SIST EN ISO 3747:2009
(Main)Acoustics - Determination of sound power levels of noise sources using sound pressure - Comparison method in situ (ISO 3747:2000)
Acoustics - Determination of sound power levels of noise sources using sound pressure - Comparison method in situ (ISO 3747:2000)
This International Standard specifies a method for determining the sound power levels of sound sources in situ, especially if non-movable. A comparison method is used and all measurements are carried out in octave bands. The measurement uncertainty depends on the test environment. The measurement uncertainty is evaluated by comparing with an indicator describing the spatial sound distribution. The accuracy will either be that of an engineering method or a survey method. The sound power level of the source under test is calculated from the measured values of the sound pressure levels produced at specified measurement points by the source and by a reference sound source, respectively. The sound power level is calculated using the calibrated values of the reference sound source and the differences between the values obtained with the source under test and those of the reference sound source. All calculations are carried out in octave bands, from which the A-weighted sound power level is determined.
Akustik - Bestimmung der Schalleistungspegel von Geräuschquellen aus Schalldruckmessungen -Vergleichsverfahren zur Verwendung unter Einsatzbedingungen (ISO 3747:2000)
1.1 Diese Internationale Norm legt ein Verfahren zur Bestimmung der Schallleistungspegel von insbesondere
ortsfesten Schallquellen unter Einsatzbedingungen fest. Es wird ein Vergleichsverfahren verwendet,
und alle Messungen werden in Oktavbändern durchgeführt. Die Messunsicherheit hängt von der
Prüfumgebung ab. Die Messunsicherheit wird durch Vergleich mit einem Indikator beurteilt, der die räumliche
Schallverteilung beschreibt. Die Genauigkeit des Verfahrens entspricht entweder Genauigkeitsklasse
2 oder Genauigkeitsklasse 3.
Der Schallleistungspegel der zu untersuchenden Quelle wird aus den gemessenen Werten der Schalldruckpegel
berechnet, die von der Quelle bzw. einer Vergleichsschallquelle an festgelegten Messpunkten
erzeugt werden. Zur Berechnung des Schallleistungspegels werden die kalibrierten Werte der Vergleichsschallquelle
verwendet sowie die Differenzen zwischen den Werten, die mit der zu untersuchenden
Quelle und der Vergleichsschallquelle ermittelt wurden. Alle Berechnungen werden in Oktavbändern
durchgeführt, aus welchen der A-bewertete Schallleistungspegel bestimmt wird.
ANMERKUNG Für transportable Schallquellen können entsprechende andere Normen aus der Reihe ISO 3740
und folgende angewendet werden.
1.2 Diese Internationale Norm ist in allen Prüfumgebungen außerhalb von Laboren anwendbar, sofern
der Fremdgeräuschpegel ausreichend niedrig ist und der Schalldruckpegel an den Mikrofonpositionen
hauptsächlich von Reflexionen an den Raumwänden abhängt.
ANMERKUNG In ISO 3744 oder ISO 9614 werden alternative Verfahren angeboten.
1.3 Diese Internationale Norm ist in erster Linie für Quellen anwendbar, die breitbandigen Schall
abstrahlen. Sie kann jedoch auch für Quellen verwendet werden, die Schmalbandgeräusch oder Einzelt
öne abstrahlen, obwohl die Messunsicherheit dann größer als hier angegeben ausfallen könnte.
ANMERKUNG Für Geräuschquellen, die ein stationäres Geräusch abstrahlen, darf alternativ ISO 9614 angewendet
werden.
Acoustique - Détermination des niveaux de puissance acoustique émis par les sources de bruit à partir de la pression acoustique - Méthode de comparaison pour une utilisation in situ (ISO 3747:2000)
La présente Norme internationale s'applique à tous les types d'environnements d'essai autres que celui rencontré en laboratoire, à condition que le niveau de bruit de fond soit suffisamment faible et que le niveau de pression acoustique aux différentes positions de microphone dépende principalement des réflexions par les surfaces de la salle.
NOTE L'ISO 3744 ou l'ISO 9614 peut fournir des méthodes alternatives. La présente Norme internationale s'applique principalement aux sources qui émettent un bruit à large bande. Cependant, elle peut également s'appliquer aux sources qui émettent un bruit à bande étroite ou des sons purs, bien que l'incertitude de mesure puisse alors devenir plus importante que celle indiquée ici.
NOTE L'ISO 9614 peut être utilisée comme norme alternative pour les sources de bruit qui émettent un bruit stable.
Akustika - Ugotavljanje ravni zvočnih moči virov hrupa z zvočnim tlakom - Primerjalna metoda in situ (ISO 3747:2000)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 3747:2009
01-november-2009
1DGRPHãþD
SIST EN ISO 3747:2001
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLYLURYKUXSD]]YRþQLPWODNRP
3ULPHUMDOQDPHWRGDLQVLWX ,62
Acoustics - Determination of sound power levels of noise sources using sound pressure -
Comparison method in situ (ISO 3747:2000)
Akustik - Bestimmung der Schalleistungspegel von Geräuschquellen aus
Schalldruckmessungen -Vergleichsverfahren zur Verwendung unter Einsatzbedingungen
(ISO 3747:2000)
Acoustique - Détermination des niveaux de puissance acoustique émis par les sources
de bruit à partir de la pression acoustique - Méthode de comparaison pour une utilisation
in situ (ISO 3747:2000)
Ta slovenski standard je istoveten z: EN ISO 3747:2009
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
SIST EN ISO 3747:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 3747:2009
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SIST EN ISO 3747:2009
EUROPEAN STANDARD
EN ISO 3747
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 17.140.01 Supersedes EN ISO 3747:2000
English Version
Acoustics - Determination of sound power levels of noise
sources using sound pressure - Comparison method in situ (ISO
3747:2000)
Acoustique - Détermination des niveaux de puissance Akustik - Bestimmung der Schalleistungspegel von
acoustique émis par les sources de bruit à partir de la Geräuschquellen aus Schalldruckmessungen -
pression acoustique - Méthode de comparaison pour une Vergleichsverfahren zur Verwendung unter
utilisation in situ (ISO 3747:2000) Einsatzbedingungen (ISO 3747:2000)
This European Standard was approved by CEN on 20 July 2009.
