Friction Loss Tables

Friction Losses in Pipe Fittings
Resistance Coefficient K (use in formula hf = Kv2/2g)
Fitting LD Nominal Pipe Size
1/2" 3/4" 1 1-1/4" 1-1/2" 2 2-1/2"-3 4 6 8-10 12-16 18-24
K Value
Angle Valve 55 1.48 1.38 1.27 1.21 1.16 1.05 0.99 0.94 0.83 0.77 0.72 0.66
Angle Valve 150 4.05 3.75 3.45 3.30 3.15 2.85 2.70 2.55 2.25 2.10 1.95 1.80
Ball Valve 3 0.08 0.08 0.07 0.07 0.06 0.06 0.05 0.05 0.05 0.04 0.04 0.04
Butterfly Valve             0.86 0.81 0.77 0.68 0.63 0.35 0.30
Gate Valve 8 0.22 0.20 0.18 0.18 0.15 0.15 0.14 0.14 0.12 0.11 0.10 0.10
Globe Valve 340 9.2 8.5 7.8 7.5 7.1 6.5 6.1 5.8 5.1 4.8 4.4 4.1
Plug Valve Branch Flow 90 2.43 2.25 2.07 1.98 1.89 1.71 1.62 1.53 1.35 1.26 1.17 1.08
Plug Valve Straightaway 18 0.48 0.45 0.41 0.40 0.38 0.34 0.32 0.31 0.27 0.25 0.23 0.22
Plug Valve 3-Way Thru-Flow 30 0.81 0.75 0.69 0.66 0.63 0.57 0.54 0.51 0.45 0.42 0.39 0.36
Standard Elbow 90° 30 0.81 0.75 0.69 0.66 0.63 0.57 0.54 0.51 0.45 0.42 0.39 0.36
45° 16 0.43 0.40 0.37 0.35 0.34 0.30 0.29 0.27 0.24 0.22 0.21 0.19
long radius
90°		 16 0.43 0.40 0.37 0.35 0.34 0.30 0.29 0.27 0.24 0.22 0.21 0.19
Close Return Bend 50 1.35 1.25 1.15 1.10 1.05 0.95 0.90 0.85 0.75 0.70 0.65 0.60
Standard Tee Thru-Flow 20 0.54 0.50 0.46 0.44 0.42 0.38 0.36 0.34 0.30 0.28 0.26 0.24
Thru-Branch 60 1.62 1.50 1.38 1.32 1.26 1.14 1.08 1.02 0.90 0.84 0.78 0.72
90 Bends,
Pipe Bends,
Flanged Elbows,
Butt-Welded
Elbows		 r/d=1 20 0.54 0.50 0.46 0.44 0.42 0.38 0.36 0.34 0.30 0.28 0.26 0.24
r/d=2 12 0.32 0.30 0.28 0.26 0.25 0.23 0.22 0.20 0.18 0.17 0.16 0.14
r/d=3 12 0.32 0.30 0.28 0.26 0.25 0.23 0.22 0.20 0.18 0.17 0.16 0.14
r/d=4 14 0.38 0.35 0.32 0.31 0.29 0.27 0.25 0.24 0.21 0.20 0.18 0.17
r/d=6 17 0.46 0.43 0.39 0.37 0.36 0.32 0.31 0.29 0.26 0.24 0.22 0.20
r/d=8 24 0.65 0.60 0.55 0.53 0.50 0.46 0.43 0.41 0.36 0.34 0.31 0.29
r/d=10 30 0.81 0.75 0.69 0.66 0.63 0.57 0.54 0.51 0.45 0.42 0.39 0.36
r/d=12 34 0.92 0.85 0.78 0.75 0.71 0.65 0.61 0.58 0.51 0.48 0.44 0.41
r/d=14 38 1.03 0.95 0.87 0.84 0.80 0.72 0.68 0.65 0.57 0.53 0.49 0.46
r/d=16 42 1.13 1.05 0.97 0.92 0.88 0.80 0.76 0.71 0.63 0.59 0.55 0.50
r/d=18 45 1.24 1.15 1.06 1.01 0.97 0.87 0.83 0.78 0.69 0.64 0.60 0.55
r/d=20 50 1.35 1.25 1.15 1.10 1.05 0.95 0.90 0.85 0.75 0.70 0.65 0.60
Mitre Bends a=0° 2 0.05 0.05 0.05 0.04 0.04 0.04 0.04 0.03 0.03 0.03 0.03 0.02
a=15° 4 0.11 0.10 0.09 0.09 0.08 0.08 0.07 0.07 0.06 0.06 0.05 0.05
a=30° 8 0.22 0.20 0.18 0.18 0.17 0.15 0.14 0.14 0.12 0.11 0.10 0.10
a=45° 15 0.41 0.38 0.35 0.33 0.32 0.29 0.27 0.26 0.23 0.21 0.20 0.18
a=60° 25 0.68 0.63 0.58 0.55 0.53 0.48 0.45 0.43 0.38 0.35 0.33 0.30
a=75° 40 1.09 1.00 0.92 0.88 0.84 0.76 0.72 0.68 0.60 0.56 0.52 0.48
a=90° 60 1.62 1.50 1.38 1.32 1.26 1.14 1.08 1.02 0.90 0.84 0.78 0.72
Note: Fittings are standard with full openings.

