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Elmer's or Heat-Fab Rigid Liner, plus tee ?'s

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by precaud, Jul 31, 2006.

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  1. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Question is, what if it isn't substituting for a 5/8" fireclay liner, but being used in conjunction with a clay liner?

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  2. Shane

    Shane Minister of Fire

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    That's a good question Brother Bart, I'll try to find an answer. One other thing to consider about wrapping a liner and why they require it is this. Technically when a masonry fireplace is constructed it should have a 1" clearance between the framing and the chase when the chase is located on an exterior wall and 2" when the chase is interior. By wrapping the liner it makes it suitable for installation into a chimney that does not meet this clearance requirement. I also assume that's why Simpson duravent pellet flex says 0 clearance to combustibles. Atleast that's my interpretation from reading sooty bob install instructions, please correct me if I'm wrong.
  3. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I just question why someone who has an inspected and approved masonry chimney, in my case over four inches of bricks and a tile liner, needs to insulate a liner to zero clearance specs. Yes, I understand the draft issue, but don't sell me insulation for it as a safety factor.

    And if the liner manufacturer can't test a liner in a NFPA211 compliant chimney, time to find another liner manufacturer. There is something wrong with their liner. Or their legal department.
  4. Shane

    Shane Minister of Fire

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    The clay liner is the key there. I don't know the official code answer, but I would imagine that is either a gray area that is not addressed or that you can infact have an uninsulated liner in a chimney with an intact clay liner. I'm going to have to do some digging there. I suspect it refers you to the manufacturers instruction which can/does require insulation. If I remember correctly Homesaver liner requires 1/4" for the insulating factor and if needed 1/2" for the zc rating. I'll get to the instuctions tomorrow I don't have my password to download the instuctions at home. It does make sense that you have it wrapped in insulation for heat resistance in cases where the flue liner is damaged (missing large chunks like happens from a chim fire) or is non-existant. As well as for the obvious heat retention factor.

    "And if the liner manufacturer can’t test a liner in a NFPA211 compliant chimney, time to find another liner manufacturer. There is something wrong with their liner. Or their legal department."

    Surely they do test in NFPA211 compliant chimneys. Maybe they also recognize the fact that many chimneys are not built exactly to code and test their liners to accomodate that too?
  5. elkimmeg

    elkimmeg Guest

    Shane I'm smilling here but if you have NFPA 211 then it is time to review it again
    one you are mixing up code air space of a liner required in a flue chase of 1" makes no matter of the location interior exterior
    the 2" to combustiable is to the frame around the fire place opening after the required amount of soild masonry is present. 2" is also reguired on the outside of any chimney passing threw a floor or roof. There is no 2" code pertaining to flues clearances

    Actually the NAPA 211 deferes to the International Mechanical Codes concerning masonry chimneys.

    on an earlier post I can save you looking for the language of reduction in poor draft in the NFPA it not there
    the reason VC encore or other 70 stoves can reduce the flue size is they had them tested with both flue sizes and proved they work either or AS an Inspector I can acept that which has been tested and listed. I can not acept a make shift situation woth out proof of testing and documentation

    Really I am trying to explain it to you and hopefully you and others will learn what I have. I am not trying to bust your chops
  6. Shane

    Shane Minister of Fire

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    No I'm not. The code requiring a space between the liner and inside wall of the chase is 7.2.12 Fireclay flue lining for residential and low-heat masonry chimneys shall be separated from the chimney wall by a minimum of 1/2" (12.7 mm) and a maximum of 4 in. (102mm) of airspace.

    The code I am referring to is 7.3.1 Minimum Airspace
    Specificially sections 7.3.1.1 & 7.3.1.2
    7.3.1.1 The minimum air space clearance between interior masonry chimneys (where any portion of the chimney is located within the exterior wall of the building) and combustible materials shall be at least the distance specified in Table 7.2, Column VIII.
    Table 7.2, Column VIII lists the clearance as 2 in./ 51 mm.

    7.3.1.2 The minimum air space clearance between exterior masonry chimneys (where the chimney is located completely outside the exterior wall of the building, excluding the soffit or cornice area) and combustible material shall be at least the distance specified in Table 7.2, Column IX.
    Table 7.2, Column IX lists the clearance as 1 in. / 25 mm.

