Wilkins BR4

Discussion in 'Irrigation' started by irrigatorsllc, Jun 15, 2006.

  1. irrigatorsllc

    irrigatorsllc LawnSite Member
    Posts: 13

    Specs: I have 160 psi Static, 1" city mainline to meter, 5/8 meter, 15 gpm.

    Pressure Losses:

    8.3psi for Water Meter
    10psi for city side DV and Irrigation side PVB combined
    5psi for total mainline
    4psi for Valves
    2psi for elevation
    30psi sprinkler
    6psi for laterals

    Total PSI LOSS = 65.3

    I would like to run 1" Class 200 everywhere.
    Of course I am using worse case senario for psi/100 value
    My PSI/100 value is at 1.9 which gives me the smallest possible pipe size at 1 1/4".


    1. - Does this mean my Dynamic PSI is around 94psi?
    2. - Should I get the Wilkins BR4 to regulate pressure?
    3. - Is there something I can use to lower the GPM to around 11 so that I can use 1" all around. (Would you save cost and figure for each section of pipe?)
    4. Am I a complete idiot for asking to many question?

    P.S. - I've yet to install a PVB or BR4 - any diagrams would be welcome on how to do this with PVC

    YOU GUYS ARE AWESOME
     
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496



    Yes... 160 minus 66 = 94 PSI.

    If that's the way you want to go. There are also pressure regulating valves and sprinklers so you have a lot of options.

    Use sprinklers that won't push any given one zone above the maximum 1" friction loss charts for 5' per second. My charts show that as long as each zone does not exceed 16 GPM then you can use 1" CL 200 pipe.

    No... This is some of the best information ever supplied with questions. :)
     
  3. Ground Master

    Ground Master LawnSite Senior Member
    Posts: 505

    I would absolutely use a pressure regulator. I would install it before your backflow.
     
  4. irrigatorsllc

    irrigatorsllc LawnSite Member
    Posts: 13

    "Use sprinklers that won't push any given one zone above the maximum 1" friction loss charts for 5' per second. My charts show that as long as each zone does not exceed 16 GPM then you can use 1" CL 200 pipe.
    "

    Could you explain this some more? This one has me kinda lost.
     
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,017

    I would leave the '30 psi sprinkler' out of the equation. It doesn't help the math. A PRV is not a 'straight-line' sort of device. Their performance curves can easily be misread. You'll set the BR4 at 100 psi or less. The pressure loss from the performance curve gets subtracted from that. Their charts are based on your having the regulated pressure at least 50 psi lower than the inlet pressure. Not a problem when you begin with 160 psi.

    So, revisit the list of numbers.

    8.3 water meter, and supply line loss don't really figure in, because they are upstream of the regulator.

    For all the rest, a 20 psi loss is more than conservative.

    The odds are good that you'll be able to set the BR4 at much less than 100 psi.
     
  6. irrigatorsllc

    irrigatorsllc LawnSite Member
    Posts: 13


    Wouldn't I want to allow for the 30psi that my highest psi sprinkler would need in order to determine my working pressure, being that it is downstream?
     
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,017

    This isn't an electric circuit, where all the numbers make a 'perfect loop' and add up to zero. This is more like 'sloppy math' where you work the numbers to make sure you have enough pressure remaining to make any one of your sprinklers operate properly.

    You pay attention to water velocity when you select pipe sizes. The idea is to prevent/reduce water hammer damage. Five feet per second is a common benchmark. Friction loss charts usually note that threshold. The longer the pipe, and faster the flow, the more water hammer you can get.
     
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Actually I design to the "worse case scenario" sprinkler; that sprinkler head that is the farthest, highest, most pressure loss, etc. on the entire system. If I can get that one sprinkler to operate properly then all other sprinklers on the system will properly function.
     
  9. Valveman

    Valveman LawnSite Member
    Posts: 53

    With the BR4 you have some adjustment. If the furtherest sprinkler is not doing what you want you would be able to adjust it by increasing or decreasing the pressure with the BR4. That is as long as your pipe system does not cause too much restriction.
     
  10. irrigatorsllc

    irrigatorsllc LawnSite Member
    Posts: 13

    My longest run is 308'. 190' until I hit my first head. So, I guess I am looking at 1 1/4" pipe for this zone. Pressure shouldn't be any problem. GPM is restricting me from using 1" I think. Not sure how to lower the flow rate to around 11 gpm on this run or overall for that matter. I was trying to save the customer some money as per request, but I don't want to save him money only to have it cost me money later on, so I'm thinking use 1 1/4" to be safe. So ok, or am I way off?
     

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