NO ONE KNOWS????? ANY INSTALLERS?????: Is the 2" Air Clearance Between Chimney Air Kit to Framing

[njkev]

Hi all,
I am in the process of framing my ZC Heatilator Constitution wood-burning fireplace just installed late last week. I made a new header placed across the stand-offs of the unit as instructed by the manual. However, I measure 1 1/2 inches clearance between the header and the (square) chimney air kit (for outside air) where the chimney pipe connects at the top of the unit. Is this an issue? If so, what can I do to resolve it?

Note, the clearance I measured between this header (including any vertical studs connected above header) to the actual chimney pipe protruding from the chimney air kit is no less than a 2 1/4 inches. The manual states that 2 inches between combustibles and chimney sections must be adhered to.

Any professional advice is appreciated,

Kevin

 

[njkev]

Some help please?? There must be an installer on this forum that knows what I am talking about......

 

[Hogwildz]

I am not a professional installer.
What type of pipe are you using for the chimney?

 

[njkev]

I am using the required SL300 double-wall 2100 deg. F pipe. I know that 2" is required from chimney section to any combustible. The question is, Is the 2" rule applicable also to the chimney air kit.....or just the pipe protruding from it?

 

[njkev]

Any advice? Any professional installers on here??

 

[njkev]

Thanks for all of your help everyone! Loads of advice for everyone! LOL

 

[Shane]

You don't have to be a jerk. Do you have the instructions that came with the air kit? Looking through the manual I would assume that the clearance stated is acceptable. Without seeing the instructions for the air kit I would do one of three things 1.) Assume the clearance is acceptable since the air kit is technically not a piece of chimney and that the clearance to actual chimney is maintained. 2.) notch my header or 3.) Call heatilator tech support and confirm whether action one or two is appropriate. If you can post the verbage or actual instructions that came with the air kit I might be a little more help.

 

[BJ64]

Hi all,
I am in the process of framing my ZC Heatilator Constitution wood-burning fireplace just installed late last week. I made a new header placed across the stand-offs of the unit as instructed by the manual. However, I measure 1 1/2 inches clearance between the header and the (square) chimney air kit (for outside air) where the chimney pipe connects at the top of the unit. Is this an issue? If so, what can I do to resolve it?

Note, the clearance I measured between this header (including any vertical studs connected above header) to the actual chimney pipe protruding from the chimney air kit is no less than a 2 1/4 inches. The manual states that 2 inches between combustibles and chimney sections must be adhered to.

Any professional advice is appreciated,

Kevin

Hang on sir,

We always like to help but we are a bit confused by the terms used and we like to see pictures in some cases. The term "outside chimney air" has me messed up since I don't know what that could be. Perhaps you may have meant "outside combustion air". If so we may have some ideas to help you with. The manual may be a clue. Usually if something needs clearance to combustables the writer tries to make it very clear. Chances are if the writers left that "2-inch" phrase out in the section you are working on then you probably don't need it. I think you are being quite correct for wanting to know for sure. Positive conformation is always a good thing and I applaud you for asking the question.

As for an "outside combustion air kit" (sometimes known as OAK on this forum) I am not aware of any need for for clearance to combustables.

Scratch that. I can tell that I was wrong about the OAK thing.

Could you be talking about the clearance to the outer wall of a double wall chimney pipe?

 

[fossil]

I'm not an installer, either. I just read through your installation manual here:

(broken link removed)

The way I read it, the "Chimney Air Kit" is a way to provide some sort of ventilation air for the proprietary chimney system, and the actual section of chimney pipe passes through the big hole in the center of that thing. I'd say the 2" required clearance to combustibles is from the outside wall of the chimney pipe itself, not this adapter bracket/kit thing. Read the book, call tech support, whatever...just STOP SCREAMING AT US HERE!. %-P Rick

 

[njkev]

BJ64 and FOSSIL.....I appreciate your responses. And SHANE, I did not mean to be "a jerk" as you had elected to label me. The "name calling" is a bit childish....ya think? I was simply frustrated that so many people were READING but providing NO advice whatsoever. If my description of the problem was confusing, simply STATING THAT FACT as a post here would have been helpful in itself! I would have gladly provided more information.

I took a photo of the area in question. Yes....I should have provided it sooner!!

The manual states nothing whatsoever with regard to clearance of combustibles to the OAK (Outside Air Kit) I did in fact e-mail Heatilator earlier today as I not getting any advice here (until just recently). The official Heatilator response was that it is NOT considered part of the chimney section, and can be less than 2". However, they suggested that I could "turn" my dual 2x4 header 90 degrees to increase the distance by another 1/2", or just simply notch out a section if it gives me "peace-of-mind". Of course, the minimum of 2" must be observed to combustibles to the pipe that is centered in the OAK; I have 2 1/4" clearance. I will likely just notch out 1/2" on the header to increase the clearance from the header to pipe for the hell of it. BTW....At all other points in my chimney setup I have over 4" clearance.

