Sprinkler Selection (2)


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Sprinkler Selection (2)

  1. 1. Sprinkler Selection
  2. 2. Sprinkler Selection <ul><li>Spray </li></ul><ul><ul><li>Pop-up </li></ul></ul><ul><ul><li>Shrub spray </li></ul></ul><ul><li>Rotating </li></ul><ul><ul><li>Impulse or Impact </li></ul></ul><ul><ul><li>Pop-up Gear driven </li></ul></ul><ul><li>Bubblers and drip irrigation </li></ul>
  3. 3. Considerations <ul><li>Goal – select the type that will cover the area properly using the least number of sprinklers </li></ul><ul><li>Windy – low angle </li></ul><ul><li>Arid climate – higher flow or multiple irrigation cycles </li></ul><ul><li>Slopes </li></ul><ul><li>Soil </li></ul>
  4. 4. Precipitation Rate <ul><li>Don’t mix on one valve circuit </li></ul><ul><li>Matched Precipitation Rate Sprinklers (MPR) </li></ul><ul><li>See Rainbird Catalog 18-22 MPR Series </li></ul><ul><li>(Stryker) Look for this feature </li></ul>
  5. 5. Spray Heads <ul><li>For smaller areas </li></ul><ul><li>For areas with enclosed borders </li></ul><ul><li>Require tightly controlled spray </li></ul><ul><li>Dense tree growth that would get in the way of rotor spray </li></ul><ul><li>Mixed plantings needing different amounts of water </li></ul>
  6. 6. Spray Heads <ul><li>Fixed spray heads </li></ul><ul><li>Fan shaped pattern of water </li></ul><ul><li>Spaced up to 18 feet apart </li></ul><ul><li>Need between 20 and 30 PSI to operate properly </li></ul>
  7. 7. Typical (Standard) Spray Patterns
  8. 8. GPM Calculation for reduction of Spray heads <ul><li>Use the chart </li></ul><ul><li>Actually just reducing the pressure </li></ul><ul><ul><li>Example: </li></ul></ul>Modified 1.65 GPM 14 ft 25 PSI Original 1.85 GPM 15 ft 30 PSI
  9. 9. Other Spray Patterns <ul><li>Specialty Strips </li></ul><ul><ul><li>Center </li></ul></ul><ul><ul><li>Side </li></ul></ul><ul><ul><li>End </li></ul></ul><ul><li>Variable Arc Nozzle </li></ul><ul><ul><li>For occasional odd shaped, in between areas </li></ul></ul><ul><ul><li>From 0 o to 360 0 </li></ul></ul><ul><li>Stream Spray - fingers of water </li></ul>
  10. 10. Stream vs Fan Sprays slopes, tight fine grain soils PR - 1-4 in/hour PR - 1/3 – 1 1/2in/hour 5-18 feet 5-22 feet (small areas) 20-30 PSI 15-30 PSI (low) Fan Stream
  11. 11. Rotors <ul><li>Rotating streams of water </li></ul><ul><li>Impact rotors – fire bursts of water </li></ul><ul><li>Gear Driven rotors </li></ul><ul><ul><li>very quiet </li></ul></ul><ul><ul><li>lower maintenance </li></ul></ul><ul><ul><li>smaller in size </li></ul></ul><ul><li>Multi-stream rotors – expensive, much higher maintenance </li></ul>
  12. 12. Rotors <ul><li>Spacing – 18 – 55 feet apart </li></ul><ul><li>5 – 100 gpm </li></ul><ul><li>PR – ¼ - 2 in/hour </li></ul><ul><li>Require more water pressure to operate than spray heads </li></ul><ul><li>(Stryker) water pressure at the head must exceed the distance between heads </li></ul><ul><ul><li>If you want 35 feet apart, be sure 35 PSI </li></ul></ul>
  13. 13. Rotors - warning <ul><li>(Stryker) Don’t rely on manufacturers’ radius on charts </li></ul><ul><li>If less than 6 GPM, maximum spacing should never be more than 35’ between sprinklers </li></ul><ul><li>(Stryker) They don’t test with wind </li></ul>
  14. 14. Rotor selection <ul><li>Select the appropriate Nozzle size for each rotor to match the precipitation rates </li></ul><ul><li>The rotation speed is the same regardless of whether the rotor is adjusted to a full circle or a quarter circle </li></ul><ul><li>If a quarter circle, passing over the same area 4 times in the same amount of time as 1 full circle </li></ul>
  15. 15. Rotor Precipitation Rates <ul><li>If the nozzle is the same the quarter circle will put down 4 times as much water on the area as a full circle </li></ul><ul><li>To match: change the nozzle to cut the amount of water to ¼ </li></ul><ul><li>Half circle – nozzle with ½ amount of the water of a full circle, etc. </li></ul><ul><li>See Rainbird catalog pg. 74 & 75 </li></ul>
