Enamel vitreous flue pipe ok for Stove?

[cutsurfer]

Hi all,

 

I was hoping somebody could answer my question regarding flue pipe. I 've had a search on google to find an answer to this question but have not seen anything specific enough to put my mind at rest.

 

I am in the process of finalising a boat that I bought at the start of summer, I have built a hearth and fireproof tiled backpanel to safety spec to ensure I won't go up in flames, however I fear I may have been hasty in buying the flue pipe for the inside of the boat.

 

The pipe I have purchased is vitreous single skinned enameled pipe (to the correct 4inch diameter for my acorn stove) but it is incredibly thin compared to other flue pipes i have seen.

 

I know it is important to fit a double skinned chimney but wondered if the vitreous pipe is fine for the internal cabin (I know this may or may not technically pass the safety for a new installation but my main concern is will it be safe?

 

I have noticed that some of the joints also have two holes drilled in and wondered apart from using fire cement whether there are any joint pieces that I may need to fit?

 

I do want to try and make this installation as safe as possible but as you can see still have the odd concern,

 

any help will be much appreciated,

 

thanks, Pete :-)

[MtB]

Thinwall vitreous enameled flue pipe is designed for use with gas an oil boilers. I remember my parents' house had it installed on a solid fuel stove with no ill effects though when I was a brat.

 

The worst that will happen in it will rot through. But it probably won't. Provided you are savvy enough to notice a hole in it, should one happen, I I don;t really see a problem with using it.

 

Trouble is, many boaters these days are NOT savvy about practical matters, so this is why we use thick wall flue pipe nowadays.

[John V]

I would question your first statement Mike......standard enamelled flue pipe has been in use on solid fuel stoves since Adam was a lad.

My logburner and Rayburn both use single wall standard flue.(Now for many years and no sign of "burning through") The only section of double wall I use is (due to the type of boat) is the first 4 foot where it comes through the deck. This is double walled and insulated for safety.

[MtB]

I would question your first statement Mike......standard enamelled flue pipe has been in use on solid fuel stoves since Adam was a lad.

 

 

You missed that I said thinwall then eh?

 

Standard wall thickness is for solid fule, but thinwall, (typically about 18SWG I'd guess) is for gas and oil.

[blackrose]

I used to have a single skin vitreous enamel flue pipe on my stove. It lasted for 6 years and was still fine when I replaced it with a mild steel flue.

 

The problem with them is that they usually don't come in the required length to reach from stove top to ceiling without a joint - and a joint inside a boat is a potential problem, given the vibrations and impacts a boat may be subjected to. That's the only reason I changed mine.

 

I still have a 1m vitreous enamel pipe on my roof as a chimney. It's now 10 years old and no signs of rot. Best chimney I've ever had on a boat (only 1mm thick). Much better than the crap stainless narrowboat chimneys that they sell at chandlers.

Edited September 18, 2015 by blackrose

[bizzard]

The best thing to do to minimize corrosion holes in thin wall flues is to not sweep it too vigorously so as to leave a thin layer of inert clag on the inside, this should protect it against most chemical and rust corrosion.

[blackrose]

The best thing to do to minimize corrosion holes in thin wall flues is to not sweep it too vigorously so as to leave a thin layer of inert clag on the inside, this should protect it against most chemical and rust corrosion.

In my experience you can sweep a thinwall vitreous enamel flue as vigorously as you like without any adverse effect.

[bizzard]

In my experience you can sweep a thinwall vitreous enamel flue as vigorously as you like without any adverse effect.

I think its down to how hot and vigorous you burn the stove. Burning nice and bright and fed little and often will burn off most of the nasties in the exhaust.. Let the stove smolder too slowly with a lot of excess fuel on it and the exhaust smoke will still contain a lot of unburnt calories and chemicals which are corrosive.

[cutsurfer]

Thanks very much for all the responses, the no joint bit worries me though, I have two 30 degree elbows pre-bought to kick the pipe away from the steel rail on my roof that site about 5 inches in, do you think this might be a problem? I was under the impression that as long as well sealed and no more than 40 degrees that elbows are ok....eeeeek?

[blackrose]

Thanks very much for all the responses, the no joint bit worries me though, I have two 30 degree elbows pre-bought to kick the pipe away from the steel rail on my roof that site about 5 inches in, do you think this might be a problem? I was under the impression that as long as well sealed and no more than 40 degrees that elbows are ok....eeeeek?

Are the joints supported?

 

If not keep a careful eye on it and make sure you have a carbon monoxide detector/alarm.

[peterboat]

I had it on my old boat, it was from machine mart and at 6 years old looked like new inside and out

[canals are us?]

I have a vitreous enamel 1.2mm steel flue in 2 pieces of 5 inch diameter. 1x metre and 0.6m.

To join them I first applied fire cement in the socket and inserted the other piece of flue cut to the required length with a angle grinder with a thin metal cutting blade. I then drilled 3 x 3.5mm holes through the socket so that I could use self tapping screws to hold the 2 wall sections together.

 

I have not had any trouble. So my advice is fire cement each joint, and reinforce it with 2-3 self tapping screws at each join. The screws then lock it all together. Stove flue socket must be uppermost so any condensation drains to the stove.

For the pipe into the roof collar I used the 1 inch rope stuff from MC and packed it into the gap between flue and collar and then finished it with black high temp sealant. With your flue you may want to build some heat shields with a 12mm air gap or buy a 1 inch larger flue and cut it in half lengthways and use rive nuts to fix it onto your flue pipe to act as a heat shield. Like below.

 

 

James

Edited September 18, 2015 by canals are us?

[cutsurfer]

Fantastic, thank you very much for the great advice all that's put my mind at rest and I have a clear idea of exactly what i'm doing now! I have silicone and fire cement to hand and will also use the self tappers...really want it to be safe and sound, I have about 6 smoke and monoxide alarms also...taking no chances :-P

 

thanks again

[blackrose]

Personally I think I'd prefer to use bands like these to support the joints rather than drilling through and using self-tappers.

 

https://www.fluedirect.co.uk/shop/image/cache/data/1-d-j_large-500x500.png

Edited September 18, 2015 by blackrose