Stovepipe clearance of 18" vs. what the stove manufacturer certification plate states?

Ludlow Posted By Ludlow, Jun 22, 2018 at 12:42 AM

  1. Ludlow

    Ludlow
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    Some people choose a certain stove based on it's close clearance claims. The instructions state that the clearances were tested with single wall. There is no directives to use any heat shielding with these clearances.
     
  2. begreen

    begreen
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    Seems a matter of whose margin of safety one wishes to believe then. Bring out the IR thermometer in December.
     
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  3. bholler

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    But the pipe has not been tested at all. The stoves clearances should be. So the only margin that is based on anything is the stoves. The pipes is based on a generic code.
     
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  4. begreen

    begreen
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    So just ignore the pipe instructions and code?

    Screen Shot 2018-07-05 at 3.42.54 PM.png
     
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  5. bholler

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    Code says absolutly nothing about honoring untested clearances given for unlisted components. Because it is unlisted those instructions legally mean nothing. And the fact that they are untested means they are based on nothing. Squisher clearly showed us that code in canada says 18" no matter what so that is what it is. But code here gives generic clearances but says follow instructions for all LISTED components.
     
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  6. bholler

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    I am curious why you are so set on following these unlisted instructions but are fine with disregarding instructions for listed prefab fireplaces.
     
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  7. begreen

    begreen
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    Similar issue, but that didn't answer the question. Just ignore the pipe instructions?
     
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  8. bholler

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    I did answer the question. Those instructions are for an unlisted product and the clearance is completly untested. So when it comes to code compliance those instructions are meaningless.
     
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  9. begreen

    begreen
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    So you ignore Ventis's explicit instructions and install according to the stove instructions instead, correct?
     
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  10. bholler

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    What did i say i do here many times? I use doublewall in that case. Infact i used double wall for anything under 19" or 20" But by code those ventis instructions mean absolutly nothing because they are for an unlisted product. And that stated clearance has no basis in reality because it was not tested. The regency one was.
     
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  11. begreen

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    Then we are both in agreement. In spite of the stove mfg. saying a closer distance is ok for single-wall we are not comfortable with single wall pipe being that close to a combustible surface.
     
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  12. Ludlow

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    The instructions clearly give tested minimums for every scenario except for horizontal run to ceiling distance, and they defer to the pipe manufacturer. That means that all others were tested and UL approved. Code is default for untested products. How close can you put an old untested stove to the wall? How about a sidewall? Aint it 3 feet absent a UL tested lesser distance?
     
  13. Ludlow

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    If a UL approved distance isnt good enough then UL testing and approval is useless.
     
  14. bholler

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    No i am not comfortable opening my self up to the potential liability. I am confident the ul testing assures the clearances are safe.
     
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  15. bholler

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    And yes it is similar. But the big difference is in this case one product is a listed and tested unit the other is unlisted and un tested. In the case of prefab fireplace the instructions you are disregarding are for a ul listed system. Which is against code.
     
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  16. thechimneysweep

    thechimneysweep
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    We encountered this issue back in 1980, when we began installing our first factory-shielded wood stove. When the stove was located at the listed rear clearance (11"), the rear surface of the stovepipe was at 15", and our local inspectors, schooled in NFPA 211, wouldn't pass it. We contacted the UL testing lab, OMNI labs in Oregon, and here's the gist of their response:

    Wood stove clearance testing is performed in calorimeter rooms, which have temperature sensors in all walls, the ceiling and even the floor. If a given stove is tested safe at 11" rear clearance but the pipe overheats the wall, that stove will not achieve an 11" clearance listing with single-wall pipe.

    I can't blame stovepipe manufacturers for specifying 18" minimum clearance, because the flue gas temperature (and resulting pipe surface temperature) will vary from one stove model to another. But if a UL test lab specifies a smaller clearance for a given stove model (say, 18" to centerline), it is because their test results support that listing.
     
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  17. bholler

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    That is basically what i have been told by manufacturers. They tested it and it passed. The pipe manufacturers havnt tested it at all.
     
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  18. Ludlow

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    So it is settled. I exceeded the 12" minimum for single wall listed by my stove by setting the stove for a 15.75 clearance to the pipe. This makes my install more than minimum safe per UL listings.
     

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