SIST EN ISO 3746:2011

Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane (ISO 3746:2010)

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 a noise source (machinery or equipment) in a test environment for which requirements are given. The sound power level (or, in the case of noise bursts or transient noise emission, the sound energy level) produced by the noise source with frequency A-weighting applied is calculated using those measurements. 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. 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. 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 with frequency A-weighting applied. The uncertainty conforms with that of ISO 12001:1996, accuracy grade 3 (survey grade).

Akustik - Ermittlung der Schallleistungs- und der Schallenergiepegel von Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der Genauigkeitsklasse 3 über einer reflektierenden Ebene (ISO 3746:2010)

Diese Internationale Norm legt Verfahren zur Ermittlung der Schallleistungspegel 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 Messumgebung befindet, an die Anforderungen angegeben werden. Der von der Geräuschquelle abgestrahlte A-bewertete Schallleistungspegel (oder Schallenergiepegel bei kurzzeitigen oder transienten Geräuschereignissen) wird aus den gemessenen Schalldruckpegeln berechnet.
ANMERKUNG Unterschiedliche Messflächenformen können zu unterschiedlichen Werten für den Schallleistungspegel der betrachteten Geräuschquelle führen. Daher sollte eine Messnorm die Auswahl der Messfläche genau festlegen.

Acoustique - Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique a partir de la pression acoustique - Méthode de contrôle employant une surface de mesure enveloppante au-dessus d'un plan réfléchissant (ISO 3746:2010)

L'ISO 3746:2010 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 une source de bruit (machine ou équipement) dans des conditions d'environnement d'essai spécifiées. 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, avec la pondération fréquentielle A appliquée, est calculé en utilisant ces mesures.
Les méthodes spécifiées dans l'ISO 3746:2010 sont applicables à tous les types de bruit (stable, non stable, fluctuant, impulsions acoustiques isolées, etc.) définis dans l'ISO 12001.
L'ISO 3746:2010 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 aux conditions de mesurage.
Les environnements d'essai qui sont applicables aux mesurages réalisés conformément à l'ISO 3746:2010 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.
Des informations sont données sur l'incertitude associée aux niveaux de puissance acoustique et aux niveaux d'énergie acoustique déterminés conformément à l'ISO 3746:2010, pour des mesurages effectués avec la pondération fréquentielle A. L'incertitude est conforme à celle de la classe de précision 3 (classe contrôle) définie dans l'ISO 12001:1996.

Akustika - Določanje ravni zvočnih moči in ravni zvočne energije virov hrupa z zvočnim tlakom - Informativna metoda z merilno ploskvijo, sklenjeno okrog vira hrupa nad odbojno ravnino (ISO 3746:2010)

Ta mednarodni standard določa metode opredeljevanja ravni zvočnih moči ali ravni zvočne energije virov hrupa z ravni zvočnega tlaka, ki se merijo na merilni ploskvi, sklenjeni okrog vira hrupa (strojev ali opreme) v preskusnem okolju, za katerega so podane zahteve. Raven zvočnih moči (ali v primeru prodorov hrupa ali prehodnih emisij hrupa raven zvočne energije), ki jo proizvede vir hrupa z uporabljenim uteženjem A, je izračunana z uporabo teh merjenj. Metode, določene v tem mednarodnem standardu, so primerne za vse tipe hrupa (ustaljeni, neustaljeni, nihajoči, izolirani izbruhi zvočne energije itd.), opredeljene v ISO 120001. Ta mednarodni standard velja za vse tipe in velikosti virov hrupa (npr. stacionarne ali počasi premikajoče se obrate, namestitve, stroje, komponente ali podsklope) pod pogojem, da so izpolnjeni pogoji za meritve. Preskusna okolja, ki se uporabljajo za merjenja, izvedena v skladu s tem mednarodnim standardom, so lahko locirana v zaprtih prostorih ali zunaj njih, z eno odbojno ravnino ali več odbojnimi ravninami nad njimi ali v bližini, kjer je nameščen vir hrupa, ki se preskuša. Podane so informacije za negotovost ravni zvočnih moči in ravni zvočne energije, določene v skladu s tem mednarodnim standardom za merjenja z uporabljenim uteženjem A. Negotovost je v skladu z negotovostjo iz ISO 12001:1996, razred točnosti 3 (razred analize).

