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  1. #1
    allen elliott's Avatar
    allen elliott Guest

    Default Single wall vent piping.

    Probably a bit of an elementary question, but how do you identify single wall vent pipe without taking it apart?

    thanks

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  2. #2
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    Default Re: Single wall vent piping.

    Pretty much just learn what b-vent looks like and by process of elimination if it is not b-vent then it is single wall (which is not "rated" by a listing agency to my knowledge.)

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  3. #3
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    Default Re: Single wall vent piping.

    Water heater pipe of that size is single wall. It would have to be 4 inch diameter to be double wall pipe.
    So whatever that white stuff is up there should be burning soon. UNless its asbestos


  4. #4
    allen elliott's Avatar
    allen elliott Guest

    Default Re: Single wall vent piping.

    thanks. Just the responses I needed.


  5. #5
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    Exclamation Re: Single wall vent piping.

    Allen, type 'B' vent is a manufactured product listed to UL 441. This pipe has a double wall construction using an aluminum inner liner and galvanized steel outer. There is a self locking mechanism at each joint. Each section of pipe must carry information identifying the manufacturer, listing, 1" clearance to combustibles, size and orientation upwards away from the appliance collar. This is usually embossed into the steel outer casing. There is a bead or groove rolled into the pipe at the female end to pinch off the space btw creating a Dewar's flask of dead air space to insulate the pipe. This is why this pipe should be screwed into it. It cannot be cut to fit.

    Single walled vent connector is just that--one wall thickness. It has a longitudinal snaplock seam the length of the vent. There are no markings on this pipe. It can be cut to fit and you can screw into it.

    If you are unsure what they look like, stop by your HVAC supply house and ask to handle a piece of each.

    BTW, type 'L' vent looks just like Bvent except it has a stainless steel inner section, is labeled L and carries a 3" or greater clearance to combustibles.

    HTH,
    Bob

    Keep the fire in the fireplace.

  6. #6
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    Default Re: Single wall vent piping.

    Bob,

    Did I miss something or is one of the "should be screwed into"/"can be screwed into" wrong?

    Quote Originally Posted by Bob Harper View Post
    This is why this pipe should be screwed into it. It cannot be cut to fit.
    Regarding B vent.

    Single walled vent connector is just that--one wall thickness. It has a longitudinal snaplock seam the length of the vent. There are no markings on this pipe. It can be cut to fit and you can screw into it.


    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  7. #7
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    Smile screwed up

    Thx Jerry:

    B-vent should NOT be screwed into....

    You may screw into single walled pipe and in fact must to secure each joint.

    Keep the fire in the fireplace.

  8. #8
    allen elliott's Avatar
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    Default Re: Single wall vent piping.

    thanks all !!


  9. #9
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    Default Re: Single wall vent piping.

    Quote Originally Posted by fritzkelly View Post
    What is the clearance needed on single wall? I always say 6 inches but don't know if I could back it up.

    From the 2006 IRC.
    - M1803.3.1 Floor, ceiling and wall penetrations. A chimney connector or vent connector shall not pass through any floor or ceiling. A chimney connector or vent connector shall not pass through a wall or partition unless the connector is listed and labeled for wall pass-through, or is routed through a device listed and labeled for wall pass-through and is installed in accordance with the conditions of its listing and label. Connectors for oil-fired appliances listed and labeled for Type L vents, passing through walls or partitions shall be in accordance with the following:
    - - 1. Type L vent material for oil appliances shall be installed with not less than listed and labeled clearances to combustible material.
    - - 2. Single-wall metal pipe shall be guarded by a ventilated metal thimble not less than 4 inches (102 mm) larger in diameter than the vent connector. A minimum 6 inches (152 mm) of clearance shall be maintained between the thimble and combustibles.

