Maybe bottom block off plates aren't always a good thing ...

[bholler]

Fuel type isn't what they were talking about. They tested a wood application with insulation and no insulation. They then provided some data and a graph that showed the performance of insulated vs. not insulated in a zero clearance install...basically showing why you need to insulate in a zero clearance install.

Ok I missed that part but they only say they tested it at the normal hight temperate run at 1000 it says nothing about the test at 2100 which is required to get ul listed for solid fuel liners.

1003.18...that's what defines the clearance requirements, doesn't it?

Yes absolutly

Let me ask a dumb question in regards to 1003.11. An approved lining material is clay. Is clay UL 1777 listed?

No but it has to conform to ASTM C 315 As required by that code. But number 2 says listed and labeled chimney liner system complying with ul 1777. Now I have repeatedly read the entire ul 1777 standard and I don't see any part of it where there is a way to certify a liner for use with solid fuel without insulation. If you can find that I will gladly admit I am wrong. But I am 99% sure it is not there. And I have been taught through csia classes the same thing.

you are trying to convince us that insulation is required all the time and it's not looking to be true.

Like I said show me the listing for that and I will gladly admit I am wrong. It is absolutely possible I missed it.

 

[bholler]

And I am done with this discussion until one of you can show me where in ul 1777 it says a liner can be listed for use with solid fuel with out insulation. We are getting no where and just saying the same things over and over and it is pointless.

 

[Highbeam]

Rather than finding where something is not required, you need to show us that it is required. I could say the same thing for pink poka dot painted liners. Show me where it says that pink poka dot paint is not required. Or maybe unicorn dust.

So until you can show us where insulation is required, then it is not required.

 

[bholler]

Liners are required to be installed according to their listing correct?

Absolutely everything I have read from UL and from reputable liner manufacturers says liners need to be insulated to maintain their UL listing. So that is why I am saying it is required by code. So again show me the UL listing for a liner for solid fuel without insulation.

 

[Highbeam]

You're right, back in circles we go. You are asking us to prove a negative. Instead, the truth is that IF your specific liner requires insulation for your specific installation then you have to use the specified insulation to maintain the UL listing. You then go on to ASSUME that all liners require insulation for all solid fuel installations which is a huge leap.

We might be saying the same thing with the exception that you assume all liners require insulation for all solid fuel installations and we don't. So we're not that far apart. How about a classic RTFM? That's what we're all saying in the end.

 

[bholler]

RTFM

What does that mean? Never heard that.

You then go on to ASSUME that all liners require insulation for all solid fuel installations which is a huge leap.

I am not assuming anything. I am connecting the dots between the codes and listings.

 

[Highbeam]

What does that mean? Never heard that.


I am not assuming anything. I am connecting the dots between the codes and listings.

Read The F'n Manual. If it says you must insulate then you must. That's a big IF though.

And yes you are absolutely assuming that all liners require this in their installation manuals. We know it's not true.

Here's one of many threads where at least three hearth.com staff members agree that insulation is not required.

https://www.hearth.com/talk/threads...nsulate-liner-is-a-reducer-a-bad-idea.124124/

 

[bholler]

And yes you are absolutely assuming that all liners require this in their installation manuals

Nope never said they all said it in their manuals I know for a fact many don't. That does not mean that they are ul listed to be used for solid fuel without insulation.

Here's one of many threads where at least three hearth.com staff members agree that insulation is not required.

I respect the guys on hearth.com but they have been wrong before I trust the csia instructors the olympia engineers and the copperfield engineers who have told me this over the word of the guys here I am sorry if that offends anyone. But those are people who do this every day for a living and do lots of research on the subject as part of their jobs. I am taking their word for it. Have you ever read the full ul 1777 standard? Have you ever seen one of these tests conducted? Have you ever talked with liner manufacturers about this?

 

[iluvjazznjava]

That is the crux of the issue. Uninsulated is ok in a completely compliant, tile-lined masonry chimney system, even if uninsulated is not ideal for draft improvement or creosote reduction. The problem is, how many masonry chimneys have code correct spacing from any combustibles? - very few, and that is the rub.

