every stove he looked at; the significance of fitting a DEFRA plate; determining whether said piece of metal had been fitted; etc; etc. My point was simply that if CO and smoke alarms were mandatory, the BSS would have ensured that a lass and her 6 year old son, sleeping on this vessel in the winter months, could have been sure of waking up refreshed from a good night's sleep, come the morning. Their well-being would not have relied on my chance (nosey!) visit to the boat and observations based on 40 odd years experience working as a plumber in rural areas.

 

With such a telling case in point (yes, he was suitably shocked) the examiner got straight on the phone to BSS HQ to be told that the need for the compulsory fitting of alarms is currently "going through the system"with respect to hire boats and that, within approx 18 months, it will be made compulsory for leisure craft. A 'result' of sorts but my response was to ask him how many folk would die over the next 18 months. [Extrapolating from the appalling boat death stats (from fire and CO poisoning) I believe the answer is about 0.1 under ten].

 

Which stove was it. The reason I ask is that the installation sounds like a typical narrowboat stove installation - i.e. 4" ID flue and no "DEFRA plate".

 

There are requirements for these in house installations but I think the double skinned flue is only advisory on boats for the BSS. Certainly there are plenty of newly fitted out boats around with only a single walled flue.

 

The manufacturers would get twitchy about it as it is illegal to supply and fit a SF stove in a house that doesn't meet DEFRA standards.

[mross]

Stove manufacturers specify a chimney height that is not practical on a boat. But boat chimneys seem to 'draw' well enough!

[MtB]

 

The combination of a seriously reduced flue diameter and the ability of the user to fully close the secondary air damper would,under certain atmospheric conditions, have resulted in the stove producing copious quantities of CO.

 

 

 

What secondary air damper is this please? I'm not sure what you mean.

 

Would have been interesting to light the stove and see if the flue drew correctly and us a proper professional gas analyser to see how much CO spilled out into the boat cabin.

 

What was the make and model of stove?

[Up-Side-Down]

 

Which stove was it. The reason I ask is that the installation sounds like a typical narrowboat stove installation - i.e. 4" ID flue and no "DEFRA plate".

 

There are requirements for these in house installations but I think the double skinned flue is only advisory on boats for the BSS. Certainly there are plenty of newly fitted out boats around with only a single walled flue.

 

The manufacturers would get twitchy about it as it is illegal to supply and fit a SF stove in a house that doesn't meet DEFRA standards.

 

Hungry Penguin

 

The manufacturers would allow a 5" flue where the DEFRA plate is fitted (aka a smoke control device). The plate was neither fitted nor returned with the stove. Same goes for tools, heat proof glove, operating instructions, installation certificate (thereby voiding any guarantee).

 

As boaters we are exempt from smoke control regs but at least the DEFRA plate (where fitted) ensures that there is always sufficient air for complete combustion of the fuel (minimising the generation of CO)

 

It transpires that the excellent pdf on boat stove installation is merely 'good practice' rather than in any way binding as far as a BSC goes – available at: https://www.google.co.uk/search?q=installing+solid+fuel+stoves+in+boats&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&ei=_RCrV7KMA8rW8gfehIzYBQ

(See Stoves in Boats pdf)

Edited August 10, 2016 by Up-Side-Down

[Up-Side-Down]

 

 

 

What secondary air damper is this please? I'm not sure what you mean.

 

Would have been interesting to light the stove and see if the flue drew correctly and us a proper professional gas analyser to see how much CO spilled out into the boat cabin.

 

What was the make and model of stove?

 

The Hungry Penguin (in common with many of its brethren) has two push/pull damper knobs under the casing – one for the primary air supply and one for secondary air. The DEFRA plate prevents the secondary air damper from being fully closed to ensure complete combustion and maintain a draw.

 

At this time of the year (and with a brand new stove) it would be difficult/impossible to simulate the conditions I had in mind:

 

1) Cold winter's night with sub zero temps – stove stoked up to the gunnels against the piercing chill

 

2) Zero wind/exterior air movement

 

3) Primary & Secondary dampers fully closed

 

4) Stove not in its first flush of youth = rope seals deteriorated so some leakage possible

[MtB]

 

As boaters we are exempt from smoke control regs but at least the DEFRA plate (where fitted) ensures that there is always sufficient air for complete combustion of the fuel (minimising the generation of CO)

 

 

I'm out of my field of expertise here but again, you write stuff that puzzles me.