General Information

• Status: Published
• Publication Date: 15-Feb-2011
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: AKU - Acoustics
• Current Stage: 6100 - Translation of adopted SIST standards (Adopted Project)
• Start Date: 16-Feb-2012
• Due Date: 14-Feb-2013
• Completion Date: 22-Aug-2012
• Directive: 2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Directive: 89/392/EEC - Machinery - Safety of machinery: general essential health and safety requirements
• Directive: 98/37/EC - Machinery
• Mandate: M/BC/CEN/88/13 - Standardization request to CEN/CENELEC relating to machinery
• Ref Project: EN ISO 3746:2010 - Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane (ISO 3746:2010)

Relations

• Replaces: SIST EN ISO 3746:2009 - Acoustics - Determination of sound power levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane (ISO 3746:1995, including Cor 1:1995)
• Effective Date: 01-Mar-2011

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 3746:2011
01-marec-2011
1DGRPHãþD
SIST EN ISO 3746:2009
$NXVWLND'RORþDQMHUDYQL]YRþQLKPRþLLQUDYQL]YRþQHHQHUJLMHYLURYKUXSD]
]YRþQLPWODNRP,QIRUPDWLYQDPHWRGD]PHULOQRSORVNYLMRVNOHQMHQRRNURJYLUD
KUXSDQDGRGERMQRUDYQLQR,62
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Survey method using an enveloping measurement
surface over a reflecting plane (ISO 3746:2010)
Akustik - Ermittlung der Schallleistungs- und der Schallenergiepegel von
Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der
Genauigkeitsklasse 3 über einer reflektierenden Ebene (ISO 3746:2010)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux
d'énergie acoustique a partir de la pression acoustique - Méthode de contrôle employant
une surface de mesure enveloppante au-dessus d'un plan réfléchissant (ISO 3746:2010)
Ta slovenski standard je istoveten z: EN ISO 3746:2010
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
SIST EN ISO 3746:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3746:2011

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SIST EN ISO 3746:2011


EUROPEAN STANDARD
EN ISO 3746

NORME EUROPÉENNE

EUROPÄISCHE NORM
December 2010
ICS 17.140.01 Supersedes EN ISO 3746:2009
English Version
Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure - Survey
method using an enveloping measurement surface over a
reflecting plane (ISO 3746:2010)
Acoustique - Détermination des niveaux de puissance Akustik - Ermittlung der Schallleistungs- und
acoustique et des niveaux d'énergie acoustique émis par Schallenergiepegel von Geräuschquellen aus
les sources de bruit à partir de la pression acoustique - Schalldruckmessungen - Hüllflächenverfahren der
Méthode de contrôle employant une surface de mesure Genauigkeitsklasse 3 über einer reflektierenden Ebene
enveloppante au-dessus d'un plan réfléchissant (ISO (ISO 3746:2010)
3746:2010)
This European Standard was approved by CEN on 13 November 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-CENELEC 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-CENELEC 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 3746:2010: E
worldwide for CEN national Members.

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SIST EN ISO 3746:2011
EN ISO 3746:2010 (E)
Contents Page
Foreword .3
Annex ZA (informative)  Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .4

2

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SIST EN ISO 3746:2011
EN ISO 3746:2010 (E)
Foreword
This document (EN ISO 3746:2010) 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 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 June 2011, and conflicting national standards shall be withdrawn at
the latest by June 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 3746:2009.
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(s).
For relationship with EU Directive(s), 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 3746:2010 has been approved by CEN as a EN ISO 3746:2010 without any modification.
3

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SIST EN ISO 3746:2011
EN ISO 3746:2010 (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 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 Union 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
corresponding 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 3746:2011

INTERNATIONAL ISO
STANDARD 3746
Third edition
2010-12-01


Acoustics — Determination of sound
power levels and sound energy levels of
noise sources using sound pressure —
Survey method using an enveloping
measurement surface 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 de contrôle employant une
surface de mesure enveloppante au-dessus d'un plan réfléchissant





Reference number
ISO 3746:2010(E)
©
ISO 2010

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
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All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland

ii © ISO 2010 – All rights reserved

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.2
3 Terms and definitions .2
4 Test environment.6
5 Instrumentation .7
6 Definition, location, installation and operation of noise source under test.7
7 Reference box and measurement surface.10
8 Determination of sound power levels and sound energy levels .13
9 Measurement uncertainty.18
10 Information to be recorded.21
11 Test report.23
Annex A (normative) Determination of the environmental correction .24
Annex B (normative) Microphone arrays on a hemispherical measurement surface .25
Annex C (normative) Microphone arrays on a parallelepiped measurement surface .30
Annex D (informative) Guidelines on the development of information on measurement uncertainty .38
Bibliography.47