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, 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
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3747:2009: E
worldwide for CEN national Members.
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SIST EN ISO 3747:2009
EN ISO 3747:2009 (E)
Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC .4
Annex ZB (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .5
2
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SIST EN ISO 3747:2009
EN ISO 3747:2009 (E)
Foreword
The text of ISO 3747:2000 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 3747:2009 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 February 2010, and conflicting national standards shall be withdrawn
at the latest by February 2010.
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 3747:2000.
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 EC Directives.
For relationship with EC Directives, see informative Annexes ZA and ZB, which are integral parts 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, 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 3747:2000 has been approved by CEN as a EN ISO 3747:2009 without any modification.
3
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SIST EN ISO 3747:2009
EN ISO 3747:2009 (E)
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/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 a means of conforming to Essential Requirements of the
New Approach Directive 98/37/EC, amended by 98/79/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 product(s) falling within the
scope of this standard.
4
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SIST EN ISO 3747:2009
EN ISO 3747:2009 (E)
Annex ZB
(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 a 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 product(s) falling within
the scope of this standard.
5
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SIST EN ISO 3747:2009
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SIST EN ISO 3747:2009
INTERNATIONAL ISO
STANDARD 3747
Second edition
2000-07-01
Acoustics — Determination of sound power
levels of noise sources using sound
pressure — Comparison method in situ
Acoustique — Détermination des niveaux de puissance acoustique émis
par les sources de bruit à partir de la pression acoustique — Méthode de
comparaison in situ
Reference number
ISO 3747:2000(E)
©
ISO 2000
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
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ii © ISO 2000 – All rights reserved
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Test methodology.3
4.1 General.3
4.2 Accuracy.3
5 Measurement uncertainty .3
6 Instrumentation.4
6.1 Instrumentation system .4
6.2 Calibration .4
7 Operating conditions of the source under test .5
8 Preliminary survey.6
8.1 Background noise.6
8.2 Characterization of the source under test .6
9 Positions of the reference sound source.6
9.1 One position.6
9.2 More than one position .6
10 Measurement procedure .7
10.1 Selection of microphone positions.7
10.2 Measurements.8
10.3 Correction for background noise.8
10.4 Evaluation of the measurement uncertainty.9
11 Calculation of sound power levels.9
11.1 One RSS position.9
11.2 Several RSS positions.9
11.3 A-weighted sound power level.9
12 Information to be recorded .10
13 Information to be reported.11
Annex A (normative) Evaluation of�L and of the measurement uncertainty.12
f
Annex B (informative) Recommendations for the location of the reference sound source and the
microphones, if only one RSS position is used .14
Bibliography.18
© ISO 2000 – All rights reserved iii
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SIST EN ISO 3747:2009
ISO 3747:2000(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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 3747 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee
SC 1, Noise.
This second edition cancels and replaces the first edition (ISO 3747:1987), which has been technically revised.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iv © ISO 2000 – All rights reserved
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
Introduction
This International Standard is one of the ISO 3740 series which, together with ISO 9614, specifies various methods
for determining sound power levels of machines, equipment and sub-assemblies thereof. When selecting one of
the methods of the 3740 series, it is necessary to decide which one is most appropriate for the conditions and
purposes of the test. General guidelines to assist in the selection are provided in ISO 3740. Insofar as the operating
and mounting conditions of the machine or equipment under test are concerned, only general principles are given
in the ISO 3740 series. Reference should be made to the test code for a specific type of machine or equipment, if
available, for specifications on mounting and operating conditions.
© ISO 2000 – All rights reserved v
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SIST EN ISO 3747:2009
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SIST EN ISO 3747:2009
INTERNATIONAL STANDARD ISO 3747:2000(E)
Acoustics — Determination of sound power levels of noise
sources using sound pressure — Comparison method in situ
1 Scope
1.1 This International Standard specifies a method for determining the sound power levels of sound sources in
situ, especially if non-movable. A comparison method is used and all measurements are carried out in octave
bands. The measurement uncertainty depends on the test environment. The measurement uncertainty is evaluated
by comparing with an indicator describing the spatial sound distribution. The accuracy will either be that of an
engineering method or a survey method.
The sound power level of the source under test is calculated from the measured values of the sound pressure
levels produced at specified measurement points by the source and by a reference sound source, respectively. The
sound power level is calculated using the calibrated values of the reference sound source and the differences
between the values obtained with the source under test and those of the reference sound source. All calculations
are carried out in octave bands, from which the A-weighted sound power level is determined.
NOTE For noise sources which can be moved, other relevant standards in the ISO 3740 series may be used.
1.2 This International Standard is applicable to all kinds of test environments which are to be found outside a
laboratory environment, provided that the background noise level is sufficiently low and the sound pressure level at
the microphone positions depends mainly on reflections from the room surfaces.