 

When I wave the pick-up wand from my gas analyser anywhere over burning coal or solid fuel, the CO reading goes off the scale and the unit goes into 'self protection' mode (at 3,000ppm).

 

This is understandable as solid fuel stoves and grates are controlled by restricting the air supply, so incomplete combustion is normal and to be expected.

 

If you supply sufficient air for complete combustion, a stove roars away out of control. Can you resolve this problem for me please? Many thanks.

[Up-Side-Down]

Stove manufacturers specify a chimney height that is not practical on a boat. But boat chimneys seem to 'draw' well enough!

Indeed they do.

 

My wee Epping, which is running 24/7 in the back cabin throughout the winter, sits on the swim with a mere 'stub' of an internal flue and performs perfectly. It does at least have 3' of insulated chimney outside the boat, whilst the installation in question had 15" of uninsulated chimney.

 

I would always ensure that the chimney butterfly was cracked open and that some draft was available through the primary air wheel at the firebox. There are a couple of smoke alarms on the boat and two CO alarms ............ and I sleep about 50' away from it!

[spadefoot]

I have a Hungry Penguin, and it's lovely. It came with all the kit including the recommended twin wall flue. I didn't bother with the defra plate.

I keep a CO alarm within 6ft of the stove, not a whimper.

Decent installation & maintenance are very important on any stove.

[David Mack]

 

 

I'm out of my field of expertise here but again, you write stuff that puzzles me.

 

When I wave the pick-up wand from my gas analyser anywhere over burning coal or solid fuel, the CO reading goes off the scale and the unit goes into 'self protection' mode (at 3,000ppm).

 

This is understandable as solid fuel stoves and grates are controlled by restricting the air supply, so incomplete combustion is normal and to be expected.

 

If you supply sufficient air for complete combustion, a stove roars away out of control. Can you resolve this problem for me please? Many thanks.

My understanding is that primary air is introduced at the bottom of the stove, and if restricted, incomplete combustion and CO results as you say. Secondary air is introduced above the fire, and combines with the CO to to produce CO2, reducing the CO in the flue gases and producing some additional heat output. As it is introduced above the coal it doesn't lead to the fire running away.

[Up-Side-Down]

 

 

I'm out of my field of expertise here but again, you write stuff that puzzles me.

 

When I wave the pick-up wand from my gas analyser anywhere over burning coal or solid fuel, the CO reading goes off the scale and the unit goes into 'self protection' mode (at 3,000ppm).

 

This is understandable as solid fuel stoves and grates are controlled by restricting the air supply, so incomplete combustion is normal and to be expected.

 

If you supply sufficient air for complete combustion, a stove roars away out of control. Can you resolve this problem for me please? Many thanks.

 

My understanding, Mike, is that all combustion produces CO and that, where there is insufficient oxygen present to support complete combustion, there will be a dis-proportionate amount of CO given off – indeed it will be the predominate gas in the firebox of a solid fuel appliance.

 

All well and good if it's being drawn up the chimney – not so clever if conditions are such that it can find its way out into the 'room'.

 

So when my neighbours on a mooring, a few years back, decided to block up the drafty low level air vents at the stern of their boat to conserve the heat given out by their solid fuel stove, they tragically ceased to be my neighbours the following morning.

 

Still, chill winter's night – no draft, no oxygen arriving at the seat of combustion (stove turned down low).

 

Now I may be missing something or misunderstanding something basic (and I genuinely bow to your experience in the field of gas boilers) so please do correct me where I'm going wrong here. My interest is purely to see an end to this disproportionate number of CO- and fire-related boat deaths and if I can learn something along the way then that's great for me too.

[Up-Side-Down]

My understanding is that primary air is introduced at the bottom of the stove, and if restricted, incomplete combustion and CO results as you say. Secondary air is introduced above the fire, and combines with the CO to to produce CO2, reducing the CO in the flue gases and producing some additional heat output. As it is introduced above the coal it doesn't lead to the fire running away.

 

That's pretty much my understanding too.

