Industrial-process control valves - Part 8-3: Noise considerations - Control valve aerodynamic noise prediction method

IEC 60534-8-3:2010 establishes a theoretical method to predict the external sound-pressure level generated in a control valve and within adjacent pipe expanders by the flow of compressible fluids. This method considers only single-phase dry gases and vapours and is based on the perfect gas laws. It is assumed that the downstream piping is straight for a length of at least 2 m from the point where the noise measurement is made. The method is applicable to the following single-stage valves:
- globe (straight pattern and angle pattern),
- butterfly,
- rotary plug (eccentric, spherical),
- ball, and
- valves with cage trims.
Specifically excluded are the full bore ball valves where the product FpC exceeds 50 % of the rated flow coefficient. This third edition cancels and replaces the second edition published in 2000. This edition constitutes a technical revision. The significant technical changes with respect to the previous edition are as follows:
- predicting noise as a function of frequency;
- using laboratory data to determine the acoustical efficiency factor.

Vannes de régulation des processus industriels - Partie 8-3: Considérations sur le bruit - Méthode de prédiction du bruit aérodynamique des vannes de régulation

La CEI 60534-8-3:2010 établit une méthode théorique pour prévoir le niveau de pression acoustique externe engendré dans une vanne de régulation et dans les raccords adjacents par le débit d'un fluide compressible. Cette méthode ne considère que les régimes monophasiques de gaz et vapeurs secs, et est basée sur la loi des gaz parfaits. On suppose que la tuyauterie aval comprend une longueur droite d'au moins 2 m à partir du point de mesure du bruit. La méthode est applicable aux vannes mono-étagées suivantes:
- à soupape (droites et d'équerre),
- à papillon,
- à obturateur rotatif (excentré, sphérique),
- à tournant sphérique, et
- aux vannes à cage.
Les vannes à tournant sphérique à passage direct, pour lesquelles le produit FpC dépasse 50 % du coefficient de débit assigné, sont spécifiquement exclues. Cette troisième édition annule et remplace la deuxième édition parue en 2000. Cette édition constitue une révision technique. Par rapport à l'édition précédente, les modifications techniques majeures sont les suivantes:
- la prédiction du bruit en fonction de la fréquence;
- l'utilisation des données de laboratoire pour déterminer le coefficient de rendement acoustique.

General Information

Status
Published
Publication Date
28-Nov-2010
Current Stage
PPUB - Publication issued
Start Date
15-Dec-2010
Completion Date
29-Nov-2010
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IEC 60534-8-3
®
Edition 3.0 2010-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Industrial-process control valves –
Part 8-3: Noise considerations – Control valve aerodynamic noise prediction
method

Vannes de régulation des processus industriels –
Partie 8-3: Considérations sur le bruit – Méthode de prédiction du bruit
aérodynamique des vannes de régulation

IEC 60534-8-3:2010

---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60534-8-3
®
Edition 3.0 2010-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE


Industrial-process control valves –
Part 8-3: Noise considerations – Control valve aerodynamic noise prediction
method

Vannes de régulation des processus industriels –
Partie 8-3: Considérations sur le bruit – Méthode de prédiction du bruit
aérodynamique des vannes de régulation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 17.140.20; 23.060.40; 25.040.40 ISBN 978-2-88912-241-7
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – 60534-8-3 ã IEC:2010
CONTENTS
FOREW ORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normativ e references . 7
3 Terms and definitions . 8
4 Symbols . 9
5 Valves with standard trim . 12
5.1 Pressures and pressure ratios. 12
5.2 Regime definition . 13
5.3 Preliminary calculations . 14
5.3.1 Valve style modifier F . 14
d
5.3.2 Jet diameter D . 14
j
5.3.3 Inlet fluid density r
. 14
1
5.4 Internal noise calculations . 15
5.4.1 Calculations common to all regimes . 15
5.4.2 Regime dependent calculations . 16
5.4.3 Downstream calculations . 18
5.4.4 Valve internal sound pressure calculation at pipe wall . 19
5.5 Pipe transmission loss calculation. 20
5.6 External sound pressure calculation . 21
5.7 Calculation flow chart . 22
6 Valves with special trim design . 22
6.1 General . 22
6.2 Single stage, multiple flow passage trim . 22
6.3 Single flow path, multistage pressure reduction trim (two or more throttling
steps) . 23
6.4 Multipath, multistage trim (two or more passages and two or more stages) . 25
7 Valves with higher outlet Mach numbers . 27
7.1 General . 27
7.2 Calculation procedure . 27
8 Valves with experimentally determined acoustical efficiency factors . 28
9 Combination of noise produced by a control valve with downstream installed two
or more fixed area stages . 29
Annex A (informative) Calculation examples . 31
Bibliography . 46

