The Ultimate Valve Cv Sheets

What is a Cv?

Control valve CV refers to the flow coefficient of the valve. It applies to the coefficient of pressure drop(ΔP) or head drop (Δh) on the valve of Q(flow capacity).

For more definitions and related information, please read this article.

What is CV of Control Valves?

Flow Coefficient Calculation Cv

The flow rate of a liquid or gas through a valve depends on many factors such as density, temperature, gravity, and the pressure drop of the liquid or gas through the valve. The design type and flow path of the valve has different effect on the flow rate through the valve. Considering the relationship between temperature, gravity, and pressure drop through the valve, a “flow coefficient” can be calculated to determine the theoretical flow rate through the valve. This coefficient is called Cv (coefficient of flow) and it is developed by the flow capacity testing from the manufacturer.

3 Typical Systems of Steam Pressure Reducing Station

If flow capacity required is known and valve selection is desired, calculate Cv with the following formula and select the appropriate valve from the manufacturer’s Cv factor chart.

Butterfly Valve Cv Flow Rate

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Generally, we work on metric systems, but many engineers still prefer to express flow coefficients in terms of Cv values. The imperial system measures flow in US GPM at 60 degrees Fahrenheit with a pressure drop of 1 psi across the valve. The following table shows the flow rate of a butterfly valve between 0°(fully closed) and 90° (fully open) with the valve at different openings. Please notice that the Cv value is not a linear increment, so it cannot be deduced just by looking at the value. These sheets of flow coefficients are just for your reference. 

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Triple Offset Butterfly Valve Cv 150LB

Triple Offset Butterfly Valve Cv 300LB

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High-Performance Butterfly Valve Cv

Resilient Seated Butterfly Valves Cv

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

Ball Valves Cv Flow Rate

The Cv values below are used to indicate the flow rate of the ball valve. Different ball type has different Cv flow rate. Hope it will be useful for your case. 

V-Port Ball Valve Cv

Valve Size	Ball Angle	15%	20%	30%	40%	50%	60%	70%	80%	90%	100%
1/2″	30°	0.1	0.1	0.2	0.3	0.5	0.8	1.1	1.6	2.2	2.6
1/2″	60°	0.1	0.1	0.3	0.5	0.9	1.4	2	3.3	4.4	6
3/4″	30°	0.1	0.2	0.5	0.7	1.1	1.8	2.4	3.3	4.5	5.4
3/4″	60°	0.1	0.2	0.7	1	1.7	2.8	4	6.5	9	12
1″	30°	0.1	0.3	0.8	1.3	2.3	3.5	5.1	9.8	8.5	10
1″	60°	0.2	0.4	1.1	1.8	3.4	5.3	7.9	12.3	15.3	21
1 1/4″	30°	0.2	0.4	1.1	2	3.7	5.5	8	10	13	15
1 1/4″	60°	0.2	0.6	1.8	3	5.5	9.5	12.8	19	26	39
1 1/2″	30°	0.3	0.6	1.6	3	5	7.5	11	14	17	20
1 1/2″	60°	0.4	0.8	2.5	4	8	13	19	27	40	52
2″	30°	0.4	1.2	3.8	6	10	15	23	31	43	60
2″	60°	0.4	1.5	4.6	9	16.5	27	39	55	83	110
2 1/2″	30°	0.4	1	4	8	12	18	28	37	62	75
2 1/2″	60°	0.4	1.5	5	10	21	34	53	75	103	150
3″	30°	0.5	1.2	4	8	14	23	33	46	65	82
3″	60°	0.5	2.5	6	14	25	40	65	91	128	165
4″	30°	0.6	2	6	15	29	48	71	100	130	159
4″	60°	0.7	3	11	25	40	59	90	141	212	356
6″	30°	0.9	3.2	14	33	60	103	155	220	280	350
6″	60°	2	5	22	60	110	190	285	416	586	800

Flow Rate for two-way Full Bore Ball Valve Cv

Valve Size	DN (mm)	Cv when fully open
¼”	8	18
⅜”	10	20
½”	15	23
¾”	20	55
1”	25	95
1 ¼”	32	155
1 ½”	40	260
2”	50	440
2 ½”	65	710
3”	80	1050
4”	100	2040

3 Way Full Bore Flanged Ball Valve Cv

Valve Size	Cv	Kv (m3/h)
1/2″	15.2	13
3/4″	23.3	20
1″	45.5	39
1-1/4″	58.4	50
1-1/2″	112	96
2″	224.1	192
2-1/2″	308.1	264
3″	409.6	351
4″	762.1	653

