Keystone Size

[Tscarborough]

Re: Keystone Size

What size is your inner arch opening?

[K79]

Re: Keystone Size

Not exactly sure yet, I don't know how I'm gong to build it. A complete arch or one like the image below. I'm leaning towards the one one in this image.

[Tscarborough]

Re: Keystone Size

Well, if you built that one, it would be 225.8 SqIn, so you would need a minimum of 33.87 SqIn of draw, and really more would be better unless you plan on a tall stack.

[K79]

Re: Keystone Size

I have 235sqin so if I go somewhere between 35 and 40 sqin for my vent opening I should be ok.

What are your thoughts on the arch itself? I was thinking of a 36" stack... too tall? I'ld love to be able to do it a little smaller.

[Tscarborough]

Re: Keystone Size

Then use an 8" round metal flue, that gives you 50.26 SqIn. 36" is a short stack, so the extra will help.

[K79]

Re: Keystone Size

I was trying to figure it out building it out of clay flue liner and brick. I couldn't find anyone local that had any ideas on how to run the 8" ss stack out the peak of the roof. Issues with the weather stripping and such. This and cost has pushed me towards the clay option. would 40 sq in work with a 36" stack?

[Tscarborough]

Re: Keystone Size

I do not understand the difference between piercing the roof with double wall pipe or masonry?

[K79]

Re: Keystone Size

I do not understand the difference between piercing the roof with double wall pipe or masonry?

I don't either... this is all new to me.

[kbartman]

Re: Keystone Size

Square/rectangular flues are measured o.d., while round ones are measured i.d., FYI.

8x8 is a common size for clay flue liners, with 30.58 SqIn of draw: 6.25 (i.d.)/2 gives a radius of 3.12, 3.1416x(3.12x3.12)=30.58. When calculating draw you draw the largest circle(s) that will fit in the area and use that dimension. The area of the flue should be around 15% of the size of the inner opening, and more is better up to a limit.

(the floor size doesn't really matter for draw)

Tscarborough,
Hope im note butting in I'm new to the furum. (More is better to a limit.) What is that limit? I'm thinking of using 8 x 17 flue on a 40 inch oven.
K79 been reading your build looks good.

[K79]

Re: Keystone Size

Tscarborough,
Hope im note butting in I'm new to the furum. (More is better to a limit.) What is that limit? I'm thinking of using 8 x 17 flue on a 40 inch oven.
K79 been reading your build looks good.

That seems like a lot. It'll be interesting to see what everyone thinks.

[Tscarborough]

Re: Keystone Size

Basically, the draw would be twice an 8x8, the floor size doesn't matter, what is the inner arch opening size?

They make the flashing for the double pipe penetration, the masonry chase is done with step flashing. In either case you probably want to offset it so that it penetrates a flat plane not the ridge. In my case I made it a shed roof for more protection in front and I didn't want to offset the flues.

[kbartman]

Re: Keystone Size

I limited to 8" on my depth and the 8" X 17" was one of standard flues stocked at the brick yard,the other were to small or to big. I thought it would work. Now I'm unsure

The other day Utahbeehiver was worried about highjacking someone's thread to answer one of my questions. Is this consider highjacking? Dont want to affend anyone. I need all the help I can get.

Thanks

[Tscarborough]

Re: Keystone Size

Up to the OP on the highjacking, some threads wander all over. That size should be OK, though.

[kbartman]

Re: Keystone Size

Thanks,
Tscarborough, OP?

[Tscarborough]

Re: Keystone Size

Original poster, the owner of the thread.