Metal open cooking hearth?
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I'm not seeing the binary choice...
I've been looking around at the '70's vintage cast iron Franklin stoves. Their functionally about 80% of what anything I could fabricate out of steel plate and people are trying to give them away. I could line the inside with fire bricks held in mechanically, which would add some thermal mass and reduce the size of the fire box to better suit a smaller fire. The franklins are designed to be used as inserts or free standing. I could use it free standing but it would dominate a 100 sqft room. Seems like I could add a completely non flammable fire place and hearth shaped alcove to push the Franklin stove into and run a metalabestos chimney strait up the out side of the wall. There should be code standards for spacing, from a "wall" made with metal studs and Sheetmetal faces, insulated with ceramic fire board and rockwool. The back wall is only 8 feet wide so I could just built it as inflammable unit.
Another thought, which veers back into the experimental, would be to build it like this, but seal the face and completely fill in around the the cast iron stove with perlite. Concerns I see are gasses and creosote leaking , and over heating the cast iron.
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These stoves are not small. They have clearances of 36" in all directions and would put out a lot of heat for a small space. Unfortunately the heat would be relatively short lived due to the inefficiency of these stoves, leading to large swings in room temp.
I've lived in cabins and tents with stoves around the same size for extended periods, but this going to be a bit more of a "retreat" if that makes sense.
Is that clearances from flammable or inflammable surfaces? Radiant heat is line of sight, so if the stove is in an inflammable alcove, that should shield the side walls. Its tight though.
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My point was that you're looking at Thoreaux like stuff.
Is the first priority to be as authentic as possible,.or is the first priority to be able to heat and cook in the space, with secondary as "vintage" as possible?
Not exclusive, but what's the primary goal.
Is the first priority to be as authentic as possible,.or is the first priority to be able to heat and cook in the space, with secondary as "vintage" as possible?
Not exclusive, but what's the primary goal.
Clearances are to combustibles. If the rear wall was all non-combustible inside and out, then it could be possible. If just interior and metal studs were used, then the outside wall or its cladding might be the nearest combustible. Proper NFPA 211 ventilated wall shielding could reduce this clearance down to 12" if done correctly. Adding an alcove complicates things further.
Are you looking to move the trailer after you build this? If you’re looking to move this down the road things like weight and weight distribution become an issue. If it only has to look like it could move down the road if you have to it may be a bit easier as you could ignore things like axle bearings and suspension. You could build a brick building on it.
Wisco Shepherd
Minister of Fire
Its not a line of sight thing. There are approved methods of decreasing clearances but just having some brick/stone/concrete in the way of 2x4s does not reduce the clearance to combustibles.
Being able to move it occasionally is part of the design criteria. That's where the question thermal mass comes in. I'm leaning towards using removable fire bricks inside the metal fireplace.
If I build a non combustible alcove around the stove, straight line clearance to the cabin side walls will be under 36".. straight line radiant heat would have to travel through a metal and rock wool wall, open exterior air and back though a melal and rock wool wall to radiate across the room air to the wood paneling.
The Franklin stoves really are to big for space though. There's a fair chance I'll end up with a larger trailer frame, so the cast iron Franklin would make more sense.
I'm liking the idea of the fire proof alcove being much larger than a free standing stove or metal fireplace. It could have its own passive venting to keep the air clean in the cabin.
I think I defined the goal pretty well in my initial post. Wood shack on trailer with an open cooking hearth. Thoreau's cabin in Walden is a good example, and was chosen as a starting point, as the hewn log cabin that I really want is less practical....
I think I defined the goal pretty well in my initial post. Wood shack on trailer with an open cooking hearth. Thoreau's cabin in Walden is a good example, and was chosen as a starting point as the hewn log cabin that I really want is less practical....
Wisco Shepherd
Minister of Fire
Sounds like you have a plan and really don't plan on deviating too much. Were you looking for advice or just looking for someone to agree with you?
Okay.
Your mention of Thoreaux made me think you are an "originalist" (nothing wrong with that), but it appears you instead have a style requirement,.i.e. have a certain look but not necessarily a copy of true old design. All combined with trailer/moving.
That was (at least to me) not clear.
Now please do have a CO detector in the thing.
Finally, while a lot of things may seem to make sense safety wise, most of those have not been shown (tested) to be safe.
That is where a lot of (e.g. clearance) advice on this forum is coming from.
As I recently heard someone say, 99% confidence is not certainty. It's a fire, and suffocating gases, in a small space you'll be sleeping in (I presume).
I would look at small boat stoves. Cast iron, able to put a pan or pot on top.
Well... If you read all 2 pages of this thread, their are a number of constructive criticisms, that I am taking into consideration while trying to reach a particular goal, and my "initial concept of a plan" has developed into a number of different approaches that I think are worth investigating to see if they are practical. I am very appreciative to those who have given constructive criticism, and I do strive to be at least civil with those who omit the constructive part.
Lots more spit balling to do on this one. Once I find a trailer frame, I'll be working with "numbers and stuff" as far as actual floor plan and how much weigh I can put on it.
I found some general code info, and it looks like there are a number of shielding options to reduce the clearances on the side 66% and the top 50%.
That point's to the cast iron Franklin stove being a possibility, and if I chose to replace it with a smaller more efficient airtight stove , I would have a more than sufficient space for it.
NFPA211
That point's to the cast iron Franklin stove being a possibility, and if I chose to replace it with a smaller more efficient airtight stove , I would have a more than sufficient space for it.
NFPA211
That reduction is for the general 36" clearance. Most old stoves (and all nonUL listed ones) would have this 36".
If you get a stove where the mfg specifies clearances (e.g. 8".or so in the manual), it can't be reduced by any percentage unless the mfg says you can in the manual.
And any clearance that can be reduced can't end up being less than 12".
If you get a stove where the mfg specifies clearances (e.g. 8".or so in the manual), it can't be reduced by any percentage unless the mfg says you can in the manual.
And any clearance that can be reduced can't end up being less than 12".
I could maintain a 12" clearance around the stove, but since there would potentially be no flammable material behind the insulated steel enclosure, I think that counts a s more than sufficient. How far the stove will have to go into the enclosure to shield the side walls side walls is a question, but can be safety checked with a yard stick.
The codes have information on masonry fire place design. "FIGURE 11.2.5.4 Fireplace Clearance to Combustible Material." is pretty interesting. At least for a fire place under 6' wide, combustible trim boards are specified at 6" clearance from opening edge and a mantle that extends past 3/4" is specified at 12" clearance, which seems like a good standard to keep even if it is beyond the yardstick test from stove.
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Looking at what's available locally, I found an Olympic franklin stove and it has a 24" clearance rating, which would simplifie a lot of the concerns, atleast on paper.
![[Hearth.com] Metal open cooking hearth?](https://www.hearth.com/talk/attachments/260246382_4007678519334005_4170985334313611137_n-1-webp.332751/ "[Hearth.com] Metal open cooking hearth?")
And I found a manual that gives 24" side clearances for the Atlanta Stove Works version.
Atlanta Franklin manual
And I found a manual that gives 24" side clearances for the Atlanta Stove Works version.
Atlanta Franklin manual
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In order for thermal mass to be any benifit you need allot more than a few firebrick. You need hundreds of pounds of mass and even then your only talking about delaying heat an hour or so. Actual effective mass heaters have multiple tons of mass.
Really just looking to bake some bread, better.
If the stove weighs 250lbs and I add 50lbs of fire brick, that's adding 20% of cant hurt.
The stove will be in an insulated alcove, so most of the heat will push out the front into the room, which will be around 100sqft, and reasonably insulated.
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