SIST EN ISO 3744:2010
Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane (ISO 3744:2010)
Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane (ISO 3744:2010)
This International Standard specifies methods for determining the sound power level or sound energy level of a noise source from sound pressure levels measured on a surface enveloping the noise source (machinery or equipment) in an environment that approximates to an acoustic free field near one or more reflecting planes. The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level) produced by the noise source, in frequency bands or with A-weighting applied, is calculated using those measurements.
Akustik - Bestimmung der Schallleistungs- und der Schallenergiepegel von Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der Genauigkeitsklasse 2 für ein im Wesentlichen freies Schallfeld über einer reflektierenden Ebene (ISO 3744:2010)
Diese Internationale Norm legt Verfahren für die Bestimmung des Schallleistungspegels oder des Schallenergiepegels einer Geräuschquelle aus Schalldruckpegeln fest, die auf einer Fläche gemessen werden, die die Geräuschquelle (eine Maschine oder ein Gerät) umschließt (Hüllfläche), wobei sich die Geräuschquelle in einer Umgebung befindet, die angenähert einem akustischen Freifeld in der Nähe einer oder mehrerer reflektierender Ebenen entspricht. Der von der Geräuschquelle erzeugte Schallleistungspegel (oder Schallenergiepegel bei Impulsen oder anderen Geräuschen von kurzer Dauer) in Frequenzbändern oder mit A-Bewertung wird aus den gemessenen Schalldruckpegeln berechnet. ANMERKUNG Unterschiedliche Messflächenformen können zu unterschiedlichen Werten des Schallleistungspegels der betrachteten Geräuschquelle führen. Daher sollten in einer Prüfnorm genaue Angaben zur Auswahl der Messfläche gemacht werden.
Acoustique - Détermination des niveaux de puissance et d'énergie acoustique émis par les sources de bruit à partir de la pression acoustique - Méthodes d'expertise pour des conditions approchant celles du champ libre sur plan réfléchissant (ISO 3744:2010)
L'ISO 3744:2010 spécifie des méthodes de détermination du niveau de puissance acoustique ou du niveau d'énergie acoustique émis par une source de bruit à partir des niveaux de pression acoustique mesurés sur une surface entourant la source de bruit (machine ou équipement), dans des conditions approchant celles du champ acoustique libre au voisinage d'un ou de plusieurs plans réfléchissants. Le niveau de puissance acoustique (ou, dans le cas d'impulsions sonores ou d'émissions sonores transitoires, le niveau d'énergie acoustique) produit par la source de bruit, par bandes de fréquences ou avec la pondération A appliquée, est calculé en utilisant ces mesures.
Les méthodes spécifiées dans l'ISO 3744:2010 sont applicables à tous les types de bruit (stable, non stable, fluctuant, impulsions acoustiques isolées, etc.) définis dans l'ISO 12001.
L'ISO 3744:2010 s'applique à tous les types de sources de bruit, quelles que soient leurs dimensions (par exemple installation, dispositif, machine, composant, sous-ensemble fixe ou se déplaçant lentement), sous réserve de pouvoir satisfaire les conditions de mesurage.
Les environnements d'essai qui sont applicables aux mesurages réalisés conformément à l'ISO 3744:2010 peuvent être en salle ou en plein air, comprendre un ou plusieurs plans acoustiques réfléchissants sur lesquels ou à proximité desquels est montée la source de bruit en essai. L'environnement idéal est un espace complètement libre, dépourvu de surfaces limites ou réfléchissantes autres que le ou les plans réfléchissants (tels que ceux d'une salle semi-anéchoïque qualifiée), mais des méthodes sont fournies pour appliquer des corrections (dans des limites spécifiées) lorsque ces environnements ne correspondent pas à ces conditions idéales.
Des informations sont données sur l'incertitude associée aux niveaux de puissance acoustique et aux niveaux d'énergie acoustique déterminés conformément à l'ISO 3744:2010 pour des mesurages effectués dans des bandes de fréquences limitées et avec la pondération fréquentielle A. L'incertitude est conforme à celle de la classe de précision 2 (classe expertise) définie dans l'ISO 12001:1996.
