Had a chimney fire today, don't want another!

Greatgimp

I have a wood burning stove. The steel pipe goes into the chimney about 2ft above. We lit the fire earlier, and before you know it the chimney was on fire - very frightening. I closed all the vents to the woodburner and closed the top chimney vent. Eventually the chimney fire went out but it took quite a while.

I've decided to rerope the door and window seals as well as sweep the chimney tomorrow, to be sure of cutting off the oxygen supply as the fire would have gone out a lot quicker than it did. Some of the problem is the steel pipe between the box and the chimney. The joint is filled with fire cement, but as is normally the case, the cement cracks up and allows the air through to make matters worse.

Does anybody know of a flexible fire cement?

noonesperfect

I'm not sure if the same appllies but when we had a chimney fire (open fire not wood burner) the firemen told us to get the chimney swept more often as burning logs leaves more deposit in the chimney and this is what catches light. It's only a small fire opening and we didn't have it raging up the fire-back! Frightened the life out of us it did!
It's really scary the noise it makes isn't it? :eek:

PS

does this stuff sound any good?

http://www.fluesystems.com/sundries/indexfirecement.htm

Greatgimp

I had a look at that website before posting. It seems that the fire cement there is the typical stuff, but the flexible stuff isn't stated that it can be used for fires or stoves. The maximum temperature it can handle is 350ºC and I'm sure any fire would far exceed that.
I only have a smallish stove which is not fixed down on the quarry tiles so opening-closing-opening-closing the doors and clonking logs against the back when inserting moves the stove around the fireplace, enough to help crack up the cement. I'm not keen on drilling through the cast iron feet to secure it in place. The search continues...

John_3:16

Greatgimp, could I ask when you last had your chimney swept and how often you do it.

Also how often your stove is lit and how you burn your timber eg hard with vents open or smoulder?

Many thanks.

Greatgimp

About 6 months ago, so well aware it's due. I'm gonna do it today - I know, after the horse has bolted. We do tend to 'keep the fire overnight' so that obviously means a slow smoulder which doesn't help. It's lit most days.

John_3:16

I would say 6 months ago was rather a short period to then have a chimney fire. I am no expert but does a fire happen when you get soot build up or tar build up. I am aware that if you have tar in the chimney sweeping may not get rid of it? I wonder if letting it smoulder or using some damp timber may have caused this?

Is your chimney lined? if so how far up? or goes your stove pipe just go into a chimney space?
Also is the chimney on an outside wall or in the house?

Sorry for all the questions but as we have a wood burner, it is interesting to find out these things.

Oblivion

It is interesting how different fuels and types of burner produce very different types of soot.

When I was a lad living in an old house in hampshire, we had traditional open coal burning fire places using traditional untreated colliery coal, and the soot in the chimney was a dark rich black, presumably denoting a high residual tar content. You could watch the soot stick to the back of the hearth during the course of one evening, and it was a source of constant delight to us children when it caught light from the fire and the glowing particles looked like a line of soldiers marching up the brickwork. Despite having the chimneys swept every year, we suffered two chimney fires and as has already been said, it is a frightening experience.

Moving on some years and when my wife and I moved into our present property some 30 plus years ago, it already had an old Parkray enclosed coal burner with a glass fronted door in the lounge. This has a back boiler which heats 4 radiators as well as heating our immersion tank via an internal coil. All very efficient and when the original unit rusted away, we had it replaced with a similar Parkray unit. This would have been about 20 years ago, and although we had the chimney swept prior to installation, it has never been swept since.

We burn small anthracite nuts on it which are technically a 'smokeless' fuel. The little amount of soot it does generate in the chimney is a light grey powder which falls back down the chimney into the internal grate quite naturally during the summer months when the fire is unused. Each commencement of winter, I just shovel this soot out and we're set to go. I've tried a blowtorch on this soot and it shows no inclination to ignite at all, I assume because the tar content is negligible.

Dave.

Canucklehead

Good morning: Excellent advice on solid fuel burning appliances is available from HETAS

HTH

Canucklehead

owned_by_2_Siamese

Hi -having averted a similar disaster I discoivered that the stove itself is not airtight (only a year old and cast iron - morso squirrel) when I tried to put the stove out after a torrent of tar poured down the stove pipe - sizzled and threatened to catch fire (smoking!)
Our sweep investigated and said it didnt need sweeping - it was condensed tar - caused by a chimney on teh outside of teh house - facing north (no protection) and a small stove that wasnt heating the chimney enough - and the stove pipes were installed upside down (by a HETAS installer) so the tar ran 'out' the joints rather than into the stove. Although the chimney was only two years old he said teh only way to avoid was to have it lined and insulated (and yes we only burn dry seasoned wood) We had a nightmare finding someone to do it - but eventually a local guy (HETAS!) came an installed it two weeks ago. He said itwas incredible taht we hadnt had a really bad chimney fire - there was a lot of tar in the bottom 2 feet of the chimney and under the 'board' that sealed the chimney above the stove and the pipe goes through. In teh end he had to 'burn it' away (controlled!) The cost of the liner, installation - removing and refitting the stove - and replacing the incorrect stove pipes was £1500. GULP.
However the stove is now phenominal - it draws properly - is controllable (it was either all or nothing before) and the heat output is significantly higher. For us that debate of to line or not line the chimney has now been a no brainer. Also I couldnt take the risk of another lucky escape (dont even ask about the mess it made....)

If your chimney sweep recommends it - and I know its expensive - lining will cure the problem!

hethmar

The OP seems to suggest he has just got a stove pipe going into the chimney void. This is the real problem - the chimney flue is not lined - and the lining should be insulated - and so the flue gases are cooling down and forming condensates on the internal walls - i.e. tar/resin. It will happen again if you dont have the job done properly.

Greatgimp

You may be right. Between the stove and the square sheet steel plate up the chimney is a rolled sheet steel pipe 26" long with a screwed access plate midway up. The square sheet steel plate moves sideways a good 6" eachway very easily on a concrete section (register plate?). I think I need this inspected.