I was told by someone (in the industry) that the 2" clearance is REALLY just an arbitrary distance, and that even a 1/2" clearance is fine. He stated "If your combustible will burn at 1/2", it will sure as hell burn at 2" too!" He went on to say that the clearances are simply stated to MAKE SURE somebody doesn't just box the flue in too tightly that it "touches" the combustibles. (Yes....of course the clearance also allows for air flow.)

Thanks again,
Kevin

 

[begreen]

Can you describe what the picture is and it's location relative to the fireplace? I suspect you are fine, an OAK normally does not get hot. But it's good to understand exactly what the concern is.

As to the friend in the industry, from what you've described, I'd say he's full of it. You'd do well to ignore him.

 

[fossil]

I don't think we're talking about an OAK here, I think we're talking about some sort of air-cooled chimney system...nothing to do with combustion air. At least, that's what I think I'm reading in the installation manual:

(broken link removed)

If I'm reading all that correctly, and seeing what I think I'm seeing in the pic, then I think this stuff is all well above the appliance somewhere and everything's prob'ly OK with that detail. I also agree with BG that the guy who spouted the drivel about how clearances aren't really "clearances" and can be ignored or fudged oughta just keep his mouth shut. Rick

 

[njkev]

Can you describe what the picture is and it's location relative to the fireplace? I suspect you are fine, an OAK normally does not get hot. But it's good to understand exactly what the concern is.

As to the friend in the industry, from what you've described, I'd say he's full of it. You'd do well to ignore him.

That photo is looking down onto the clearance area between the header and the OAK. The OAK is right on top of the fireplace. The flue is coming right up out of the OAK. The clearance from header to OAK is 1 1/2". The clearance from flue to header is 2 1/4".

 

[njkev]

I don't think we're talking about an OAK here, I think we're talking about some sort of air-cooled chimney system...nothing to do with combustion air. At least, that's what I think I'm reading in the installation manual:

(broken link removed)

If I'm reading all that correctly, and seeing what I think I'm seeing in the pic, then I think this stuff is all well above the appliance somewhere and everything's prob'ly OK with that detail. I also agree with BG that the guy who spouted the drivel about how clearances aren't really "clearances" and can be ignored or fudged oughta just keep his mouth shut. Rick

Yes...you are correct. The lower flex pipe is the combustion air intake. The upper is for chimney airflow. Photo attached (taken before header and studs added.) It is hard to see the "air kit" on top of the unit because I had the manual set in front of it in the photo. You can see both flex pipes on the right side though.

Honestly though, you can't honestly tell me that if a combustible were placed at 1" it WOULD burn...and that at 2" it WOULD NOT. I believe that you can't ever be TOO SAFE, otherwise I wouldn't be here posting my concerns. However, I am an engineer, and have reasonable understanding of how to interpret specifications. I personally believe that if a combustible had any chance of burning at 1", they would specify like a 6" to 8" clearance! I thinks it is more plausible that the 2" clearance simply reduces the possibility of combustibles (i.e. loose paper on sheet-rock/fiberglass) ever touching the pipe.

 

[begreen]

I believe the air space is to reduce the risk of pyrolysis, not combustion of debris. It's directed and assumed the area is debris free.

 

[RocketMan]

I would be more concerned with the lack of drywall in the chase to retain the insulation.

 

[njkev]

I would be more concerned with the lack of drywall in the chase to retain the insulation.

Correct me if I am wrong......but I don't believe there is any requirement for drywall in the chase. The insulation is not loose as the (combustible) paper side of the insulation is stapled to the studs. The "glass" portion of the insulation certainly won't burn even if that were to ever touch the flue. The pipe is the required double-walled SL300, and I am told it actually remains reasonably cool to the touch. The fireplace is a ZC, but the manual does require 1" clearance (for air flow) around the back and sides of the galvanized steel box. I have ~ 1" in the back and about 18" on the sides. I will certainly consider using a few of those steel insulation securing rods after I staple the insulation up between the studs above the fireplace before sheet rocking, for added safety.

 

[begreen]

I would use unfaced (non-paper backed) insulation.

Sheetrock may not be required, but is recommended.

"Additionally, Hearth & Home Technologies recommends that the inside surfaces be sheet rocked and taped (or the use of an equivalent method) for maximum air tightness."

 

[BJ64]

I think you will be OK. I don't want to degrade your install by comparing it to a trailer house install but there is some similarities to support this conclusion.

The double wall non insulated chimney pipe is used in pre-fab home applications. I have noticed that there is usually at least 3 or 4-inches of clearance about the chimney pipe. The air flow between the inner and outer pipe is sometimes supplied by and out side air kit. That outside air supply line (if used) is always strapped to the wall with cheap plastic banding.

I do have one question. Is the wall behind the fireplace an interior or exterior wall? I suspect that the wall behind the fireplace is not an exterior wall because the fiberglass insulation appears to be backwards for that usage. For the benefit of other readers; normally the paper side of the insulation faces the interior of the house. I was just wondering.

 

[njkev]

I think you will be OK. I don't want to degrade your install by comparing it to a trailer house install but there is some similarities to support this conclusion.

