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.
1-1/2" PVC Sch-40
VEL
LOSS
HEAD
LOSS
PSI
4 0.63 0.13 0.06
6 0.94 0.27 0.12
8 1.26 0.45 0.19
10 1.57 0.68 0.29
12 1.89 0.96 0.42
15 2.36 1.45 0.63
18 2.83 2.03 0.88
20 3.15 2.46 1.07
25 3.94 3.73 1.62
30 4.72 5.22 2.26
35 5.51 6.95 3.01
40 6.30 8.90 3.85
45 7.08 11.07 4.79
50 7.87 13.45 5.82
55 8.66 16.05 6.95
60 9.44 18.85 8.16
65 10.23 21.87 9.47
70 11.02 25.08 10.86
75 11.81 28.50 12.34
80 12.59 32.12 13.91
85 13.38 35.94 15.56
90 14.17 39.95 17.30
95 14.95 44.16 19.12
100 15.74 48.56 21.02 
110 17.31 57.93 25.08
120 18.89 68.06 29.47
130 20.46 78.93 34.18
140 22.04 90.55 39.21
150 23.61 102.89 44.55
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