Pipeline ancillaries
HVB3aslltvoaplveaslve
Simplified equations for sizing (Kv values = Cv x 0.86)
For steam and gases
Where:
Sub-critical flow
When:
DP<0.5 F
L
2P
1
For gases
(volumetric flowrate)
Cv=
��
prT
295 P
1
2 - P
2
2
For gases
(mass flowrate)
Critical flow
When:
DP>0.5 F
L
2P
1
For gases
(volumetric flowrate)
Cv=
��
prT
257 F
L
P
1
For gases
(mass flowrate)
�
�
T
Cv =
311 F
L
P
1
pr
For saturated steam
Cv =
��s
11.95 F
L
P
1
For superheated steam
Cv=
��s(1+0.00126Tso)
11.95 F
L
P
1
Cv =
F
L
=
pr =
P
1
=
P
2
=
T =
V =
m =
Tso =
m
S
=
Flow coeffecient of the valve
Pressure recovery factor
Specific density of gas (air = 1)
Upstream pressure (bar a)
Downstream presure (bar a)
Inlet temperature in °K (°C + 273)
Flowrate of gas in Nm3/h (at 15°C and 1 bar a)
Flowrate of gas in in kg/h
Superheating of steam in °C
(Temperature of superheated steam - Temperature
of saturated steam)
Flowrate of steam in kg/h
T
Cv =
360 (P
1
2 - P
2
2)pr
For saturated steam
Cv =
��s
13.81 P
1
2 - P
2
2
For superheated steam
Cv=
��
s(1+0.00126Tso)
13.81 P
1
2 - P
2
2
Note: These equations are only a simplified version of the
original sizing equations of the ISA and IEC regulations. The
results are sufficiently close for practical use. There could be a
maximum error of 8% in the transition of non-choked flowrate
to choked flowrate.
��
Cv values (Kv values = Cv x 0.86)
Valve
size
Pipe
size
Rotation
0°
9°
18°
27°
36°
45°
54°
63°
72°
81°
90°
DN25
25 mm
0.00
0.00
0.96
1.61
2.56
3.88
6.51
9.61
15.50
24.49
31.00
32 mm
0.00
0.00
0.96
1.61
2.56
3.87
6.48
9.50
15.06
22.85
27.86
40 mm
0.00
0.00
0.96
1.61
2.56
3.87
6.45
9.42
14.73
21.75
25.92
50 mm
0.00
0.00
0.96
1.61
2.55
3.86
6.41
9.29
14.24
20.27
23.52
DN40
40 mm
0.00
0.00
2.94
4.93
7.82
11.85
19.91
29.39
47.40
74.89
94.80
50 mm
0.00
0.00
2.94
4.93
7.81
11.81
19.74
28.86
45.28
67.26
80.57
65 mm
0.00
0.00
2.94
4.92
7.80
11.78
19.57
28.33
43.30
61.23
70.77
80 mm
0.00
0.00
2.94
4.92
7.79
11.74
19.38
27.77
41.39
56.16
63.24
DN50
50 mm
0.00
0.00
3.41
5.72
9.08
13.75
23.10
34.10
55.00
86.90
110.00
65 mm
0.00
0.00
3.41
5.72
9.08
13.74
23.05
33.94
54.33
84.33
104.92
80 mm
0.00
0.00
3.41
5.72
9.07
13.71
22.93
33.57
52.85
79.08
95.30
100 mm
0.00
0.00
3.41
5.72
9.06
13.69
22.80
33.15
51.26
74.04
86.83
DN65
65 mm
0.00
0.00
7.15
11.99
19.02
28.81
48.41
71.46
115.25
182.10
230.50
80 mm
0.00
0.00
7.15
11.99
19.00
28.74
48.09
70.45
111.15
167.10
202.12
100 mm
0.00
0.00
7.15
11.97
18.96
28.60
47.44
68.43
103.70
144.56
165.48
150 mm
0.00
0.00
7.14
11.96
18.91
28.44
46.71
66.31
96.71
127.22
140.79
DN80
80 mm
0.00
0.00
8.99
15.08
23.93
36.25
60.90
89.90
145.00
229.10
290.00
100 mm
0.00
0.00
8.99
15.07
23.91
36.17
60.53
88.71
140.16
211.30
256.20
150 mm
0.00
0.00
8.99
15.06
23.86
36.00
59.74
86.30
131.20
183.85
211.18
200 mm
0.00
0.00
8.98
15.06
23.84
35.93
59.40
85.27
127.65
174.44
197.26
DN100
100 mm
0.00
0.00
17.36
29.12
46.20
70.00
117.60
173.60
280.00
442.40
560.00
150 mm
0.00
0.00
17.35
29.10
46.10
69.66
116.00
168.58
260.27
374.87
438.72
200 mm
0.00
0.00
17.35
29.08
46.03
69.40
114.81
164.97
247.56
339.58
384.87
250 mm
0.00
0.00
17.35
29.06
45.98
69.24
114.10
162.89
240.69
322.47
360.47
DN150
150 mm
0.00
0.00
23.25
39.00
61.88
93.75
157.50
232.50
375.00
592.50
750.00
200 mm
0.00
0.00
23.25
38.99
61.85
93.66
157.07
231.12
369.29
570.71
707.20
250 mm
0.00
0.00
23.25
38.99
61.82
93.55
156.53
229.43
362.50
546.56
662.73
300 mm
0.00
0.00
23.25
38.98
61.80
93.47
156.18
228.32
358.16
532.04
637.31
F
L
- - 0.96 0.94
0.92 0.88 0.82
0.75
0.68
0.62
0.50
M45 ISO Ball Valve for Control of Fluids - Sizing Sheet
TI-P133-47 ST Issue 1
7.4.154
