Cv Flow Coefficients of a Ball Valve
The flow coefficient or Cv flow Value is the number of US gallons of water the valve will pass through a valve with a pressure differential of 1 psi through the valve at 60F. i.e. 10 psi inlet with 9 psi at the outlet. However, the higher the pressure difference, the higher the flow and vice versa.
Kv is the metric value of Cv and is calculated as Kv = Cv x 0.865.
Cv varies with both type and size of valve, but provides a reference for comparing liquid flow capabilities for different ball valves.
The table below provides typical Cv flow values for fully open ball valves.
Motor Ball Valves → View Products
Ball Valve Flow Table Size / CV Flow Factors (US Gallons of water with pressure drop 1psi)
| Size BSP |
DN mm |
CV fully open |
| 1/4 |
8 |
18 |
| 3/8 |
10 |
20 |
| 1/2 |
15 |
23 |
| 3/4 |
20 |
55 |
| 1 |
25 |
95 |
| 11/4 |
32 |
155 |
| 11/2 |
40 |
260 |
| 2 |
50 |
440 |
| 21/2 |
65 |
710 |
| 3 |
80 |
1050 |
| 4 |
100 |
2040 |
Ball Valve Flow Table Size and Type / CV Flow Factors (US Gallons of water with pressure drop 1psi)
| SIZE / RATING | 150 | 300 | 600 | 900 | 1500 | 2500 |
|---|---|---|---|---|---|---|
| 1/2" | 19 | 19 | 19 | 18 | 16 | 18 |
| 3/4"x1/2" | 14 | 14 | 14 | 13 | 11 | 10 |
| 3/4" | 45 | 45 | 44 | 42 | 40 | 37 |
| 1"x3/4" | 29 | 29 | 28 | 28 | 27 | 21 |
| 1" | 87 | 96 | 84 | 82 | 77 | 57 |
| 1 1/2" x 1" | 51 | 51 | 45 | 48 | 48 | 31 |
| 1 1/2" | 220 | 246 | 225 | 205 | 199 | 154 |
| 2"x 1 1/2" | 121 | 134 | 142 | 133 | 133 | 105 |
| 2" | 432 | 464 | 431 | 361 | 344 | 305 |
| 3"x 2" | 195 | 201 | 224 | 226 | 181 | 211 |
| 3" | 1110 | 1113 | 1036 | 965 | 849 | 690 |
| 4"x 3" | 569 | 553 | 574 | 578 | 517 | 559 |
| 4" | 2063 | 2138 | 1947 | 1813 | 1645 | 1352 |
| 6"x 4" | 813 | 792 | 913 | 923 | 745 | 865 |
| 6" | 4743 | 5116 | 4635 | 4372 | 3874 | 2856 |
| 8"x 6" | 2340 | 2292 | 2316 | 2288 | 2082 | 1987 |
| 8" | 9706 | 9675 | 8786 | 8245 | 7444 | 5748 |
| 10"x 8" | 4606 | 4518 | 4472 | 4572 | 4256 | 4111 |
| 10" | 15771 | 15656 | 14287 | 13606 | 12002 | 9100 |
| 12"x 10" | 8832 | 8698 | 8661 | 7622 | 7931 | 7318 |
| 14"x 10" | 6225 | 6003 | 5972 | 5506 | 5711 | 5233 |
| 12" | 23671 | 23473 | 21851 | 20211 | 16807 | 13462 |
| 14"x 12" | 13972 | 14027 | 13944 | 13403 | 13364 | 12345 |
| 16"x 12" | 10744 | 10792 | 10882 | 10343 | 10405 | - |
| 14" | 28722 | 27979 | 26163 | 24100 | 22138 | - |
| 16"x 14" | 14844 | 14887 | 14715 | 14528 | 14169 | - |
| 16" | 38718 | 37887 | 35183 | 32862 | 29953 | - |
| 18"x 16" | 20721 | 20738 | 21102 | 20088 | 19447 | - |
| 20"x 16" | 17896 | 17982 | 18090 | 14305 | 13392 | - |
| 18" | 51656 | 50758 | 47378 | 43864 | 39666 | - |
| 20"x 18" | 28137 | 28209 | 28596 | 26977 | 24379 | - |
| 20" | 64558 | 62680 | 59133 | 56470 | 50894 | - |
| 24"x 20" | 27677 | 27680 | 27870 | 26400 | 24227 | - |
| 22" | 73062 | 71202 | 67357 | 51092 | 44930 | - |
| 24" | 97484 | 94720 | 93532 | 81286 | 71422 | - |
| 30"x 24" | 40532 | 40331 | 39867 | 38720 | 37130 | - |
| 26" | 106226 | 102087 | 97547 | 82605 | 71670 | - |
| 30"x 26" | 51377 | 51337 | 51238 | - | - | - |
| 28" | 127601 | 126158 | 118420 | 96770 | 84220 | - |
| 30" | 129337 | 121380 | 102799 | 112037 | 98390 | - |
| 36"x 30" | 70314 | 70006 | 70692 | 70095 | 65010 | - |
| 32" | 147306 | 144189 | 139906 | 129076 | 113800 | - |
| 36"x 32" | 87000 | 87000 | 87000 | 69500 | - | - |
| 34" | 183702 | 176536 | 164619 | 134485 | 129550 | - |
| 36" | 219178 | 211933 | 197055 | 167762 | 145950 | - |
| 42"x 36" | 96700 | 96700 | 96700 | - | - | - |
| 40" | 229927 | 229927 | 226344 | 248400 | - | - |
| 42" | 296175 | 296175 | 288550 | 275500 | - | - |
| 56"x 42" | 89000 | 89000 | 89000 | - | - | - |
| 44" | 351600 | 351600 | 331000 | 306400 | - | - |
| 48" | 398250 | 398250 | 388575 | 373200 | - | - |
| 56" | 563075 | 563075 | 554375 | - | - | - |