Fitting L/D Minimum
Velocity for
Full Disc Lift		 Nominal Pipe Size
1/2" 3/4" 1 1-1/4" 1-1/2" 2 2-1/2"-3 4 6 8-10 12-16 18-24
General
ft/sec		 Water
ft/sec		 K Value
Swing Check Valve 100 35 4.40 2.70 2.50 2.30 2.20 2.10 1.90 1.80 1.70 1.50 1.40 1.30 1.20
50 48 6.06 1.40 1.30 1.20 1.10 1.10 1.00 0.90 0.90 0.75 0.70 0.65 0.60
Lift Check Valve 600 40 5.06 16.2 15.0 13.08 13.2 12.6 11.4 10.8 10.2 9.0 8.4 7.8 7.2
55 140 17.7 1.50 1.40 1.30 1.20 1.20 1.10 1.00 0.94 0.83 0.77 0.72 0.66
Tilting Disc Check Valve 5 80 10.13           0.76 0.72 0.68 0.60 0.56 0.39 0.24
15 30 3.80           2.30 2.20 2.00 1.80 1.70 1.20 0.72
Foot Valve with Strainer
Poppet Disc		 420 15 1.90 11.3 10.5 9.70 9.30 8.80 8.00 7.60 7.10 6.30 5.90 5.50 5.0
Foot Valve with Strainer
Hinged Disc		 75 35 4.43 2.00 1.90 1.70 1.70 1.70 1.40 1.40 1.30 1.10 1.10 1.00 0.90

Fitting Description All Pipe Sizes
K Value
Pipe Exit Projecting
Sharp-Edged
Rounded		 1.00
Pipe Entrance Inward Projecting 0.78
Pipe Entrance Flush Sharp-Edged 0.50
r/d=0.02 0.28
r/d=0.04 0.24
r/d=0.06 0.15
r/d=0.10 0.09
r/d<0.14 0.04

The K values given below are for making estimates of friction loss in cases not covered in the previous tables.

Type of Fitting K Value
Disk or Wobble Meter 3.4 - 10
Rotary Meter (Star or Cog-Wheel Piston) 10
Reciprocating Piston Meter 15
Turbine Wheel (Double-Flow) Meter 5 - 7.5
Bends w/Corrugated Inner Radius 1.3 - 1.6 times value for smooth bend
Example: Determine L (friction loss in pipe fittings in terms of equivalent length
in feet of straight pipe).
Assume a 6" angle valve for Schedule 40 pipe size.
Select the appropriate K value for such and select D and f for Schedule 40 pipe
from the table below where K is the pipe diameter in feet.
Pipe Size
Inches
Sch. 40		 D
feet		 f Pipe Size
Inches
Sch. 40		 D
feet		 f Pipe Size
Inches
Sch. 40		 D
feet		 f Pipe Size
Inches
Sch. 40		 D
feet		 f
1/2"
3/4"
1
1-1/4"
1-1/2"
2		 0.0518
0.0687
0.0874
0.1150
0.1342
0.1723		 0.027
0.025
0.023
0.022
0.021
0.019		 2-1/2"
3
4
5
6
8		 0.2058
0.2557
0.3355
0.4206
0.5054
0.6651		 0.018
0.018
0.017
0.016
0.015
0.014		 10
12
14
16
18
20		 0.8350
0.9948
1.0937
1.250
1.4063
1.5678		 0.014
0.013
0.013
0.013
0.012
0.012		 24
30
36
42
48		 1.8857
2.3333
2.8333
3.3333
3.8333		 0.012
0.011
0.011
0.010
0.010

