How would you water this?

Discussion in 'Irrigation' started by justgeorge, Feb 28, 2008.

  1. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    Bidding on a commercial job. The biggest area to water is about 400'x70'. A new water meter will be set for the POC and is only 20' from where the big area starts.

    What size water meter and what size lines would you run? I use Hunter, should I stay with Hunter I-20s and run 8 or 10 on a zone with 35' spacing and 1 1/2" lines? The 70' dimension fits really nice for that. If I move up to the I-25s or I-35s the spray pattern won't adapt very well to the 70'; most nozzles are in the 45-55' range.

    Seems like 3 rows of I-20s using 1 1/2" line with a 1" water meter could cover that area with about 40 rotors and 4-5 zones.

    Thoughts?

    Thanks,
    George
     
  2. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    You really need to get your pipe size, GPM, and PSI at the POC before you can determine number of zones, number of heads, pipe size for laterals and main, and GPM for zones.
     
  3. Kiril

    Kiril LawnSite Fanatic
    Posts: 18,308

    Ditto. Get the necessary data before designing the system unless you like doing things twice, and the second time for free.
     
  4. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    Sorry, that's my point. The water meter isn't there yet, so the system can be designed with whatever size meter and mainline/lateral lines work best. Coming directly off a city water main. Figure at least 100 psi, so I'll most likely need to regulate that downward. The building has a fire-supression sprinkler so there has to be tons of pressure and GPM available.

    Thanks
     
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,997

    You might actually ask the city what the pressure is in that main you'll connect to. I've seen old systems use something like a 50 foot triangular spacing on a 70x400 plot, and get the job done with 20 heads.
     
  6. hoskm01

    hoskm01 LawnSite Fanatic
    Posts: 5,690

    Without knowing more, a shot in the dark...

    If money is no matter, go as big as possible, meter, valves, heads etc, and throw some 70 footers in the corners and down the sides.



    Drawing nowhere near scale, but you get the point. Main down the middle, if possible, in-line valves, RB8000 would be my choice, Hunter is probably fine if you prefer.

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  7. justgeorge

    justgeorge LawnSite Senior Member
    Posts: 352

    Interesting design - sure would cut down on labor with only 14 heads. Material costs would be higher, 14 heads @ $50 each vs 40 heads at $13 each. The corner nozzles would be about 13gpm vs 22gpm on the sides, so not too far off even coverage (although a 13gpm nozzles drops the spray down to 59'). About the same number of zones. Your design would use less pipe, but would need bigger $$ pipe & valves. 2" meter vs 1" meter.

    Waiting to hear from a plumber who can tell me more about my options for meters, etc. The meter pit is a big concrete vault so there should be plenty of room for whatever is needed.

    Thanks.
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,997

    Stagger 6 heads down the middle, and you get the 50 foot triangular spacing.
     
  9. hoskm01

    hoskm01 LawnSite Fanatic
    Posts: 5,690


    This should be a good one. Have you won the job, or going for bid? Pics? When do you start?

    Kiril would like you to see if you can get some more turf in there, not quite enough as is.
     
  10. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    But you still don't know the specs at the POC. right? For all I know it could be a 3/4" supply, so installing a 1 1/2" mainline or a 2" meter is probably overkill and a waste of money. We can't design zones without knowing the available GPM or PSI. we can guess at it, but I think we've all stopped doing that because we've screwed up once or twice in the early days by doing this.
     

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