NOTE ISO 3744 or ISO 9614 may provide alternative methods.
1.3 This International Standard is primarily applicable to sources which radiate broad-band noise. It may,
however, also be used for sources which radiate narrow-band noise or discrete tones, although the measurement
uncertainty might then become larger than stated herein.
NOTE For noise sources emitting stationary noise, ISO 9614 may be used as an alternative.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 6926, Acoustics — Requirements for the performance and calibration of reference sound sources used 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.
IEC 60942, Electroacoustics — Sound calibrators.
© ISO 2000 – All rights reserved 1
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave band filters.
1)
IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications.
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
reference sound source
RSS
stable and steady source emitting constant broad-band noise with an adequate sound power level, in conformance
with and calibrated according to ISO 6926
3.2
calibration position
position, well-defined relative to reflecting surfaces, in which the reference sound source has been calibrated
3.3
reference box
hypothetical surface which is the smallest rectangular parallelepiped that just encloses the source and terminates
on the reflecting plane(s)
3.4
reverberant sound field
that portion of the sound field in the test room over which the influence of sound received directly from the source is
negligible
3.5
measurement distance
d
m
closest distance from the reference box to a microphone position
3.6
background noise
noise from all sources other than the source under test
NOTE Background noise may include contributions from airborne sound, structure-borne vibration, and electrical noise in
instrumentation.
3.7
frequency range of interest
for general purposes, the frequency range of interest includes the octave bands with midband frequencies from
125 Hz to 8 000 Hz
NOTE 1 For special purposes, it is permissible to extend or reduce the frequency range of interest at either end, provided
that the test environment, reference sound source and instrument accuracy are satisfactory for use over the extended or
reduced frequency range. For sources which radiate predominantly high (or low) frequency sound, it is permissible to extend or
reduce the frequency range of interest in order to optimize the test procedures.
NOTE 2 For determination of A-weighted sound power levels (or other frequency-weighted levels), frequency components
within the range which do not contribute to the A-weighted sound power level may be disregarded.
1) To be published. (Revision of IEC 60651 and IEC 60804)
2 © ISO 2000 – All rights reserved
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
3.8
comparison method
method in which the sound power level is calculated by comparing the measured sound pressure levels produced
by the source under test in an environment with the sound pressure levels produced in the same environment by a
reference sound source of known sound power output
3.9
excess of sound pressure level at a given distance
�L
f
difference, in decibels, for a reference sound source with a reference calibration, at a given distance, between the
spatial sound distribution curve of the room and the spatial sound distribution curve for a free field (6 dB per
distance doubling) according to annex A
NOTE This term and its definition differ from that of ISO 14257 which relates to an average difference over a given
distance range.
4 Test methodology
4.1 General
The test method is a comparison method, that is the sound power output of the source under test is compared with
that of a reference sound source with known sound power level. In order to obtain a good comparison, at least the
following condition must be fulfilled:
� the test environment is sufficiently reverberant to cause the directivity of the source under test to have only an
insignificant influence on the measured sound pressure levels.
The better the above condition is fulfilled, the lower the measurement uncertainty will be. To make an objective
evaluation of the measurement conditions, it is necessary to determine one indicator, �L , for the test environment.
f
Further information about this indicator is given in annex A.
4.2 Accuracy
�L will be influenced by the selection of the reference sound source and the microphone positions. Thus it may, in
f
some cases, be possible to improve the measurement accuracy from that of a survey method to that of an
engineering method by changing these positions; see annex A.
5 Measurement uncertainty
A single value of the sound power level of a sound source determined according to the procedures of this
International Standard is likely to differ from the true value by an amount within the measurement uncertainty. The
uncertainty in determinations of the sound power level arises from several factors which affect the results, some
associated with environmental conditions in the test environment and others with experimental techniques and the
directional characteristics of the sound source under test.
If a particular source were to be transported to each of a number of different test environments and if, in each
environment, the sound power level of that source were to be determined in accordance with the provisions of this
International Standard, the results would show a scatter. The standard deviations of the measured octave band
values could be calculated (examples are given in ISO 7574-4:1985, annex B) and would vary. These standard
deviations would, with few exceptions, not exceed those listed in Table 1 for the A-weighted sound power level.
The standard deviation will depend on the indicator �L . If this indicator is not evaluated, the default standard
f
deviation of reproducibility, s ,is4,0dB.
R
© ISO 2000 – All rights reserved 3
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SIST EN ISO 3747:2009
ISO 3747:2000(E)
Table 1 — Estimated upper values of the standard deviation of reproducibility, s , of A-weighted sound
R
power levels of sound sources determined according to this International Standard
Upper values of standard
deviation of reproducibility Grade of
Indicator values
for the A-weighted sound accuracy
power level
a
1,5 dB Grade 2
�L W 7dB
fA
�L � 7 dB or not determined 4,0 dB Grade 3
fA
a
To be met by all microphone positions.
NOTE 1 The standard deviations given in Table 1 might become larger for sources that radiate narrow-band noise, discrete
tones and combinations of these. In these cases the engineering grade of accuracy might not be achieved.
The values given in Table 1 are standard deviations of reproducibility, s , as defined in ISO 7574-1. The values of
R
Table 1 take into account the cumulative effects of measurement uncertainty in applying the procedures of this
International Standard, but exclude variations in the sound power output caused by changes in operating
conditions (e.g. rotational speed, line voltage) or mounting conditions.