My chimney is completely compliant according to the WETT inspection I got a couple years ago. There was a proper gap between the clay tile liner and the surrounding brick (min 1" I believe). There was also proper clearances between the chimney and the house. I have no safety concerns with my uninsulated liner because of this.

Besides, if there was a problem, I'm pretty sure my house would have been ashes by now. My significant other lit up a full load in the stove one afternoon and then went shopping for a few hours and forgot about it (another potential downside to a basement stove). When I arrived home from work the stove temp was well above 700 (the thermometer had maxed out and the temperature markings on it had even browned due to the heat!) and the stove pipe was glowing red. She is new to wood burning, but now I know the abuse that my setup can take (but I don't intend to repeat it).

I do get a bit of creosote in my liner, but nothing too bad. I got about 1/2 a coffee can of powdery creosote from about 2 chords of burning (my typical winter). There was a bit of glaze in the top two feed of the chimney where it sticks out above the masonry chimney. I think annual cleanings with my typical use will keep my flue sufficiently clean.

 

[branchburner]

Besides, if there was a problem, I'm pretty sure my house would have been ashes by now.

I'm sure your setup is safe, and the fact that you produce little creosote is great. It means you are unlikely to have a chimney fire, and I think THAT is the real danger that the code most seriously addresses. The incident you described might result in a pretty hot flue, but NOT hot like the hot of an actual chimney fire.

 

[iluvjazznjava]

I'm sure your setup is safe, and the fact that you produce little creosote is great. It means you are unlikely to have a chimney fire, and I think THAT is the real danger that the code most seriously addresses. The incident you described might result in a pretty hot flue, but NOT hot like the hot of an actual chimney fire.

Agreed - and I think we can all agreed that no install or setup is ever 100% safe in the event of a chimney fire. However, having everything up to spec and code I'm sure gives a much better chance of coming out unscathed in the end.

 

[iluvjazznjava]

The discussion on this thread has been fascinating, and frankly beyond my expertise and knowledge.

I stopped by my stove shop to see what kind of liner they had installed for me and they pulled out the paperwork from the install and confirmed that it was an EXCELiner. It is actually mostly rigid wall pipe, with a section of flex liner at the bottom that was used to get through the smoke shelf area of the chimney. They were also kind enough to pull out a copy of the install instructions and talk me through the requirements for clearances and insulation regarding the install.

A copy of the manual can be found at this link:

(broken link removed to http://icc-chimney.com/c/icc/file_db/docs_document.file_en/L-II-A_2015-08.pdf)

I think the chart on page 5 clarifies things quite nicely - in the US and Canada this chimney liner can be installed uninsulated in a masonry chimney. Of course, insulation can be used on the liner, but it is abundantly clear to me that its not required to meet ULC and UL standards.

 

[Highbeam]

Yeah, I figured as much. Good to know you installed it right!

 

[begreen]

Thanks for posting. Seems self-explanatory. It depends on the clearance of the masonry chimney to combustibles. Looks like the Canadian standard is a little tougher - 2" for exterior chimney.



The footnote is interesting:

 

[yooper08]

I think it's pretty clear. Many installation manuals have these requirements detailed for insulated vs no insulation (as I've tried to point out). As the manufacturer and their engineers have to submit their product to UL for testing (and are visited by UL, probably consulted by UL as well), I imagine they understand the requirements pretty well.

Here's the problem if the manufacturers are wrong. If they're wrong about not requiring insulation and there's a fire that takes down a house, the insurance company can potentially go after them to recoup their payout. I doubt lawyers for virtually the entire industry would've missed that.

Also, fun fact. A 4" masonry chimney with the code required 2" airspace wouldn't meet UL 1777 approval in the 8 hr 1000*F flue gas test. Combustibles with that gap can reach above 90*F above ambient. Despite chimneys meeting code, insulate anyway (best practice.....as always).

 

[bholler]

Here's the problem if the manufacturers are wrong. If they're wrong about not requiring insulation and there's a fire that takes down a house, the insurance company can potentially go after them to recoup their payout. I doubt lawyers for virtually the entire industry would've missed that.

