Ball Valve Flow Coefficient (Cv value)

Ball valve flow coefficient Cv value for sizes 1/2" to 24", pressure rating Class 150 to 2500. The Flow Coefficient Cv value is the flow rate of water (gallons/minute) through a fully opening valve with a pressure draop of 1 psi to find the flow of liquid through the valve with Cv.

Ball Valve Flow Coefficient (Cv value) Specification

Size (inch)	150LB	300LB	300LB	900LB	1500LB
1/2	25	25	20	16	16
3/4	56	56	48	34	34
1	95	95	64	55	55
1-1/2	308	308	308	165	165
2	500	430	370	320	320
3	1360	1100	1020	920	820
4	2500	2000	1850	1760	1600
6	5300	5250	4400	4300	4150
8	10750	10100	8450	8475	8010
10	17500	16820	14250	14160	13220
12	26750	25950	22550	21200	18800
14	31850	30900	28500	26700	24180
16	44000	42600	38150	36600	33150
18	58000	55870	51150	49000	45703
20	75500	72500	68500	64600	60750
22	91770	86850	80150
24	113400	109340	98860

Note:
1. All sizes are full bore.
2. Pressure rating as ASME B16.34

The Flow Coefficient Cv value is the flow rate of water (gallons/minute) through a fully open valve with a pressure draop of 1 psi to find the flow of liquid through the value with Cv, use the following formulas.

Liquid Flow:
QL=Cv(P/G) ^1/2
QL=Flow rate of liquid (gal./min.)
P=differential pressure across the valve
G=specific gravity of liquid (for water, G=1)

Gas Flow:
Qg=61Cv (P₂P/g)^1/2
(For non-critical flow, P/P＜ 1.0)
Qg=Flow rate of gas (CFH at STP)
P₂=outlet pressure (psia)
g=specific gravity of gas (for air, g=1.0)