The measurement uncertainty depends on the standard deviation of reproducibility tabulated in Table 1, the
systematic errors discussed below, and the degree of confidence that is desired. As examples, excluding the
systematic errors, there is a 90 % confidence that the expected value of the sound power level of a source lies
within the range� 1,645s , of the measured value and a 95 % confidence that it lies within the range� 1,96s For
R R.
further examples, see ISO 7574-4.
NOTE 2 Where s exceeds 2 dB, the ranges of confidence intervals may not apply.
R
Normally the A-weighted sound power level is mainly influenced by the levels in the 250 Hz to 4 000 Hz octave
bands. The A-weighted sound power level is determined with a standard deviation which varies with the indicator
values as shown in Table 1. If frequencies lower than 500 Hz are very important for the A-weighted level, the
standard deviation will become higher. If frequencies higher than 2 000 Hz are important the source may be highly
directional. If, in such cases, there are strongly absorbing surfaces close to the machine under test (e.g. an
absorbing ceiling), the measurement uncertainty may become greater.
NOTE 3 One reason, specific for this International Standard, for increased measurement uncertainty at low frequencies is
that the reference sound source is not always used in calibrated positions. Thus calibration errors are introduced. These errors
occur at low frequencies where the RSS is located at distances in relation to nearby reflecting surfaces which are different from
the ones used during the calibration.
6 Instrumentation
6.1 Instrumentation system
The instrumentation system, including the microphone and cable, shall meet the requirements for a class 1
instrument specified in IEC 61672-1. The calibrator shall meet the requirements for class 1 specified in IEC 60942.
For measurements in octave bands, the instrumentation system shall meet the requirements of IEC 61260.
6.2 Calibration
6.2.1 Measuring system
During each series of measurements, apply the sound calibrator to the microphone for checking the calibration of
the entire measuring system at one or more frequencies over the frequency range of interest.
4 © ISO 2000 – All rights reserved
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SIST EN ISO 3747
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Akustik - Bestimmung der Schalleistungspegel von Geräuschquellen aus Schalldruckmessungen -Vergleichsverfahren zur Verwendung unter Einsatzbedingungen (ISO 3747:2000)Acoustique - Détermination des niveaux de puissance acoustique émis par les sources de bruit à partir de la pression acoustique - Méthode de comparaison pour une utilisation in situ (ISO 3747:2000)Acoustics - Determination of sound power levels of noise sources using sound pressure - Comparison method in situ (ISO 3747:2000)17.140.01Acoustic measurements and noise abatement in generalICS:Ta slovenski standard je istoveten z:FprEN ISO 3747kSIST FprEN ISO 3747:2009en01-junij-2009kSIST FprEN ISO 3747:2009SLOVENSKI
STANDARD
kSIST FprEN ISO 3747:2009
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMFINAL DRAFTFprEN ISO 3747March 2009ICS 17.140.01Will supersede EN ISO 3747:2000
English VersionAcoustics - Determination of sound power levels of noisesources using sound pressure - Comparison method in situ (ISO3747:2000)Acoustique - Détermination des niveaux de puissanceacoustique émis par les sources de bruit à partir de lapression acoustique - Méthode de comparaison pour uneutilisation in situ (ISO 3747:2000)Akustik - Bestimmung der Schalleistungspegel vonGeräuschquellen aus Schalldruckmessungen -Vergleichsverfahren zur Verwendung unterEinsatzbedingungen (ISO 3747:2000)This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the TechnicalCommittee CEN/TC 211.If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations whichstipulate 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 languagemade by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has thesame status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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.Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice andshall not be referred to as a European Standard.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre:
Avenue Marnix 17,
B-1000 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. FprEN ISO 3747:2009: EkSIST FprEN ISO 3747:2009
FprEN ISO 3747:2009 (E) 2 Contents Page Foreword .3Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 98/37/EC .4Annex ZB (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 2006/42/EC .5 kSIST FprEN ISO 3747:2009
FprEN ISO 3747:2009 (E) 3 Foreword The text of ISO 3747:2000 has been prepared by Technical Committee ISO/TC 43 “Acoustics” of the International Organization for Standardization (ISO) and has been taken over as FprEN ISO 3747:2009 by Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS. This document is currently submitted to the Unique Acceptance Procedure. This document will supersede EN ISO 3747:2000. 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 EC Directives. For relationship with EC Directives, see informative Annexes ZA and ZB, which are integral parts of this document. Endorsement notice The text of ISO 3747:2000 has been approved by CEN as a FprEN ISO 3747:2009 without any modification. kSIST FprEN ISO 3747:2009
FprEN ISO 3747:2009 (E) 4
Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 98/37/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 a means of conforming to Essential Requirements of the New Approach Directive 98/37/EC, amended by 98/79/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 product(s) falling within the scope of this standard. kSIST FprEN ISO 3747:2009
FprEN ISO 3747:2009 (E) 5 Annex ZB (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 a 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 product(s) falling within the scope of this standard.