No they all have disclaimers about the need to follow all applicable codes so if you don't follow the code with your install then you are out of luck it is not their problem.

I am also curious how in that table they can ignore the requirement of 2" for internal chimneys with no insulation and why there is no mention of fuel used when referencing clearances. Insulation is not required on any liner servicing oil or gas by code.

And again regardless of code an insulated liner will always be safer and work better. As evidenced by your performance issues with your uninsulated liner.

And by the way how were you able to confirm that you have proper clearance to combustibles the entire length of the chimney? Is the chimney freestanding?

 

[iluvjazznjava]

And by the way how were you able to confirm that you have proper clearance to combustibles the entire length of the chimney? Is the chimney freestanding?

Well I didn't ... but the WETT inspector did. He spent a lot of time checking everything and he has no reason to lie. The chimney is essentially freestanding outside the house - only one side of it is along the house.

I do remember the WETT inspector saying that the chimney was relatively new (<20 yrs) compared to the rest of the house (originally built 1924) and that it appeared to have been professionally built.

 

[bholler]

Well I didn't ... but the WETT inspector did. He spent a lot of time checking everything and he has no reason to lie. The chimney is essentially freestanding outside the house - only one side of it is along the house.

I am not saying he lied or even that he was wrong. But In all my years of inspecting chimneys I have found very few that proper clearances could be confirmed. Like I said I don't know Canadian code but here in your situation you would need 1" from the outside of that chimney to any combustible material I think yours may be 1/2" for exterior by what that table said. But then again they were wrong on the American code so I don't know if I trust it. . The only spot combustibles can touch is 1" in on the corners for trim. Otherwise you need space. And unless he removed that trim there is no way he confirmed proper clearance. As far as it being professionally built most are and most do not have clearances. The fact is I have talked to many masons about it and very few even knew they needed any clearance.

 

[ccmac]

That's true about some masons not knowing the requirements about clearances. I was surprised how little my mason knew. He didn't have a clue about chimney size as it relates to wood stoves. How it affected draft, how much intake air my fireplace would need. He basically knew how to construct a really big beautiful fireplace and chimney. No real clue what affected it's performance.

 

[iluvjazznjava]

I am not saying he lied or even that he was wrong. But In all my years of inspecting chimneys I have found very few that proper clearances could be confirmed. Like I said I don't know Canadian code but here in your situation you would need 1" from the outside of that chimney to any combustible material I think yours may be 1/2" for exterior by what that table said. But then again they were wrong on the American code so I don't know if I trust it. . The only spot combustibles can touch is 1" in on the corners for trim. Otherwise you need space. And unless he removed that trim there is no way he confirmed proper clearance. As far as it being professionally built most are and most do not have clearances. The fact is I have talked to many masons about it and very few even knew they needed any clearance.

Well there is a metal flashing on the top of the roof where it meets the chimney - because there is a gap between the chimney and the roof. The hardee board siding comes pretty close to the chimney on the sides (1/4 - 1/2" I would say), but I'm not worried about that since hardee board is very thin (1/8") and has at least a 1 hour fire rating. Behind the hardee board is old stucco - also not flammable. There was a gap between the roof rafters and the chimney. I remember this from when I redid the insulation in my attic. This was around the time of the WETT inspection and the inspector did go into the atic to take a look. He also removed some of the metal flashing in the roof to take a look up there too.

 

[bholler]

Well there is a metal flashing on the top of the roof where it meets the chimney - because there is a gap between the chimney and the roof.

That is good most do not have that.

The hardee board siding comes pretty close to the chimney on the sides (1/4 - 1/2" I would say), but I'm not worried about that since hardee board is very thin (1/8") and has at least a 1 hour fire rating.

It can touch on the corners so that would not be an issue here atleast

Behind the hardee board is old stucco - also not flammable.

To meet code here you would need the air gap in there somewhere. If that stucco is touching it would just be a continuation of the masonry.


From what you say your inspector did allot more than any do here so there is a decent chance you do have required clearances. Which would mean no safety issues. But you are still having performance issues which would be helped by insulation.