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Optimum Triangular spacing

Discussion in 'Irrigation' started by MarcSmith, Apr 26, 2005.

  1. MarcSmith

    MarcSmith LawnSite Fanatic
    Posts: 7,157

    We just had some Irrigation work done and the General contractor wants to sign off on the irrigation and I don't.... We do not have as builts yet, and I am going out today to measure and run the system in zero wind conditions...When we tested the system we had a slight breeze. and had some coverage issues.

    The system utilitlizes mostly 12' and 15' rain bird sprays in triangular spacing with a few areas under square....Given zero wind, optimun pressure, flat terrain, what are the max distances the heads shoudl be apart...in a square and triangular pattern

    Some zones are bed areas and some are turf areas....

  2. Broker

    Broker LawnSite Senior Member
    Posts: 382

    go to rainbird.com and look up the nozzles and input the gpm and operating pressure.
  3. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    I haven't looked up that info in a long time. The correct answer is in a chart somewhere, and it varies by location and prevailing winds. I generally use (If I have to do max spacing which I avoid) 60% of diamater. So 18' between rows for 15' heads. FWIW, About 6 or 7 years ago, I bailed out the sales guy I was working for/with by using Triangular spacing on I-25's. We used Head to head within Rows and Max distance between rows and that system works very well. We also combined like heads within the zones. i.e. all full circle heads are on dedicated zones and the also only have half nozzles and run twice the time. I like this solution because you get more uniform distances. The larger nozzles for the full circles, not only cost you extra zones, they throw a percentage farther than side heads that use 1/4 or 1/2 the gpm.
  4. MarcSmith

    MarcSmith LawnSite Fanatic
    Posts: 7,157

    thanks guys, the 60% was number I was looking for... what a system they installed :( Ive got more low/no coverage than I can count on two hands. and thats before they install any shrubs...

    they streched themselves pretty thin. I ran the system this morning after I made my post. so I had no wind and in theory no pressure issues...Al though I have no idea what the pressure it is fed from about 30ft below the installation, so a booster pump may be needed...Pressure did seem kind of low....but with no guage its a SWAG
  5. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    Just out of curiousity, how far are they spaced? If it is a pressure issue, sometimes smaller nozzles can make a difference. Did they use all Van's or fixed spray nozzles? You might be able to fix this yet.

    Good luck

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