Butterfly Valves - Flow Coefficients Cv
Typical flow coefficients - Cv - for butterfly valves.
The table below can be used to indicate butterfly valves and their flow coefficients at different open (or closed) positions. Manufacturers data should always be checked before actual use.
| Valve Size | Flow Coefficient - Cv | ||||||
|---|---|---|---|---|---|---|---|
| Openness (disc angle) | Maximum flow velocity (ft/sec) | ||||||
| inches | mm | 90 deg (wide open) | 70 deg | 50 deg | 30 deg | ANSI 150 | ANSI 300 |
| 2 | 50 | 85 | 65 | 35 | 15 | 90 | 90 |
| 2 1/2 | 65 | 160 | 120 | 65 | 29 | 80 | 90 |
| 3 | 80 | 260 | 195 | 104 | 47 | 80 | 80 |
| 4 | 100 | 475 | 356 | 190 | 86 | 80 | 80 |
| 5 | 125 | 770 | 577 | 308 | 139 | 80 | 80 |
| 6 | 150 | 1125 | 844 | 450 | 203 | 75 | 80 |
| 8 | 200 | 2110 | 1583 | 844 | 380 | 70 | 75 |
| 10 | 250 | 3350 | 2513 | 1340 | 603 | 60 | 70 |
| 12 | 300 | 4800 | 3600 | 1920 | 864 | 50 | 60 |
| 14 | 350 | 6900 | 5175 | 2760 | 1224 | 50 | |
| 16 | 400 | 9000 | 6750 | 3600 | 1620 | 50 | |
| 18 | 450 | 11800 | 8850 | 4720 | 2124 | 50 | |
| 20 | 500 | 14300 | 10725 | 5720 | 2574 | 50 | |
- 1 ft/s = 0.3048 m/s
