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# Water Control Valves - Kv Calculation

## Designing water process control valves and their Kv values.

The table below can be used to estimate the Kv values for process control valves used in water systems.

1. Go to the left column and select the pressure drop for the valve
2. Go right in table close to the actual water flow. Interpolate to find the approximately Kv value

For full table - rotate the screen!

Water Control Valves - Kv Values vs. Water Flow and Pressure Drop
Pressure dropWater flow (kg/h)
36721081441803607201080144018003600
(kPa)(bar)
Water flow (kg/s)
0.010.020.030.040.050.10.20.30.40.51
1 0.01 0.36 0.72 1.1 1.4 1.8 3.6 7.2 10.8 14.4 18.0 36.0
2 0.02 0.25 0.51 0.76 1.0 1.3 2.6 5.1 7.6 10.2 12.7 25.5
3 0.03 0.21 0.42 0.62 0.83 1.0 2.1 4.2 6.2 8.3 10.4 20.8
4 0.04 0.18 0.36 0.54 0.72 0.90 1.8 3.6 5.4 7.2 9.0 18.0
5 0.05 0.16 0.32 0.48 0.64 0.80 1.6 3.2 4.8 6.4 8.1 16.1
10 0.1 0.11 0.23 0.34 0.46 0.57 1.1 2.3 3.4 4.6 5.7 11.4
20 0.2 0.08 0.16 0.24 0.32 0.40 0.80 1.6 2.4 3.2 4.0 8.1
30 0.3 0.07 0.13 0.2 0.26 0.33 0.66 1.3 2.0 2.6 3.3 6.6
40 0.4 0.06 0.11 0.17 0.23 0.28 0.57 1.1 1.7 2.3 2.9 5.7
50 0.5 0.05 0.10 0.15 0.20 0.25 0.51 1.0 1.5 2.0 2.6 5.1
100 1 0.04 0.07 0.11 0.14 0.18 0.36 0.72 1.1 1.4 1.8 3.6
200 2 0.03 0.05 0.08 0.10 0.13 0.25 0.51 0.76 1.0 1.3 2.6
300 3 0.02 0.04 0.06 0.08 0.10 0.21 0.42 0.62 0.83 1.0 2.1
400 4 0.02 0.04 0.05 0.07 0.09 0.18 0.36 0.54 0.72 0.9 1.8
500 5 0.02 0.03 0.05 0.06 0.08 0.16 0.32 0.48 0.64 0.8 1.6
1000 10 0.01 0.02 0.03 0.05 0.06 0.11 0.23 0.34 0.46 0.57 1.1
2000 20 0.01 0.02 0.02 0.03 0.04 0.08 0.16 0.24 0.32 0.40 0.80
3000 30 0.01 0.01 0.02 0.03 0.03 0.07 0.13 0.20 0.26 0.33 0.66
4000 40 0.01 0.01 0.02 0.02 0.03 0.06 0.11 0.17 0.23 0.28 0.57

For full table - rotate the screen!

Water Control Valves - Kv Values vs. Water Flow and Pressure Drop
Pressure dropWater flow (kg/h)
72001080014400180003600072000108000144000180000360000720000
(kPa)(bar)
Water flow (kg/s)
23451020304050100200
1 0.01 72.0 108 144 180 360 720 1080 1440 1800 3600 7200
2 0.02 50.9 76.4 102 127 254 509 763 1019 1273 2546 5091
3 0.03 41.6 62.4 83.1 103 207 415 623 831 1039 2078 4157
4 0.04 36.0 54.0 72.0 90.0 180 360 540 720 900 1800 3600
5 0.05 32.2 48.3 64.4 80.5 161 321 483 644 805 1610 3220
10 0.1 22.8 34.2 45.5 56.9 113 227 342 455 569 1138 2277
20 0.2 16.1 24.2 32.2 40.3 80.5 161 242 322 402 805 1610
30 0.3 13.2 19.7 26.3 32.9 65.7 131 197 263 329 657 1315
40 0.4 11.4 17.1 22.8 28.5 56.9 114 171 228 285 569 1138
50 0.5 10.2 15.3 20.4 25.5 50.9 102 153 204 255 509 1018
100 1 7.2 10.8 14.4 18.0 36.0 72.0 108 144 180 360 720
200 2 5.1 7.6 10.2 12.7 25.5 50.9 76.4 102 127 255 509
300 3 4.2 6.2 8.3 10.4 20.8 41.6 62.4 83.1 104 208 416
400 4 3.6 5.4 7.2 9.0 18.0 36.0 54.0 72.0 90.0 180 360
500 5 3.2 4.8 6.4 8.1 16.1 32.2 48.3 64.4 80.5 161 322
1000 10 2.3 3.4 4.6 5.7 11.4 22.8 34.2 45.5 56.9 114 228
2000 20 1.6 2.4 3.2 4.0 8.1 16.1 24.2 32.2 40.3 80.5 161
3000 30 1.3 2.0 2.6 3.3 6.6 13.2 19.7 26.3 32.9 65.7 131
4000 40 1.1 1.7 2.3 2.9 5.7 11.4 17.1 22.8 28.5 56.9 114

### Example - Kv for a Water Control Valve

For a water control valve with

• pressure drop 2 bar
• water flow 1 kg/s

- the Kv value should be approximately 2.6 according the table above.

Kv can be calculated as:

Kv = q / (dp)1/2                     (1)

where

Kv = Kv value

q = water flow (m3/h)

dp = pressure drop (bar)

## Related Topics

• ### Control Valves

Control Valve terminology, bodies, trim, flow characteristics, Cv and Kv sizing, noise, actuators and positioners
• ### Process Control

Instrumentation and process control systems - design and documentation.
• ### Water Systems

Hot and cold water service systems - design properties, capacities, sizing and more.

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## Citation

• The Engineering ToolBox (2003). Water Control Valves - Kv Calculation. [online] Available at: https://www.engineeringtoolbox.com/control-valves-water-d_265.html [Accessed Day Month Year].

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12.8.9