Figure 1 – Single stage, multiple flow passage trim . 23
Figure 2 – Single flow path, multistage pressure reduction trim . 24
Figure 3 – Multipath, multistage trim (two or more passages and two or more stages) . 26
Figure 4 – Control valve with downstream installed two fixed area stages . 30

Table 1 – Numerical constants N . 15
Table 2 – Typical values of valve style modifier F (full size trim) . 15

d
Table 3 – Overview of regime dependent equations . 17

---------------------- Page: 4 ----------------------
60534-8-3 ã IEC:2010 – 3 –
Table 4 – Typical values of A and St . 18
h p
Table 5 – Indexed frequency bands . 19
Table 6 – Frequency factors G (f) and G (f) . 21
x y
Table 7 – “A” weighting factor at frequency f . 22
i

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– 4 – 60534-8-3 ã IEC:2010
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

INDUSTRIAL-PROCESS CONTROL VALVES –

Part 8-3: Noise considerations –
Control valve aerodynamic noise prediction method


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60534-8-3 has been prepared by subcommittee 65B:
Measurements and control devices, of IEC technical committee 65: Industrial-process
measurement, control and automation.
This third edition cancels and replaces the second edition published in 2000. This edition
constitutes a technical revision.
The significant technical changes with respect to the previous edition are as follows:
· predicting noise as a function of frequency;
· using laboratory data to determine the acoustical efficiency factor.

---------------------- Page: 6 ----------------------
60534-8-3 ã IEC:2010 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
65B/765/FDIS 65B/780/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts of the IEC 60534 series, under the general title Industrial-process
control valves can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
 reconfirmed,
 withdrawn,
 replaced by a revised edition, or
 amended.

---------------------- Page: 7 ----------------------
– 6 – 60534-8-3 ã IEC:2010
INTRODUCTION
The mechanical stream power as well as acoustical efficiency factors are calculated for
various flow regimes. These acoustical efficiency factors give the proportion of the
mechanical stream power which is converted into internal sound power.
This method also provides for the calculation of the internal sound pressure and the peak
frequency for this sound pressure, which is of special importance in the calculation of the
pipe transmission loss.
At present, a common requirement by valve users is the knowledge of the sound pressure
level outside the pipe, typically 1 m downstream of the valve or expander and 1 m from the
pipe wall. This standard offers a method to establish this value.
The equations in this standard make use of the valve sizing factors as used in IEC 60534-1
and IEC 60534-2-1.
In the usual control valve, little noise travels through the wall of the valve. The noise of
interest is only that which travels downstream of the valve and inside of the pipe and then
escapes through the wall of the pipe to be measured typically at 1 m downstream of the
valve body and 1 m away from the outer pipe wall.
Secondary noise sources may be created where the gas exits the valve outlet at higher
Mach numbers. This method allows for the estimation of these additional sound levels which
can then be added logarithmically to the sound levels created within the valve.
Although this prediction method cannot guarantee actual results in the field, it yields
calculated predictions within 5 dB(A) for the majority of noise data from tests under
laboratory conditions (see IEC 60534-8-1). The current edition has increased the level of
confidence of the calculation. In some cases the results of the previous editions were more
conservative.
The bulk of the test data used to validate the method was generated using air at moderate
pressures and temperatures. However, it is believed that the method is generally applicable
to other gases and vapours and at higher pressures. Uncertainties become greater as the
fluid behaves less perfectly for extreme temperatures and for downstream pressures far
different from atmospheric, or near the critical point. The equations include terms which
account for fluid density and the ratio of specific heat.
NOTE Laboratory air tests conducted with up to 1 830 kPa (18,3 bar) upstream pressure and up to 1 600 kPa (16,0
bar) downstream pressure and steam tests up to 225 °C showed good agreement with the calculated values.
A rigorous analysis of the transmission loss equations is beyond the scope of this standard.
The method considers the interaction between the sound waves existing in the pipe fluid
and the first coincidence frequency in the pipe wall. In addition, the wide tolerances in pipe
wall thickness allowed in commercial pipe severely limit the value of the very complicated
mathematical approach required for a rigorous analysis. Therefore, a simplified method is
used.
Examples of calculations are given in Annex A.
This method is based on the IEC standards listed in Clause 2 and the references given in
the Bibliography.

