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Plastic pipe: friction loss (in feet of head) per 100’ of pipe

Feet of head is typically measured in terms of vertical lift. However, the diameter and length of pipe can have a significant effect on the performance of the pump as well. (Especially if the pipe diameter is too small.) A pump must have the power to not only push the water up to a vertical of height of the waterfall, but to also overcome the friction loss created by the pipe. Total Dynamic Head is the feet of head (lift) added to the friction loss created by the pipe. In most small ponds, with short pipe runs, friction loss is not typically the problem. However, in a feature with long streams or high flow rates, friction loss can have a big impact on the performance of the pump. To determine the Total Dynamic Head you would and the feet of head and the friction loss. The chart below lists the feet of head equivalent created by flow and pipe diameter. (Figures shown are based on a 100’ length of pipe.)

 

Example: We are pumping 4200 GPH. The chart shows that 4200 GPH through 100’ of 2” pipe equals 7.76’ of head while a 3” pipe only equals 1.13’ of head. If your waterfall is 10’ high and 100’ away, you will have a total head of 17.76’ using 2” pipe but only 11.13’ using 3” pipe.

10.00’ Vertical Lift                                     10.00’ Vertical Lift

            + 7.76’ Friction Loss                                              +7.76’ Friction Loss

           = 17.76’ Total Dynamic Head                              = 11.13’ Total Dynamic Head
 

Plastic pipe: Friction loss (in Feet of head) per 100' of pipe

GPM

GPH

1"

1 1/4"

1 1/2"

2"

3"

4"

6"

8"

10"

20

1200

21.75

5.59

2.61

0.76

0.11

 

 

 

 

30

1800

 

11.85

5.53

1.62

0.23

 

 

 

 

40

2400

 

20.18

9.43

2.75

0.4

0.12

 

 

 

50

3000

 

 

10.51

4.25

0.66

0.17

 

 

 

60

3600

 

 

19.98

5.84

0.85

0.25

 

 

 

70

4200

 

 

 

7.76

1.13

0.33

 

 

 

80

4800

 

 

 

9.94

1.44

0.41

 

 

 

90

5400

 

 

 

12.37

1.8

0.52

 

 

 

100

6000

 

 

 

15.03

2.18

0.63

0.08

 

 

125

7500

 

 

 

 

3.31

0.95

0.13

 

 

150

9000

 

 

 

 

4.63

1.33

0.18

 

 

175

10500

 

 

 

 

6.16

1.78

0.23

 

 

200

12000

 

 

 

 

7.88

2.07

0.3

 

 

250

15000

 

 

 

 

11.93

3.16

0.45

0.12

 

300

18000

 

 

 

 

 

4.45

0.63

0.17

 

350

21000

 

 

 

 

 

5.87

0.84

0.22

 

400

24000

 

 

 

 

 

7.52

1.08

0.28

 

500

30000

 

 

 

 

 

 

1.66

0.42

0.14

600

36000

 

 

 

 

 

 

2.35

0.59

0.19

700

42000

 

 

 

 

 

 

3.65

0.79

0.26

800

48000

 

 

 

 

 

 

 

1.02

0.33

900

54000

 

 

 

 

 

 

 

1.27

0.41

1000

60000

 

 

 

 

 

 

 

2.15

0.5

1250

75000

 

 

 

 

 

 

 

2.2

0.73

1500

90000

 

 

 

 

 

 

 

3.07

1.01

 

Confused? Contact us at 248-889-8400.

Pipe Comparison

Many people mistakenly think that there really isn’t much difference between (for example) 1 ½” and 2” pipe or between 3” to 4” pipe. The chart to the right shows how many square inches of surface area are on the inside of flexible PVC pipe.
 

Pipe Size Dia.

Square Inches of Surface Area

1"

0.79

1 1/2"

1.77

2"

3.14

3"

7.07

4"

12.57

6"

28.27

8"

50.26

 

As you can see, there is a big difference between 1 ½” and 2” pipe- almost 80% more space! This shows why using the correct size pipe is important to the output of your pump.

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