Irrigation Leak Down Testing

Discussion in 'Irrigation' started by ktgatlin, Jun 3, 2008.

  1. ktgatlin

    ktgatlin LawnSite Member
    from So Cal
    Posts: 24

    This might be a beginner question. I was just wondering if there is such a thing as a leak down test, either Hyrdo or Air for PVC lines.

    In essence it would mean capping all the main and branch lines and then pressurizing the lines with air or water with PSI guage on the line.

    Leave the "fluid" in the lines for a set amount of time and look for slippage on the PSI guage.

    I did research and found that pressurizing PVC lines with air can be a bad thing. It sounds like PVC can shatter like a grenade, especially pressurized with air.

    I did a few checks like this before burying my lines and I found a few leaks, 2 leaks.

    I laid out a majority of my lines in PVC. I will be running some 1/2 and 1/4 in poly but those runs will be pretty short.


  2. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    Years ago when I worked for someone else, we installed two systems for state run rest stops along the highway. We had to do a pressure test like you mentioned on the mainline. Used air, no liquid. But I don't remember specifics on it.
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,708

    You don't need high pressures for leak testing, so the usual PVC caution needn't apply. In the real world of lawn sprinkler zones, a dripping fitting on a zone is no biggie.
  4. WalkGood

    WalkGood LawnSite Bronze Member
    Posts: 1,910

    I've never seen 1/4 poly. :confused:
  5. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    1/4" spaghetti drip tubing maybe...
  6. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Take a pressure test at the distal end of each of your zones on install, then you have a baseline pressure to work with in order to diagnose zone performance and any possible leaks.
  7. Ditto... Not sure why you'd get a hangover about small leaks in lateral line pipes. One technique we use on mains is to shut the water down at the dcva or poc. leave it off for 10 minutes. Turn it back on and if the meter needle jumps we have a small leak. No movement at all we are safe. Not a 100% perfect method but a low cost way to evaluate for leaks sometimes.
  8. Waterit

    Waterit LawnSite Silver Member
    Posts: 2,906

    We do a lot of installs "on board" our local Navy base. They require pressure testing of all piping before it can be covered. We install everything except the funny pipe and screw teflon'd plugs into the end fittings. Then use a compressor to pump it up to about 75 PSI. If it holds with no more than a 2PSI drop over 2 hours, we are good to go.

    Ridiculous? Of course. But that's the military for you.
  9. ktgatlin

    ktgatlin LawnSite Member
    from So Cal
    Posts: 24

    I did almost the same test on my system. Turned out pretty good. I also did a water test, plugged all the outlets (all 1/2 threaded) and found leaks.

    My biggest issues were leaks on 1in threaded PVC fittings. I used both teflon paste and teflon wrap. Two of those MAs refused to comply and kept leaking. I redid it twice and still it leaked. I cut it out and did all glue socket fittings. I found these during wet testing.

    Im not too worried about leaks in lateral lines. I used PVC for lots of my supply lines. I should have planned on using more PE instead of PVC. I just went with what I knew and was comfortable with. I will still use PE but I ran PVC lateral lines to major pick up points where I will continue with PE.

    I wish that I could have been a good irrigation installer's helper for a few jobs...what I would have learned...
  10. ktgatlin

    ktgatlin LawnSite Member
    from So Cal
    Posts: 24


    Thanks! This sounds cool. I will try this and see what I get.

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