---------------------- Page: 8 ----------------------
60534-8-3 ã IEC:2010 – 7 –
INDUSTRIAL-PROCESS CONTROL VALVES –

Part 8-3: Noise considerations –
Control valve aerodynamic noise prediction method



1 Scope
This part of IEC 60534 establishes a theoretical method to predict the external sound-
pressure level generated in a control valve and within adjacent pipe expanders by the flow
of compressible fluids.
This method considers only single-phase dry gases and vapours and is based on the perfect
gas laws.
This standard addresses only the noise generated by aerodynamic processes in valves and
in the connected piping. It does not consider any noise generated by reflections from
external surfaces or internally by pipe fittings, mechanical vibrations, unstable flow patterns
and other unpredictable behaviour.
It is assumed that the downstream piping is straight for a length of at least 2 m from the
point where the noise measurement is made.
This method is valid only for steel and steel alloy pipes (see Equations (21) and (23) in 5.5).
The method is applicable to the following single-stage valves: globe (straight pattern and
angle pattern), butterfly, rotary plug (eccentric, spherical), ball, and valves with cage trims.
Specifically excluded are the full bore ball valves where the product F C exceeds 50 % of
p
the rated flow coefficient.
For limitations on special low noise trims not covered by this standard, see Clause 8. When
the Mach number in the valve outlet exceeds 0,3 for standard trim or 0,2 for low noise trim,
the procedure in Clause 7 is used
The Mach number limits in this standard are as follows:
Mach number limit
Clause 7
Mach number location
Clause 5 Clause 6
High Mach number
Standard trim Noise-reducing trim
applications
Freely expanded jet M No limit No limit No limit
j
Valve outlet M 0,3 0,2 1,0
o
Downstream reducer inlet M Not applicable Not applicable 1,0
r
Downstream pipe M 0,3 0,2 0,8
2
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest
edition of the referenced document (including any amendments) applies.

---------------------- Page: 9 ----------------------
– 8 – 60534-8-3 ã IEC:2010
IEC 60534 (all parts), Industrial-process control valves
IEC 60534-1, Industrial-process control valves - Part 1: Control valve terminology and
general considerations
3 Terms and definitions
For the purposes of this document, all of the terms and definitions given in the IEC 60534
series and the following apply:
3.1
acoustical efficiency
h
ratio of the stream power converted into sound power propagating downstream to the
stream power of the mass flow
3.2
external coincidence frequency
f
g
frequency at which the external acoustic wavespeed is equal to the bending wavespeed in a
plate of equal thickness to the pipe wall
3.3
internal coincidence frequency
f
o
lowest frequency at which the internal acoustic and structural axial wave numbers are equal
for a given circumferential mode, thus resulting in the minimum transmission loss
3.4
fluted vane butterfly valve
butterfly valve which has flutes (grooves) on the face(s) of the disk. These flutes are
intended to shape the flow stream without altering the seating line or seating surface
3.5
independent flow passage
flow passage where the exiting flow is not affected by the exiting flow from adjacent flow
passages
3.6
peak frequency
f
p
frequency at which the internal sound pressure is maximum
3.7
valve style modifier
F
d
ratio of the hydraulic diameter of a single flow passage to the diameter of a circular orifice,
the area of which is equivalent to the sum of areas of all identical flow passages at a given
travel

