Chimney Height

[parryvt]

Getting ready to install a 2020 QuadraFire 4300 Millennium. Manual states the stove was tested for a 14'-16' tall chimney from the base of the stove. From the hearth to the top of the chimney is about 22'. Think it'll be good?

 

[DAKSY]

It may overdraft. You might have to install a stove pipe damper...

 

[parryvt]

It may overdraft. You might have to install a stove pipe damper...

Well, that's not the response I was expecting! Guess I'll give it a go and if a damper is needed... Thank you!

 

[begreen]

It may be ok. We have 20 ft and no issues. Try it out. A damper can be added if need be.

 

[parryvt]

It may be ok. We have 20 ft and no issues. Try it out. A damper can be added if need be.

Thanks! I've read that 2' can be deducted for every 90 deg. angle in the piping, so that would bring it down to 18'. That's pretty close. 14'-16' isn't very high. We'll see!

 

[begreen]

Thanks! I've read that 2' can be deducted for every 90 deg. angle in the piping, so that would bring it down to 18'. That's pretty close. 14'-16' isn't very high. We'll see!

If this is connected to an exterior chimney, then there are two 90º turns, one for the elbow and one for the tee. Is the exterior chimney metal or masonry?

 

[parryvt]

If this is connected to an exterior chimney, then there are two 90º turns, one for the elbow and one for the tee. Is the exterior chimney metal or masonry?

It's a stainless steel flexible liner inside a terra cotta lined flue.

 

[bholler]

It's a stainless steel flexible liner inside a terra cotta lined flue.

Yes but it makes a 90 at the bottom right? So 2 90s. Is the liner insulated?

 

[parryvt]

Yes but it makes a 90 at the bottom right? So 2 90s. Is the liner insulated?

Yes, two 90 degree angles. It's a work in progress, so not insulated yet. But it will be with pouring insulation. Everguard.

 

[bholler]

Yes, two 90 degree angles. It's a work in progress, so not insulated yet. But it will be with pouring insulation. Everguard.

Do you have room for the required 1" of everguard? Pour in actually requires allot more space than wrap.

 

[parryvt]

Do you have room for the required 1" of everguard? Pour in actually requires allot more space than wrap.

Just barely. Not concerned about proximity to combustibles. The chimney make up is square flue tile, chimney block, brick and concrete on all four sides. Might sacrifice a cleaning rod to use as a tamper to help the insulation down.

 

[bholler]

Just barely. Not concerned about proximity to combustibles. The chimney make up is square flue tile, chimney block, brick and concrete on all four sides. Might sacrifice a cleaning rod to use as a tamper to help the insulation down.

Do you have the required clearance from the outside of the chimney to any combustible material? Masonry structure transmits heat very well

 

[parryvt]

Do you have the required clearance from the outside of the chimney to any combustible material? Masonry structure transmits heat very well

It's 19" through the thimble. Even thicker on the sides.

 

[bholler]

It's 19" through the thimble. Even thicker on the sides.

Ok but do you have the required clearance from the outside of the masonry to combustibles?

 

[parryvt]

Ok but do you have the required clearance from the outside of the masonry to combustibles?

The bricks make direct contact with with the siding on the exterior and with paneling, sheetrock and flooring on the interior. 18" minimum away from the flue.

 

[MongoMongoson]

Attached is a snippet of a document bholler provided a link to in another thread about chimney clearances. He really is a wealth of knowledge. I guess that's why we pay sweeps.

I am attaching the snippet because I enjoy the commentary. It also might help clarify exactly what he is getting at. What bholler is talking about above is that the basic code states that it doesn't matter if your chimney is 4' of brick between the flue liner and combustibles that it touches. If it does not have the minimum clearance to combustibles, it violates code.

When he said that, I was wondering... How do we build a modern house like that? An interior chimney would have to be free standing with metal flashing up top where you have a roof penetration. The commentary in the snip I attached calls it "unbuildable". It also mentions that the basic code does not allow mass or thickness to compensate for clearance.

In your case, you need an insulated liner because you likely have combustibles touching your chimney. It is good to hear that you are installing one. That insulated liner only counts if you install it properly. If you don't have 1" clearance for the Everguard insulation to fill, it is not installed correctly. In that case your chimney is, as far as code and the insurance company are concerned, not insulated.

The entire document is located here: https://www.rumford.com/code/clearances.html#chimneys

 

[bholler]

Attached is a snippet of a document bholler provided a link to in another thread about chimney clearances. He really is a wealth of knowledge. I guess that's why we pay sweeps.

