Does anyone install a drain on indoor RPZ's?

Discussion in 'Irrigation' started by Dirty Water, Jun 17, 2007.

  1. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799


    Does anyone here do this?
  2. Mad Estonian

    Mad Estonian LawnSite Senior Member
    Posts: 280

    I've never had to, and DCVAs are the code here, but if I was installing one inside, I'd make sure the relief port water had somewhere to go. Which kind of raises an interesting question that I asked my Cross Connection class instructor. Namely, if the water that's backflowing might be toxic, that being the whole idea obviously, shouldn't the relief port drainage be directed somewhere it can't cause any contamination? He didn't really have an answer for that.
  3. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    I've never installed one inside, but have serviced probably 20-25 that are. Out of those 20-25, probably less than 5 have the drain even though it is required by building code. One couple had one installed a few years ago. They had a plumber take out the PVB outside, and put in the RP inside, and didn't put in the drain. When I saw it I commented on it and the wife called the plumber immediately and had me talk to him. He had no idea it was code, even though he is licensed.
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,720

    Since the entire outdoors is more or less considered to be contaminated, the outdoor above-grade installation of an RPZ would cover all bases. The indoor drainage of the relief ports (note the air-gap fittings in the picture) gets you the same deal, since there really isn't anything such as a 'non-toxic' drain pipe.

    I imagine a lot of RPZs were installed indoors, in the early days, when sprinkler guys were being (mis)informed by some suppliers that the new-fangled RPZ could go in the basement plumbing in the exact same way the no-longer-approved DCVA would.
  5. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,984

    That's a nice install, Jon. It's exactly how we wrote the code for Bainbridge
    Island, proper air gap & drain to stormwater. We did permit drains to sump
    in outdoors, tho there is still some thought about this method. In a lot of
    outdoor installs, there is no option. RPs should all go in this way!
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,720

    One major flaw with all indoor installs like the one pictured, is the lack of a strainer on the supply side of the RPZ. Without one, it is possible for debris to plug the port that supplies the pressure to keep the relief valve closed. Were that to occur, the relief blows wide open, and your air gap and drain are not prepared for that event.
  7. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,984

    Good point..mite be suggesting that to the purveyors for inclusion & BATs
    should remember to check that strainer when annual test is done. Should be
    on the test report also.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,720

    I could escape an absolute need for the indoor drain, if I were to install a PRV at the inlet of the RPZ. That supplies a strainer, and also, depending on pressure setting, eliminates the relief valve 'burping' ~ in general, though, I don't want to see them indoors. I'll do the extra winterizing work, and be glad no indoor flooding can happen.
  9. Mjtrole

    Mjtrole LawnSite Member
    Posts: 226

    indoor rp drains need to be on them if they are getting inspected, I have yet to see an inspector let one go without a drain. I don't think the whole drain idea is to route it to a floor drain, it maybe the idea of when it discharges that contamination doesn't get on a water meter or other materials like in dirty's picture.

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