Akustika - Ugotavljanje ravni zvočnih moči virov hrupa z merjenjem zvočnega tlaka - Inženirska metoda v pretežno prostem polju nad odbojno ravnino (ISO 3744:2010)
Ta mednarodni standard določa metode ugotavljanja ravni moči zvoka ali ravni energije zvoka iz virov hrupa iz ravni zvočnega tlaka, merjenih na površju, ki obdaja vir hrupa (stroji ali oprema), v okolju, ki se približuje akustičnemu prostemu polju v bližini ene ali več odbojnih ravnin. Raven moči zvoka (ali v primeru prodorov hrupa ali prehodnih emisij hrupa raven zvočne energije), ki jo proizvede vir hrupa v frekvenčnih pasovih ali z uporabljenim A-uteženjem, je izračunana z uporabo teh merjenj.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 3744:2010
01-december-2010
1DGRPHãþD
SIST EN ISO 3744:2009
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLYLURYKUXSD]PHUMHQMHP]YRþQHJD
WODND,QåHQLUVNDPHWRGDYSUHWHåQRSURVWHPSROMXQDGRGERMQRUDYQLQR ,62
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Engineering methods for an essentially free field over a
reflecting plane (ISO 3744:2010)
Akustik - Bestimmung der Schallleistungs- und der Schallenergiepegel von
Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der
Genauigkeitsklasse 2 für ein im Wesentlichen freies Schallfeld über einer reflektierenden
Ebene (ISO 3744:2010)
Acoustique - Détermination des niveaux de puissance et d'énergie acoustique émis par
les sources de bruit à partir de la pression acoustique - Méthodes d'expertise pour des
conditions approchant celles du champ libre sur plan réfléchissant (ISO 3744:2010)
Ta slovenski standard je istoveten z: EN ISO 3744:2010
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
SIST EN ISO 3744:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 3744:2010
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SIST EN ISO 3744:2010
EUROPEAN STANDARD
EN ISO 3744
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2010
ICS 17.140.01 Supersedes EN ISO 3744:2009
English Version
Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure -
Engineering methods for an essentially free field over a
reflecting plane (ISO 3744:2010)
Acoustique - Détermination des niveaux de puissance et Akustik - Bestimmung der Schallleistungs- und der
d'énergie acoustiques émis par les sources de bruit à partir Schallenergiepegel von Geräuschquellen aus
de la pression acoustique - Méthodes d'expertise pour des Schalldruckmessungen - Hüllflächenverfahren der
conditions approchant celles du champ libre sur plan Genauigkeitsklasse 2 für ein im Wesentlichen freies
réfléchissant (ISO 3744:2010) Schallfeld über einer reflektierenden Ebene (ISO
3744:2010)
This European Standard was approved by CEN on 14 August 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3744:2010: E
worldwide for CEN national Members.
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SIST EN ISO 3744:2010
EN ISO 3744:2010 (E)
Contents Page
Foreword .3
Annex ZA .4
2
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SIST EN ISO 3744:2010
EN ISO 3744:2010 (E)
Foreword
The text of ISO 3744:2010 has been prepared by Technical Committee ISO/TC 43 “Acoustics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 3744:2010 by
Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by April 2011, and conflicting national standards shall be withdrawn at the
latest by April 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3744:2009.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive.
For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 3744:2010 has been approved by CEN as a EN ISO 3744:2010 without any modification.
3
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SIST EN ISO 3744:2010
EN ISO 3744:2010 (E)
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide one means of conforming to Essential Requirements of
the New Approach Directive 2006/42/EC on machinery.
Once this standard is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the normative
clauses of this standard confers, within the limits of the scope of this standard, a presumption of conformity
with the relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING — Other requirements and other EU Directives may be applicable to the products falling
within the scope of this standard.
4
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SIST EN ISO 3744:2010
INTERNATIONAL ISO
STANDARD 3744
Third edition
2010-10-01
Acoustics — Determination of sound
power levels and sound energy levels of
noise sources using sound pressure —
Engineering methods for an essentially
free field over a reflecting plane
Acoustique — Détermination des niveaux de puissance et d'énergie
acoustiques émis par les sources de bruit à partir de la pression
acoustique — Méthodes d'expertise pour des conditions approchant
celles du champ libre sur plan réfléchissant
Reference number
ISO 3744:2010(E)
©
ISO 2010
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
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ii © ISO 2010 – All rights reserved
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.2
3 Terms and definitions .2
4 Test environment.8
5 Instrumentation .11
6 Definition, location, installation, and operation of noise source under test.12
7 Reference box and measurement surface.14
8 Determination of sound power levels and sound energy levels .18
9 Measurement uncertainty.26
10 Information to be recorded.29
11 Test report.31
Annex A (normative) Qualification procedures for the acoustic environment .32
Annex B (normative) Microphone arrays on a hemispherical measurement surface .37
Annex C (normative) Microphone arrays on a parallelepiped measurement surface .44
Annex D (informative) Microphone arrays on a cylindrical measurement surface.55
Annex E (normative) Calculation of A-weighted sound power levels and A-weighted sound
energy levels from frequency band levels.59
Annex F (normative) Alternative microphone array on a hemispherical measurement surface for
direct measurements of A-weighted sound pressure levels .61
Annex G (normative) Sound power level and sound energy level under reference meteorological
conditions.64
Annex H (informative) Guidelines on the development of information on measurement uncertainty .66
Bibliography.77
© ISO 2010 – All rights reserved iii
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3744 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This third edition of ISO 3744 cancels and replaces the second edition (ISO 3744:1994) and ISO 4872:1978,
of which it constitutes a merger and a technical revision.
