Square vs Triangular

Discussion in 'Irrigation' started by burlap, Oct 15, 2005.

  1. burlap

    burlap LawnSite Member
    from Indiana
    Posts: 66

    Designing a system for our yard a square arrangement of heads seems to be so much easier to work with and set up. A triangular arrangement seems much more difficult, especially on the ends. Is a triangular arrangement that much better? Also I see formulae for precip rates and I wonder if they take overlap into consideration. Whether square or triangular, areas of the lawn will have 2,3,&4 times overlap-especially at head to head. Is there a formula that takes spacing into account. Thanks, burlap
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,697

    Use whatever spacing works for you. You can always take the area watered and the gpm used, and calculate a precipitation rate from that. Or just place a tunafish can on the lawn and see how long it takes to fill up from the sprinklers.
  3. sheshovel

    sheshovel LawnSite Fanatic
    Posts: 5,112

    I am not sure I understand exactly what you are asking.
  4. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    According to the manuals triangular spacing is more efficient and allows you to stretch head spacings, possibly reducing the overall number of heads. However, for triangular spacing to work some of the heads must throw across your zone boundary (because the boundary sprinklers are also set farther apart) which could cause excessive water to planters, hardscapes, buildings, etc. The nature of a sprinkler head is that when the end of the radius is reached the amount of water at that point is mostly just a trace element and will not support good plant growth. That's why the triangulated sprinklers have to be bumped in the direction of the boundary.

    I use both types (square/triangular) in my designs. For a typical square/rectangle area I'll use square spacing with head-to-head coverage. I've noted no lack of coverage or precipitation. On sports fields you almost always have to use some type of triangulation due to the odd shapes you encounter. I always design perimeter sprinklers on their own valves and full circles on their own. This way the amount of water reaching specific areas can be controlled by the program and length of watering and an overall watering balance is achieved. (A typical HS baseball field will have 10-13 zones depending on its unique layout.)

    In your situation (typical residential) I'd just stick to the square spacing. Now on my front yard (corner lot) I installed head-to-head (vs. triangular wide spacing) along the borders and then triangulated the interior FC heads allowing me to bump away from the borders. I have separate valves for PC/FC sprinklers that allows me better control over the entire area.
  5. burlap

    burlap LawnSite Member
    from Indiana
    Posts: 66

    Thanks for the help. On the precip rate, I've seen formula for determining the rate, but they don't ask whether it's head to head, 80%,or 60%. I would think that would make a difference. I'm still working on irrigation timing, I also use one of my pumps to air condition my house and I'm trying to figure a schedule. Thanks again, burlap

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