null
 

Pipe Sizing Chart Guide

Properly sizing your pipe for an irrigation project will make a world of difference in the functionality of your system. It would help if you were choosing a pipe size that can safely supply the volume of water needed throughout your system. The flow is measured in gallons per minute (GPM). Your friction loss through a pipe is measured in pounds per square inch (PSI), and the velocity is measured in feet per second (FPS). Velocity is the rate of speed at which the water is traveling. The proper size mainline for your project will be the size closest to your flow rate without restricting it or exceeding the safe velocity.

 

Tubing Type and Size

Max Flow Rate

Velocity

Pressure Loss per 100’

Polyethylene

1/2"

4 GPM

4.22

6.35

 

3/4"

8 GPM

4.81

5.84

 

1"

12 GPM

4.45

3.82

 

1 1/2"

30 GPM

4.72

2.59

 

2"

50 GPM

4.77

1.98

Schedule 40 PVC

1/2"

4 GPM

4.5

6.55

 

3/4"

7 GPM

4.42

4.52

 

1"

12 GPM

4.62

3.69

 

1 1/2"

30 GPM

4.84

2.42

 

2"

50 GPM

4.87

1.83

Schedule 80 PVC

1/2"

3 GPM

4.42

7.42

 

3/4"

6 GPM

4.70

5.74

 

1"

10 GPM

4.67

4.20

 

1 1/2"

26 GPM

4.87

2.67

 

2"

44 GPM

4.91

2.00

Class 200 PVC

1/2"

5 GPM

4.21

4.89

 

3/4"

10 GPM

4.93

4.79

 

1"

16 GPM

4.78

3.38

 

1 1/2"

34 GPM

4.8

2.21

 

2"

55 GPM

4.95

1.80