iv © ISO 2010 – All rights reserved
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
Introduction
[2] [6]
This International Standard is one of the series ISO 3741 to ISO 3747 , which specify various methods for
determining the sound power levels and sound energy levels of noise sources including machinery, equipment
[1]
and their sub-assemblies. General guidelines to assist in the selection are provided in ISO 3740 . The
selection depends on the environment of the available test facility and on the precision of the sound power
level or sound energy level values required. It may be necessary to establish a noise test code (see
ISO 12001) for the individual noise source in order to select the appropriate sound measurement surface and
[2] [6]
microphone array from among those allowed in each member of the ISO 3741 to ISO 3747 series, and to
give requirements on test unit mounting, loading and operating conditions under which the sound power levels
or sound energy levels are to be obtained. The sound power emitted by a given source into the test
environment is calculated from the mean square sound pressure that is measured over a hypothetical
measurement surface enclosing the source, and the area of that surface. The sound energy for a single sound
event is calculated from this sound power and the time over which it existed.
The methods specified in this International Standard permit the determination of the sound power level and
the sound energy level in frequency bands optionally with frequency A-weighting applied.
[2]
For applications where greater accuracy is required, reference can be made to ISO 3745, ISO 3741 or
[13]-[15]
ISO 9614 . If the relevant criteria for the measurement environment specified in this International
[13]-[15]
Standard are not met, it might be possible to refer to another standard from this series, or to ISO 9614 .
This International Standard describes methods of accuracy grade 2 (engineering grade) as defined in
ISO 12001, when the measurements are performed in a space that approximates an acoustically free field
over a reflecting plane. Such an environment can be found in a specially designed room, or within industrial
buildings or outdoors. Ideally, the test source should be mounted on a sound-reflecting plane located in a
large open space. For sources normally installed on the floor of machine rooms, corrections are defined to
account for undesired reflections from nearby objects, walls and the ceiling, and for the residual background
noises that occur there.
© ISO 2010 – All rights reserved v
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SIST EN ISO 3744:2010
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SIST EN ISO 3744:2010
INTERNATIONAL STANDARD ISO 3744:2010(E)
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure —
Engineering methods for an essentially free field over a
reflecting plane
1 Scope
1.1 General
This International Standard specifies methods for determining the sound power level or sound energy level of
a noise source from sound pressure levels measured on a surface enveloping the noise source (machinery or
equipment) in an environment that approximates to an acoustic free field near one or more reflecting planes.
The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level)
produced by the noise source, in frequency bands or with A-weighting applied, is calculated using those
measurements.
NOTE Differently shaped measurement surfaces can yield differing estimates of the sound power level of a given
noise source and an appropriately drafted noise test code (see ISO 12001) gives detailed information on the selection of
the surface.
1.2 Types of noise and noise sources
The methods specified in this International Standard are suitable for all types of noise (steady, non-steady,
fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.
This International Standard is applicable to all types and sizes of noise source (e.g. stationary or slowly
moving plant, installation, machine, component or sub-assembly), provided the conditions for the
measurements can be met.
NOTE It is possible that the conditions for measurements given in this International Standard are impracticable for
very tall or very long sources such as chimneys, ducts, conveyors and multi-source industrial plants. A noise test code for
the determination of noise emission of specific sources can provide alternative methods in such cases.
1.3 Test environment
The test environments that are applicable for measurements made in accordance with this International
Standard can be located indoors or outdoors, with one or more sound-reflecting planes present on or near
which the noise source under test is mounted. The ideal environment is a completely open space with no
bounding or reflecting surfaces other than the reflecting plane(s) (such as that provided by a qualified hemi-
anechoic chamber), but procedures are given for applying corrections (within limits that are specified) in the
case of environments that are less than ideal.