    As for the Homesaver liner & the 1/4" & 1/2" clearance requirements I have quoted three paragraphs from the copperfield catalog pg. 25

    "One Wrap of 1/4" FlexWrap For 1" of Clearance
    One wrap of HomeSaver 1/4" Foil-Face FlexWrap gives you a UL 1777 listing when you have 1" of airspace clearance from the masonry chimney to exterior combustibles.
    Out in the "real world" however, it's rare that you'll find a masonry chimney where 1" of airspace to exterior combustibles exists. Therefore, you'll usually want to insulate with 1/2" Foil-Face FlexWrap (above) or two wraps of 1/4" FlexWrap, as explained at right.(24)"


    "Two Wraps of 1/4" FlexWrap For Zero Clearance
    Two wraps of HomeSaver 1/4" FlexWrap give you a UL 1777 Listing when less than 1" or even zero clearance from a masonry chimney to exterior combustibles exists.
    It's an option you can use when you don't have 1/2" FlexWrap in stock or you prefer two wraps.
    Thermix and HomeSaver InsulationMix, page 27, also give a zero clearance listing when installed according to manufacturer's instructions.(24)"


    "The Importance Of Proper Insulation
    All ceramic blankets are not alike. Even brands with similar factory ratings have shown dramatically different insulating characteristics when put to a heat test in a "real-world" chimney. This is why it's so important that genuine HomeSaver Foil-Face FlexWrap be used with Homesaver flex.
    Additionally, please understand that to create a HomeSaver relining job that meets UL Listing Standards, you must use only HomeSaver Foil-Face FlexWrap, InsulationMix, or TherMix.
    Two reasons to insulate:
    First, under extremely hot flue conditions, insulation keeps the high temperature from spreading through the masonry chimney to exterior combustibles.
    Second, insulation keeps flue gases warm, stabilizing draft for peak efficiency, and minimizing creosote and condensation problems. Questions? Call our Technical Department at 800-256-1926."




    As for the flue size reduction to alleviate overdrafting I cannot find. I am contacting Alternative Energy Retailer to request a copy of the article in which they were discussing the changes to NFPA211. I am sure it was mentioned in that article and may have not made it in or something.
  7. webbie

    webbie Seasoned Moderator Staff Member

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    Just as an interesting aside here, perhaps we have some good engineers on board.......let's see how good.....

    Assume a 6" round pipe, which can only at most contact an inner ceramic tile liner for a very small area. Now, take the interior of the said 6" round pipe up to 1000 degrees on a constant basis - for purposes of this, let's assume the OUTSIDE of the pipe is 1000 degrees.

    Given that small point of contact and 5" of masonry (tile liner plus 4"), what is the maximum temperature that will be generated along a surfact at the outside of the masonry?

    Of course, it is virtually impossible to sustain pipe temps of 1000 degrees, and UL tests also take short burst of higher INTERIOR temps into account, but these bursts are not long enough to heat though masonry to any degree.

    The strange thing is, said fireplace is perfectly legal to be used as is with tile liner as inspected, built and approved by local officials......

    Here's another theoretical - line tile lined 12x12 chimney with 6" pipe that has spacers which prevent it from touching tile liner. Assume at least 1" space. What would be the maximum temp reached at the outside of the masonry?

    My experience tells me in both cases it would be vastly less than the combustion point of wood, and in the second case I doubt it would ever reach even 50 degrees over ambient with normal use.

    The above is for discussions sake only.....obviously we will never sort out all those instructions and codes......

    Just FYI, radiant heat transfers according to the surface area in sq inches or feet which directly faces the receiving object. When either object (source or target) is round or on an angle, the radiant heat is vastly reduced. Again, hopefully we can get an engineer to chime in.

    Yes, I think that manufacturers should test these liners in various chimney types (lined, unlined, etc.), but consider a couple factors:
    1. Most manufacturers test in-house and ONLY to pass the current standard. In other words, they do not even send pipe to UL, just test results.
    2. Manufacturers also like to sell insulation.

    It is also a mistake to think of any code as the be-all, end-all of knowledge. Codes are constantly updated and influenced by manufacturers, trade groups, etc. ---- The same codes told us to do it a different way years ago - at a time when the stoves were much more dangerous and ran constantly higher flue temps.

