Critique this layout...

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by beachfront71, Jun 17, 2011.

  1. beachfront71

    beachfront71 New Member

    Messages:
    43
    Location:
    newport beach, ca
    Double Sink / Share DWV pipes? UPC/California

    Hello and thanks,

    Can anyone give me a quick yes or no on the UPC / California code with regards to double sinks in a bathroom?

    Specifically, can we run one drain and vent and branch off of that to the 2 sinks as oppossed to running seperate drains down and vents up for both?

    I can not find any info regarding this per code?

    Thanks,
    Last edited: Jun 18, 2011
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    quote; Specifically, can we run one drain and vent and branch off of that to the 2 sinks as oppossed to running seperate drains down and vents up for both

    The question is NOT whether you can do it, but rather HOW you do it. In most cases that is how a plumber WOULD do it, but it has to be done properly, not just start putting fittings together and insert a tee wherever you want a sink.
  3. beachfront71

    beachfront71 New Member

    Messages:
    43
    Location:
    newport beach, ca
    thanks HJ,

    A plumber is doing the work, I just read a short blurb that IPC allows it but UPC does not .. that is where the confusion was at ..
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    California uses UPC code.

    The comments I've seen about adding tees on the horizontal, I haven't seen that done on the West Coast. That's an East Coast IPC thing.
  5. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    Maine uses the UPC. You can indeed use one single drain/vent for double lavs provided your distances are correct. remember that this section of piping is the trap arm.

    To help clarify this; It would be a major hassle to pile a 3 bay culinary sink if you had to separate the drains.
  6. beachfront71

    beachfront71 New Member

    Messages:
    43
    Location:
    newport beach, ca
    thanks for the info ..

    would this same thing apply to both double bay sinks as well as 2 seperate sinks .. say 3 feet apart?
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    yes........................
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    quote; I just read a short blurb that IPC allows it but UPC does not .. that is where the confusion was at ..

    IF the installation is done properly, the both codes allow it. IT is a specific "improper" installation that the IPC allows, but the UPC does not.
  9. plumber2011

    plumber2011 Expert Plumber

    Messages:
    70
    Location:
    Boston, Massachusetts
    Hi Beachfront...

    Assuming 2 lavatories, side by side, in California, the following picture showing ABS (black) plastic piping materials should demonstrate appropriate piping requirements. In most cases, the elbows will want to come out of the wall at about 18", so be sure to figure for that while remembering the 1/4" pitch per foot of piping needed for proper drainage. In CA, apparantly you guys can use the double combination wye fitting...in my area, the fitting must be a double sanitary tee fitting (see picture with PVC (white pipe) fittings).

    Double check with your plumber, of course!!

    Good luck!

    PS: Terry, I don't know anywhere on the East Coast that uses sanitary tee fittings on the horizontal for drains....for vents, yes, but not to pick up drains! PA may be an exception, but PA has some super crazy codes and they don't count!...;)

    Attached Files:

    Last edited: Jun 19, 2011
  10. Yersmay

    Yersmay Writing, constructionDIY Member

    Messages:
    62
    Location:
    Los Angeles
    question

    I am posting in the spirit of advancing -- hopefully not hijacking -- this interesting thread.

    Plumber 2011, I'm curious why your area requires a double sanitary t, instead of a double combination Y. What does a double sanitary 't' have to offer that double combination 'y' can't accomplish? In fact, to my uneducated eye, it would seem that a double combination 'y' would have less cross flow than a sanitary 't'. If there is a concept to learn about how these two fittings drain somewhat differently, I am very interested to hear. Thank you in advance!
  11. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,311
    Location:
    Maine
    When you use a wye, either single or double, with proper pitch and distance it possible for the trap weir to be above the wye inlet which creates an S trap.
  12. plumber2011

    plumber2011 Expert Plumber

    Messages:
    70
    Location:
    Boston, Massachusetts
    Yersmay...good question.

    In fact, many inspectors dislike the double sanitary tee fitting as they argue a snake could cross over and into the other sink, but it is code and as Tom said, "with proper pitch and distance it's possible for the trap weir to be above the double combo. wye inlet which creates an S trap". The double combo. wye, in effect, reduces the contribution of the vent, but still legal in many areas.

    See the image below for more clarification. Note here, that the picture is clearly exaggerated to drive home the point, but it should help...

    Attached Files:

    Last edited: Jun 19, 2011
  13. beachfront71

    beachfront71 New Member

    Messages:
    43
    Location:
    newport beach, ca
    Thanks to all for all the info .. it is appreciated.
  14. beachfront71

    beachfront71 New Member

    Messages:
    43
    Location:
    newport beach, ca
    Prob a dumb follow up question but when building a wetwall directly in front of another existing wall is there any condensation issues that would come up with leaving the existing drywall on the wall that will end up behind the wetwall?

    This is a bed to bath conversion that will be inspected ...

    Just thought I would ask as a wetwall is now required due to a beam location...

    THanks again ..
Similar Threads: Critique layout
Forum Title Date
Plumbing Forum, Professional & DIY Advice DWV Layout Critique........Bathroom & Laundry Room. Mar 10, 2010
Plumbing Forum, Professional & DIY Advice critique my drain layout - is this an S-trap? Mar 6, 2010
Plumbing Forum, Professional & DIY Advice Would appreciate critique of DWV Layout Jan 18, 2007
Plumbing Forum, Professional & DIY Advice Please Critique DWV Mock-Up Sep 11, 2014
Plumbing Forum, Professional & DIY Advice Critique this drain mockup please May 30, 2014

Share This Page