kSIST FprEN ISO 3747:2009
kSIST FprEN ISO 3747:2009
ReferencenumberISO3747:2000(E)©ISO2000INTERNATIONALSTANDARDISO3747Secondedition2000-07-01Acoustics—Determinationofsoundpowerlevelsofnoisesourcesusingsoundpressure—ComparisonmethodinsituAcoustique—Déterminationdesniveauxdepuissanceacoustiqueémisparlessourcesdebruitàpartirdelapressionacoustique—MéthodedecomparaisoninsitukSIST FprEN ISO 3747:2009
ISO3747:2000(E)PDFdisclaimerThisPDFfilemaycontainembeddedtypefaces.InaccordancewithAdobe'slicensingpolicy,thisfilemaybeprintedorviewedbutshallnotbeeditedunlessthetypefaceswhichareembeddedarelicensedtoandinstalledonthecomputerperformingtheediting.Indownloadingthisfile,partiesacceptthereintheresponsibilityofnotinfringingAdobe'slicensingpolicy.TheISOCentralSecretariatacceptsnoliabilityinthisarea.AdobeisatrademarkofAdobeSystemsIncorporated.DetailsofthesoftwareproductsusedtocreatethisPDFfilecanbefoundintheGeneralInforelativetothefile;thePDF-creationparameterswereoptimizedforprinting.EverycarehasbeentakentoensurethatthefileissuitableforusebyISOmemberbodies.Intheunlikelyeventthataproblemrelatingtoitisfound,pleaseinformtheCentralSecretariatattheaddressgivenbelow.©ISO2000Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromeitherISOattheaddressbeloworISO'smemberbodyinthecountryoftherequester.ISOcopyrightofficeCasepostale56CH-1211Geneva20Tel.+41227490111Fax+41227490947E-mailcopyright@iso.chWebwww.iso.chPrintedinSwitzerlandii©ISO2000–AllrightsreservedkSIST FprEN ISO 3747:2009
ISO3747:2000(E)©ISO2000–AllrightsreservediiiContentsPageForeword.ivIntroduction.v1Scope.12Normativereferences.13Termsanddefinitions.24Testmethodology.34.1General.34.2Accuracy.35Measurementuncertainty.36Instrumentation.46.1Instrumentationsystem.46.2Calibration.47Operatingconditionsofthesourceundertest.58Preliminarysurvey.68.1Backgroundnoise.68.2Characterizationofthesourceundertest.69Positionsofthereferencesoundsource.69.1Oneposition.69.2Morethanoneposition.610Measurementprocedure.710.1Selectionofmicrophonepositions.710.2Measurements.810.3Correctionforbackgroundnoise.810.4Evaluationofthemeasurementuncertainty.911Calculationofsoundpowerlevels.911.1OneRSSposition.911.2SeveralRSSpositions.911.3A-weightedsoundpowerlevel.912Informationtoberecorded.1013Informationtobereported.11AnnexA(normative)EvaluationofLfandofthemeasurementuncertainty.12AnnexB(informative)Recommendationsforthelocationofthereferencesoundsourceandthemicrophones,ifonlyoneRSSpositionisused.14Bibliography.18kSIST FprEN ISO 3747:2009
ISO3747:2000(E)iv©ISO2000–AllrightsreservedForewordISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISOmemberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhastherighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,inliaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalstandardization.InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/IECDirectives,Part3.DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting.PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiescastingavote.AttentionisdrawntothepossibilitythatsomeoftheelementsofthisInternationalStandardmaybethesubjectofpatentrights.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights.InternationalStandardISO3747waspreparedbyTechnicalCommitteeISO/TC43,Acoustics,SubcommitteeSC1,Noise.Thissecondeditioncancelsandreplacesthefirstedition(ISO3747:1987),whichhasbeentechnicallyrevised.AnnexAformsanormativepartofthisInternationalStandard.AnnexBisforinformationonly.kSIST FprEN ISO 3747:2009
ISO3747:2000(E)©ISO2000–AllrightsreservedvIntroductionThisInternationalStandardisoneoftheISO3740serieswhich,togetherwithISO9614,specifiesvariousmethodsfordeterminingsoundpowerlevelsofmachines,equipmentandsub-assembliesthereof.Whenselectingoneofthemethodsofthe3740series,itisnecessarytodecidewhichoneismostappropriatefortheconditionsandpurposesofthetest.GeneralguidelinestoassistintheselectionareprovidedinISO3740.Insofarastheoperatingandmountingconditionsofthemachineorequipmentundertestareconcerned,onlygeneralprinciplesaregivenintheISO3740series.Referenceshouldbemadetothetestcodeforaspecifictypeofmachineorequipment,ifavailable,forspecificationsonmountingandoperatingconditions.kSIST FprEN ISO 3747:2009
kSIST FprEN ISO 3747:2009