1.4 Measurement uncertainty
Information is given on the uncertainty of the sound power levels and sound energy levels determined in
accordance with this International Standard, for measurements made in limited bands of frequency and with
frequency A-weighting applied. The uncertainty conforms to ISO 12001:1996, accuracy grade 2 (engineering
grade).
© ISO 2010 – All rights reserved 1
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
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.
ISO 3382-2, Acoustics — Measurement of room acoustic parameters — Part 2: Reverberation time in ordinary
rooms
ISO 3745, Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Precision methods for anechoic test rooms and hemi- anechoic test rooms
ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
ISO 6926, Acoustics — Requirements for the performance and calibration of reference sound sources for the
determination of sound power levels
ISO 12001:1996, Acoustics — Noise emitted by machinery and equipment — Rules for the drafting and
presentation of a noise test code
ISO/IEC Guide 98-3, Uncertainty in measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
sound pressure
p
difference between instantaneous pressure and static pressure
[21]
NOTE 1 Adapted from ISO 80000-8:2007 , 8-9.2.
NOTE 2 Sound pressure is expressed in pascals.
3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of a
reference value, p , expressed in decibels
0
2
p
L = 10 lg dB (1)
p
2
p
0
where the reference value, p , is 20 µPa
0
[20]
[ISO/TR 25417:2007 , 2.2]
2 © ISO 2010 – All rights reserved
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
NOTE 1 If specific frequency and time weightings as specified in IEC 61672-1 and/or specific frequency bands are
applied, this is indicated by appropriate subscripts; e.g. L denotes the A-weighted sound pressure level.
pA
[21]
NOTE 2 This definition is technically in accordance with ISO 80000-8:2007 , 8-22.
3.3
time-averaged sound pressure level
L
p,T
ten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p,
during a stated time interval of duration, T (starting at t and ending at t ), to the square of a reference value,
1 2
p , expressed in decibels
0
t
⎡⎤2
1
2
⎢⎥
pt()dt
∫
⎢⎥
T
t
⎢⎥1
L = 10 lg dB (2)
pT,
⎢⎥2
p
0
⎢⎥
⎢⎥
⎢⎥
⎣⎦
where the reference value, p , is 20 µPa
0
NOTE 1 In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily determined
over a certain measurement time interval.
NOTE 2 Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by L , which is
pA,T
usually abbreviated to L .
pA
[20]
NOTE 3 Adapted from ISO/TR 25417:2007 , 2.3.
3.4
single event time-integrated sound pressure level
L
E
ten times the logarithm to the base 10 of the ratio of the integral of the square of the sound pressure, p, of an
isolated single sound event (burst of sound or transient sound) over a stated time interval T (starting at t and
1
ending at t ), to a reference value, E , expressed in decibels
2 0
t
⎡⎤
2
2
⎢⎥
pt()dt
∫
⎢⎥
t
⎢⎥1
L = 10 lg dB (3)
E
⎢⎥
E
0
⎢⎥
⎢⎥
⎢⎥
⎣⎦
2 −10 2
where the reference value, E , is (20 µPa) s = 4 × 10 Pa s
0
⎡⎤
T
NOTE 1 This quantity can be obtained by L +10 lg dB , where T = 1 s.
⎢⎥
pT,
0
T
0
⎣⎦
NOTE 2 When used to measure sound immission, this quantity is usually called “sound exposure level”
[20]
(see ISO/TR 25417:2007 ).
© ISO 2010 – All rights reserved 3
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
3.5
measurement time interval
T
portion or a multiple of an operational period or operational cycle of the noise source under test for which the
time-averaged sound pressure level is determined
NOTE Measurement time interval is expressed in seconds.
3.6
acoustic free field
sound field in a homogeneous, isotropic medium free of boundaries
NOTE In practice, an acoustic free field is a field in which the influence of reflections at the boundaries or other
disturbing objects is negligible over the frequency range of interest.
3.7
acoustic free field over a reflecting plane
acoustic free field in the half-space above an infinite reflecting plane in the absence of any other obstacles
3.8
reflecting plane
sound reflecting planar surface on which the noise source under test is located
3.9
frequency range of interest
for general purposes, the frequency range of octave bands with nominal mid-band frequencies from 125 Hz to
8 000 Hz (including one-third octave bands with mid-band frequencies from 100 Hz to 10 000 Hz)
NOTE For special purposes, the frequency range can be extended or reduced, provided that the test environment
and instrument specifications are satisfactory for use over the modified frequency range. Changes to the frequency range
of interest are included in the test report.