I am attaching the snippet because I enjoy the commentary. It also might help clarify exactly what he is getting at. What bholler is talking about above is that the basic code states that it doesn't matter if your chimney is 4' of brick between the flue liner and combustibles that it touches. If it does not have the minimum clearance to combustibles, it violates code.

When he said that, I was wondering... How do we build a modern house like that? An interior chimney would have to be free standing with metal flashing up top where you have a roof penetration. The commentary in the snip I attached calls it "unbuildable". It also mentions that the basic code does not allow mass or thickness to compensate for clearance.

In your case, you need an insulated liner because you likely have combustibles touching your chimney. It is good to hear that you are installing one. That insulated liner only counts if you install it properly. If you don't have 1" clearance for the Everguard insulation to fill, it is not installed correctly. In that case your chimney is, as far as code and the insurance company are concerned, not insulated.

The entire document is located here: https://www.rumford.com/code/clearances.html#chimneys

View attachment 280407

Thanks for posting that

 

[DeadTreeBurner]

Attached is a snippet of a document bholler provided a link to in another thread about chimney clearances. He really is a wealth of knowledge. I guess that's why we pay sweeps.

I am attaching the snippet because I enjoy the commentary. It also might help clarify exactly what he is getting at. What bholler is talking about above is that the basic code states that it doesn't matter if your chimney is 4' of brick between the flue liner and combustibles that it touches. If it does not have the minimum clearance to combustibles, it violates code.

When he said that, I was wondering... How do we build a modern house like that? An interior chimney would have to be free standing with metal flashing up top where you have a roof penetration. The commentary in the snip I attached calls it "unbuildable". It also mentions that the basic code does not allow mass or thickness to compensate for clearance.

In your case, you need an insulated liner because you likely have combustibles touching your chimney. It is good to hear that you are installing one. That insulated liner only counts if you install it properly. If you don't have 1" clearance for the Everguard insulation to fill, it is not installed correctly. In that case your chimney is, as far as code and the insurance company are concerned, not insulated.

The entire document is located here: https://www.rumford.com/code/clearances.html#chimneys

View attachment 280407

When did this code come into effect? Seems kinda nutty, but I could see potential trouble with a degraded masonry chimney. But definitely silly as far as I'm concerned if you're running even an uninsulated SS single wall liner in a masonry chimney in decent condition. Unless you have the SS liner jammed in there with serious surface area contact on the clay liner walls (impossible?), the amount of heat transfer to the clay/masonry is going to be insignificant, especially when that heat would have transfer through several inches of masonry to make it to a combustible and be anywhere close to that material's flash point.
The real question I have is what about the countless homes that were built prior to this code with masonry chimneys that violate this code, but are being used w/out a liner? Are they really that dangerous?

My house, two floors w/ a cinder block basement and built in '88 has a terracotta lined masonry chimney on the exterior and penetrates the roof through the soffit. I have no idea if there's an air gap between the chimney and exterior wall sheathing. No idea if there's an air gap between the clay liner and brickwork either. But I've not noticed any appreciable heat or warmth on the exterior brickwork of the chimney down low, back when I was using my Buck Model 81. Now in the basement where the clay thimble goes through the block wall, I've measured temps of up to 180 degrees right around the thimble if I remember correctly, but even this dissipates in a very short distance to just being warm within a foot. At the roof line there's no heat and I guess at the top of the liner, it is warmer than the cold air. Even if there's a chimney fire, how hot and how long would it need to burn to become an issue in a chimney in good repair? Creosote swells significantly when it burns, so it would seem that if there's enough creosote to really heat a chimney, the swelling ash would close the chimney and choke out the O2 and fire.

I obviously have limited to no experience with chimney fires, so what do I really know. Homes do burn from them, but I would expect the chimneys would be in poor condition. I know someone years ago that had the bright idea of building a hot fire in their fireplace to soften/liquify built up creosote built up over the previous season using a woodstove and lo and behold, it caught fire, the ash expanded exponentially closing off the flue resulting in smoke pouring into the house! lol Thankfully he was able to use a garden hose to put his wood fire out quickly, and the creosote fire smothered itself. Coulda been bad!
Anyway, that's my stream of consciousness ramblings...

 

[bholler]

When did this code come into effect? Seems kinda nutty, but I could see potential trouble with a degraded masonry chimney. But definitely silly as far as I'm concerned if you're running even an uninsulated SS single wall liner in a masonry chimney in decent condition. Unless you have the SS liner jammed in there with serious surface area contact on the clay liner walls (impossible?), the amount of heat transfer to the clay/masonry is going to be insignificant, especially when that heat would have transfer through several inches of masonry to make it to a combustible and be anywhere close to that material's flash point.
The real question I have is what about the countless homes that were built prior to this code with masonry chimneys that violate this code, but are being used w/out a liner? Are they really that dangerous?