INTERNATIONALSTANDARDISO3747:2000(E)©ISO2000–Allrightsreserved1Acoustics—Determinationofsoundpowerlevelsofnoisesourcesusingsoundpressure—Comparisonmethodinsitu1Scope1.1ThisInternationalStandardspecifiesamethodfordeterminingthesoundpowerlevelsofsoundsourcesinsitu,especiallyifnon-movable.Acomparisonmethodisusedandallmeasurementsarecarriedoutinoctavebands.Themeasurementuncertaintydependsonthetestenvironment.Themeasurementuncertaintyisevaluatedbycomparingwithanindicatordescribingthespatialsounddistribution.Theaccuracywilleitherbethatofanengineeringmethodorasurveymethod.Thesoundpowerlevelofthesourceundertestiscalculatedfromthemeasuredvaluesofthesoundpressurelevelsproducedatspecifiedmeasurementpointsbythesourceandbyareferencesoundsource,respectively.Thesoundpowerleveliscalculatedusingthecalibratedvaluesofthereferencesoundsourceandthedifferencesbetweenthevaluesobtainedwiththesourceundertestandthoseofthereferencesoundsource.Allcalculationsarecarriedoutinoctavebands,fromwhichtheA-weightedsoundpowerlevelisdetermined.NOTEFornoisesourceswhichcanbemoved,otherrelevantstandardsintheISO3740seriesmaybeused.1.2ThisInternationalStandardisapplicabletoallkindsoftestenvironmentswhicharetobefoundoutsidealaboratoryenvironment,providedthatthebackgroundnoiselevelissufficientlylowandthesoundpressurelevelatthemicrophonepositionsdependsmainlyonreflectionsfromtheroomsurfaces.NOTEISO3744orISO9614mayprovidealternativemethods.1.3ThisInternationalStandardisprimarilyapplicabletosourceswhichradiatebroad-bandnoise.Itmay,however,alsobeusedforsourceswhichradiatenarrow-bandnoiseordiscretetones,althoughthemeasurementuncertaintymightthenbecomelargerthanstatedherein.NOTEFornoisesourcesemittingstationarynoise,ISO9614maybeusedasanalternative.2NormativereferencesThefollowingnormativedocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthisInternationalStandard.Fordatedreferences,subsequentamendmentsto,orrevisionsof,anyofthesepublicationsdonotapply.However,partiestoagreementsbasedonthisInternationalStandardareencouragedtoinvestigatethepossibilityofapplyingthemostrecenteditionsofthenormativedocumentsindicatedbelow.Forundatedreferences,thelatesteditionofthenormativedocumentreferredtoapplies.MembersofISOandIECmaintainregistersofcurrentlyvalidInternationalStandards.ISO6926,Acoustics—Requirementsfortheperformanceandcalibrationofreferencesoundsourcesusedforthedeterminationofsoundpowerlevels.ISO7574-1,Acoustics—Statisticalmethodsfordeterminingandverifyingstatednoiseemissionvaluesofmachineryandequipment—Part1:Generalconsiderationsanddefinitions.IEC60942,Electroacoustics—Soundcalibrators.kSIST FprEN ISO 3747:2009
ISO3747:2000(E)2©ISO2000–AllrightsreservedIEC61260:1995,Electroacoustics—Octave-bandandfractional-octavebandfilters.IEC61672-1,Electroacoustics—Soundlevelmeters—Part1:Specifications.1)3TermsanddefinitionsForthepurposesofthisInternationalStandard,thefollowingtermsanddefinitionsapply.3.1referencesoundsourceRSSstableandsteadysourceemittingconstantbroad-bandnoisewithanadequatesoundpowerlevel,inconformancewithandcalibratedaccordingtoISO69263.2calibrationpositionposition,well-definedrelativetoreflectingsurfaces,inwhichthereferencesoundsourcehasbeencalibrated3.3referenceboxhypotheticalsurfacewhichisthesmallestrectangularparallelepipedthatjustenclosesthesourceandterminatesonthereflectingplane(s)3.4reverberantsoundfieldthatportionofthesoundfieldinthetestroomoverwhichtheinfluenceofsoundreceiveddirectlyfromthesourceisnegligible3.5measurementdistancedmclosestdistancefromthereferenceboxtoamicrophoneposition3.6backgroundnoisenoisefromallsourcesotherthanthesourceundertestNOTEBackgroundnoisemayincludecontributionsfromairbornesound,structure-bornevibration,andelectricalnoiseininstrumentation.3.7frequencyrangeofinterestforgeneralpurposes,thefrequencyrangeofinterestincludestheoctavebandswithmidbandfrequenciesfrom125Hzto8000HzNOTE1Forspecialpurposes,itispermissibletoextendorreducethefrequencyrangeofinterestateitherend,providedthatthetestenvironment,referencesoundsourceandinstrumentaccuracyaresatisfactoryforuseovertheextendedorreducedfrequencyrange.Forsourceswhichradiatepredominantlyhigh(orlow)frequencysound,itispermissibletoextendorreducethefrequencyrangeofinterestinordertooptimizethetestprocedures.NOTE2FordeterminationofA-weightedsoundpowerlevels(orotherfrequency-weightedlevels),frequencycomponentswithintherangewhichdonotcontributetotheA-weightedsoundpowerlevelmaybedisregarded.1)Tobepublished.(RevisionofIEC60651andIEC60804)kSIST FprEN ISO 3747:2009
ISO3747:2000(E)©ISO2000–Allrightsreserved33.8comparisonmethodmethodinwhichthesoundpowerleveliscalculatedbycomparingthemeasuredsoundpressurelevelsproducedbythesourceundertestinanenvironmentwiththesoundpressurelevelsproducedinthesameenvironmentbyareferencesoundsourceofknownsoundpoweroutput3.9excessofsoundpressurelevelatagivendistanceLfdifference,indecibels,forareferencesoundsourcewithareferencecalibration,atagivendistance,betweenthespatialsounddistributioncurveoftheroomandthespatialsounddistributioncurveforafreefield(6dBperdistancedoubling)accordingtoannexANOTEThistermanditsdefinitiondifferfromthatofISO14257whichrelatestoanaveragedifferenceoveragivendistancerange.4Testmethodology4.1GeneralThetestmethodisacomparisonmethod,