3.10
reference box
hypothetical right parallelepiped terminating on the reflecting plane(s) on which the noise source under test is
located, that just encloses the source including all the significant sound radiating components and any test
table on which the source is mounted
NOTE If required, the smallest possible test table can be used for compatibility with emission sound pressure
[18]
measurements at bystander positions in accordance with, for example, ISO 11201 .
3.11
characteristic source dimension
d
O
distance from the origin of the co-ordinate system to the farthest corner of the reference box
NOTE Characteristic source dimension is expressed in metres.
3.12
measurement distance
d
distance from the reference box to a parallelepiped measurement surface
NOTE Measurement distance is expressed in metres.
3.13
measurement radius
r
radius of a hemispherical, half-hemispherical or quarter-hemispherical measurement surface
NOTE Measurement radius is expressed in metres.
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SIST EN ISO 3744:2010
ISO 3744:2010(E)
3.14
measurement surface
hypothetical surface of area, S, on which the microphone positions are located at which the sound pressure
levels are measured, enveloping the noise source under test and terminating on the reflecting plane(s) on
which the source is located
3.15
background noise
noise from all sources other than the noise source under test
NOTE Background noise includes contributions from airborne sound, noise from structure-borne vibration, and
electrical noise in the instrumentation.
3.16
background noise correction
K
1
correction applied to the mean (energy average) of the time-averaged sound pressure levels over all the
microphone positions on the measurement surface, to account for the influence of background noise
NOTE 1 Background noise correction is expressed in decibels.
NOTE 2 The background noise correction is frequency dependent; the correction in the case of a frequency band is
denoted K , where f denotes the relevant mid-band frequency, and that in the case of A-weighting is denoted K .
1f 1A
3.17
environmental correction
K
2
correction applied to the mean (energy average) of the time-averaged sound pressure levels over all the
microphone positions on the measurement surface, to account for the influence of reflected or absorbed
sound
NOTE 1 Environmental correction is expressed in decibels.
NOTE 2 The environmental correction is frequency dependent; the correction in the case of a frequency band is
denoted K , where f denotes the relevant mid-band frequency, and that in the case of A-weighting is denoted K .
2f 2A
NOTE 3 In general, the environmental correction depends on the area of the measurement surface and usually K
2
increases with S.
3.18
surface time-averaged sound pressure level
L
p
mean (energy average) of the time-averaged sound pressure levels over all the microphone positions, or
traverses, on the measurement surface, with the background noise correction, K , and the environmental
1
correction, K , applied
2
NOTE Surface time-averaged sound pressure level is expressed in decibels.
3.19
surface single event time-integrated sound pressure level
L
E
mean (energy average) of the single event time-integrated sound pressure levels at all the microphone
positions, or traverses, on the measurement surface, with the background noise correction, K , and the
1
environmental correction, K , applied
2
NOTE Surface single event time-integrated sound pressure level is expressed in decibels.
© ISO 2010 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 3744:2010
ISO 3744:2010(E)
3.20
sound power
P
through a surface, product of the sound pressure, p, and the component of the particle velocity, u , at a point
n
on the surface in the direction normal to the surface, integrated over that surface
[21]
[ISO 80000-8:2007 , 8-16]
NOTE 1 Sound power is expressed in watts.
NOTE 2 The quantity relates to the rate per time at which airborne sound energy is radiated by a source.
3.21
sound power level
L
W
ten times the logarithm to the base 10 of the ratio of the sound power of a source, P, to a reference value, P ,
0
expressed in decibels
P
L = 10 lg dB (4)
W
P
0
where the reference value, P , is 1 pW
0
NOTE 1 If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands are applied, this
is indicated by appropriate subscript
...
SLOVENSKI STANDARD
oSIST prEN ISO 3744:2006
01-junij-2006
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLYLURYKUXSD]PHUMHQMHP]YRþQHJD
WODND,QåHQLUVNDPHWRGDYSUHWHåQRSURVWHPSROMXQDGRGERMQRUDYQLQR ,62',6
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Engineering method in an essentially free field over a
reflecting plane (ISO/DIS 3744:2006)
Akustik - Bestimmung der Schallleistungs- und der Schallenergiepegel von
Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der
Genauigkeitsklasse 2 für ein im Wesentlichen freies Schallfeld über einer reflektierenden
Ebene (ISO/DIS 3744:2006)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux
d'énergie acoustique émis par les sources de bruit a partir de la pression acoustique -
Méthode d'expertise pour des conditions approchant celles du champ libre sur plan
réfléchissant (ISO/DIS 3744:2006)
Ta slovenski standard je istoveten z: prEN ISO 3744
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
oSIST prEN ISO 3744:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
EUROPEAN STANDARD
DRAFT
prEN ISO 3744
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2006
ICS Will supersede EN ISO 3744:1995
English Version
Acoustics - Determination of sound power levels of noise
sources using sound pressure - Engineering method in an
essentially free field over a reflecting plane (ISO/DIS 3744:2006)
Acoustique - Détermination des niveaux de puissance
acoustique et des niveaux d'énergie acoustique émis par
les sources de bruit à partir de la pression acoustique -
Méthode d'expertise pour des conditions approchant celles
du champ libre sur plan réfléchissant (ISO/DIS 3744:2006)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 211.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 3744:2006: E
worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
prEN ISO 3744:2006 (E)
Foreword
This document (prEN ISO 3744:2006) has been prepared by Technical Committee ISO/TC 43
"Acoustics" in collaboration with Technical Committee CEN/TC 211 "Acoustics", the
secretariat of which is held by DS.