3 Way Reduced Port Threaded Ball Valve Cv

Valve Size	Cv	Kv (m3/h)
1/4″	12.8	11
3/8″	12.8	11
1/2″	15.2	13
3/4″	17.5	15
1″	36.2	31
1-1/4″	45.5	39
1-1/2″	72.4	62
2″	120.2	103
2-1/2″	239.2	205
3″	270.7	232
4″	480.8	412

Globe Type Control Valve Cv Flow Rate

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globe Control valve cv

For example: 1″ globe valve cv. The Cv (flow coefficient) of a 1″ globe valve will depend on a range of factors, including the valve design, the flow medium, and the pressure drop across the valve. The Cv value is a measure of a valve’s flow capacity, and it represents the number of gallons of water that can pass through the valve at a pressure drop of one psi. For a 1″ globe valve, the Cv value could range from 0.14 to 15, depending on the specific valve model and application requirements.

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Manual Globe Valve Cv Table

Here is a table showing some typical Cv values for manual globe valves of varying sizes:

Valve Size	Cv Value
1/2″	2 – 7
3/4″	5 – 20
1″	7 – 50
1 1/4″	15 – 80
1 1/2″	25 – 130
2″	40 – 250

Please note that these Cv values are just examples and may vary depending on the specific valve model and application requirement.

Gate Valve Cv

Gate valves do not have a Cv curve like some other types of valves because they operate with the valve fully open or fully closed. The Cv value is not used to determine the flow rate through a gate valve, but rather to size the valve based on the required flow rate and pressure drop.

Bolted Bonnet Gate Valve Cv (Full Open）

Valve Size	150LB	300LB	600LB	900LB	1500LB
11/2 2 21/2 3 4 5 6 8 10 12 14 16 18 20 24 30 36	165 307 490 710 1300 2090 3110 5720 8935 13350 16275 21560 28720 35760 52165 86235 129500	165 307 490 710 1300 – 3110 5720 8935 13350 16275 21560 27890 34840 51050 84765 125825	165 307 490 710 1300 – 3110 5540 8495 12800 15370 29170 26270 32140 46710 75530 114250	– – – 650 1220 – 2850 5025 7850 11475 13910 – – – – – –	138 270 400 600 1070 1600 2500 4375 6840 9980 12000 – – – – – –

Pressure Seal Gate Valve Cv (Full Open）

Valve Size	600LB	900LB	1500LB	2500LB
21/2 3 4 6 8 10 12 14 16 18 20 24	350 525 925 2150 3775 5750 8600 10275 13425 17200 20950 30850	350 450 850 1925 3575 5250 7550 9150 11950 15575 19200 27675	275 415 730 1675 2925 4550 6570 7890 10325 13425 16825 24150	190 275 460 1100 1970 3130 4535 5500 7210 9215 11450 16575

Pressure Seal Venturi Gate Valve Cv (Full Open）

Valve Size	600LB	900LB	1500LB	2500LB
8 x 6 x 8 10 x 8 x 10 12 x 10 x 12 14 x 12 x 14 16 x 14 x 16 18 x 16 x 18 20 x 18 x 20 22 x 20 x 22 26 x 24 x 26	1570 2795 4485 7310 9000 11000 14200 16800 25000	1385 2385 4065 6285 7200 9760 12185 16005 23000	1185 2155 3450 5640 6270 8465 11120 14130 –	815 1430 2515 3855 4415 6165 7960 9645 –

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Check Valve Cv

Bolted Cap Swing Check Valve Cv (Full Open）

Cushioned Swing Check Valves

Valve Size	150LB	300LB	600LB	900LB	1500LB
11/2 2 21/2 3 4 6 8 10 12 14 16 18 20 24 30	63 142 217 356 716 1414 2961 5720 7860 10416 13800 13420 16708 33384 54556	63 168 275 392 740 1992 2340 5720 8544 19464 13800 13029 16276 36672 54652	97 139 227 246 499 1334 3359 5440 7045 9840 12912 – 19540 – –	– – – 358 605 1623 2508 4069 6316 – – – – – –	– 111 – 315 564 1520 – – – – – – – – –

Pressure Seal Tilting Disc Check Valve Cv (Full Open）

Valve Size	900LB	1500LB	2500LB
21/2 3 4 6 8 10 12 14 16 18 20 24	95 146 268 627 1062 1722 2420 2955 3945 4900 6275 9295	80 132 230 536 940 1465 2110 2550 3395 4365 5465 8060	60 94 146 355 627 1020 1420 1775 2355 3025 3705 5465

 Pressure Seal Venturi Tilting Disc Check Valve Cv (Full Open)

