Wood stove and forge sharing a flue?

[herchammer]

I was wondering if any of you have ever seen a shop where the forge and a wood stove shared a flue? I am planning on doing this in my shop, and I'm wondering about the problems others may have encountered in doing this.

[Ramsberg]

Yep, sure have.

At the local historical shop in which meetings are held(which I no longer attend), the single brick chimney handles two coal forges(both side draft) and one pot belly stove.

The two forges feed right into the bottem of the forge from oposite sides. The stoves pipe enters the chimney about half way up or so, it just goes right into the side.

As long as the main flue is large and tall enough there shouldn't be any problem.

Actually, I recall the forges drawing better when the stove was going, I think that the added hotter gases from the stove kept the chimney pulling even when the forges were not going full blast.

I hope that this helps.

Caleb Ramsby

[Jura T]

Yep, sure have.
As long as the main flue is large and tall enough there shouldn't be any problem.

Actually, I recall the forges drawing better when the stove was going, I think that the added hotter gases from the stove kept the chimney pulling even when the forges were not going full blast.

My plan is also to attach the forge and the stove to same flue. So it is good to hear that it actually works :)

[divermike]

Be aware of the differences in the product going into the shared system. If creosote is allowed to form, to any degree, your chimney can catch fire and you might have a problem. Coal burns so much cleaner than wood, that some people forget about the creosote, make sure that if the wood burning section is run a lot, that a hot fire is burned on a regular basis to burn out the creosote.

[welder19]

You will need to make sure the dia. is big enough if your planning on burning more than one at a time.
I would also recomend dampers in ea pipe so you can slow down or cut off the draft to one or the other.
I don't know if your in a place or a position to be concerned but it may not fly with the local code.

welder19

[Glenn]

If creosote is allowed to form, to any degree, your chimney can catch fire and you might have a problem. Coal burns so much cleaner than wood, that some people forget about the creosote, make sure that if the wood burning section is run a lot, that a hot fire is burned on a regular basis to burn out the creosote.

a hot fire is burned on a regular basis to burn out the creosote

That sounds like a chimney fire !!

I have found that if you watch the exhaust coming from the chimney (wood or coal) you can then adjust and optimize the burn rate of the fire. There should be only a small amount of smoke, a whisp of smoke, if any smoke at all, coming from the chimney if the fire is burning well.

[Ted T]

Be aware of the differences in the product going into the shared system. If creosote is allowed to form, to any degree, your chimney can catch fire and you might have a problem.

Stove Pipe Installation.
From experience I have seen the burnt-out results of a home where men have installed the chimney stack the wrong way.
So I would suggest that you make sure you understand how to stack your chimney sections to gather properly when you assemble your chimney pipe.
The question is: Fe-male end up and Male end down and to the inside? Or is it the other way around?
I would suggest that you look up your local building codes for the “installation and use of a wood stove”.
I would also consult with a wood stove dealer to confirm that you are doing it correctly!
I will not tell you how to do it because maybe I am incorrect! You need to know for sure for your own good.
I have had several people oppose what I say is the correct way to do this until I would show them the code requirement and the manufacture instructions.
Here is a sample (only) of instructions, but make sure you follow your own building code requirements.
-------------------------
Installation Tips:
- Put 3 screws into each pipe joint. This helps prevent the pipe from vibrating apart if a chimney fire occurs
- The crimped (male) end of the pipe always points TOWARD the stove; this keeps creosote accumulation running inside the pipe rather than dribbling outside of it- Match the stove pipe to the flue outlet size on your appliance; reducing the pipe size is not advised.
- Keep black pipe 18" from combustibles!
- Use the straightest run possible. Do not exceed 3' of horizontal pipe unless the stove manufacturer specifically ALLOWS you to!
- Provide 1/4" rise for every 1' of horizontal run. Never allow stove pipe to slope downwards.
- Don't use more than one 90 degree elbow
- When installing a rear vent stove, exit the stove with a tee, not an elbow. This helps contain creosote buildup in the drop port on the tee.
- When connecting black pipe to the wall thimble, the pipe should extend completely through the thimble into the flue, but not protrude into the flue. This keeps any creosote drip inside the flue.
- Black pipe can only be installed where it's visible in the room. This means it cannot be installed inside a fireplace or inside of a masonry chimney, inside a closet or attic, cannot be used as a wall pass-through.
--------------------------------------
But here is a hint toward the principle that is used. You will find that you want the creosote to run down the inside of the pipe back to the source of the flame so it cannot leak out.
Checking (inspecting) the inside of your pipe stack for creosote as often as it is recommended is very important.
The whole idea when installing the stove pipe sections is to stack the pipe sections so as keep the creosote from running down and out of the joints to the outside of the pipe. If the creosote can find its way out, it will very likely result in combustion and start a un-wanted chimney fire on the outside of the chimney stack.
Please be very careful. There is a reason I would take the time to challenge you to find out for your self about this issue.
I have seen the sad results with my own eyes, and have heard about it several times over my life time of fires that started due to up-side down installation of the stove pipe.
Ted Throckmorton Edited November 5, 2008 by Ted T

[Doug C]

Ted,
Great explanation. I am in the process of buying what I need to set up a forge in my shed so this is really timely and useful. I thought the male pipe always pointed away from the stove so you just saved my bacon big time. Thanks.

[Jura T]

Thanks Ted!

[herchammer]

Great responses,all! I'm never disappointed when I post, or read posts on this board.

Thanks!

[Frosty]

Ted:

I have yet to find a code that contradicts your stove pipe joint orientation advise. I will admit I haven't checked every state, county, city, etc. code and reg so there may be someone out there officially off their rocker.

Been burning wood for heat off and on for 36 years.

Frosty

[easilyconfused]

I can concur that you want it properly installed. Had a chimney fire one afternoon and it's a scary thing. Sounds like a jet engine roaring through. Proper installation kept it inside the chimney and nothing got burned because of the space between it and any wood. I'd like to say my throwing pails of water onto the roof outside to keep the wood wet helped but I'm sure i just got myself wetter than the wood for nothing. Another point, try to not leave any fire unatended, even if things are properly installed and maintained. Accidents can happen and it's better if you know what to do and are able to do it before it's out of hand. One last point, keep your head if something does happen. We deal with fires and dangerous situations as a normal happenstance so why panic? Stupid mistakes happen when you don't think.