This document is currently submitted to the parallel Enquiry.
This document will supersede EN ISO 3744:1995.
This document has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements
of EU Directive(s).
Endorsement notice
The text of ISO 3744:2006 has been approved by CEN as prEN ISO 3744:2006 without any
modifications.
2
---------------------- Page: 3 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 3744
ISO/TC 43/SC 1 Secretariat: DS
Voting begins on: Voting terminates on:
2006-03-30 2006-08-30
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure —
Engineering method for an essentially free field over a reflecting
plane
Acoustique — Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique émis
par les sources de bruit à partir de la pression acoustique — Méthode d'expertise pour des conditions
approchant celles du champ libre sur plan réfléchissant
[Revision of second edition (ISO 3744:1994) and ISO 4872:1978]
ICS 17.140.01
ISO/CEN PARALLEL ENQUIRY
The CEN Secretary-General has advised the ISO Secretary-General that this ISO/DIS covers a subject
of interest to European standardization. In accordance with the ISO-lead mode of collaboration as
defined in the Vienna Agreement, consultation on this ISO/DIS has the same effect for CEN
members as would a CEN enquiry on a draft European Standard. Should this draft be accepted, a
final draft, established on the basis of comments received, will be submitted to a parallel two-month FDIS
vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
© International Organization for Standardization, 2006
---------------------- Page: 4 ----------------------
ISO/DIS 3744
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Violators may be prosecuted.
©
ii ISO 2006 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/DIS 3744
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
1.1 General .1
1.2 Types of noise and noise sources.1
1.3 Test environment.1
1.4 Measurement uncertainty.1
2 Normative references.2
3 Terms and definitions .2
4 Test environment.7
4.1 General .7
4.2 Criteria for background noise .7
4.3 Criterion for acoustic adequacy of test environment.9
5 Instrumentation .10
5.1 General .10
5.2 Calibration.10
6 Definition, location, installation and operation of noise source under test.10
6.1 General .10
6.2 Auxiliary equipment .10
6.3 Noise source location .11
6.4 Mounting of the noise source .11
6.5 Installation and mounting conditions for moving noise sources .12
6.6 Operation of source during test.12
7 Reference box and measurement surface.12
7.1 Reference box.12
7.2 Measurement surface.13
8 Determination of sound power levels and sound energy levels .16
8.1 Criterion for measurement protocol.16
8.2 Microphone positions on the measurement surface.17
8.3 Determination of sound power levels .19
8.4 Determination of sound energy levels .23
8.5 Calculation of apparent directivity indices.26
8.6 Calculation of apparent surface sound pressure level non-uniformity index .26
8.7 A-weighted sound power level and sound energy level .26
9 Measurement uncertainty.26
10 Information to be recorded.27
10.1 General.27
10.2 Noise source under test.27
10.3 Test environment.27
10.4 Instrumentation.28
10.5 Acoustical data.28
11 Information to be reported.29
Annex A (normative) Qualification procedures for the acoustic environment .30
Annex B (normative) Microphone arrays on a hemispherical measurement surface .35
Annex C (normative) Microphone arrays on a parallelepiped measurement surface .43
© ISO 2005 – All rights reserved iii
DRAFT 2006
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ISO/DIS 3744
Annex D (informative) Microphone arrays on a cylindrical measurement surface . 50
Annex E (normative) Calculation of A-weighted sound power levels and A-weighted sound
energy levels from frequency band levels . 55
Annex F (normative) Alternative microphone array on a hemispherical measurement surface for
direct measurements of A-weighted sound pressure levels . 57
Annex G (normative) Sound power level and sound energy level under reference meteorological
conditions. 60
Annex H (informative) Guidance on the development of information on measurement uncertainty. 62
Bibliography. 69
iv © ISO 2005 – All rights reserved
DRAFT 2006
---------------------- Page: 7 ----------------------
ISO/DIS 3744
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3744 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This third edition of ISO 3744 cancels and replaces the second edition (ISO 3744:1994) and also
ISO 4872:1978, which have been merged and technically revised.
