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" PVC Sch-40
VEL
LOSS
HEAD
LOSS
PSI
6 0.57 0.08 0.03
8 0.76 0.13 0.06
10 0.95 0.20 0.09
12 1.15 0.28 0.12
15 1.43 0.43 0.19
18 1.72 0.60 0.26
20 1.91 0.73 0.32
25 2.39 1.10 0.48
30 2.86 1.55 0.67
35 3.34 2.06 0.89
40 3.82 2.64 1.14
45 4.30 3.28 1.42
50 4.77 3.99 1.73
55 5.25 4.76 2.06
60 5.73 5.59 2.42
65 6.21 6.48 2.81
70 6.68 7.44 3.22
75 7.16 8.45 3.66
80 7.64 9.52 4.12
85 8.12 10.65 4.61
90 8.59 11.84 5.13
95 9.07 13.09 5.67
100 9.55 14.40 6.24
110 10.50 17.18 7.44
120 11.46 20.18 8.74
130 12.41 23.40 10.13
140 13.37 26.85 11.63
150 14.32 30.51 13.21
160 15.28 34.38 14.89
170 16.23 38.46 16.65
180 17.19 42.76 18.52
190 18.14 47.26 20.46
200 19.10 51.97 22.50
220 21.01 62.01 26.85
240 22.92 72.85 31.54
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