© ISO 2010 – All rights reserved iii

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SIST EN ISO 3746:2011
ISO 3746:2010(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 3746 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This third edition cancels and replaces the second edition (ISO 3746:1995), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 3746:1995/Cor.1:1995.
iv © ISO 2010 – All rights reserved

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
Introduction
[2] [6]
This International Standard is one of the series ISO 3741 to ISO 3747 , which specify methods for
determining the sound power levels and sound energy levels of noise sources including machinery, equipment
[1]
and their sub-assemblies. Guidelines to select one of those methods 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 test code for the individual
noise source in order to select the appropriate sound measurement surface and microphone array from
[1] [6]
among those allowed in each of the ISO 3740 to ISO 3747 series, and to give requirements for 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.
This International Standard specifies methods giving results of ISO 12001:1996, accuracy grade 3 (survey
grade) when measurements are performed 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.
The methods specified in this International Standard permit the determination of the sound power level and
the sound energy level with frequency A-weighting applied.
[5]
For applications where greater accuracy is required, reference can be made to ISO 3744, ISO 3745 or an
[14]-[16]
appropriate part of ISO 9614 . If the relevant criteria for the measurement environment specified in this
[2] [6]
International Standard are not met, it might be possible to refer to another of the ISO 3741 to ISO 3747
[14]-[16]
series, or to an appropriate part of ISO 9614 .

© ISO 2010 – All rights reserved v

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SIST EN ISO 3746:2011

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SIST EN ISO 3746:2011
INTERNATIONAL STANDARD ISO 3746:2010(E)

Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure — Survey
method using an enveloping measurement surface 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 a noise source (machinery or
equipment) in a test environment for which requirements are given. The sound power level (or, in the case of
noise bursts or transient noise emission, the sound energy level) produced by the noise source with frequency
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 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 The conditions for measurements given in this International Standard can 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 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.
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 with frequency A-weighting applied. The
uncertainty conforms with that of ISO 12001:1996, accuracy grade 3 (survey grade).
© ISO 2010 – All rights reserved 1

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SIST EN ISO 3746:2011
ISO 3746:2010(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 3744, 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 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
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 of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
sound pressure
p
difference between instantaneous pressure and static pressure
[23]
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
[22]
[ISO/TR 25417:2007 , 2.2]
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
[23]
NOTE 2 This definition is technically in accordance with ISO 80000-8:2007 , 8-22.
2 © ISO 2010 – All rights reserved

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
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
⎢ ⎥
(2)
L = 10 lg dB
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
[22]
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” (see
[22]
ISO/TR 25417:2007 ).
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.
© ISO 2010 – All rights reserved 3

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
3.6
reflecting plane
sound-reflecting planar surface on which the noise source under test is located
3.7
frequency range of interest
frequency range of octave bands with nominal mid-band frequencies from 125 Hz to 8 000 Hz
3.8
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] [21]
measurements at bystander positions in accordance with, for example, the ISO 11201 to ISO 11204 series.
3.9
characteristic source dimension
d
0
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.
3.10
measurement distance
d
distance from the reference box to a parallelepiped measurement surface
NOTE Measurement distance is expressed in metres.
3.11
measurement radius
r
radius of a hemispherical, half-hemispherical or quarter-hemispherical measurement surface
NOTE Measurement radius is expressed in metres.
3.12
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
3.13
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.
3.14
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-weighting is denoted
K .
1A
4 © ISO 2010 – All rights reserved

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SIST EN ISO 3746:2011
ISO 3746:2010(E)
3.15
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-weighting is denoted K .
2A
NOTE 3 In general, the environmental correction depends on the area of the measurement surface and usually K
2A
increases with S.
3.16
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.
3.17
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.
3.18
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
[23]
[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.
3.19
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
should be indicated by appropriate subscripts; e.g. L denotes the A-weighted sound power level.
WA
[23]
NOTE 2 This definition is technically in accordance with ISO 80000-8:2007 , 8-23.
[22]
[ISO/TR 25417:2007 , 2.9]
© ISO 2010 – All rights reserved 5