© ISO 2005 – All rights reserved v
DRAFT 2006
---------------------- Page: 8 ----------------------
ISO/DIS 3744
Introduction
0.1 This International Standard is one of the series ISO 3740 to ISO 3747, that specifies methods for
determining the sound power levels and sound energy levels of noise sources including machinery, equipment
and their sub-assemblies. Guidelines to select one of those methods are provided in ISO 3740. The selection
will depend on the environment of the available test facility and on the precision of the sound power level or
sound energy level values required. It may be necessary to establish a test code for the individual noise
source in order to select the appropriate sound measurement surface and microphone array from among
those allowed in each standard, and to give requirements on test unit mounting, loading and operating
conditions under which the sound power levels or sound energy levels are to be obtained. The sound power
emitted by a given source into the test environment is calculated from the mean square sound pressure that is
measured over a hypothetical measurement surface enclosing the source, and the area of that surface. The
sound energy for a single machine event is calculated from this sound power and the time over which it
existed.
0.2 This International Standard provides an engineering grade of accuracy (grade 2) as defined in
ISO 12001 when the measurements are performed in a space that approximates an acoustically free field
over a reflecting plane. Such an environment can be found in a specially-designed room, or within industrial
buildings or outdoors. Ideally, the test source should be mounted on a sound reflecting plane located in a
large open space. For sources normally installed on the floor of machine rooms, corrections are defined to
account for undesired reflections from nearby objects, walls and the ceiling, and for the residual background
noises that occur there.
0.3 The methods specified in this International Standard permit the determination of the sound power level
and the sound energy level in frequency bands and/or with frequency weighting A applied.
0.4 For applications where greater accuracy is required, reference can be made to ISO 3745, ISO 3741 or
an appropriate part of ISO 9614. If the relevant criteria for the measurement environment specified in this
International Standard are not met, it might be possible to refer to another standard from this series, or to an
appropriate part of ISO 9614.
vi © ISO 2005 – All rights reserved
DRAFT 2006
---------------------- Page: 9 ----------------------
ISO/DIS 3744
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure —
Engineering method for an essentially free field over a reflecting
plane
1 Scope
1.1 General
This International Standard specifies methods for determining the sound power level or sound energy level of
a noise source from sound pressure levels measured on a surface enveloping the noise source (machinery or
equipment) in an environment that approximates to an acoustic free-field near one or more reflecting planes.
The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level)
produced by the noise source, in frequency bands or with frequency-weighting A applied, is calculated using
those measurements.
NOTE Differently shaped measurement surfaces can yield differing estimates of the sound power level of a given
noise source and a test code should give detailed information on the selection of the surface.
1.2 Types of noise and noise sources
The methods specified in this International Standard are suitable for all types of noise (steady, non-steady,
fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.
This International Standard is applicable to all types and sizes of noise source (e.g. stationary or slowly
moving plant, installation, machine, component or sub-assembly), provided the conditions for the
measurements can be met.
NOTE The conditions for measurements given in this International Standard could be impracticable for very tall or
very long sources such as chimneys, ducts, conveyors and multi-source industrial plants. A test code for the determination
of noise emission of specific sources can provide alternative methods in such cases.
1.3 Test environment
The test environments that are applicable for measurements made in accordance with this International
Standard may be located indoors or outdoors, with one or more sound-reflecting planes present on or near
which the noise source under test is mounted. The ideal environment is a completely open space with no
bounding or reflecting surfaces other than the reflecting plane(s) (such as that provided by a qualified hemi-
free-field chamber) but procedures are given for applying corrections (within limits that are specified) in the
case of environments that are less than ideal.
1.4 Measurement uncertainty
Information is given on the uncertainty of the sound power levels and sound energy levels determined in
accordance with this International Standard, for measurements made in limited bands of frequency and with
frequency weighting A applied. The uncertainty conforms with that of the engineering grade of accuracy
(grade 2) defined in ISO 12001.
© ISO 2005 – All rights reserved 1
DRAFT 2006
---------------------- Page: 10 ----------------------
ISO/DIS 3744
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.