thatisthesoundpoweroutputofthesourceundertestiscomparedwiththatofareferencesoundsourcewithknownsoundpowerlevel.Inordertoobtainagoodcomparison,atleastthefollowingconditionmustbefulfilled:thetestenvironmentissufficientlyreverberanttocausethedirectivityofthesourceundertesttohaveonlyaninsignificantinfluenceonthemeasuredsoundpressurelevels.Thebettertheaboveconditionisfulfilled,thelowerthemeasurementuncertaintywillbe.Tomakeanobjectiveevaluationofthemeasurementconditions,itisnecessarytodetermineoneindicator,Lf,forthetestenvironment.FurtherinformationaboutthisindicatorisgiveninannexA.4.2AccuracyLfwillbeinfluencedbytheselectionofthereferencesoundsourceandthemicrophonepositions.Thusitmay,insomecases,bepossibletoimprovethemeasurementaccuracyfromthatofasurveymethodtothatofanengineeringmethodbychangingthesepositions;seeannexA.5MeasurementuncertaintyAsinglevalueofthesoundpowerlevelofasoundsourcedeterminedaccordingtotheproceduresofthisInternationalStandardislikelytodifferfromthetruevaluebyanamountwithinthemeasurementuncertainty.Theuncertaintyindeterminationsofthesoundpowerlevelarisesfromseveralfactorswhichaffecttheresults,someassociatedwithenvironmentalconditionsinthetestenvironmentandotherswithexperimentaltechniquesandthedirectionalcharacteristicsofthesoundsourceundertest.Ifaparticularsourceweretobetransportedtoeachofanumberofdifferenttestenvironmentsandif,ineachenvironment,thesoundpowerlevelofthatsourceweretobedeterminedinaccordancewiththeprovisionsofthisInternationalStandard,theresultswouldshowascatter.Thestandarddeviationsofthemeasuredoctavebandvaluescouldbecalculated(examplesaregiveninISO7574-4:1985,annexB)andwouldvary.Thesestandarddeviationswould,withfewexceptions,notexceedthoselistedinTable1fortheA-weightedsoundpowerlevel.ThestandarddeviationwilldependontheindicatorLf.Ifthisindicatorisnotevaluated,thedefaultstandarddeviationofreproducibility,sR,is4,0dB.kSIST FprEN ISO 3747:2009
ISO3747:2000(E)4©ISO2000–AllrightsreservedTable1—Estimateduppervaluesofthestandarddeviationofreproducibility,sR,ofA-weightedsoundpowerlevelsofsoundsourcesdeterminedaccordingtothisInternationalStandardIndicatorvaluesUppervaluesofstandarddeviationofreproducibilityfortheA-weightedsoundpowerlevelGradeofaccuracyLfAW7dBa1,5dBGrade2LfA7dBornotdetermined4,0dBGrade3aTobemetbyallmicrophonepositions.NOTE1ThestandarddeviationsgiveninTable1mightbecomelargerforsourcesthatradiatenarrow-bandnoise,discretetonesandcombinationsofthese.Inthesecasestheengineeringgradeofaccuracymightnotbeachieved.ThevaluesgiveninTable1arestandarddeviationsofreproducibility,sR,asdefinedinISO7574-1.ThevaluesofTable1takeintoaccountthecumulativeeffectsofmeasurementuncertaintyinapplyingtheproceduresofthisInternationalStandard,butexcludevariationsinthesoundpoweroutputcausedbychangesinoperatingconditions(e.g.rotationalspeed,linevoltage)ormountingconditions.ThemeasurementuncertaintydependsonthestandarddeviationofreproducibilitytabulatedinTable1,thesystematicerrorsdiscussedbelow,andthedegreeofconfidencethatisdesired.Asexamples,excludingthesystematicerrors,thereisa90%confidencethattheexpectedvalueofthesoundpowerlevelofasourcelieswithintherange1,645sR,ofthemeasuredvalueanda95%confidencethatitlieswithintherange1,96sR.Forfurtherexamples,seeISO7574-4.NOTE2WheresRexceeds2dB,therangesofconfidenceintervalsmaynotapply.NormallytheA-weightedsoundpowerlevelismainlyinfluencedbythelevelsinthe250Hzto4000Hzoctavebands.TheA-weightedsoundpowerlevelisdeterminedwithastandarddeviationwhichvarieswiththeindicatorvaluesasshowninTable1.Iffrequencieslowerthan500HzareveryimportantfortheA-weightedlevel,thestandarddeviationwillbecomehigher.Iffrequencieshigherthan2000Hzareimportantthesourcemaybehighlydirectional.If,insuchcases,therearestronglyabsorbingsurfacesclosetothemachineundertest(e.g.anabsorbingceiling),themeasurementuncertaintymaybecomegreater.NOTE3Onereason,specificforthisInternationalStandard,forincreasedmeasurementuncertaintyatlowfrequenciesisthatthereferencesoundsourceisnotalwaysusedincalibratedpositions.Thuscalibrationerrorsareintroduced.TheseerrorsoccuratlowfrequencieswheretheRSSislocatedatdistancesinrelationtonearbyreflectingsurfaceswhicharedifferentfromtheonesusedduringthecalibration.6Instrumentation6.1InstrumentationsystemTheinstrumentationsystem,includingthemicrophoneandcable,shallmeettherequirementsforaclass1instrumentspecifiedinIEC61672-1.Thecalibratorshallmeettherequirementsforclass1specifiedinIEC60942.Formeasurementsinoctavebands,theinstrumentationsystemshallmeettherequirementsofIEC61260.6.2Calibration6.2.1MeasuringsystemDuringeachseriesofmeasurements,applythesoundcalibratortothemicrophoneforcheckingthecalibrationoftheentiremeasuringsystematoneormorefrequenciesoverthefrequencyrangeofinterest.kSIST FprEN ISO 3747:2009
