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This chart gives friction losses for a given flow rate per 100 feet of pipe.

Example: If you have a 1200 gallon per hour (gph) flow and you are using 1" pipe and you have 30 feet of pipe, your friction loss is 21.75 x 0.3 = 6.52 feet. See the fittings chart below this chart to continue the calculation.

Friction Loss Calculator
Friction Loss Factor
(From Charts Below)
  Total Length
of Pipe
ft.    

Friction Loss Per 100 Feet of SCH 40 Plastic Pipe

Nominal Pipe Diameter

 
GPH* 1/2" 3/4" 1" 1 1/4" 1 1/2" 2" 3" 4"
60 2.08 0.51 - - - - - -
120 4.16 1.02 0.55 0.14 0.07 - - -
300 23.44 5.73 1.72 0.44 0.22 0.066 0.015 -
420 43.06 10.52 3.17 0.81 0.38 0.11 0.021 -
600 82.02 20.04 6.02 1.55 0.72 0.21 0.03 -
900 - 42.46 12.77 3.28 1.53 0.45 0.07 -
1200 - 72.34 21.75 5.59 2.61 0.76 0.11 0.03
1500 - - 32.88 8.45 3.95 1.15 0.17 0.04
1800 - - 46.08 11.85 5.53 1.62 0.23 0.06
2100 - - - 15.76 7.36 2.15 0.31 0.08
2400 - - - 20.18 9.43 2.75 0.41 0.11
2700 - - - 25.1 11.73 3.43 0.51 0.17
3000 - - - 30.51 14.25 4.16 0.61 0.16
3600 - - - - 19.98 5.84 0.85 0.22
4200 - - - - - 7.76 1.13 0.31
4500 - - - - - 8.82 1.28 0.34
4800 - - - - - 9.94 1.44 0.38
5400 - - - - - 12.37 1.8 0.47
6000 - - - - - 15.03 2.18 0.58
7500 - - - - - - 3.31 0.88
9000 - - - - - - 4.63 1.22
10500 - - - - - - 6.16 1.63
12000 - - - - - - 7.88 2.08
15000 - - - - - - 11.93 3.15

*Gallons Per Hour

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Total the number of fittings and use the chart below to determine the friction loss in the fittings. Add this amount to the pipe total. This section does not apply if you are using flexible PVC.


Friction Loss in PVC Fittings = Equivalent Feet of Straight Pipe
 
Pipe Size 1/2" 3/4" 1" 1 1/4" 1 1/2" 2" 3" 4"
90 ELBOW 1.5 2 2.25 4 4 6 8 12
45 ELBOW 0.75 1 1.4 1.75 2 2.5 4 5
GATE VALVE 0.3 0.4 0.6 0.8 1 1.5 2 3
TEE-Flow-RUN 1 1.4 1.7 2.3 2.7 4.3 6.3 8.3
TEE-Flow-Branch 4 5 6 7 8 12 16 22

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