---------------------- Page: 10 ----------------------
60534-8-3 ã IEC:2010 – 9 –
4 Symbols
Symbol Description Unit
2
A Area of a single flow passage m
Valve correction factor for acoustical efficiency Dimensionless
A
h
(see Table 4)
2
A Total flow area of last stage of multistage trim with n m
n
stages at given travel
C Flow coefficient (K and C ) Various
v v
(see IEC 60534-
1)
c External speed of sound (dry air at standard conditions = m/s
a
343 m/s)
C Flow coefficient for last stage of multistage trim with n stages Various
n
(see IEC 60534-
1)
c Speed of sound of the pipe (for steel = 5 000 m/s) m/s

s
c Speed of sound in the vena contracta at subsonic m/s
vc
flow conditions
c Speed of sound in the vena contracta at critical flow conditions m/s
vcc
c Speed of sound at downstream conditions m/s
2
D Valve outlet diameter m
d Diameter of a flow passage (for other than circular, use m
d )
H
d Hydraulic diameter of a single flow passage m
H
d Smaller of valve outlet or expander inlet internal m
i
diameters
D Internal downstream pipe diameter m
i
D Jet diameter at the vena contracta m
j
d Diameter of a circular orifice, the area of which equals m
o
the sum of areas of all flow passages at a given travel
F Valve style modifier Dimensionless
d
F Liquid pressure recovery factor of a valve without Dimensionless
L
attached
fittings (see Note 4)
F Liquid pressure recovery factor of last stage Dimensionless
Ln
of low noise trim
F Combined liquid pressure recovery factor and piping Dimensionless
LP
geometry factor of a control valve with attached fittings
(see Note 4)
F Piping geometry factor Dimensionless
p
f External coincidence frequency Hz
g
f Internal coincidence pipe frequency Hz
o
f Generated peak frequency Hz
p
f Generated peak frequency in valve outlet or reduced Hz
pR
diameter of expander
f Ring frequency Hz
r
f Structural loss factor reference frequency = 1 Hz Hz
s

---------------------- Page: 11 ----------------------
– 10 – 60534-8-3 ã IEC:2010
Symbol Description Unit
G , G Frequency factors (see Table 4) Dimensionless
x y
I Length of a radial flow passage m
l Wetted perimeter of a single flow passage m
w
L Correction for Mach number dB (ref p )
g o
L (f) Frequency-dependent external sound-pressure level 1 m dB(ref p )
pe,1m o
from pipe wall
L A-weighted overall sound-pressure level 1 m from pipe dB(A) (ref p )
o
pAe,1m
wall
L Overall Internal sound-pressure level at pipe wall dB (ref p )
pi o
L (f) Frequency-dependent internal sound-pressure level at dB (ref p )
pi o
pipe wall
L Overall Internal sound-pressure level at pipe wall for dB (ref p )
piR o
noise created by outlet flow in expander
L (f) Frequency-dependent internal sound-pressure level at dB (ref p )
piR o
pipe wall for noise created by outlet flow in expander
L (f) Combined internal frequency-dependent sound-pressure dB (ref p )
piS o
at the pipe wall, caused by the valve trim and expander
L Total internal sound power level dB (ref W )
wi o
M Molecular mass of flowing fluid kg/kmol
M Freely expanded jet Mach number in regimes II to IV Dimensionless
j
M Freely expanded jet Mach number of last stage in Dimensionless
jn
multistage valve with n stages
M Freely expanded jet Mach number in regime V Dimensionless
j5
M Mach number at valve outlet Dimensionless
o
M Mach number in the entrance to expander Dimensionless
R
M Mach number at the vena contracta Dimensionless
vc
M Mach number in downstream pipe Dimensionless
2
& Mass flow rate kg/s
m
N Numerical constants (see Table 1) Various
n Number of independent and identical flow passages Dimensionless
o
in valve trim
p Actual atmospheric pressure outside pipe Pa (see Note 3)
a
p Absolute stagnation pressure at inlet of the last stage of Pa
n
multistage valve with n stages
–5
p Reference sound pressure = 2 ´ 10 (see Note 5) Pa
o
p Standard atmospheric pressure (see Note 1) Pa
s
p Absolute vena contracta pressure at subsonic Pa
vc
flow conditions
p Valve inlet absolute pressure Pa
1
p Valve outlet absolute pressure Pa
2
R Universal gas constant = 8 314 J/kmol ´ K
St Strouhal number for peak frequency calculation (see Dimensionless
Table 4)

