Butterfly Valves

Even though we work on a metric system, measures of flow are commonly given as a CV value which is an; Imperial measure flow in US gallons per minute of water at 60° fahrenheit with pressure drop of 1 psi across the valve. Below is a table of the flow rates for Butterfly Valves at different opening stages between zero degrees (fully closed) and ninety degrees (fully open). Please note that a CV value is not a linear progression so it cannot be extrapolated out just by looking at the values, it is really just meant to give you a comparison flow rate.

 

Size Cv Value at different degrees of opening
inch mm 10° 20° 30° 40° 50° 60° 70° 80° 90°
2 50 0.1 5 12 24 45 64 90 125 135
2 1/2 65 0.2 8 20 37 65 98 144 204 220
3 80 0.3 12 22 39 70 116 183 275 302
4 100 0.5 17 36 78 139 230 364 546 600
5 125 0.8 29 61 133 237 392 620 930 1022
6 150 2 45 95 205 366 605 958 1437 1579
8 200 3 89 188 408 727 1202 1903 2854 3136
10 250 4 151 320 694 1237 2047 3240 4859 5340
12 300 5 234 495 1072 1911 3162 5005 7507 8250
14 350 6 338 715 1549 2761 4568 7230 10844 11917
16 400 8 464 983 2130 3797 6282 9942 14913 16388
18 450 11 615 1302 2822 5028 8320 13168 19752 21705
20 500 14 791 1674 3628 6465 10698 16931 25396 27908
22 550 17 965 2042 4426 7887 13052 20655 30983 34048
24 600 22 1222 2587 5605 9989 16528 26157 39236 43116
26 650 26 1434 3036 6578 11723 19397 29263 46047 50600
28 700 30 1663 3522 7630 12599 20036 30482 46899 58696
30 750 35 1912 4050 8142 13152 20411 31226 47562 63328
32 800 45 2387 4791 8736 13788 20613 31395 48117 68250
34 850 51 2697 5414 9872 15580 23293 35476 54372 77123
36 900 60 3021 6063 11055 17449 26086 39731 60895 86375
40 1000 84 4183 8395 15307 24159 36166 55084 84425 119750
42 1050 350 4095 9040 17108 27150 43640 70500 106890 117500
48 1200 455 5365 11840 22400 30600 51200 92300 140000 154000