Heat shield and wall design.

[Kali's Revenge]

This my second post on a first purchase of a wood stove oven, Nectre N350.

We intend to install the stove in front of an unused door leading outside. I intend to take out the door and rebuild a wall that will be behind the stove. Rebuilding the wall the gives me the opportunity to build the wall to confirm to the requirements suggested by the manufacturer.

We are in Japan, so I am taking information from both the North American literature as well as the Japanese literature. Requirements are not that different, so I am attempting to incorporate both requirements.

We will be using 6" double wall insulated pipe.

The Japanese literature (PDF with English notes included) states that I can maintain a small clearance (85 mm or 3 3/8" ) to a wall with heat shield and noncombustible finishes with a 1" air gap (bottom row of the Wall specification column).

It seems that the North American literature does not list any clearances using a heat shield and air gap.

We are looking at this product for a heat shield:

DIXNEUF heat shield

Which states that the material is calcium silicate and steel. The installation comes with standoffs for a 1" air gap.

As for the construction of the wall, I intend to use 2 x 6 studs to match adjacent wall construction with an interior panel of 1/2" calcium silicate board instead of drywall.

So, from inside to outside:

[Steel heat/ calcium silicate shield] -> [1" gap] -> [1/2" calcium silicate board] -> [fiberglass insulation] -> etc.



We have no problem with clearances from the sides of the stove.

Am I missing something critical about this design?

Thanks in advance for any comments, criticisms, recommendations.

 

[begreen]

The most important details are the 1" spacing behind the shield and the wall shield must be at least 1" off the floor or baseboard and open at the top. This is so that air can enter at the bottom and freely convect behind the shield, then exit at the top.

 

[begreen]

I don't read Japanese except via Google, but it looks like the rear distance is 125mm for double-wall stove pipe with a shield. Google is giving me an odd translation for the second, 85mm case. It says double-straight cylinder shield mounting which sounds like some kind of stove pipe shielding added. Verify with Nectar or to be safe, stick with the 125 mm clearance with the wall shield.

 

[TomMcDonald]

They could be referring to a set up like pictured, which is very popular in Australia where this stove is manufactured.
The single wall pipe has a stainless shield attached to the rear, sometimes doubled up.

 

[begreen]

They could be referring to a set up like pictured, which is very popular in Australia where this stove is manufactured.
The single wall pipe has a stainless shield attached to the rear, sometimes doubled up.

View attachment 309072

That was my thought too, but I have never seen a shield like that put on double-wall stove pipe, only single wall here which reduces the single-wall clearance to 6" with the shield attached on spacers.

 

[Kali's Revenge]

I don't read Japanese except via Google, but it looks like the rear distance is 125mm for double-wall stove pipe with a shield. Google is giving me an odd translation for the second, 85mm case. It says double-straight cylinder shield mounting which sounds like some kind of stove pipe shielding added. Verify with Nectar or to be safe, stick with the 125 mm clearance with the wall shield.

Hi,

I appreciate the comments.

That was my thought too, but I have never seen a shield like that put on double-wall stove pipe, only single wall here which reduces the single-wall clearance to 6" with the shield attached on spacers.

I agree. The specification is a bit ambiguous. The contractor will be here in a few days and I will confirm that with him.

From what I read and understand. (Google is terrible, use DeepL.):

The second to last row (125mm) reads:
Combustible walls + noncombustible finishes with no air gap.

The last row (85mm) is:
Combustible walls + heat shields and other non-combustible materials with an 25 mm air gap (which I am thinking for the back wall construction).

On the plan, to the left of the stove, it reads:
Noncombustible heat shields, etc.
25 mm air space

Both rows refer to a double walled pipe with a "shield". So, the real difference from 85 mm to 125 mm is if there is an air gap behind the heat shield/wall, as the "shield" for the pipe requirement is the same.

Searching in the Japanese catalogs, the only shields that are available are specified for single walled pipes.

So, the question which I think I need to confirm with the contractor is what they mean by "double walled pipe shield attached".

I will get back to you with the information I get from the contractor.

 

[TomMcDonald]

Hi,

I appreciate the comments.



I agree. The specification is a bit ambiguous. The contractor will be here in a few days and I will confirm that with him.

From what I read and understand. (Google is terrible, use DeepL.):

The second to last row (125mm) reads:
Combustible walls + noncombustible finishes with no air gap.

The last row (85mm) is:
Combustible walls + heat shields and other non-combustible materials with an 25 mm air gap (which I am thinking for the back wall construction).

On the plan, to the left of the stove, it reads:
Noncombustible heat shields, etc.
25 mm air space

Both rows refer to a double walled pipe with a "shield". So, the real difference from 85 mm to 125 mm is if there is an air gap behind the heat shield/wall, as the "shield" for the pipe requirement is the same.

Searching in the Japanese catalogs, the only shields that are available are specified for single walled pipes.

So, the question which I think I need to confirm with the contractor is what they mean by "double walled pipe shield attached".

I will get back to you with the information I get from the contractor.

Some single wall heat shields are supplied with 2 shields, as in this link from NZ.

https://www.mitre10.co.nz/shop/pioneer-double-flue-shield/p/280193