---------------------- Page: 17 ----------------------

SIST EN ISO 3746:2011
ISO 3746:2010(E)
3.20
sound energy
J
integral of the sound power, P, over a stated time interval of duration T (starting at t and ending at t )
1 2
t
2
J = Pt()dt (5)
∫
t
1
NOTE 1 Sound energy is expressed in joules.
NOTE 2 The quantity is particularly relevant for non-stationary, intermittent sound events.
[22]
[ISO/TR 25417:2007 , 2.10]
3.21
sound energy level
L
J
ten times the logarithm to the base 10 of the ratio of the sound energy, J, to a reference value, J , expressed
0
in decibels
J
L = 10 lg dB (6)
J
J
0
where the reference value, J , is 1 pJ
0
NOTE If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands are applied, this
should be indicated by appropriate subscripts; e.g. L denotes the A-weighted sound energy level.
JA
[22]
[ISO/TR 25417:2007 , 2.11]
4 Test environment
4.1 General
The test environments that are applicable for measurements in accordance with this International Standard
are a room or a flat outdoor area which is adequately isolated from background noise (see 4.2) and which
meets the qualification requirements of 4.3.
Environmental conditions having an adverse effect on the microphones used for the measurements (e.g.
strong electric or magnetic fields, wind, impingement of air discharge from the noise source being tested, high
or low temperatures) shall be avoided. The instructions of the manufacturers of the measuring instrumentation
regarding adverse environmental conditions shall be followed.
In an outdoor area, care shall be taken to minimize the effects of adverse meteorological conditions (e.g.
temperature, humidity, wind, precipitation) on the sound propagation and on the sound generation over the
frequency range of interest or on the background noise during the course of the measurements.
At altitudes above 1 500 m, sound power levels and sound energy levels shall be corrected to reference
meteorological conditions in accordance with ISO 3744.
When a reflecting surface is not a ground plane or is not an integral part of a test room surface, particular care
should be exercised to ensure that the plane does not radiate any appreciable sound due to vibrations.
6 © ISO 2010 – All rights reserved

---------------------- Page: 18 ----------------------

SIST EN ISO 3746:2011
ISO 3746:2010(E)
4.2 Criterion for background noise
The A-weighted sound pressure levels due to background noise averaged over the microphone positions, or
traverses, on the measurement surface shall be at least 3 dB below the mean sound pr
...

SLOVENSKI SIST EN ISO 3746

STANDARD
marec 2011












Akustika – Določanje ravni zvočne moči in ravni zvočne energije virov
hrupa z zvočnim tlakom – Informativna metoda z merilno ploskvijo,

sklenjeno okrog vira hrupa nad odbojno ravnino (ISO 3746:2010)
Acoustics – Determination of sound power levels and sound energy levels of
noise sources using sound pressure – Survey method using an enveloping
measurement surface over a reflecting plane (ISO 3746:2010)
Acoustique – Détermination des niveaux de puissance acoustique et des
niveaux d'énergie acoustique a partir de la pression acoustique – Méthode de
contrôle employant une surface de mesure enveloppante au-dessus d'un plan
réfléchissant (ISO 3746:2010)
Akustik – Ermittlung der Schallleistungs- und Schallenergiepegel von
Geräuschquellen aus Schalldruckmessungen – Hüllflächenverfahren der
Genauigkeitsklasse 3 über einer reflektierenden Ebene (ISO 3746:2010)















Referenčna oznaka
ICS 17.140.01 SIST EN ISO 3746:2011 (sl)


Nadaljevanje na straneh II in III ter od 1 do 50



© 2012-09. Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 3746 : 2011
NACIONALNI UVOD

