Maximum Dripper Line Runs

 

Star-Tip 1022

Gardening Tips for successful and beautiful Landscapes and Gardens

 

Often a customer is trying to make some additions to their landscape or perhaps trying to correct a flow problem. It is important to have an idea regarding the maximum number of emitters (drippers) that can be used from a single ¼ inch tubing.

 

Due to the typical complexity of most irrigation designs, simple charts showing how many feet you can run 1/4 “ feeder line with emitters at various spacing may (or may not) not be useful.

 

Maximum ¼ inch line run chart

Maintaining Pressure in your Drip System

First; Your ½ inch supply line

Next; Your 1/4 “ Feeder line

Pressure loss Example

 

 

Maximum ¼ inch line run chart

Maximum run of 1/4" feeder tubing and 1/2" (.600 ID) supply hose with PC emitters

 Flow Deviation 7%

 Emitter spacing in feet on 1/4" feeder tubing

 Emitter spacing in feet on 1/2" supply poly tubing

Products

  Flow rates

 1'

 2'

3'

4'

 5'

 1'

 2'

3'

 4'

 5'

PC Emitter

 1 gph

 35

 50

 72

 88

105

 320

 530

 670

820

970

PC Emitter

 2 gph

 25

 36

 45

 56

 65

 190

 310

 420

 510

 610

PC Emitter

 4 gph

 14

 22

30

 36

 40

120

200

 250

 320

 450

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Maintaining Pressure in your Drip System

 

When making decisions about how many drips (emitters) you can have in one zone, and then how to lay these drips out, you need to take into consideration “loss of pressure” through the valve, and across the supply and feeder lines. If you begin with a regulated 20 lb. pressure, you can not afford to lose more than 5 lbs. before the end emitter and expect to have reliable water supply. You can lose as much as 6 psi at your control valve. If you use an in-line pressure regulator, the loss of pressure from the valve is not relevant.

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First; Your ½ inch supply line

Pressure loss in ½” supply hose in PSI

 GPH

 

 10’

 20’

 50’

 100’

 200’

 300’

 400’

 500’

 600’

 700’

 800’

 900’

  120

 

 0.2

 0.4

 0.9

 1.8

 3.6

5.4

  7.2

 9.0 5.4

 10.8

 5.4

 7.2

 16.2

 180

 

 0.4

 0.8

 2.0

3.9

 7.8

 13.7

 15.6

19.5

 23.4

 27.3

 31.2

 35.1

 240

 

0.7

 1.3

 3.4

 6.7

 13.4

 20.1

 26.8

 33.5

 40.2

 46.9

 53.6

 60.3

 300

 

 1.0

2.0

 5.1

 10.1

 20.2

 30.3

 40.4

 50.5

 60.6

 70.7

 80.8

 90.9

360

 

1.4

 2.8

7.1

14.1

 28.2

 42.3

 56.4

 70.5

 84.6

 98.7

 112.8

 126.9

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Next; Your ¼ “ Feeder line

Pressure loss in ¼ “  feeder tube in PSI

 GPH

 2’

 4’

 10’

 20’

 Length of ¼ “ feeder tube to create 2 psi loss

GPH

 Feet

2

  120

 5

45

 10

13

 30

3

 

 

10

0.3

 0.6

 1.5

 3.0

20

 1.0

 2.0

 5.0

 10.0

30

 2.1

 4.2

 10.5

 21.0

40

 3.7

 7.4

 18.5

 37.0

50

 5.5

 11.0

 27.5

55.0

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Pressure loss Example

Pressure loss (psi) on 1/4" feeder tube with 1 gph emitter

 Number of emitters

Feeder length in feet

 Pressure loss in psi

1

  3 

0.02

 5

15

0.65

 10

 30

5.46**

15

 45

 17.31*

* Not recommended    ** Not recommended with 20 lb. regulator

 

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© 2009, Star Nursery, Inc.                    Copy Provided courtesy of Star Nursery www.StarNursery.com