    Another comment which can show how little testing the manufacturers must do - Homesaver for instance make liners that are round, square, rectangular and oval. They make sizes from 4 inch to 16" and bigger. OK, so are you going to tell me that a 6" liner in a 12x12 gets anywhere near as hot as a 10" SQUARE liner in the same chimney. Let's do the math - one has an outside area of about 480 square inches per foot and the other one has 75 square inches. Also, one is almost up against the tile and has flat sides! One has large areas radiating directly to the flat surfaces, and other other is round. Even without any engineering experience, I can guess that the radiant effect of the square liner on the combustibles outside (given the same surface temp of the metal) has to be by a factor of 10 or more!

    This, if nothing else, shows the folly in current testing or lack thereof. My guess is the Homesaver and others will not give you straight answers to concerns such as these.
  8. Shane

    Shane Minister of Fire

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    I agree totally. If the chimney has:
    - a 5/8" thick flue tile liner
    - there is a min. of 1/2" airspace between the flue tile liner & the inside wall of the brick chase.
    - there isa min. of 1"-2" between the outside wall of the chase and combustible framing

    It would seem that the necessity to insulate due to the risk of heat transfer should be void. The part that sucks is that, like you said due to lack of testing, the 1/4" of insulation will be required regardless because that is how the system was tested and listed. That is for that specific system some others may allow you to not insulate so long as your installing their liner into a code approved fireplace.

    Again I doubt it would happen. The simple matter is though that current code requires the outside of the chase to have a 1" air gap between an outside chase and a 2" air gap with an inside chase. And honestly the majority of fireplaces I run into do not meet that requirement. In this instance a manufacturer has noted this requirement and tested their liner to be compliant in situations where the airspace exists as well as where it doesnt.

    I agree again codes are always changing. But we as industry professionals simply need ot abide by current code. We cannot pick and choose what we want to follow and what we don't. I guess my major point is that code does require an airspace between teh outer wall of the chase and combustibles as well as a airspace between clay flue tiles and the inner wall of the chase. Whether or not this is reasonable is not up to me.
  9. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Thank you Craig.
  10. elkimmeg

    elkimmeg Guest

    edited I picked up the 2002 NFPA 211 and the rest of the post did not make sense sorry I would have added nothing
  11. webbie

    webbie Seasoned Moderator Staff Member

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    I wish things were so simple when I sold and installed stoves. We'd get called to jobs to install a wood stove in an old chimney - and find out that said chimney had 4 bends and a 6" liner would barely sqeeze though if we jumped on it!

    We'd do MANY jobs where the owners manual for the stove (the be-all, end-all in some opinions) was directly in contradiction with either code or best practice. Example: Many of the stoves that are approved for installations in pre-fab fireplaces show only a pipe up the damper! I'll bet this is still true today....

    So, my comments are in no way meant to tell folks to do an inferior job. In fact, when we installed into prefabs even 15 years ago we completely relined EVERY chimney even though it was often not in the instructions.

    Then again, we installed hundreds of UL approved inserts in code-approved fashion by just slipping them into the fireplace.

    A true "Professional" is like a surgeon - certainly there is a best way to perform a gall bladder removal, but once the pro gets inside, there may be other existing factors which contribute to decisions.
  12. Shane

    Shane Minister of Fire

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    Hmm my last post didn't post. I'll try again.
    Admittedly calls do have to be made from time to time. I did not mean to insinuate that you were promoting sub-par work Craig that would be "illogical":). Sometimes installers & AHJ have to make judgement calls. I was trying to point out that if you are doing something that is "technically" against code, you need to really weigh the risk.
    I do have to agree that it must take some special circumstances for combustible framing to ignite that is right next to the outside of chase. This is obvious because there are numerous chimney fires in fireplaces every year, that do not meet the clearance requirement, and the framing does not ignite. This piece of code could be overkill? Surely there is some scientific research or documented cases to support the code being there right? I don't know. It is obvious that there are many chimneys built and used every day that are not 100% up to code but they work and they appear to work safely. Maybe the insulation is a marketing gimmick. Maybe they could have tested the liner without any insulation and still recieved the UL1777. Maybe they didn't even try, they claim to have tested it with "other" insulation and having negative results. Let's check some other liners like Heatfab, Elmers, & Simpson Duravent and see what they have to say, maybe that will help us come to a better conclusion. It'd be really nice to be able to actually run some of these tests independantly to see what result we get.
  13. Shane

    Shane Minister of Fire

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  14. webbie

    webbie Seasoned Moderator Staff Member

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    Nothing at that url. Might be a "frame".

