Figuring GPM

Discussion in 'Irrigation' started by tomcl, May 6, 2007.

  1. tomcl

    tomcl LawnSite Member
    Posts: 43

    How are most of you figuring out gpm for larger pipe than off a hose bib?? Like a 2" or 3" line. I have a toro guage but I need to do larger pipe--Anyone??
     
  2. No Rush

    No Rush LawnSite Member
    Posts: 203

    what size water meter do you have?
     
  3. tomcl

    tomcl LawnSite Member
    Posts: 43

    2 inch water meter
     
  4. No Rush

    No Rush LawnSite Member
    Posts: 203

    a 2" meter is designed for 32 to 160 gpm.
     
  5. tomcl

    tomcl LawnSite Member
    Posts: 43

    is there any easy of getting that number a little more exact?
    Thanks for your responses.
     
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,014

    What are the watering needs of the system? How much acreage are you covering?
     
  7. tomcl

    tomcl LawnSite Member
    Posts: 43

    about 65,000 irrigated square feet.

    PSI is about 62-sorry I didn't mention that earlier
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,014

    Sight unseen, I would consider using about 30-40 gpm, which 2-inch poly can handle without much friction loss. That way, you could plow in poly pipe for the system. With a 2 inch meter, and a 2 or 3 inch supply line, you almost eliminate friction losses in the supply, and can hope for around 50 psi at the heads.
     
  9. No Rush

    No Rush LawnSite Member
    Posts: 203

    There are many variables that go into a design; elevation (changes), PSI, water meter size, pipe sizing, valve sizes, friction loss calculations and you should always try to make your connection as close as possible to the water meter. We would need to know more about what you are trying to accomplish.
     
  10. Remote Pigtails

    Remote Pigtails LawnSite Senior Member
    Posts: 581

    I looked up Forsyth on the map. East MT north of the Crow reservation. What's happening in that area is it growing? Just curious. I love traveling MT.
     

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