My house, two floors w/ a cinder block basement and built in '88 has a terracotta lined masonry chimney on the exterior and penetrates the roof through the soffit. I have no idea if there's an air gap between the chimney and exterior wall sheathing. No idea if there's an air gap between the clay liner and brickwork either. But I've not noticed any appreciable heat or warmth on the exterior brickwork of the chimney down low, back when I was using my Buck Model 81. Now in the basement where the clay thimble goes through the block wall, I've measured temps of up to 180 degrees right around the thimble if I remember correctly, but even this dissipates in a very short distance to just being warm within a foot. At the roof line there's no heat and I guess at the top of the liner, it is warmer than the cold air. Even if there's a chimney fire, how hot and how long would it need to burn to become an issue in a chimney in good repair? Creosote swells significantly when it burns, so it would seem that if there's enough creosote to really heat a chimney, the swelling ash would close the chimney and choke out the O2 and fire.

I obviously have limited to no experience with chimney fires, so what do I really know. Homes do burn from them, but I would expect the chimneys would be in poor condition. I know someone years ago that had the bright idea of building a hot fire in their fireplace to soften/liquify built up creosote built up over the previous season using a woodstove and lo and behold, it caught fire, the ash expanded exponentially closing off the flue resulting in smoke pouring into the house! lol Thankfully he was able to use a garden hose to put his wood fire out quickly, and the creosote fire smothered itself. Coulda been bad!
Anyway, that's my stream of consciousness ramblings...

It came into effect in the mid to late 80s. It was introduced into code because of many fires caused by heat transfer through the masonry. It happens after years of the wood being heated and pyrolized lowering it's kindling point.

 

[parryvt]

It came into effect in the mid to late 80s. It was introduced into code because of many fires caused by heat transfer through the masonry. It happens after years of the wood being heated and pyrolized lowering it's kindling point.

Looks like I'll have to re-evaluate this project. By trying to come into code it seems I'm possibly putting myself out of compliance. Pre-insulated, wrap, and poured are the only options acceptable, correct?

 

[bholler]

Looks like I'll have to re-evaluate this project. By trying to come into code it seems I'm possibly putting myself out of compliance. Pre-insulated, wrap, and poured are the only options acceptable, correct?

Unless you have the required clearances yes you need proper insulation on the liner

 

[DeadTreeBurner]

Looks like I'll have to re-evaluate this project. By trying to come into code it seems I'm possibly putting myself out of compliance. Pre-insulated, wrap, and poured are the only options acceptable, correct?

Is your SS liner single wall? Or double ply smooth wall? There are double ply smooth wall liners that are tested and approved to UL1777 zero clearance standards. I just bought one, 6" x 30' in a kit for just under $500.

 

[bholler]

Is your SS liner single wall? Or double ply smooth wall? There are double ply smooth wall liners that are tested and approved to UL1777 zero clearance standards. I just bought one, 6" x 30' in a kit for just under $500.

Only if they are double wall insulated. Most are ul1777 listed some even say listed for zero clearance. But if you read the actual listing data it is only listed for zero clearance if it is properly insulated.

 

[DeadTreeBurner]

Only if they are double wall insulated. Most are ul1777 listed some even say listed for zero clearance. But if you read the actual listing data it is only listed for zero clearance if it is properly insulated.

Hmm, I only see it's rated for zero clearance, no qualifications. This actually is the manufacturer, Forever Vent. Seems like they left this important piece of info out...

FOREVER® VENT 6 INCH DIAMETER SMOOTHWALL STAINLESS STEEL CHIMNEY LINER KITS | eBay

SmoothWall Double Ply. Stainless Steel Chimney Liner Kits. A section of Flex-All Double Ply. 012 316L Stainless Steel Chimney Liner. FOREVER® VENT. Tested and approved to UL1777 zero clearance standards .

www.ebay.com

 

[bholler]

Hmm, I only see it's rated for zero clearance, no qualifications. This actually is the manufacturer, Forever Vent. Seems like they left this important piece of info out...

FOREVER® VENT 6 INCH DIAMETER SMOOTHWALL STAINLESS STEEL CHIMNEY LINER KITS | eBay

SmoothWall Double Ply. Stainless Steel Chimney Liner Kits. A section of Flex-All Double Ply. 012 316L Stainless Steel Chimney Liner. FOREVER® VENT. Tested and approved to UL1777 zero clearance standards .

www.ebay.com

What does the included listing info say? What does the installation instructions say about it?