    If nothing else, I'm going to get ahold of the test standards for liner just to see how it is and how it isn't tested.
  15. Shane

    Shane Minister of Fire

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    Go to the editorial button and choose article archive from the pop up menu. It's about 1/2 way down the page under installation articles. "To Insulate or Not to Insulate"

    "The results of the stringent testing process a chimney liner must go through in order to carry the full UL 1777 listing is what determines the specific insulating requirements for each specific chimney liner. During a simulated chimney fire, UL measures the amount of heat transferred from within the liner to the exterior of a non-conforming masonry chimney. If UL measures too much heat transfer, then the liner fails the test. Given the nature of any single wall chimney liner, heat transfer of an uninsulated liner is going to be high. With high density insulation, heat transfer is reduced tremendously. This allows for a safe installation even in a non-conforming chimney, thus allowing a "Zero Clearance" installation."

    That's a quote from the article that gives vague explanation of the testing procedure.
  16. webbie

    webbie Seasoned Moderator Staff Member

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    OK, so one part falls into place. A "non-comforming" meaning same chimney should be red tagged and not allowed to be used for wood burning. In other words, a chimney that was build wrong, inspected incorrectly and certified incorrectly.

    How can building and mechanical inspectors all over the country be making such a common mistake? Maybe Elk can enlighten us.

    Now, a BIG question that the article does not address is exactly what size liner is used in the tests and what size chimney it is used in. These are such big variables.....
    We're gonna get to the bottom of this one sooner or later.....
  17. Shane

    Shane Minister of Fire

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    I cannot find the standard for free and don't have 400 clams to purchase it. Tested to 1000 degree continuous temperature and max temp of 2100. Exactly how the test is carried out is not known and i assume must be purchased. Yeah the non-conforming part means exactly what you said the fireplace should be red-tagged. But in reality you and I both know that those clearances are largely ignored and yet we don't have this major epidemic of houses burning down due to that particular clearance not being met. To me that is the real question what case study, scientific research etc. was done to prove that the clearance requirement is necessary? I mean 90% of chimneys meet the code referring to space between the flue tile and inside wall, actually 90% of them fail to meet the requirement by having more than 4" or clearance. That's another discussion though. Apparantly they feel that there is enough heat transfer potential to require the clearances however and I really want to know what led to that conclusion. Also who is quality control for these tests? Are they self regulated by the manufacturers? I can definately see where it would be beneficial for a manufacturer to require that their liner be wrapped to meet UL1777. Are they required to test without insulation just to see if they can meet the standard?
    Also the Homesaver liner requires atleast 1/4" of insulation even if the chimney meets the clearance requirements in order ot retain the UL1777 listing.

    I think the key to how or why so many fireplaces are built incorrectly probably has to do with the length of time this has been a requirement. I know it's been in there since the 1984 edition (that's the oldest one I have)

    Another portion of code that I see constantly violated is the 7.2.14 Multiple flues.

    Where there are multiple flues in one chimney a separation of solid masonry (wythe) not less than 4" in thickness is required between the flues. On top of that 7.2.12.1 says there should be no more than 4" of airspace around the flue tile. How many sweeps/installers here have ever taken the chimney crown off of a chimney and found alot more than 4" of airspace around a flue tile and no masonry wythe separating multiple flues? I can personally attest to atleast 100 of them. Why is this missed in the construction process? Could it have to do with the masons not getting things inspected in stages?
  18. elkimmeg

    elkimmeg Guest

    No masonry chimney of fireplace is NFPA compliant
  19. Shane

    Shane Minister of Fire

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    This is one of those tricky statments isn't it Elk? What have you got up your sleeve? Does this have to do with your earlier statement that the NFPA211 defers to International Mechanical Code concerning the construction of masonry fireplaces?
    If so can you tell us what requirements etc. are in the IMC. I don't personally own a copy of it though I admit I should.
  20. webbie

    webbie Seasoned Moderator Staff Member

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    The test is something like this,

    1000 continuous
    2100 for 10 minutes
    and some stuff in between for longer bursts....