ISO3747:2000(E)©ISO2000–Allrightsreserved5VerifythecomplianceofthecalibratorwiththerequirementsofIEC60942onceayearandthecomplianceoftheinstrumentationsystemwiththerequirementsofIEC61672-1atleasteverytwoyearsinalaboratorymakingtraceablecalibrations.RecordthedateofthelastcheckandconfirmationofthecompliancewiththerelevantIECstandard.6.2.2ReferencesoundsourceThereferencesoundsourceshallbeinconformancewithandcalibratedaccordingtoISO6926.NOTENormallythiscalibrationisvalidonlyforpositionsawayfromwallswiththereferencesoundsourceeitherdirectlyonthefloororonastandataspecifiedelevationabovethefloor.IftheRSSisusedinotherpositions,unlessithasbeencalibratedspecificallyinthesepositions,systematicerrorsmayoccuratlowfrequencies.7OperatingconditionsofthesourceundertestDuringthemeasurementsusetheoperatingconditionsspecifiedintherelevanttestcode,ifoneexistsfortheparticulartypeofmachineryorequipmentundertest.Ifthereisnotestcode,operatethesource,ifpossible,inamannerwhichistypicalofnormaluse.Insuchcases,oneormoreofthefollowingoperatingconditionsshallbeselected:deviceunderspecifiedloadandoperatingconditions;deviceunderfullload(ifdifferentfromabove);deviceundernoload(idling);deviceunderoperatingconditioncorrespondingtomaximumsoundgenerationrepresentativeofnormaluse;devicewithsimulatedloadoperatingundercarefullydefinedconditions;deviceunderoperatingconditionwithcharacteristicworkcycle.Thesoundpowerlevelofthesourcemaybedeterminedforanydesiredsetofoperatingconditions(i.e.loading,devicespeed,temperature,etc.).Thesetestconditionsshallbeselectedbeforehandandshallbeheldconstantduringthetest.Thesourceshallbeinthedesiredoperatingconditionbeforeanynoisemeasurementsaremade.Ifthenoiseemissiondependsonsecondaryoperatingparameters,suchasthetypeofmaterialbeingprocessedorthetypeoftoolbeingused,asfaraspracticable,thoseparametersshallbeselectedthatgiverisetothesmallestvariationsandthataretypicaloftheoperation.Thenoisetestcodeforaspecificfamilyofmachinesshallspecifythetoolandthematerialforthetest.Forspecialpurposesitisappropriatetodefineoneormoreoperatingconditionsinsuchawaythatthenoiseemissionofmachinesofthesamefamilyishighlyreproducibleandthattheoperatingconditionswhicharemostcommonandtypicalforthefamilyofmachinesarecovered.Theseoperatingconditionsshallbedefinedinspecifictestcodes.Ifsimulatedoperatingconditionsareused,theyshallbechosentogivesoundpowerlevelsrepresentativeofnormaluseofthesourceundertest.Ifappropriate,theresultsforseveralseparateoperatingconditions,eachlastingfordefinedperiodsoftime,shallbecombinedbyenergy-averagingtoyieldtheresultforacompositeoveralloperatingprocedure.Theoperatingconditionsofthesourceduringtheacousticalmeasurementsshallbefullydescribedinthetestreport.kSIST FprEN ISO 3747:2009
ISO3747:2000(E)6©ISO2000–Allrightsreserved8Preliminarysurvey8.1BackgroundnoiseWiththesourceundertestturnedoff,identify,firstbylisteningorbyusingasoundlevelmeter,possiblezoneswithhighbackgroundnoise.WiththesourceundertestandtheRSSturnedonseparately,makeroughevaluationsofnoiselevelsinthezoneswherebackgroundnoiseispresentandconcludewhetherthesezonesareallowedornotconsideringthebackgroundnoisecriteriaof10.3.Forlateruse,selectzoneswithnobackgroundnoiseproblems.8.2CharacterizationofthesourceundertestWalkaroundthesourceundertestanddetectbylisteningwhether,amongtheradiatingpartsofthesourceundertest,oneclearlydominates.Iftheanswerisyes,considerthegeometricalcentreofittobetheacousticcentreofthesource.Iftheanswerisno,excludeallpartsofthesourceundertestnotradiatingnoiseandconsiderthegeometricalcentreoftheremaindertobetheacousticcentreofthesource.Measurethesoundpressureatadistanceof1mfromthereferenceboxandataheight,H,abovethefloor.NormallyselectH=1,5m.Ifthesourceundertestradiatespredominantlyupwards,selectavalueofHhighenoughtoensurethatthemicrophonepositionsareilluminatedproperlybytheacousticcentreofthesource.Ifthesoundpressurelevelalongthiscontourvariesbynomorethan4dB,thesourceundertestisconsideredtobeomnidirectional.Ifitvariesmorethan4dB,itisconsideredtobedirectional.9Positionsofthereferencesoundsource9.1OnepositionNormallyoneRSSpositionisenough.Positionthereferencesoundsourceascloseaspossibletotheacousticcentreofthesourceundertest.Unlessanotherpositionwillsimulatetheradiationpatternofthesourceundertestsignificantlybetter,positiontheRSS,wheneverpractical,ontopofthesourceundertest.Ifthisisnotpossible,selectapositionalongthesidesofthesourceundertestataheightandpositionbestsimulatingtheradiationpatternofthesourceundertest.Inthesecases,avoidpositionscloserthan0,5mtothelateralsurfacesofthereferenceboxunlesstheRSShasbeencalibratedinsuchpositions.Foranomnidirectionalsourcemakesurethattheheightmakesitpossib
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