 

As I understand it CO2 is not a killer as such, so if some of the gas from the burning charge doesn't all make it up the chimney – due to restricted flue area or insufficient draft – it's not, on its own, an immediate threat to life.

 

So the DEFRA plate, in ensuring that there is always secondary air present, whilst not totally eliminating CO, does substantially reduce it. It also goes a long way to help burn off the particulates and anything else that produces smoke, hence its other name: smoke control device (and it's requirement to be fitted in smokeless zones).

[Up-Side-Down]

I have a Hungry Penguin, and it's lovely. It came with all the kit including the recommended twin wall flue. I didn't bother with the defra plate.

I keep a CO alarm within 6ft of the stove, not a whimper.

Decent installation & maintenance are very important on any stove.

 

I think they are a beautifully built piece of kit (and, as such, justify their relatively high price) and I hope the lass in question can get all the bits and pieces to go with it. Chilli Penguin are away on hols at the moment but I expect they will see her right.

 

In essence CP say twin walled, 5" flue and DEFRA plate or 6" twin wall and the DEFRA plate does not need to be fitted.

 

I don't think you can over emphasise your installation and maintenance points. Looking at it as I type, I think my Epping could use a bit of the latter before the onset of winter!

[MtB]

My understanding is that primary air is introduced at the bottom of the stove, and if restricted, incomplete combustion and CO results as you say. Secondary air is introduced above the fire, and combines with the CO to to produce CO2, reducing the CO in the flue gases and producing some additional heat output. As it is introduced above the coal it doesn't lead to the fire running away.

 

 

This plugs a gap in my knowledge, I had no idea air will combine with CO to make (relatively) benign CO2. Will investigate this when I have time.

 

CO2 is by no means safe to breathe either. This was discussed a few months back and it is surprisingly dangerous stuff too, perfectly capable of killing you in low-ish concentrations.

[Chewbacka]

 

 

This plugs a gap in my knowledge, I had no idea air will combine with CO to make (relatively) benign CO2. Will investigate this when I have time.

 

CO2 is by no means safe to breathe either. This was discussed a few months back and it is surprisingly dangerous stuff too, perfectly capable of killing you in low-ish concentrations.

Town gas - what we used befors natural gas if you are old enough to remember - was made from coal and contained a lot of CO (a bit under 3% from memory) which is why sticking your head in the gas oven was a quick suicide method.

CO will burn with Oxygen to give CO2.

I think town gas also contained hydrogen as well as other gasses from the coal.

Edited August 10, 2016 by Chewbacka

[mross]

Any gas is dangerous in the wrong concentration. If Oxygen level rises above 23% the slightest spark can cause your clothes to catch fire and burn extremely rapidly and this applies to anything combustible nearby. CO2 levels of 4% plus are dangerous. Nitrogen levels above the normal 78% will reduce the O2 levels. O2 levels below 18% affect judgement and rational thought and below 12% lead to unconsciousness and death. Carbon Monoxide is very dangerous at concentrations above 1,600 ppm (0.16%) causing death within 2 hours.

 

I once breathed in some pure CO2 and it was like being punched in the stomach! It causes you to breathe out involuntarily and forcefully giving a sort of choking feeling.

[Guest]

You make an excellent point. CO Alarms should be mandatory in boats and caravans.

 

Since we had a CO alarm go off in a narowboat (we used to take a portable one with us on a share boat that didn't have one) showing up a real issue with the stove in time to keep us safe I have them every where on our boat and at home.

Although not mandatory in the strictest legal sense all new caravans sold made by any manufacturer and sold through any dealer who is a member of the trade body the National Caravan council must have both a smoke alarm and a a CO detector in order to comply with their standards.

 

This covers just about every new caravan (and motor home) sold new in the UK. Our 'van was supped with both fitted.

 

I believe this applies to any used caravans they sell too if these are not already fitted from new.

 

Quite why the boat building and retail industry lags behind in this respect is beyond me. £20 for both seems ridiculous set against the price of a new narrowboat.

Edited August 10, 2016 by MJG

[Up-Side-Down]

Need to check my facts edit.