    Now, remember these are interior flue gas temps. The outsides never see anything close to 2100 - perhaps Metal can fill us in if he is lurking.
  21. Shane

    Shane Minister of Fire

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    In the NFI manual it says that the tests involve the amount of heat radiated from the pipe. If it's above x amount the liner fails the test and has to use insulation to decrease the radiant heat. What amount of radiant heat I don't know. Man this is eating me now. I really want to get to the bottom of this. I can find the "scope" of the test but not the specific procedures and controls used etc. I also want to crack the IMC book and see what it has to say. I found a .pdf version of it for 60 bucks. I'm going ot ask the bossman if we can invest in it. I can't see shelling out 60 of my personal funds for something that will be used by the company. Where does NFPA defer you to IMC Elk? I think your opinion is greatly needed here.
  22. elkimmeg

    elkimmeg Guest

    NFPA has no jusisdiction in one two and 3 familly dwellings. Infact NFPA has no national government reconision No state has adopted it. ITs reconition ( residential codes) is to sprinklers and fire alarms, but even alarms are covered in the national Electrical codes
    There masonry chimney codes are ported over from the National mechanical codes, yet they are selective and did not include all.
    They have no jusirdiction in the building codes. They can not appoint inspectors there or govern any there there is no NFPA certification progran for building or mechanical inspectors only to fire fighters

    Imagine how you would feel when Johnie come lately to the dance starts dictating to you life long professional builder his code.
    Since 9/11 Fire marshals have taken on there new found hero status and started meddling into the building codes. Its like someone just arriving tell you he now is the authority without an once of building experience So what is his qualifications he saved a cat up a tree or put out a dumpster fire. As you can see building inspectors that have to have pass national examines Keep contact hours are not going to relinquish their certification to a fire fighter who the chief can appoint to preform a function without certification.
    It's not going to happen.

    Most fireplace products are tested to NFPA 211 standards however also pointed out is the governing body that administers the code. The town or district can elect to have the fire dept handle the permitting and code enforcement only if the building commissioner agrees to that situation. Because the NFPA is a code not reconised. As an inspector I can choose to reconise which ever code I deam to follow.
    By the manufacturer listing tested to NFPA 211 It gives me the authority to use and reconise that code. Note I do not have to.

    There are two National codes the whole vollume of codes and then a separate residential codes. With in the residential codes are Mechanical and plumbing gas building ect.

    I am correct to say no masonry chinmney or stove or solid fuel burning appliance has to conform to NFPA 211. Why would one apply an unreconised code?

    Untill recently the national mechanical codes have not reconised NFPA. The 2006 Mechanical codes for the first time refferenced them in solid fuel appliance applications.

    Shane you could go into your office and announce you are not going to install to NFPA 211 codes and be 100% correct. You need the real reconised governing codes the international codes PM me.
  23. elkimmeg

    elkimmeg Guest

    Shane you brought up some valid points whethere it be a NFPA or international code chimney it has to meet simmilar criteria

    The 4" parting partition or wyth has only recently made any code aroung 1998. that means most chimneys could have multy flues in one chase servicing different appliances providing the joint were staggered 7"
    The intent od the wyth is one flue to one appliance per chase. This being so. almost all chimneys prior to 1998 would be non code compliant applying todays revised codes. All would require liners.


    Another point you or craig brought forward, is how one know if the chimney is built properly? So far this year I have order 3 to come down and to be built correctly and there are two more that may come down pending engineering approval

    The inspection starts once I get out of the truck. I look ant the manons' setup the stock he is using the general appearance of the job
    things thrown around sets off alarms to look real close as to what is going on I do a throat inspection that inspection hase to pass for that chinmey construction to continue.
    What I want to see is the damper placement the lintal support the correct thiskness od masonry in place anf the transition and shaping the skoke path to the application of the first flue. Which should be the beginning of the wyths. I will climb the staging and examine it from top to bottom. But Im not done my final Mechanical inspection I look at the entire setup again. I visulize it relationship to the roof line then simple math calculate the height required according to the roof pitch finally I will count the bricks.
    the fire box gets examined again I tap the bricks to make sure I do not hear a hollow sound. It is code that the fire bricks be backed with solid masonry. First hillow tap I hear out will come my angle mirror and flashlight. You would be amazed what I have seem behind there blacks of wood Mcdonalds bags dead animals. Every insert that is installed the fire box intergertiy should be checked for solid fill., Finally I look up threw the clue liner and damper there should be no pieces of motar sticking out for cersote traps. If I see any the inspection fails. the most important thing to look at is how the front facing bricks setup to the lintal and the smoke shelf looking up inside the fire bos to the front should be a sealed masonry surface no open joints no cracks or missing masoney voids. EVERY insert installer should be looking that this. It is common to find voids and cracks. Leading as a straight path to the combustiable header above. got to run work is calling
  24. rstewart

    rstewart New Member

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    HeatFab is preferable. We have used and sold same for over 25 years. Great product
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