Friction Loss of Water in Pipe Fittings in Terms of Equivalent
Length - Feet of Straight Pipe
Nominal
pipe size		 Actual
inside
diameter
inches
d		 Friction
factor
f		 Gate
valve
-
full
open		 90°
elbow		 Long
radius
90° or
45° sth
elbow		 Sth
tee
-
thru
flow		 Sth
tee
-
branch
flow		 Close
return
bend		 Swing
check
valve
-
full open		 Angle
valve
-
full
open		 Globe
valve
-
full
valve		 Butter-
fly valve		 90°Welding
elbow		 Mitre bend
r/d = 1 r/d = 2 45° 90°
1/2"
3/4"
1
1-1/4"
1-1/2"		 .622
.824
1.049
1.380
1.610		 .027
.025
.023
.022
.021		 .41
.55
.70
.92
1.07		 1.55
2.06
2.62
3.45
4.03		 .83
1.10
1.40
1.84
2.15		 1.04
1.37
1.75
2.30
2.68		 3.11
4.12
5.25
6.90
8.05		 2.59
3.43
4.37
5.75
6.71		 5.18
6.86
8.74
11.5
13.4		 7.78
10.3
13.1
17.3
20.1		 17.6
23.3
29.7
39.1
45.6		          
2
2-1/2"
3
4
5		 2.067
2.469
3.068
4.026
5.047		 .019
.018
.018
.017
.016		 1.38
1.65
2.04
2.68
3.36		 5.17
6.17
7.67
10.1
12.6		 2.76
3.29
4.09
5.37
6.73		 3.45
4.12
5.11
6.71
8.41		 10.3
12.3
15.3
20.1
25.2		 8.61
10.3
12.8
16.8
21.0		 17.2
20.6
25.5
33.6
42.1		 25.8
30.9
38.4
50.3
63.1		 58.6
70.0
86.9
114
143		 7.75
9.26
11.5
15.1
18.9		 3.45
4.12
5.11
6.71
8.41		 2.07
2.47
3.07
4.03
5.05		 2.58
3.08
3.84
5.03
6.31		 10.3
12.3
15.3
20.1
25.2
6
8
10
12
14		 6.065
7.981
10.02
11.938
13.124		 .015
.014
.014
.013
.013		 4.04
5.32
6.68
7.96
8.75		 15.2
20.0
25.1
29.8
32.8		 8.09
10.6
13.4
15.9
17.5		 10.1
13.3
16.7
19.9
21.8		 30.3
39.9
50.1
59.7
65.6		 25.3
33.3
41.8
49.7
54.7		 50.5
33.3
41.8
49.7
54.7		 75.8
99.8
125
149
164		 172
226
284
338
372		 22.7
29.9
29.2
34.8
38.3		 10.1
13.3
16.7
19.9
21.8		 6.07
7.98
10.0
11.9
13.1		 7.58
9.98
12.5
14.9
16.4		 30.3
39.9
50.1
59.7
65.6
16
18
20
24
30		 15.00
16.876
18.814
22.628
28		 .013
.012
.012
0.12
.011		 10.0
16.9
12.5
15.1
18.7		 37.5
42.2
47.0
56.6
70		 20.0
22.5
25.1
30.2
37.3		 25.0
28.1
31.4
37.7
46.7		 75.0
84.4
94.1
113
140		 62.5
70.3
78.4
94.3
117		 62.5
70.3
78.4
94.3
 188
210
235
283
 425
478
533
641
 31.3
35.2
39.2
47.1
 25.0
28.1
31.4
37.7
46.7		 15.0
16.9
18.8
22.6
28		 18.8
21.1
23.5
28.3
35		 75.0
84.4
94.1
113
140
36
42
48		 34
40
46		 .011
.010
.010		 22.7
26.7
30.7		 85
100
115		 45.3
53.3
61.3		 56.7
66.7
76.7		 170
200
230		 142
167
192		         56.7
66.7
76.7		 34
40
46		 43
50
58		 170
200
230
L/D 8 30 16 20 60 50 1/2" to 6
= 100
24 to 48
=50		 150 340   20 12 15 60

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