Question about the slope of a 3" line...

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Southpaw134, Feb 3, 2009.

  1. Southpaw134

    Southpaw134 New Member

    Messages:
    35
    Location:
    Florida
    is there such a thing as over sloping (too extreme of an angle) an outdoor 3" sewerline?

    I assume there isn't, I assume there are some sewer lines that run vertical..., but assuming is, an, umm...big assumption.

    Also, if I have a vertical line that I need to connect to a horizontal line is there a minimum or mximum angle of connection between the two (i.e., 45 or 90 degrees)?

    Thanks in advance.
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    1/4" per foot is a minimum pitch.

    The old liquids outrunning the solids is a myth that has been busted.
  3. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    As far as I know, there is nothing such as oversloping, unless your talking about a p-trap in proximity to a vent.
    The minimum slope between 2 connections is 1/4" per ft or 2% there is no maximum
  4. kingsotall

    kingsotall Plunger/TurdPuncher

    Really¿ So we just do it because it's code¿
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    If you read your code chances are it states that it is a minimum pitch...
  6. Southpaw134

    Southpaw134 New Member

    Messages:
    35
    Location:
    Florida
    Thanks for the replies.
  7. kingsotall

    kingsotall Plunger/TurdPuncher

    I always saw the validity in the liquids outrunning the solids.
  8. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Liquids will always outrun the solids. If you flush a toilet with a wad of toilet paper in it do you think that it gets to the city sewer on on flush?

    Not a chance!

    Infact a sewer relies heavily on other flows to clear the line.
  9. tjbaudio

    tjbaudio Sound and Light Suppervisor for a School District

    Messages:
    162
    Location:
    Wisconsin
    That is one reason the shower is near the end of the line in my house, right after the toilet.
  10. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    If there were maximum pitch rules then you couldn't run a vertical stack :D

    Sewage systems are designed to move waste at 2 feet per second.
  11. C NUMB

    C NUMB Plumbing Contractor

    Messages:
    135
    Location:
    NPR, FL
    In your location it is what Redwood said 1/4" per ft. On the vertical to horizontal use either 2 45's or a long sweep 90.
  12. quinocampa

    quinocampa Mechanical engineer in marketing. Uhuh.

    Messages:
    36
    Location:
    Indianapolis
    I've inspected all of my drain pipes in the crawlspace. My home is only 20 years old, and the entire drainage system is basically flat. The new lines I'm installing are sloped properly, but I wonder why it was done this way. During my bathroom remodel, I've also found a hard vent duct that was crushed to go over the top of a shower drain in a 2nd floor joist bay, soft HVAC ducts in the crawlspace draped over joists 'til they're choked off, and two bathroom fans with no exhaust ducting attached. One of them was blowing directly into insulation, which was right on top of the fan. I've corrected all of these shortcuts. I will defend my right as a homeowner to do my own work when this quality of work is the alternative. Don't even get me started about last year's contracted attic remodeling.
    Last edited: Feb 4, 2009
  13. Southpaw134

    Southpaw134 New Member

    Messages:
    35
    Location:
    Florida
    Thanks again for all of the help and information.
  14. kingsotall

    kingsotall Plunger/TurdPuncher

    Guess this greenhorn has a lot to learn! Thanks for the insight fellas.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,038
    Location:
    Cave Creek, Arizona
    offset

    There is no "code" requirement as to how you make a change in elevation, but the prudent way is to make the transition as smooth as possible. If you have room the best way is to just deflect the pipe, the next best is two 22 1/2 bends, or move on to using two 45's, and if there is not enough space for that, then two 90's is the last option.
  16. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
  17. Southpaw134

    Southpaw134 New Member

    Messages:
    35
    Location:
    Florida
    Thanks Redwood, that was a good read.
  18. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    So you'd want the catchers mitt before the bucket. :D

    In a vertical stack the water actually clings to the inside of the pipe and swirls it's way to the bottom. The center is mostly empty.
  19. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,038
    Location:
    Cave Creek, Arizona
    drains

    In a vertical stack the water actually clings to the inside of the pipe and swirls it's way to the bottom. The center is mostly empty.

    Which is why they make "anti vortex" roof drains so the pipe WILL be full and thus can be made smaller.
  20. rmelo99

    rmelo99 Network Engineer

    Messages:
    349
    Location:
    Connecticut
    Good reading, thanks
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