Custom Low-Profile Clamping Drain

Discussion in 'UPC Plumbing Code Questions' started by RSquirrel, Feb 21, 2021.

  1. RSquirrel

    RSquirrel New Member

    Joined:
    Apr 18, 2012
    Location:
    California
    I am replacing an acrylic tub with a walk-in shower. The tub’s 1-1/2” drain is centered ~3-7/16” above a concrete floor slab. The drain is fed into a 2-inch no-hub cast-iron P-trap (Charlotte EZS 10) in a common wall between two back-to-back bathrooms. Of course, I need to match the elevation of the existing P-trap inlet, but with the lowest-profile commercial clamping drain I can find (KBRS SO-42281), I still end up with an approximate 9-inch high shower curb. This is based on a dimension of ~3” from the upper surface of the drain’s bottom piece to the center of its outlet (see attached drawing for details).

    Of course, I would like to reduce that step-in height as much as possible, so my thought is that by combining a standard Oatey 42314 clamping drain with a Charlotte 2” ABS 706-X Solvent Weld P-Trap I can get the outlet higher (1-1/2” vs. 3” from the upper surface of the drain’s bottom piece). This will give me a more reasonable 7-1/2” curb, plus it will reduce my pre-sloped bed mud requirement by approximately 1.7 c.f. Clearance for the P-trap in the concrete floor slab will be needed, but that’s not difficult.

    Basically, I am adding a second P-trap to the one that’s already in the common wall.

    Q1. Does this violate any 2019 Uniform Plumbing Code requirements?

    Q2. Would it introduce any other issues that I should be aware of?
     

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  2. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    UPC 1001.2 Where required.. blah blah blah... Not more than one trap shall be permitted on a trap arm. More blah blah blah..

    UPC 1004.1 Prohibited... Blah blah blah... No fixture may be double trapped. More blah blah blah.

    Of course I can only find the bad stuff.. but not the part of the code that allows the installation of a shower on a tub drain without upsizing the trap arm so long as only ONE showerhead is operable at any given time... still looking for that exception. We do it all the time. Inspectors generally insist that a bushing be installed in the shower drain body.
     
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  4. RSquirrel

    RSquirrel New Member

    Joined:
    Apr 18, 2012
    Location:
    California
    Thanks for the informative response. In the meantime, I have found a clamping drain with a side outlet that will meet my needs (APPROVED VENDORS, 2" NO HUB ANGLE SHOWER DRAIN, CAST IRON, ROUND TOP, M77489). BTW, I too stumbled upon the okay for a shower to keep a converted tub's 1-1/2" drain with one head, but it was only someone's statement, NOT a direct code reference.

    BTW. The website says that to connect the outlet, an ERB is required. Does "ERB" mean anything to you?
     
  5. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    ERB doesn't ring a bell. Got a link to that drain?
     
  6. RSquirrel

    RSquirrel New Member

    Joined:
    Apr 18, 2012
    Location:
    California
    Hi TR,

    Here's the link to the drain I cited.

    https://www.mrsupply.com/approved-v...NcaxrQoQKtqXAQNZBI_umWTDeyqyxKu8aAj_TEALw_wcB


    I got the one above confused with another similar one. The reference to 'ERB' is found in the description for the one below. I assume that since the two are similar, the first one might also need an 'ERB,' but without knowing what it is, I may be wrong. (here's the link to this second product):

    https://www.alpineandyork.com/index...uKowPjAkmANv80Aa4sAOA3aycJzAdTd0aAq4uEALw_wcB
     
  7. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    ERB is a suffix to the model number to indicate the typical 2" threaded adjustable grate/finished metal strainer piece.

    • 4" throat, 2" outlet ***No Suffix needed***
    • 8" overall diameter
    • To adapt to 2" throat add ERB ***Suffix needed for this style top. You want this***
    And likely the Infinity drain is going to be PVC or ABS which is way easier to work with than the other drain, which I think is a Mifab product and likely cast iron.
     
  8. RSquirrel

    RSquirrel New Member

    Joined:
    Apr 18, 2012
    Location:
    California
    TR,
    Once again, you've helped me down the right path. As for needing the adjustable grate, I don't believe I do need it, as I will be using a Home Depot-marketed linear drain (IPTLD-SP26 by IPT Sink) which includes its own externally-threaded adapter (standard 2" PT) with internal O-rings to accept the drain pan's outlet. As for the Infinity Drain product, it costs a lot more and its grate seems to be of a larger diameter (not 2" PT) thread. I have to adapt to no-hub cast iron P-trap in the common wall anyway, so don't think a cast iron drain won't be any issue.
     
    Tuttles Revenge likes this.

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