Valve Size	150LB	300LB	600LB
8 x 6 x 8 10 x 8 x 10 12 x 10 x 12 14 x 12 x 14 16 x 14 x 16 18 x 16 x 18 20 x 18 x 20 22 x 20 x 22	565 955 1550 2175 2660 3550 4410 5650	480 845 1320 1900 2295 3055 3930 4920	320 565 920 1275 1598 2120 2725 3335

Globe Valve, Stop-Check Valve, and Lift-Check Valve Cv

Frequently Asked Questions About Globe Valves

Pressure Seal T-Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open)

Valve Size	900LB	1500LB	2500LB
21/2 3 4 6 8 10 12 14	90 105 195 455 800 1250 1820 2205	65 95 170 395 695 1085 1580 –	45 65 105 265 470 750 1100 –

Pressure Seal Venturi Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open)

Valve Size	900LB	1500LB	2500LB
8 x 6 x 8 10 x 8 x 10 12 x 10 x 12 14 x 12 x 14 16 x 14 x 16	450 770 1215 1775 2125	390 690 1055 1550 –	260 465 745 1070 –

Pressure Seal Venturi Y-Globe Stop, Stop-Check, and Lift-Check Valve Cv (Full Open）

Valve Size	600LB	900LB	1500LB	2500LB
8 10 12 14 16 18 20 24	2025 3025 4600 4300 7650 7325 11800 16450	1750 2725 3825 3650 6000 5825 9125 13500	1750 2725 3825 3650 6000 5825 9125 13500	1175 1875 2650 4075 3775 6625 6225 9050

Introduction of Intelligent Positioner in Control Valves

Globe Valve Cv

How is the characteristic determined in a globe valve?

Bolted Bonnet Globe Valve Cv (Full Open）

Valve Size	Plug or Ball Disc (150LB)	V-Port Disc (150LB)	Plug or Ball Disc (300LB)	V-Port Disc (300LB)	Plug or Ball Disc (600LB)	V-Port Disc (600LB)	Plug or Ball Disc (900LB)
11/2 2 21/2 3 4 5 6 8 10 12	23 43 70 100 185 297 440 810 1260 1890	– 40 – 92 170 273 405 745 1150 –	23 43 70 100 185 – 440 810 1260 1890	21 40 – 92 170 – 405 745 – –	23 43 70 100 185 – 440 780 – 1810	– 40 – 92 170 – 405 – – –	– – – 90 170 – – – – –

Seat Port Area For Pressure Seal Y-Type Globe Valves Cv (in²)

Valve Size	900LB	1500LB	2500LB
8 10 12 14 16 18 20 24	39.9 61.9 86.6 86.6 135.4 135.4 198.1 302.6	39.9 61.9 86.6 86.6 135.4 135.4 198.1 302.6	27.2 42.8 60.1 86.6 86.6 135.4 135.4 198.1

Globe Control Valve Manufacturer- THINKTANK

How to Use Valve Cv?

The valve coefficient (Cv) is a number that represents a valve’s ability to pass flow. The bigger the Cv, the more flow a valve can pass with a given pressure drop. A Cv of 1 means a valve will pass 1 gallon per minute (GPM) of 60oF water with a pressure drop (dp) of 1 PSI across the valve. A Cv of 350 means a valve will pass 350 GPM of 60oF water with a dp of 1 PSI.

Equation 1: Flow Capacity LBS/Hr (steam or water)

dp= pressure drop in PSI

F=flow rate in lbs./hr.

=square root of a specific volume in ft3/lb. (downstream of the valve)

Equation 2: Flow Capacity GPM (Water or other liquids)

dp= pressure drop in PSI

Sg=specific gravity

Q=flow rate in GPM

Restrictions

The velocity equation is invalid under the following conditions.

a. For compressible fluids, the pressure drop is more than half of the inlet pressure.

b. For incompressible fluids, when the pressure drop causes cavitation or flashing.

c. For two-phase flows, such as a mixture of steam and water.

The optimum operating speed should be within these ranges when sizing check valves as below.

Question A:

What is the pressure drop through a 14″ Class 900 pressure seal gate valve with 400oF water, 1500 PSIG, and 5,000,000 lbs/hr flow rate?

Answer A: Use Equation 1

F=5,000,000

=0.137 (from the chart for water at 400^oF)

Cv=9150 (from pressure seal gate valve Cv sheet)

Question B:

What is the pressure drop through a 14″x12″x14″ Class 900 Venturi pressure seal gate valve with the same conditions as question A.

Answer B: Use Equation 1

Cv = 6285 (from Venturi pressure seal gate valve Cv Sheet)

Question C:

What is the smallest Class 2500 gate valve that will have less than a 5 PSI pressure drop in 900oF, 1200 PSI steam service at a flow rate of 500,000 lbs/hr?

