Pressure and GPM - Designing System

Discussion in 'Irrigation' started by jbell36, Sep 24, 2012.

  1. muddywater

    muddywater LawnSite Bronze Member
    Posts: 1,813

    I doubt the op had a 100 ft high mountain in the backyard he was working with. Realistically, probably a 30' rise at most whereas .06 of lb pressure isn't going to amount to didley squat. NOW if he was building a water tank in his client's back yard he just might need your expertise!

    Rule of thumb is still off by .03 psi.

    Cool job we are working on. I need to get a pic of all 91 heads in this sections running at once.

    irrig1.jpg
     
    Last edited: Sep 26, 2012
  2. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,092

    Right is right, wrong is wrong. Generally rule of thumb is where we find a sweet spot for daily use.

    That doesn't excuse sleeping in class.
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  3. muddywater

    muddywater LawnSite Bronze Member
    Posts: 1,813

    Well if right is right and wrong is wrong then your rule of thumb is wrong. If i ever install irrigation with a poc at the bottom of a mountain, i will just google it like you did.
     
  4. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,092

    Don't you ever call me a liar punk
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  5. muddywater

    muddywater LawnSite Bronze Member
    Posts: 1,813

    Time to pour you a liquor drink mr jim. You must have one hell of a better memory than all the rest of us. Either that or you install alot of pipe up mountains.
     
  6. muddywater

    muddywater LawnSite Bronze Member
    Posts: 1,813

    Actually .5 is more conservative than .433 when going up an incline. I am banking on a 50 lb pressure loss with .5 and you are banking on a 43 lb pressure loss per 100'. 6.7 psi of gravy.
     
  7. txirrigation

    txirrigation LawnSite Senior Member
    from Texas
    Posts: 977

    Rule of thumb is a Jim Crow law pertaining to the size of stick you could beat your wife with; as it could be no thicker than your thumb. Therefore by saying "rule of thumb" he means a rough measurement that is quick....

    .... holy crap, that was the first time I actually used my expensive degree.


    In the real world of installing there are a lot of "rule of thumb" measurements made. If you would like to walk onto a commercial job site and stop everything to get scientific more power to you, but you'll go broke quick. Making quick judgement calls based on experience and knowledge you can recall quickly is what separates the Men from the Boys. Having a solid "rule of thumb" list invaluable.
     
  8. muddywater

    muddywater LawnSite Bronze Member
    Posts: 1,813

    Well I agree. I doubt I will be able to get .433 out of my head for awhile now(many thanks jim), but I was always able to remember 1/2 lb per foot. And that is a more conservative number when going uphill.
     
  9. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,092

    You're welcome
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