The double wall non insulated chimney pipe is used in pre-fab home applications. I have noticed that there is usually at least 3 or 4-inches of clearance about the chimney pipe. The air flow between the inner and outer pipe is sometimes supplied by and out side air kit. That outside air supply line (if used) is always strapped to the wall with cheap plastic banding.

I do have one question. Is the wall behind the fireplace an interior or exterior wall? I suspect that the wall behind the fireplace is not an exterior wall because the fiberglass insulation appears to be backwards for that usage. For the benefit of other readers; normally the paper side of the insulation faces the interior of the house. I was just wondering.

My house is "stick" construction NOT "pre-fab". The SL300 pipe was REQUIRED for this unit as a complete system. I do have an exterior chase. The wall behind is an exterior wall. You know....I did not pick up on that fact until you just mentioned it....you are right about the insulation being backwards. The face of the glass insulation is not going to burn. In fact, the original (low-efficiency) ZC fireplace was in that chase for 10 years without any issue! I do propose to add the insulation (wire) rods between the studs from the fire-stop down to the top of the unit on the back wall as a safety measure to prevent the insulation from ever sagging down on top of the unit. Obviously, I can't get down lower behind that unit!

I have an additional question though: The interior wall originally had insulation above the fireplace between the studs. Is it OK to put it back, or better off not?

 

[Shane]

And SHANE, I did not mean to be "a jerk" as you had elected to label me. The "name calling" is a bit childish....ya think? I was simply frustrated that so many people were READING but providing NO advice whatsoever. If my description of the problem was confusing, simply STATING THAT FACT as a post here would have been helpful in itself! I would have gladly provided more information.

I was told by someone (in the industry) that the 2" clearance is REALLY just an arbitrary distance, and that even a 1/2" clearance is fine. He stated "If your combustible will burn at 1/2", it will sure as hell burn at 2" too!" He went on to say that the clearances are simply stated to MAKE SURE somebody doesn't just box the flue in too tightly that it "touches" the combustibles. (Yes....of course the clearance also allows for air flow.)

Thanks again,
Kevin

About as childish as throwing a fit because your post wasn't answered according to your time table. Your description wasn't confusing at all, I answered your question with almost the same response you got from Heatilator. I apologize for trying to help you, I'll refrain from offending you with answers in the future.

 

[njkev]

And SHANE, I did not mean to be "a jerk" as you had elected to label me. The "name calling" is a bit childish....ya think? I was simply frustrated that so many people were READING but providing NO advice whatsoever. If my description of the problem was confusing, simply STATING THAT FACT as a post here would have been helpful in itself! I would have gladly provided more information.

I was told by someone (in the industry) that the 2" clearance is REALLY just an arbitrary distance, and that even a 1/2" clearance is fine. He stated "If your combustible will burn at 1/2", it will sure as hell burn at 2" too!" He went on to say that the clearances are simply stated to MAKE SURE somebody doesn't just box the flue in too tightly that it "touches" the combustibles. (Yes....of course the clearance also allows for air flow.)

Thanks again,
Kevin

About as childish as throwing a fit because your post wasn't answered according to your time table. Your description wasn't confusing at all, I answered your question with almost the same response you got from Heatilator. I apologize for trying to help you, I'll refrain from offending you with answers in the future.

I apologize SHANE. I was simply frustrated at seeing 100+ reads and not a single shred of advice. Yes...you did give the exact same advice as Heatilator, and I appreciate you taking the time to answer my post; at least you DID respond! Again....I am sorry.
Kev

 

[Shane]

I apologize for calling you a jerk. I hope you enjoy your new fireplace it looks like a nice unit!

 

[njkev]

I apologize for calling you a jerk. I hope you enjoy your new fireplace it looks like a nice unit!

Hi Shane,
Thanks! I am dying to fire it up! I still have lots more work before I get there though! :-( BTW....I would really appreciate any advice you might have for my latest concern with regard to material & clearance from unit to the back wall. (Please read the earlier posts on my thread beginning with the post by ROCKETMAN).

Kev

 

[PeteD]

I would be more concerned with the lack of drywall in the chase to retain the insulation.

Correct me if I am wrong......but I don't believe there is any requirement for drywall in the chase. The insulation is not loose as the (combustible) paper side of the insulation is stapled to the studs. The "glass" portion of the insulation certainly won't burn even if that were to ever touch the flue. The pipe is the required double-walled SL300, and I am told it actually remains reasonably cool to the touch. The fireplace is a ZC, but the manual does require 1" clearance (for air flow) around the back and sides of the galvanized steel box. I have ~ 1" in the back and about 18" on the sides. I will certainly consider using a few of those steel insulation securing rods after I staple the insulation up between the studs above the fireplace before sheet rocking, for added safety.

From this description and the picture, it sounds like the paper on your insulation is to the outside. This is backwards and could cause a moisture problem down the road. The paper should go towards the heated side (inside) of the house.

Check out www.buildingscience.com for some great articles on insulation (Thanks BeGreen). You want to avoid having the dew point occur within the insulation.

Good luck.

Pete