clearances Jotul F8 - where does back clearance turns into side clearance

[lilon]

Hi,

Jotul F8 has 200 mm back clearance requirement and a 600 mm side clearance requirement. If I set up my Jotul 210 mm from the back wall I am OK, but if 400 mm along that back wall (which is parallel to the back of the heater) there is a timber stud, am I then in breach of the side clearance? or is the side clearance does not relate to the back wall?
Similarly, if I need a 600 mm side clearance, does it mean that the hearth needs to extend 600 mm to both sides so that the floorboards are not closer to the heater than 600 mm>

Sorry, this must be a naive question, but I am a newbie.

Thanks

 

[Oldman47]

Have a look at your stove clearance diagram. It will have back and side clearances for the stove and for the flue pipe but it will also have corner clearance numbers in a separate diagram. Your example of something outside the back clearance range may more resemble the corner clearance if I am understanding your question right. As far as the floor, there is always a set of specifications for the hearth area which is what determines where normal flooring must stop and floor protection must start. Often the floor protected area is smaller than the wall and side specifications.

 

[begreen]

What is the wall construction behind the stove? It sounds like conventional stud construction. Is it drywall covered?

Double check those clearances. Are they to a combustible or Australian code approved non-combustible wall or to a combustible wall?

Unfortunately there are no docs on the Jotul.au website, but comparing the requirements for GB, the clearances stated don't match. The rear clearance for a combustible wall is listed as 800mm and the side as 550mm. Not sure why the disparity.

 

[lilon]

Thanks very much for responses. I wasn't clear enough I guess with the first part of my question. My stove is not in a corner situation. It is sitting against a straight back wall. But if you think about it, the relationship between the stove and the back wall is not only to the very back (90 degrees). So my question was, at what point (if at all) do I look at this analogue ongoing relationship between the stove and the back wall using not the 200 mm requirement but the 600 side one? Or is it that since this is a 'back wall', it is always judged based on the 200 mm standard. This would be the case only if the heat projected from the side of the heater which supposedly goes much warmer than the back wall (otherwise why 600 and not 200) is projected only from 90 degrees sideways and forward and not diagonally to the back wall. So with this clarification, I'd still be happy for advice.

I couldn't find the clearances diagram for my stove because I bought the house with it and am just moving it to a new place.

Yes, its an internal stud wall, though I think I will fill it with earth or some form of thermal mass to absorbe the heat and release it slowly.

Thanks again

 

[lilon]

Anyone please?
Thanks

 

[begreen]

Where is the 200 mm measurement coming from? That sounds like it is for a non-combustible wall, but we don't know because we don't have the AU manual for this stove. In lieu of that I would either go to a local Jotul dealer and get a copy of the manual or go by the European clearance specifications which are 800mm from a stud wall. In the US this clearance can be reduced only by using an NFPA 211 heat shield. I'm not sure if AU permits the same. Here is an article on how to reduce clearances using a proper heat shield.
https://www.hearth.com/econtent/index.php/articles/stove_wall_clear

 

[DougA]

This may or may not be your answer. When I had my inspection done for my flat wall installation, the inspector wanted to use BOTH the flat wall specs along with the corner specs. He insisted he had to do that but I called the mfg and you can't combine them. If you have a flat wall installation and you have 210mm clearance to the wall and there is something combustible 400 mm along that back wall, it is acceptable. That's the info I rec'd but I am not an expert, just relaying what I was told by the tech rep for a well regarded company. Side clearances are for corner installations.My guess is that the heat can dissipate very easily at the corners & sides in a flat wall installation, whereas a corner prevents the heat from moving away as easily.
Of course, if your inspector disagrees like mine did, the only choice is to modify the installation or find a better inspector.

 

[begreen]

If the stud wall is drywall covered the paper on the drywall is considered combustible, even if the drywall is rated as a fire barrier.

 

[lilon]

Thanks to both. Yes, DougA, this was my question and I am happy to hear this about the flat wall. In the case of the side clearances, though, I think they will still hold in relation to any furniture that I might have wanted to place along the back wall closer than 600 mm to the heater.

Re the wall - one option was drywall. Another is to use cobbing to create a wall that is a thermal mass (cobbing?), but I haven't worked out yet if the trouble of building such a wall is worth the effort in terms of heat retention.

What I still don't know is if the side clearances of 600 mm mean that the hearth (floor) needs to extend 600mm on both sides. If not, does anyone know how wide the hearth needs to be for a Jotul 8dt?

thanks again.

 

[begreen]

I think you may need to drop the idea of 200mm rear clearance unless you put in an Australian code approved wall shield. Cobbing may or may not qualify. We can't say. You should download the manual for the 8TD from a dealer or from the GB site and meet with the local inspecting authority to see what is permissible. Based on this article it looks like AU may have similar requirements as here. If so, the cob wall would work, if it has a ventilated air space between it and the wall.

http://inspectapedia.com/chimneys/Fire_Clearance_WoodStove.htm#Shields

 

[DougA]

It should be 600 mm on each side as I read it for the Aus specs. You should have the full installation manual and if you have any questions or concerns, you really should contact Jotul to get the exact and legal info. I could not find an Aus. installation manual on line, which is odd.

I've got real rock veneer behind my stove that is about 1/2" thick, mortared to durock, which is a cement based board rather than a plaster based board. I did it for appearance and not for heat retention. The hottest I have measured the rock is 95, even though it is just over min distance from the stove and stove pipe. So, in my case, there is no heat to retain and even if it was hot, the mass is so little, it will be meaningless.

 

[begreen]

Doug, where did you find the AU spec?

 

[DougA]

http://www.subirest.com.au/_assets/...otul/subirest-heating-wood-jotul-brochure.pdf
page 11
Just basic info on a sales brochure.

Usually all this info is readily available. It seems the Aus. regulations are not country wide from what I gleaned in a quick look.

 

[begreen]

Thanks. That verified the 200mm rear clearance spec. This requires the rear heat shield on the stove. I think that must be the difference between the European docs and this spec.