---------------------- Page: 12 ----------------------
60534-8-3 ã IEC:2010 – 11 –
Symbol Description Unit
T Inlet absolute temperature at last stage of multistage K
n
valve
with n stages
T Vena contracta absolute temperature at subsonic K
vc
flow conditions
T Vena contracta absolute temperature at critical K
vcc
flow conditions
T Inlet absolute temperature K
1
T Outlet absolute temperature K
2
TL(f) Frequency-dependent transmission loss dB
t Pipe wall thickness m
s
U Gas velocity in downstream pipe m/s
p
U Gas velocity in the inlet of diameter expander m/s
R
W Sound power for noise crated by valve flow and W
a
propagating downstream
W Sound power for noise generated by the outlet flow and W
aR
propagating downstream
W Stream power of mass flow W
m
W Stream power of mass flow rate at sonic velocity W
ms
W Converted stream power in the expander W
mR
–12
W Reference sound power = 10 (see Note 5) W
o
x Differential pressure ratio Dimensionless
x Vena contracta differential pressure ratio at critical flow Dimensionless
vcc
conditions
x Differential pressure ratio at break point Dimensionless
B
x Differential pressure ratio at critical flow conditions Dimensionless
C
x Differential pressure ratio where region of constant Dimensionless
CE
acoustical efficiency begins
Recovery correction factor Dimensionless
a
b Contraction coefficient for valve outlet or expander inlet Dimensionless
Specific heat ratio Dimensionless
g
A-Weighting correction based on frequency dB
DL (f)
A
DTL Damping factor for transmission loss dB
Acoustical efficiency factor for noise created by valve Dimensionless
h
flow (see Note 2)
Acoustical efficiency factor for noise created by outlet Dimensionless
h
R
flow in expander
Frequency-dependent structural loss factor Dimensionless
h (f)
s
3
Density of fluid at p and T kg/m
r
1 1 1
3
Density of fluid at p and T kg/m
r
2 2
2
3
Density of fluid at last stage of multistage valve kg/m
r
n
with n stages at p and T
n n

3
r Density of the pipe kg/m
s
Relative flow coefficient Dimensionless
F

---------------------- Page: 13 ----------------------
– 12 – 60534-8-3 ã IEC:2010
Symbol Description Unit

Subscripts
e Denotes external
i Denotes internal or used as an index for the frequency
band number
n Denotes last stage of trim
p Denotes peak
R Denotes conditions in downstream pipe or pipe expander

NOTE 1 Standard atmospheric pressure is 101,325 kPa or 1,01325 bar.
NOTE 2 Subscripts 1, 2, 3, 4 and 5 denote regimes I, II, III, IV and V respectively.
2 5
NOTE 3 1 bar = 10 kPa = 10 Pa.
NOTE 4 For the purpose of calculating the vena contracta pressure, and therefore velocity, in this standard,
pr
...

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