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Do I need a firestop?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Kitchen, Jan 28, 2013.

  1. Kitchen

    Kitchen New Member

    Joined:
    Jan 20, 2013
    Messages:
    41
    Loc:
    Shawangunk Mountains, NYS
    I have an outside chase that houses the pipe for my furnace and Class A pipe for my wood stove. It is a straight run in this chase with no floor penetration. Second floor is cathedral celing. A chimney installer indicated that I would need a firestop in this chase between the first/second floor and another one 8 feet up from that. My builder is saying that there is no requirement for a firestop since the chase and pipes are on the outside of the house with no floor or attic floor penetration. I live in Ulster County, NY if that makes a difference. Who is correct?

    Chimney Chase.png

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  2. begreen

    begreen Mooderator Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    46,973
    Loc:
    South Puget Sound, WA
    If this were for a zc fireplace a firestop would be required, even when on the exterior of the house. But I'm not sure about in this case.
  3. DAKSY

    DAKSY Patriot Guard Rider Staff Member

    Joined:
    Dec 2, 2008
    Messages:
    5,003
    Loc:
    Averill Park, NY, on Burden Lake II...
    The local building inspector with need to make that call. He's the Authority Having Jurisdiction (AHJ). He may or may not agree with your builder. IMHO, it's not required as long as you meet the 2" clearance-to-combustibles within the chase. If you were to build your Class A system up the outside of your house, it wouldn't be required. If you decided to frame it in at a later date, for aesthetic reasons, I don't believe you'd have to install a firestop. Better ask the inspector.
    A1Stoves.com, jjs777_fzr and Kitchen like this.
  4. Kitchen

    Kitchen New Member

    Joined:
    Jan 20, 2013
    Messages:
    41
    Loc:
    Shawangunk Mountains, NYS
    Thanks. I agree and so do others locally that I asked. If I was going to put in the firestops, I'd have to open up the entire outside of the chase and probably couldn't have salvaged any of the cedar siding. Plus the wife would have definitely divorced me over that "f'ing wood stove."
  5. DAKSY

    DAKSY Patriot Guard Rider Staff Member

    Joined:
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    Loc:
    Averill Park, NY, on Burden Lake II...
    Technically, if you've got some sort of support box at your transition from connector to the Class A, I'd think that would qualify as a firestop, as long a it's in some sort of deck. The sheathing of the house can be considered a as a firestop between the chase & the house for the rest of the run. That's how the inspectors in this area look at those installs, & they are considered acceptable.
  6. tfdchief

    tfdchief Minister of Fire

    Joined:
    Nov 24, 2009
    Messages:
    3,331
    Loc:
    Tuscola, IL
    International Residential Building Code states in part:

    R302.11 Fireblocking. In combustible construction, fireblocking shall be provided to cut off all concealed draft openings (both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space.

    Fireblocking shall be provided in wood-frame construction in the following locations:
    1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs, as follows:
    1.1. Vertically at the ceiling and floor levels.
    1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
    2. At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings.
    3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R302.7.
    4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. The material filling this annular space shall not be required to meet the ASTM E 136 requirements.
    5. For the fireblocking of chimneys and fireplaces, see Section R1003.19.
    6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    R1003.19 Chimney fireblocking. All spaces between chimneys and floors and ceilings through which chimneys pass shall be fireblocked with noncombustible material securely fastened in place. The fireblocking of spaces between chimneys and wood joists, beams or headers shall be self-supporting or be placed on strips of metal or metal lath laid across the spaces between combustible material and the chimney.

    If that its truly the case, I would not require fire stopping in the chase. For me, the issue would be a fire in the chase getting out horizontally into a floor joist/ceiling joist space, or the attic.
  7. ddahlgren

    ddahlgren Feeling the Heat

    Joined:
    Apr 18, 2011
    Messages:
    435
    Loc:
    SE CT
    If you build it without a permit and no inspection along the way you pay what you do for mot having it inspected during construction. It is only my opinion so free and maybe not worth more than what you pay for it but anything that can burn a house down the inspector is your friend. If you have a fire and the stops are required and you do not have them how do you think that is going to play with the insurance company? When I put my stove in last fall my first call was to the insurance company to find out what they required. I was told if installed to manufacturer's specs and national fire protection code they were ok with it. I went with well beyond both code and manufacturer's specs as it cost about 100 more and will never have to have a painful conversation if something bad happens. As a bonus with the stops the chimney might very well draft better too. Like Isaid free so no doubt worthless..

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