Equivalent Feet of Straight Pipe

Written by Matt Milbury on . Posted in Pipe Layout Datasheets

When modeling a piping system, sometimes it is easier to model the entire system as a straight pipe and apply the flow equations to the pipe length.  The table below is what the equivalent straight line pipe can be used.  To use these, sum the amount of horizontal pipe plus the total equivalent length of sum of the fittings.  This will give you a reasonable approximation of the expected pressure drop through the pipe.  For more precise solutions, a flow modeling program should be used. 

Equivalent Feet Tables

Pipe Size Inside Dia Gate or Ball Fully Open 90° Elbow Long Rad 90° or 45° Std Elbow Std Tee - Thru Flow Std Tee Branch Flow Close Return Bend Angle Valve Full open Globe Valve Full open Butterfly Valve 90° Weld Elbow Mitre Bend Swing Check
r/d = 1 r/d = 2 45° 90°
1/2 0.622 0.41 1.55 0.83 1.04 3.11 2.59 7.78 17.6           5.18
3/4 0.824 0.55 2.06 1.1 1.37 4.12 3.43 10.3 23.3           6.86
1 1.049 0.7 2.62 1.4 1.75 5.25 4.37 13.1 29.7           8.74
1 1/4 1.38 0.92 3.45 1.84 2.3 6.9 5.75 17.3 39.1           11.5
1 1/2 1.61 1.07 4.03 2.15 2.68 8.05 6.71 20.1 45.6           13.4
2 2.067 1.38 5.17 2.76 3.45 10.3 8.61 25.8 58.6 7.75 3.45 2.07 2.58 10.3 17.2
2 1/2 2.469 1.65 6.17 3.29 4.12 12.3 10.3 30.9 70 9.26 4.12 2.47 3.08 12.3 20.6
3 3.068 2.04 7.67 4.09 5.11 15.3 12.8 38.4 86.9 11.5 5.11 3.07 3.84 15.3 25.5
4 4.026 2.68 10.1 5.37 6.71 20.1 16.8 50.3 114 15.1 6.71 4.03 5.03 20.1 33.6
5 5.047 3.36 12.6 6.73 8.41 25.2 21 63.1 143 18.9 8.41 5.05 6.31 25.2 42.1
6 6.065 4.04 15.2 8.09 10.1 30.3 25.3 75.8 172 22.7 10.1 6.07 7.58 30.3 50.5
8 7.981 5.32 20 10.6 13.3 39.9 33.3 99.8 226 29.9 13.3 7.98 9.98 39.9 33.3
10 10.02 6.68 25.1 13.4 16.7 50.1 41.8 125 284 29.2 16.7 10 12.5 50.1 41.8
12 11.938 7.96 29.8 15.9 19.9 59.7 49.7 149 338 34.8 19.9 11.9 14.9 59.7 49.7
14 13.124 8.75 32.8 17.5 21.8 65.6 54.7 164 372 38.3 21.8 13.1 16.4 65.6 54.7
16 15 10 37.5 20 25 75 62.5 188 425 31.1 25 15 18.8 75 62.5
18 16.876 16.9 42.2 22.5 28.1 84.4 70.3 210 478 35.2 28.1 16.9 21.1 84.4 70.3
20 18.814 12.5 47 25.1 31.4 94.1 78.4 235 533 39.2 31.4 18.8 23.5 94.1 78.4
24 22.628 15.1 56.6 30.2 37.7 113 94.3 283 641 47.1 37.7 22.6 28.3 113 94.3
30 28 18.7 70 37.3 46.7 140         46.7 28 35 140  
36 34 22.7 85 45.3 56.7 170         56.7 34 43 170  
42 40 26.7 100 53.3 66.7 200         66.7 40 50 200  
48 46 30.7 115 61.3 76.7 230         76.7 46 58 230  

 

Pipe Size Equivalent Length in terms of small d Entrance Exit
Enlargement Contraction └── └──
Sudden Std. Reducer Sudden Std. Reducer ◄▬ ▬►
d/D = ¼ d/D = ½ d/D = ¾ d/D = ½ d/D = ¾ d/D = ¼ d/D = ½ d/D = ¾ d/D = ½ d/D = ¾ ┌── ┌──
1/2 1.7 1.1 0.38 1.3 0.38 0.9 0.63 0.38 0.38   1 2
3/4 2.5 1.5 0.51 1.7 0.51 1.3 0.9 0.51 0.51   1.5 2.8
1 3.2 2 0.7 2.3 0.7 1.8 1.3 0.7 0.7   2 4
1 1/4 4.8 3 1 3.3 1 2.2 1.8 1 1   2.7 5.5
1 1/2 5 3 1 4 1 3 2.2 1 1   3.3 6.8
2 7 4 1 5 1 3 3 1 1   4.5 9
2 1/2 8 5 2 6 2 4 3 2 2   5.5 11
3 10 6 2 8 2 5 4 2 2   9 18
4 12 8 3 10 3 6 5 3 3   10 20
6 18 12 4 14 4 9 7 4 4 1 17 33
8 25 16 5 19 5 12 9 5 5 2 23 46
10 31 20 7 24 7 15 12 6 6 2 30 60
12 37 24 8 28 8 18 14 7 7 2 40 80
14 42 26 9     20 16 8     42 84
16 47 30 10     24 18 9     50 100
18 53 35 11     26 20 10     60 120
20 60 38 13     30 23 11     70 1470
22 65 42 14     32 25 12     80 160
24 70 46 15     35 27 13     90 180

Tags: Tables