Standard SIST EN ISO 3746 (sl), Akustika – Določanje ravni zvočne moči in ravni zvočne energije
virov hrupa z zvočnim tlakom – Informativna metoda z merilno ploskvijo, sklenjeno okrog vira hrupa
nad odbojno ravnino (ISO 3746:2010), 2011, ima status slovenskega standarda in je enakovreden
evropskemu standardu EN ISO 3746 (en, de, fr), Acoustics – Determination of sound power levels and
sound energy levels of noise sources using sound pressure – Survey method using an enveloping
measurement surface over a reflecting plane (ISO 3746:2010), 2010.
NACIONALNI PREDGOVOR
Evropski standard EN ISO 3746:2010 je pripravil tehnični odbor Evropskega komiteje za
standardizacijo CEN/TC 211 Akustika. Slovenski standard SIST EN ISO 3746:2011 je prevod
evropskega standarda EN ISO 3746:2010. V primeru spora glede besedila slovenskega prevoda v
tem standardu je odločilen izvirni evropski standard v enem izmed treh uradnih jezikov CEN.
Slovensko izdajo standarda je pripravil tehnični odbor SIST/TC AKU Akustika.
Ta dokument nadomešča SIST EN ISO 3746:2009.
Odločitev za izdajo tega standarda je dne 14. februarja 2011 sprejel SIST/TC AKU Akustika.
ZVEZA Z NACIONALNIMI STANDARDI
S privzemom tega evropskega standarda veljajo za omejeni namen referenčnih standardov vsi
standardi, navedeni v izvirniku, razen tistih, ki so že sprejeti v nacionalno standardizacijo:
SIST EN ISO 3744 Akustika – Ugotavljanje ravni zvočnih moči virov hrupa z merjenjem
zvočnega tlaka – Inženirska metoda v pretežno prostem polju nad odbojno
ravnino (ISO 3744:2010)
SIST ISO 5725 (vsi deli) Točnost (pravilnost in natančnost) merilnih metod in rezultatov
SIST EN ISO 12001 Akustika – Emisija hrupa naprav in opreme – Pravila za oblikovanje in
pripravo pravil za merjenje hrupa (ISO 12001:1996)
SIST EN 60942:2004 Elektroakustika – Kalibratorji za zvokomere
SIST EN 61672-1:2004 Elektroakustika – Merilniki zvočne jakosti – 1. del: Specifikacije
OSNOVA ZA IZDAJO STANDARDA
–  privzem standarda EN ISO 3746:2010
PREDHODNA IZDAJA
– SIST EN ISO 3746:2009, Akustika – Ugotavljanje ravni zvočnih moči virov hrupa z merjenjem
zvočnega tlaka – Informativna metoda z merilno ploskvijo, sklenjeno okrog vira hrupa nad
odbojno ravnino
OPOMBE
– Povsod, kjer se v besedilu standarda uporablja izraz ''evropski standard'', v
SIST EN ISO 3746:2011 to pomeni ''slovenski standard''.
–  Nacionalni uvod in nacionalni predgovor nista sestavni del standarda.



II

---------------------- Page: 2 ----------------------

SIST EN ISO 3746 : 2011
–  Ta nacionalni dokument je enakovreden EN ISO 3746:2010 in je objavljen z dovoljenjem
CEN
Management Centre
Avenue Marnix 17
B-1000 Bruselj
– This national document is identical with EN ISO 3746:2010 and is published with the permission of
CEN
Management Centre
Avenue Marnix 17
B-1000 Brussels

III

---------------------- Page: 3 ----------------------

SIST EN ISO 3746 : 2011










(Prazna stran)
IV

---------------------- Page: 4 ----------------------

EVROPSKI STANDARD EN ISO 3746
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM december 2010


ICS 17.140.01 Nadomešča EN ISO 3746:2009




Slovenska izdaja

Akustika – Določanje ravni zvočne moči in ravni zvočne energije virov hrupa z
zvočnim tlakom – Informativna metoda z merilno ploskvijo, sklenjeno okrog
vira hrupa nad odbojno ravnino (ISO 3746:2010)

Acoustics – Determination of Acoustique – Détermination des Akustik – Ermittlung der Schallleistungs-
sound power levels and niveaux de puissance acoustique et und Schallenergiepegel von
sound energy levels of noise des niveaux d'énergie acoustique a Geräuschquellen aus
sources using sound pressure partir de la pression acoustique – Schalldruckmessungen –
– Survey method using an Méthode de contrôle employant une Hüllflächenverfahren der
enveloping measurement surface de mesure enveloppante Genauigkeitsklasse 3 über einer
surface over a reflecting au-dessus d'un plan réfléchissant reflektierenden Ebene
plane (ISO 3746:2010) (ISO 3746:2010) (ISO 3746:2010)




