Results 1 to 15 of 15
  1. #1
    Stephen G Sheldon's Avatar
    Stephen G Sheldon Guest

    Default Flue Vent Thru Roof

    NHIE Practice Exam

  2. #2
    Join Date
    Mar 2007
    Location
    Oregon
    Posts
    2,365

    Default Re: Flue Vent Thru Roof

    Lots of factors including roof slope, nearby structures (dormers, etc.). The best thing is to find the manufacturer's specs.

    There's a snapshot of the section in the Codecheck book that deals with is.

    In general, I'm often surprised at how close they can be in many applications. Most of the time I'm suspicious I look it up and it's okay.

    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images

  3. #3
    Stephen G Sheldon's Avatar
    Stephen G Sheldon Guest

    Default Re: Flue Vent Thru Roof

    Matt,

    Thanks.


  4. #4
    A.D. Miller's Avatar
    A.D. Miller Guest

    Default Re: Flue Vent Thru Roof

    As MF stated there are many factors to consider: type of vent, type of appliance, distance from sidewalls, etc:

    Try: http://www.duravent.com/docs/instruct/l950_nov99.pdf

    or:

    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images

  5. #5
    Richard Pultar's Avatar
    Richard Pultar Guest

    Default Re: Flue Vent Thru Roof

    excess height is very common code violation.


  6. #6
    Join Date
    Mar 2007
    Location
    Spring Hill (Nashville), TN
    Posts
    5,847

    Default Re: Flue Vent Thru Roof

    Quote Originally Posted by Richard Pultar View Post
    excess height is very common code violation.
    Why would a properly supported and constructed flue that is higher than the code requirement and meets the appliance manufacturers requirements be a problem or violation as you call it?

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

  7. #7
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Flue Vent Thru Roof

    Quote Originally Posted by Richard Pultar View Post
    excess height is very common code violation.

    Richard,

    I'm wondering the same thing as Scott.

    First, though, define "excess height" when only a "minimum" height is stated ... what would "excess height" be?

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

  8. #8
    Richard Pultar's Avatar
    Richard Pultar Guest

    Default Re: Flue Vent Thru Roof

    A B vent to a gas appliancemust be sized properly to heat up rapidly to ensure a strong draft, and minimal condensation. Excessive vent exposed to cold outdoor temperatures is to be avoided.Since vent walls are supposed to heat up and dry out the condensation before the appliance cycles off.
    Long connector runs in cold air spaces are also discouraged. Because of condensation and corrosion .
    The sizing tables are clear that there are minimum and maximum BTU inputs. The Idea that bigger is better is not appropriate. here. This includes the overall length of the system.


  9. #9
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Flue Vent Thru Roof

    Quote Originally Posted by Richard Pultar View Post
    The sizing tables are clear that there are minimum and maximum BTU inputs.
    Richard,

    I am aware of the sizing tables and the sizes and heights, however, the other sections of the code and the manufacturer's installation instructions specify "minimum" heights, not 'maximum' heights.

    I also understand why the vents are not to be oversized, again, however, one must go by the manufacturer's requirements and the code, which specify "minimum" heights.

    If a home inspector wants to get into this in more depth and start checking sizing of vents, then their work will become very in-depth and very time consuming - otherwise the code and manufacturers address (being repeated here) "minimum" heights - not "maximum" heights.

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

  10. #10
    Jack Murdock's Avatar
    Jack Murdock Guest

    Default Re: Flue Vent Thru Roof

    Stephen,
    The 3 2 10 rule is easy to remember. The b-vent pipe must come at least 3 feet above the roof and be 2 feet higher than anything within 10 feet. This does not apply to direct vent appliances which must follow manufacturers instructions.

    Jack


  11. #11
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Flue Vent Thru Roof

    Quote Originally Posted by Jack Murdock View Post
    Stephen,
    The 3 2 10 rule is easy to remember. The b-vent pipe must come at least 3 feet above the roof and be 2 feet higher than anything within 10 feet. This does not apply to direct vent appliances which must follow manufacturers instructions.
    Jack,

    That's for chimneys, not vents.

    Vents is a more complicated:
    1*, 2-8/10 rule I made
    *the minimum height depends on the slope of the roof, the least allowed being 1 foot

    It is not as easy of a rule to remember, or as simple to apply, as the 3, 2-10 rule for chimneys.

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

  12. #12
    Jack Murdock's Avatar
    Jack Murdock Guest

    Default Re: Flue Vent Thru Roof

    Jerry,
    you are 100% correct. I apply 3/2/10 for everything....my bad.

    Thanks


  13. #13
    Richard Pultar's Avatar
    Richard Pultar Guest

    Default Re: Flue Vent Thru Roof

    3 2 10 is for solid fuel burning CHIMNEYS,
    VENTS as in B vents are vents they have the same minimum as a plumbing vent.
    according to the Simpson Dura--Vent Sizing handbook .
    Excess height is to be avoided IF you want to do the job code proper.


  14. #14
    Join Date
    Mar 2007
    Location
    Near Philly, Pa.
    Posts
    1,643

    Smile Re: Flue Vent Thru Roof

    Richard, I guess we're still missing what part of the code you are referring to with regards to max. stack heights. Sure, there is a functional limit but your injection of that word 'code' adds another dimension to it.

    FYI, 3/2/10 is for ALL chimneys regardless of fuel.

    There is a difference btw code requirements vs. good vent design and codes do not guarantee performance.

    Bob

    Keep the fire in the fireplace.

  15. #15
    Richard Pultar's Avatar
    Richard Pultar Guest

    Default Re: Flue Vent Thru Roof

    National Fuel Gas Code ANSI Z223.1 , NFPA 54, NFPA211, and the International Fuel Gas Code.
    I am only addressing Category I gas appliances.
    I find the use of flue and vent in the same term a oxymoron.


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •