Law Supply, Inc.
Web Page - Friction Loss Chart
Velocity in Ft./SEC.  Fiction Head Loss in feet of water per 100ft. of pipe
Gals. Per Min.
2-1/2" PVC Sch-40
VEL
LOSS
HEAD
LOSS
PSI
8 0.54 0.06 0.03
10 0.67 0.09 0.04
12 0.80 0.12 0.05
15 1.00 0.18 0.08
18 1.20 0.25 0.11
20 1.34 0.31 0.13
25 1.67 0.47 0.20
30 2.01 0.65 0.28
35 2.34 0.87 0.38
40 2.68 1.11 0.48
45 3.01 1.38 0.60
50 3.35 1.68 0.73
55 3.68 2.00 0.87
60 4.02 2.35 1.02
65 4.35 2.73 1.18
70 4.69 3.13 1.36
75 5.02 3.56 1.54
80 5.35 4.01 1.74
85 5.69 4.49 1.94
90 6.02 4.99 2.16
95 6.36 5.51 2.39
100 6.69 6.06 2.62
110 7.36 7.23 3.13
120 8.03 8.50 3.68
130 8.70 9.86 4.27
140 9.37 11.31 4.90
150 10.04 12.85 5.56
160 10.71 14.48 6.27
170 11.38 16.20 7.01
180 12.05 18.01 7.80
190 12.72 19.91 8.62
200 13.39 21.89 9.48
220 14.72 26.12 11.31
240 16.06 30.68 13.28
260 17.40 35.59 15.41
280 18.74 40.82 17.68
300 20.08 46.38 20.08
320 21.42 52.27 22.63
340 22.76 58.48 25.32
360 24.09 65.02 28.15
380 25.43 71.86 31.12
LBS. per square in. = Head in ft. x .433
Head in ft. = lbs. per sq. in. x 2.31'
The velocity of two (2) feet per second is generally accepted as the velocity ot carry solids.
Data shown is calculated form Williams and Hazen formula:
   H = 1043.94 X ((Q^1.852) / ((C^1.852 X D^4.8655)))
USING: C = 150 for water at 60 degrees F. and plastic pipe.
           (coefficient for roughness of the interior pipe surface)
       H = head loss in FT.
       V = fluid velocity in FT/SEC.
       D = inside diameter of the pipe in INCHES.
       Q = flow rate GPM

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Last updated 05/19/2003