1)
ISO 3382-2 , Acoustics — Measurement of the reverberation time — Part 2: Ordinary rooms
ISO 6926, Acoustics — Requirements for the performance and calibration of reference sound sources for the
determination of sound power levels
ISO 7574-1, Acoustics — Statistical methods for determining and verifying stated noise emission values of
machinery and equipment — Part 1: General considerations and definitions
ISO 12001, Acoustics — Noise emitted by machinery and equipment — Rules for the drafting and
presentation of a noise test code
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
Guide to the expression of uncertainty in measurement (GUM). International Organization for Standardization,
Geneva, Switzerland. ISBN 92-67-10188-9, First Edition 1993, corrected and reprinted 1995
3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
sound pressure
p
a fluctuating pressure superimposed on the static pressure by the presence of sound, expressed in pascals
3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of a
reference value, p , expressed in decibels
0
2
p
L = 10lg dB (1)
p
2
p
0
–5
The reference value, p , is 20 µPa (2 × 10 Pa).
0
NOTE The frequency weighting or the midband frequency of the frequency band used should be indicated in the
symbol.
1) In preparation
2 © ISO 2005 – All rights reserved
DRAFT 2006
---------------------- Page: 11 ----------------------
ISO/DIS 3744
3.3
time-averaged sound pressure level
L
p,T
level of the time-averaged square of the sound pressure over the measurement time interval T = t – t ,
2 2
expressed in decibels
t
2
2
1 p (t)
L = 10lg dt dB (2)
p,T
∫
2
T
p
0
t
1
NOTE 1 In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily determined
over a certain measurement time interval.
NOTE 2 Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by L , which is
A,
p T
usually abbreviated to L .
pA
3.4
single-event sound pressure level
L
E
level of the time-integrated square of the sound pressure of an isolated single sound event (burst of sound or
transient sound) of specified duration T (or specified measurement time interval T = t – t ) normalized to
2 1
reference time interval T = 1 s, expressed in decibels
0
t
2
2
1 p (t) T
L = 10lg dt dB = L + 10lg dB (3)
E p,T
∫
2
T T
0 p 0
t 0
1
3.5
measurement time interval
T
portion or a multiple of an operational period or operational cycle of the noise source under test, for which the
time-averaged sound pressure level is determined, expressed in seconds
3.6
acoustic free field
sound field in a homogeneous, isotropic medium free of boundaries; in practice, it is a field in which reflections
at the boundaries are negligible over the frequency range of interest
3.7
acoustic free field over a reflecting plane
acoustic free field in the half-space above an infinite reflecting plane in the absence of any other obstacles
3.8
reflecting plane
sound reflecting planar surface on which the noise source under test is located
3.9
frequency range of interest
for general purposes, the range of octave bands with nominal midband frequencies from 125 Hz to 8 000 Hz
(including one-third octave bands with midband frequencies from 100 Hz to 10 000 Hz)
NOTE For special purposes, the range may be extended or reduced, provided that the test environment and
instrument specifications are satisfactory for use over the modified range. For sources which emit sound at predominantly
high or low frequencies, it might be desirable to extend or reduce the frequency range of interest in order to optimize the
test facility and procedures, provided this is made clear in the test report.
© ISO 2005 – All rights reserved 3
DRAFT 2006
---------------------- Page: 12 ----------------------
ISO/DIS 3744
3.10
reference box
hypothetical rectangular parallelepiped terminating on the reflecting plane(s) on which the noise source under
test is located, that just encloses the source including all the significant sound radiating components and any
test table on which the source is mounted (see 6.2)
3.11
characteristic source dimension
d
0
distance from the origin of the co-ordinate system to the farthest corner of the reference box (see 7.1),
expressed in metres
3.12
measurement distance
d
distance from the reference box to a measurement surface, expressed in metres
3.13
measurement radius
r
radius of a hemispherical measurement surface, expressed in metres
3.14
measurement surface
hypothetical surface of area S, on which the microphone positions are located at which the sound pressure
levels are measured, enveloping the noise source under test and terminating on the reflecting plane(s) on
which the source is located
3.15
background noise
noise from all sources other than the noise source under test
NOTE Background noise may include contributions from airborne sound, noise from structure-borne vibration, and
electrical noise in the instrumentation.
3.16
background noise correction
K
1
correction applied to the measured time-averaged sound pressure levels to account for the influence of
background noise, expressed in decibels
NOTE The background noise correction is frequency dependent; the correction in the case of a frequency band is
denoted K , where f denotes the relevant midband frequency, and that in the case of A-weighting is denoted K .
1f 1A
3.17
environmental correction
K
2
correction applied to the mean (energy-average) of the time-av
...
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