The coefficient of flow or Cv Value is the number of US gallons of water the valve will pass with a differential pressure of 1psi through the valve at 60°F.
Kv is the metric value of Cv and is calculated as Kv=Cv x 0.85.
Cv varies with both style and size of valve, but provides an index for comparing liquid capacities of different valves under a standard set of conditions. Table below provides Cv values of fully opened ball valves and are approximate values. The ball valve suppliers shall be consulted for getting the actual applicable values.
| 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"x1" | 51 | 51 | 45 | 48 | 48 | 31 |
| 1 1/2" | 220 | 246 | 225 | 205 | 199 | 154 |
| 2"x1 1/2" | 121 | 134 | 142 | 133 | 133 | 105 |
| 2" | 432 | 464 | 431 | 361 | 344 | 305 |
| 3"x2" | 195 | 201 | 224 | 226 | 181 | 211 |
| 3" | 1110 | 1113 | 1036 | 965 | 849 | 690 |
| 4"x3" | 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"x6" | 2340 | 2292 | 2316 | 2288 | 2082 | 1987 |
| 8" | 9706 | 9675 | 8786 | 8245 | 7444 | 5748 |
| 10"x8" | 4606 | 4518 | 4472 | 4572 | 4256 | 4111 |
| 10" | 15771 | 15656 | 14287 | 13606 | 12002 | 9100 |
| 12"x10" | 8832 | 8698 | 8661 | 7622 | 7931 | 7318 |
| 14"x10" | 6225 | 6003 | 5972 | 5506 | 5711 | 5233 |
| 12" | 23671 | 23473 | 21851 | 20211 | 16807 | 13462 |
| 14"x12" | 13972 | 14027 | 13944 | 13403 | 13364 | 12345 |
| 16"x12" | 10744 | 10792 | 10882 | 10343 | 10405 | - |
| 14" | 28722 | 27979 | 26163 | 24100 | 22138 | - |
| 16"x14" | 14844 | 14887 | 14715 | 14528 | 14169 | - |
| 16" | 38718 | 37887 | 35183 | 32862 | 29953 | - |
| 18"x16" | 20721 | 20738 | 21102 | 20088 | 19447 | - |
| 20"x16" | 17896 | 17982 | 18090 | 14305 | 13392 | - |
| 18" | 51656 | 50758 | 47378 | 43864 | 39666 | - |
| 20"x18" | 28137 | 28209 | 28596 | 26977 | 24379 | - |
| 20" | 64558 | 62680 | 59133 | 56470 | 50894 | - |
| 24"x20" | 27677 | 27680 | 27870 | 26400 | 24227 | - |
| 22" | 73062 | 71202 | 67357 | 51092 | 44930 | - |
| 24" | 97484 | 94720 | 93532 | 81286 | 71422 | - |
| 30"x24" | 40532 | 40331 | 39867 | 38720 | 37130 | - |
| 26" | 106226 | 102087 | 97547 | 82605 | 71670 | - |
| 30"x26" | 51377 | 51337 | 51238 | - | - | - |
| 28" | 127601 | 126158 | 118420 | 96770 | 84220 | - |
| 30" | 129337 | 121380 | 102799 | 112037 | 98390 | - |
| 36"x30" | 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"x36" | 96700 | 96700 | 96700 | - | - | - |
| 40" | 229927 | 229927 | 226344 | 248400 | - | - |
| 42" | 296175 | 296175 | 288550 | 275500 | - | - |
| 56"x42" | 89000 | 89000 | 89000 | - | - | - |
| 44" | 351600 | 351600 | 331000 | 306400 | - | - |
| 48" | 398250 | 398250 | 388575 | 373200 | - | - |
| 56" | 563075 | 563075 | 554375 | - | - | - |