Answer C: Use Equation1.

F=500,000

=0.785 (from chart for steam at 900oF, 1200 PSIG)

==2.24

The closest higher Cv is a 10″ Class 2500 gate with a Cv of 3130. This is the smallest valve with a pressure drop of less than 5 PSIG.

Selected Properties of Water and Steam

For Water (Downstream)

Temperature	100oF	200oF	300oF	400oF	500oF	600oF
All Pressures	0.127	0.129	0.132	0.137	0.143	0.154

For Steam (Downstream)

Pressure PSIG	Sat	500oF	600oF	700oF	800oF	900oF	1000oF	1100oF
100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1600 1800 2000 2500 3000 4000 5000 6000	1.97 1.46 1.21 1.06 0.950 0.865 0.801 0.747 0.701 0.662 0.628 0.598 0.570 0.545	2.20 1.61 1.30 1.11 0.979 0.895	2.32 1.68 1.38 1.19 1.06 0.960 0.880 0.815 0.759 0.710 0.670 0.629 0.590 0.559	2.44 1.77 1.46 1.26 1.12 1.02 0.941 0.875 0.821 0.773 0.732 0.695 0.662 0.633 0.58 0.54 0.50 0.41 0.31 0.17 0.16 0.16	2.54 1.85 1.52 1.32 1.18 1.08 0.994 0.926 0.870 0.816 0.781 0.745 0.710 0.683 0.63 0.59 0.55 0.48 0.42 0.32 0.24 0.19	2.64 1.95 1.60 1.38 1.23 1.13 1.04 0.972 0.914 0.865 0.823 0.785 0.752 0.723 0.67 0.63 0.59 0.52 0.46 0.38 0.32 0.28	2.74 2.00 1.65 1.43 1.28 1.17 1.08 1.01 0.955 0.917 0.872 0.813 0.789 0.752 0.70 0.66 0.62 0.55 0.49 0.42 0.36 0.32	2.84 2.07 1.71 1.47 1.33 1.22 1.12 1.05 0.99 0.94 0.90 0.86 0.83 0.79 0.74 0.69 0.65 0.58 0.52 0.44 0.39 0.35

Calculating Seat Port Velocity　

The following formulas can be used to calculate seat port velocity in any valve:

Flow (lbs/hr): vel: (fps) = F()2  /25A

Flow (GPM): vel: (fps) = 0.32Q/A

Where: F=flow (lbs/hr)

=square root of specific volume

A=seat port area (in2)

Q=flow (GPM)

Case A:

What is the seat port velocity in a 12″ Figure 58809 (Class 900) check valve with a flow rate of 90,000 lbs/hr of steam at 500 oF and 200 PSIG?

Solution A:

From the steam sheet is 1.61, and from the seat port area sheet A is 78.5 in².

Vel (fps) =F()² /25A    ⁼ 90,000 (1.61)²  /25(78.5)= 118.8 fps

Case B:

What is the seat port velocity in a 12″ Figure 180 (Class 150) Swing Check Valve with a flow rate of 90,000 lbs/hr of steam at 500oF and 200 PSIG?

Solution B:

From the Sheet is 1.61 and A is 113.1 in³.

Vel (fps) =F()² /25A =90,000 (1.61)²/25(113.1)= 82.5 fps

Figure 1 Bolted Bonnet Globe Valves

Characteristic Flow Curves for Globe Stop, Stop-Check, Lift-Check Valves

Estimating Cv For Less Than Fully Open Valves

Figure 2. Globe Stop, Stop-Check, and Lift-Check Valves

Figure 3. Y-Globe Stop, Stop-Check and Lift-Check Valves

The flow coefficient (Cv) listed in the tables applies to fully open valves only. Flow coefficients other than fully open may be approximated by use of the characteristic flow curves for tilting disc check and globe valves. Gate valves are not recommended for throttling service.

Case 3:

What is the Cv of a 12 inch Class 900 Pacific pressure seal globe valve 1/4 open?

Solution 3:

From the flow coefficient table above, the fully open Cv for a 12 inch, Class 900 globe valve is 1820.

Consulting Figure 2, the percent of fully open Cv at 1/4 valve open is 52%.

The Cv at 1/4 open is then computed as:

0.52 x 1820 = 946.

The above information is only for general use, all the data and formulae may not be suitable for all engineers, plant experts, and purchasing managers. Some data may be delayed or changed and we do not assume any responsibility for any failure to notify you at the first opportunity.

THINKTANK is a major valve manufacturer and optimal fluid solution provider, which supplies control valves, self-operated pressure regulators, butterfly valves, ball valves, eccentric plug valves, knife gate valves, globe valves, fusible link valves, and gate valves around the world.