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Friction Loss Flow Charts

Feet Of Head Pressure Loss Per 100 Ft. of Plastic Pipe

Example: Using 1" pipe flowing at 5 GPM you would lose 1.72 feet of head pressure per hundred feet

GPM Pipe Diameter
1/2" 3/4" 1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4" 5" 6"
1 2.08 0.51                  
2 4.16 1.02 0.55 0.14 0.07            
5 23.44 5.73 1.72 0.44 0.22 0.066 0.038 0.015      
7 43.06 10.52 3.17 0.81 0.38 0.11 0.051 0.021      
10 82.02 20.04 6.02 1.55 0.72 0.21 0.09 0.03      
15   42.46 12.77 3.28 1.53 0.45 0.19 0.07      
20   72.34 21.75 5.59 2.61 0.76 0.32 0.11 0.03    
25     32.88 8.45 3.95 1.15 0.49 0.17 0.04    
30     46.08 11.85 5.53 1.62 0.68 0.23 0.06 0.02  
35       15.76 7.36 2.15 0.91 0.31 0.08 0.03  
40       20.18 9.43 2.75 1.16 0.40 0.11 0.03  
45       25.10 11.73 3.43 1.44 0.50 0.13 0.04  
50       30.51 14.25 4.16 1.75 0.60 0.16 0.05 0.02
60         19.98 5.84 2.46 0.85 0.22 0.07 0.03
70           7.76 3.27 1.13 0.30 0.10 0.04
75           8.82 3.71 1.28 0.34 0.11 0.05
80           9.94 4.19 1.44 0.38 0.13 0.05
90           12.37 5.21 1.80 0.47 0.16 0.06
100           15.03 6.33 2.18 0.58 0.19 0.08
125             9.58 3.31 0.88 0.29 0.10
150             13.41 4.63 1.22 0.40 0.20
175               6.16 1.63 0.54 0.20
200               7.88 2.08 0.69 0.30
250               11.93 3.15 1.05 0.40
300                 4.41 1.46 0.60
350                 5.87 1.95 0.80
400                 7.52 2.49 1.00
450                   3.09 1.30
500                   3.90 1.50



Friction Loss in PVC Fittings = EQUIVALENT FEET OF STRAIGHT PIPE


Using fittings creates friction loss:

Below we show the comparison of friction loss of "average" fittings compared to "average" feet water travels inside pipe.

Example: using one 1/2" 90 degree elbow is approx. the same as using 1 1/2 feet of 1/2" pipe

The less fittings that you are able to use, the less friction loss you'll have!

PVC
Type
Pipe Size
1/2" 3/4" 1" 1-1/4" 1-1/2" 2" 2-1/2" 3" 4" 6" 8"
90° elbow 1.5 2.0 2.25 4.0 4.0 6.0 8.0 8.0 12.0 16.7 21.0
45° elbow 0.75 1.0 1.4 1.75 2.0 2.5 3.0 4.0 5.0 8.0 10.6
insert coupling 0.5 0.75 1.0 1.25 1.5 2.0 3.0 3.0 4.0 -- --
gate valve 0.3 0.4 0.6 0.8 1.0 1.5 1.6 2.0 3.0 -- --
male/female adapter 1.0 1.5 2.0 2.75 3.5 4.5 5.5 6.5 9.5 -- --
tee-flow (run) 1.0 1.4 1.7 2.3 2.7 4.3 5.1 6.3 8.3 12.3 14.0
tee-flow (branch) 4.0 5.0 6.0 7.0 8.0 12.0 15.0 16.0 22.0 32.7 49.0

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