  16. 16. Rotor adjustment <ul><li>If you adjust the radius you need to adjust the nozzle too </li></ul><ul><li>(Stryker) Don’t use rotors with nozzle flows less than 2.5 GPM except in corners (1/4 circle) </li></ul>
  17. 17. GPM Calculation for reduction of Rotor heads <ul><li>GPM stays the same </li></ul><ul><ul><li>Doesn’t change the amount of the water coming out of the nozzle </li></ul></ul><ul><ul><li>Use the pin to reduce the radius </li></ul></ul><ul><ul><li>Uneven water, dry spots </li></ul></ul><ul><ul><li>Should be reducing the GPM too, but you don’t </li></ul></ul><ul><li>Only use the radius adjustment screw on rotors when nothing else will work </li></ul>
  18. 18. Stryker’s Cheat Chart – Rotors 20-29’ Spacing 3.2 GPM 30 PSI Full Circle 2.4 GPM 30 PSI ¾ circle 1.6 GPM 30 PSI ½ circle .8 GPM 30 PSI ¼ circle
  19. 19. Stryker’s Cheat Chart – Rotors 30-39’ Spacing 6.0 GPM 40 PSI Full Circle 4.5 GPM 40 PSI ¾ circle 3.0 GPM 40 PSI ½ circle 1.5 GPM 40 PSI ¼ circle
  20. 20. Stryker’s Cheat Chart – Rotors 40-55’ Spacing 11.0 GPM 55 PSI Full Circle 8.0 GPM 55 PSI ¾ circle 5.5 GPM 55 PSI ½ circle 3.0 GPM 55 PSI ¼ circle
  21. 21. How to decide Irrigation Water City Water Need 40 PSI minimum Lower PSI Costs more per sprinkler Less per sprinkler Less trenching More sprinklers, more trenching 18-55 feet apart Up to 18 feet apart Rotor Spray
  22. 22. Body Styles <ul><li>Pop-up </li></ul><ul><ul><li>Installed below ground </li></ul></ul><ul><ul><li>Available 3”, 4”, 6” 12” above ground </li></ul></ul><ul><ul><ul><li>Need to clear the lawn height </li></ul></ul></ul><ul><li>Shrub style </li></ul><ul><ul><li>On a ‘riser’ </li></ul></ul><ul><ul><li>Use away from traffic patterns </li></ul></ul><ul><li>Cost the same </li></ul>
  23. 24. Metal or Plastic <ul><li>Metal is more durable </li></ul><ul><li>Until 1970’s, metal was preferred material </li></ul><ul><li>Now plastic is the most common </li></ul><ul><li>Metal too expensive </li></ul><ul><li>Some have a brass fitting </li></ul><ul><li>(Stryker) not much difference today </li></ul>
  24. 25. What to look for <ul><li>Spring retraction </li></ul><ul><ul><li>Use a spring to pull the pop-up riser down into the case </li></ul></ul><ul><ul><li>Stay away from gravity retraction </li></ul></ul><ul><li>Wiper Seal – soft plastic seal around the pop-up riser stem that seals the riser wo it won’t leak </li></ul><ul><ul><li>Keeps the dirt out </li></ul></ul><ul><li>3” pop-up height or higher </li></ul><ul><ul><li>Most pros use 4” in lawn areas and 6”-12” in shrub areas </li></ul></ul>
  25. 27. Pressure Requirements <ul><li>Spray Type </li></ul><ul><ul><li>(Stryker) When designing, use 30 PSI unless you know that it is lower </li></ul></ul><ul><ul><li>If the pressure is lower, place sprinklers closer together </li></ul></ul><ul><li>Rotor Type </li></ul><ul><ul><li>Won’t work well with less than 30 PSI </li></ul></ul><ul><li>Drip Emitters </li></ul><ul><ul><li>Usually best at around 20 PSI </li></ul></ul>
  26. 28. Mix and Match <ul><li>Don’t mix and match on the same valve </li></ul><ul><li>Special valve to reduce the pressure for the lower pressure sprinklers </li></ul><ul><li>Design for the high pressure </li></ul>
  27. 29. Trajectory of Water <ul><li>As water comes out of the sprinkler head, it travels in a curved path through the air to the ground.. Trajectories of spray include: </li></ul><ul><li>0 degree trajectory -- this flat spray can be used for throwing water under low shrubs </li></ul><ul><li>10 degree trajectory -- this low angle spray can be used in a high wind situation and for shrub and groundcover beds </li></ul><ul><li>22-26 degree of trajectory -- this is the standard trajectory thrown by most sprinklers </li></ul><ul><li>30-35 degree trajectory -- this is a special trajectory used for throwing water over plant material such as groundcovers and gardens </li></ul>