Why double walled chimney pipe?

[Dan94550]

I've got most of my framing done around the oven and getting ready to start on the roof. I have an 8" diameter steel pipe with a damper that came with the oven and was planning to extend it with double walled pipe and spark arrestor. Looking at the dimensions of the double walled pipe and allowing for clearance, it seems to me that it will look a little oversized (too wide) for the look I was going for.

Is there a reason why regular single walled pipe can't be used? Are steel studs and HB considered combustables?

[james]

Re: Why double walled chimney pipe?

Hi Dan,

As long as you are doing to insulate around your single wall pipe, and of course set it back from combustibles, you can use single wall steel pipe. Metal studs and HB are not combustible, though you will want to build an enclosure around the pipe and insulate it.

In fact, the Casa and Premio vent pieces are designed to take single wall pipe (in cm's not inches), without an adapter.

The advantage of the double wall pipe is that all the insulating work is done for you. It's easy to just snap it all together, and know that it is UL approved and that is will stay hot on the inside (which keeps it clean and drawing well) and cool on the outside. That said, it is more expensive.

Hope this helps.
James

[Dan94550]

Re: Why double walled chimney pipe?

Thanks James,

I realize the benefits of the double walled pipe, but esthetically it just seems too wide. I'll try drawing it up with a chase around it (although it will be wider), it may look ok.

Cheers,
Dan

[sarah h]

Re: Why double walled chimney pipe?

Can anyone tell me - If I used single-walled pipe, what kind and depth of insulation would I need in order to brick in around it?

Sarah

[dmun]

Re: Why double walled chimney pipe?

I would think that an inch of insulating blanket, or two inches of vermiculite concrete would be about right. Remember, single wall pipe is for freestanding ovens only. Code won't allow it for use in structures.