 

And I couldn't fathom why the leisure boat industry has to wait 18 months while the hire boat industry is cajoled into fitting alatms

[Sea Dog]

And I couldn't fathom why the leisure boat industry has to wait 18 months while the hire boat industry is cajoled into fitting alatms

I'm guessing the early implementation in hire boats is because the industry has a duty of care to its customer who has to rely on the company to provide them with a safe boat and someone will be in the dock if anything bad happens. For private boaters it would be a personal misadventure, but also the danger is one that we can personally act upon to mitigate, as we can fit our own alarms immediately. Either way, the result would be the same though, so it's hard to fathom why they intend to wait 18 months. Perhaps it's to do with the time it takes for legislation and not wanting to delay the former whilst dealing with the latter?

[Neil Walker]

Somebody was running a petrol genny on their Trad narrowboat the genny was at the top of the steps and the doors had blown shut! I knocked to give him a warning and was told to F off as thanks cant educate pork can you

I am currently watching a smokey old gen on the back of a trad with the exhaust getting sucked in through the vent. At what point do I knock?! 3 mins or midnight?! Mind you he came out coughing as I typed this so I guess he's ok . . .

[Up-Side-Down]

I'm guessing the early implementation in hire boats is because the industry has a duty of care to its customer who has to rely on the company to provide them with a safe boat and someone will be in the dock if anything bad happens. For private boaters it would be a personal misadventure, but also the danger is one that we can personally act upon to mitigate, as we can fit our own alarms immediately. Either way, the result would be the same though, so it's hard to fathom why they intend to wait 18 months. Perhaps it's to do with the time it takes for legislation and not wanting to delay the former whilst dealing with the latter?

 

That makes sense.

 

As a general observation I think that, whilst it is difficult to legislate against ignorance and stupidity per se, it is easier to legislate against the outcomes of same. So in this instance there will always be instances where stoves and the like are installed without regard to best (even good) practice: making the fitting of alarms compulsory will go a long way to ensuring that the outcomes are not fatal.

[mross]

I am currently watching a smokey old gen on the back of a trad with the exhaust getting sucked in through the vent. At what point do I knock?! 3 mins or midnight?! Mind you he came out coughing as I typed this so I guess he's ok . . .

I think I would try and start a friendly chat and then mention the recent deaths. If you did nothing and then read of his death, you would feel terrible, I'm sure. Was it petrol?

[Neil Walker]

I think I would try and start a friendly chat and then mention the recent deaths. If you did nothing and then read of his death, you would feel terrible, I'm sure. Was it petrol?

Of course I would! I tried engaging him earlier and he blanked me. I must have a look in the mirror and check my scary status! Yes petrol, took him 30 mins to start it. I wouldn't normally bother but he's been holed up all day (never get that on a nice day) will take the dog out in a minute and see what's what. If he manages to crack a smile I have a spare alarm I might donate. Or I might run mine for a bit(LPG) and see if I can pizz him off enough to come for a chat! mind you he won't hear it!

[Manuel_Hung]

I was in Apsley marina a few months back and got a tap on the boat. It was the local fire service handing out free carbon monoxide/smoke alarms (FireAngel branded). I offered to pay but was told 'You've already paid in taxes'. Anyone else had this?

[David Mack]

I'm guessing the early implementation in hire boats is because the industry has a duty of care to its customer who has to rely on the company to provide them with a safe boat and someone will be in the dock if anything bad happens.

But equally, one could argue that the commercial realities of that position would mean that hire companies would fit CO detectors even if not required to do so. It is the private owners who need the nudge that making it a BSS requirement would add.

[churchward]

Although not mandatory in the strictest legal sense all new caravans sold made by any manufacturer and sold through any dealer who is a member of the trade body the National Caravan council must have both a smoke alarm and a a CO detector in order to comply with their standards.

 

This covers just about every new caravan (and motor home) sold new in the UK. Our 'van was supped with both fitted.

 

I believe this applies to any used caravans they sell too if these are not already fitted from new.

 

Quite why the boat building and retail industry lags behind in this respect is beyond me. £20 for both seems ridiculous set against the price of a new narrowboat.

That's good to hear but there should also be regulations to retro fit to older caravans too outside of commercial resales.

 

I completly agree new boats should also be fitted with CO and smoke alarms from new as standard there really is no excuse for it. With the BSC process we also have a method to make sure all boats have them too.

Edited August 10, 2016 by churchward