    - G2427.7 (503.7) Single-wall metal pipe. Single-wall metal pipe vents shall comply with Sections G2427.7.1 through G2427.7.12.
    - - G2427.7.1 (503.7.1) Construction. Single-wall metal pipe shall be constructed of galvanized sheet steel not less than 0.0304 inch (0.7 mm) thick, or other approved, noncombustible, corrosion-resistant material.
    - - G2427.7.2 (503.7.2) Cold climate. Uninsulated single-wall metal pipe shall not be used outdoors for venting appliances in regions where the 99-percent winter design temperature is below 32ºF (0ºC).
    - - G2427.7.3 (503.7.3) Termination. Single-wall metal pipe shall terminate at least 5 feet (1524 mm) in vertical height above the highest connected appliance draft hood outlet or flue collar. Single-wall metal pipe shall extend at least 2 feet (610 mm) above the highest point where it passes through a roof of a building and at least 2 feet (610 mm) higher than any portion of a building within a horizontal distance of 10 feet (3048 mm) (see Figure G2427.6.4). An approved cap or roof assembly shall be attached to the terminus of a single-wall metal pipe (see also Section G2427.7.8, Item 3).
    - - G2427.7.4 (503.7.4) Limitations of use. Single-wall metal pipe shall be used only for runs directly from the space in which the appliance is located through the roof or exterior wall to the outdoor atmosphere.
    - - G2427.7.5 (503.7.5) Roof penetrations. A pipe passing through a roof shall extend without interruption through the roof flashing, roof jack, or roof thimble. Where a single-wall metal pipe passes through a roof constructed of combustible material, a noncombustible, nonventilating thimble shall be used at the point of passage. The thimble shall extend at least 18 inches (457 mm) above and 6 inches (152 mm) below the roof with the annular space open at the bottom and closed only at the top. The thimble shall be sized in accordance with Section G2427.10.15.
    - - G2427.7.6 (503.7.6) Installation. Single-wall metal pipe shall not originate in any unoccupied attic or concealed space and shall not pass through any attic, inside wall, concealed space, or floor. The installation of a single-wall metal pipe through an exterior combustible wall shall comply with Section G2427.10.15. Single-wall metal pipe used for venting an incinerator shall be exposed and readily examinable for its full length and shall have suitable clearances maintained.
    - - G2427.7.7 (503.7.7) Clearances.Minimum clearances from single-wall metal pipe to combustible material shall be in accordance with Table G2427.7.7. The clearance from single-wall metal pipe to combustible material shall be permitted to be reduced where the combustible material is protected as specified for vent connectors in Table G2409.2.
    - - G2427.7.8 (503.7.8) Size of single-wall metal pipe. A venting system constructed of single-wall metal pipe shall be sized in accordance with one of the following methods and the appliance manufacturer’s instructions:
    - - - 1. For a draft-hood-equipped appliance, in accordance with Section G2428.
    - - - 2. For a venting system for a single appliance with a draft hood, the areas of the connector and the pipe each shall be not less than the area of the appliance flue collar or draft hood outlet, whichever is smaller. The vent area shall not be greater than seven times the draft hood outlet area.
    - - - 3. Other approved engineering methods.
    - - G2427.7.9 (503.7.9) Pipe geometry. Any shaped single-wall metal pipe shall be permitted to be used, provided that its equivalent effective area is equal to the effective area of the round pipe for which it is substituted, and provided that the minimum internal dimension of the pipe is not less than 2 inches (51 mm).
    - - G2427.7.10 (503.7.10) Termination capacity. The vent cap or a roof assembly shall have a venting capacity not less than that of the pipe to which it is attached.
    - - G2427.7.11 (503.7.11) Support of single-wall metal pipe. All portions of single-wall metal pipe shall be supported for the design and weight of the material employed.
    - - G2427.7.12 (503.7.12) Marking. Single-wall metal pipe shall comply with the marking provisions of Section G2427.6.11.

    Table G2427.7.7


    TABLE G2427.7.7 (503.8.7)a
    CLEARANCES FOR CONNECTORS
    MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL
    Single-wall metal pipe

    Listed appliances with draft hoods and appliances listed for use with Type B gas vents = "6 inches" clearance for single-wall metal vent

    Residential boilers and furnaces with listed gas conversion burner and with draft hood = "9 inches" clearance for single-wall metal vent

    Residential appliances listed for use with Type L vents = "9 inches" clearance for single-wall metal vent

    Listed gas-fired toilets = "as listed" for single-wall metal vent

    Unlisted residential appliances with draft hood = "9 inches" clearance for single-wall metal vent

    Residential and low-heat appliances other than above = "18 inches" clearance for single-wall metal vent

    Medium-heat appliances = "36 inches" clearance for single-wall metal vent


    Last edited by Jerry Peck; 04-23-2009 at 08:11 PM.
    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
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    Default Re: Single wall vent piping.

    Listed gas-fired toilets = "
    I want one !!
    BILLY
    Let's see you find one of those


  11. #11
    Ted Menelly's Avatar
    Ted Menelly Guest

    Default Re: Single wall vent piping.

    Quote Originally Posted by wayne soper View Post
    Listed gas-fired toilets = "
    I want one !!
    BILLY
    Let's see you find one of those

    This might be a hillbilly or redneck question but aren't all toilets gas fired


  12. #12
    Craig Ervin's Avatar
    Craig Ervin Guest

    Default Re: Single wall vent piping.

    Get a new phone, thats one crappy pic.

    Fire is not the only reason for having B or L vent, its to keep the flue gases hot so they don't condense and drain back into the device. If it looks like white stuff has been dripping or run on the outside of the pipe, thats the water in the flue condensing and is very corrosive.


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