Ta evropski standard je CEN sprejel 13. novembra 2010.
Člani CEN morajo izpolnjevati notranje predpise CEN/CENELEC, s katerimi je predpisano, da mora
biti ta standard brez kakršnih koli sprememb sprejet kot nacionalni standard. Seznami najnovejših
izdaj teh nacionalnih standardov in njihovi bibliografski podatki so na voljo pri Upravnem centru CEN
in članicah CEN.
Ta evropski standard obstaja v treh izvirnih izdajah (angleški, francoski, nemški). Izdaje v drugih
jezikih, ki jih članice CEN na lastno odgovornost prevedejo in izdajo ter prijavijo pri Upravnem centru
CEN, veljajo kot uradne izdaje.
Člani CEN so nacionalni organi za standardizacijo Avstrije, Belgije, Bolgarije, Cipra, Češke republike,
Danske, Estonije, Finske, Francije, Grčije, Hrvaške, Islandije, Irske, Italije, Latvije, Litve,
Luksemburga, Madžarske, Malte, Nemčije, Nizozemske, Norveške, Poljske, Portugalske, Romunije,
Slovaške, Slovenije, Španije, Švedske, Švice in Združenega kraljestva.




CEN
Evropski komite za standardizacijo
European Committee for Standardisation
Europäisches Komitee für Normung
Comité Européen de Normalisation

Upravni center: Avenue Marnix 17, B-1000 Bruselj


© 2010 CEN Lastnice avtorskih pravic so vse države članice CEN Ref. št. EN ISO 3746:2010: E

---------------------- Page: 5 ----------------------

SIST EN ISO 3746 : 2011
Vsebina Stran
Predgovor k evropskemu standardu .3
Dodatek ZA (informativni): Povezava med tem evropskim standardom in bistvenimi zahtevami
Direktive EU 2006/42/EC.4
Predgovor k mednarodnemu standardu.5
Uvod .6
1 Področje uporabe .7
2 Zveza s standardi .7
3 Izrazi in definicije .8
4 Preskusno okolje .11
5 Instrumentarij.12
6 Opis, lokacija, postavitev in obratovanje vira hrupa med preskušanjem .13
7 Referenčni boks in merilna ploskev.15
8 Določanje ravni zvočne moči in zvočne energije .18
9 Merilna negotovost .22
10 Informacije, ki jih je treba zapisati .25
11 Poročilo o preskusu.26
Dodatek A (normativni): Določanje okoljskega popravka.27
Dodatek B (normativni): Razporeditev mikrofonov na polkrogelni merilni ploskvi .28
Dodatek C (normativni): Razporeditev mikrofonov na merilni ploskvi v obliki paralelepipeda.33
Dodatek D (normativni): Smernice o razvoju informacij o merilni negotovosti.41
Literatura.49
2

---------------------- Page: 6 ----------------------

SIST EN ISO 3746 : 2011
Predgovor k evropskemu standardu
Ta dokument (EN ISO 3746:2010) je pripravil tehnični odbor ISO/TC 43 Akustika v sodelovanju s
tehničnim odborom CEN/TC 211 Akustika, katerega sekretariat vodi DS (Danish Standards).
Ta evropski standard mora dobiti status nacionalnega standarda bodisi z objavo istovetnega besedila
ali z razglasitvijo najpozneje do junija 2011, nacionalne standarde, ki so z njim v nasprotju, pa je treba
razveljaviti najpozneje do junija 2011.
Opozoriti je treba na možnost, da so nekateri elementi tega dokumenta lahko predmet patentnih
pravic. CEN (in/ali CENELEC) ne prevzema odgovornosti za identifikacijo katerihkoli ali vseh takih
patentnih pravic.
Ta dokument nadomešča EN ISO 3746:2009.
Ta dokument je bil pripravljen v okviru mandata, ki sta ga Evropska komisija in Evropsko združenje za
prosto trgovino (EFTA) dala CEN, in podpira bistvene zahteve direktive (direktiv) Evropske unije.
Za povezavo z direktivo(-ami) EU glejte informativni dodatek ZA, ki je sestavni del tega dokumenta.
V skladu z notranjimi predpisi CEN/CENELEC so ta evropski standard dolžne privzeti nacionalne
organizacije za standardizacijo naslednjih držav: Avstrije, Belgije, Bolgarije, Cipra, Češke republike,
Danske, Estonije, Finske, Francije, Grčije, Hrvaške, Islandije, Irske, Italije, Latvije, Litve,
Luksemburga, Madžarske, Malte, Nemčije, Nizozemske, Norveške, Poljske, Portugalske, Romunije,
Slovaške, Slovenije, Španije, Švedske, Švice in Združenega kraljestva.

Razglasitvena objava
Besedilo ISO 3746:2010 je CEN odobril kot EN ISO 3746:2010 brez kakršnihkoli sprememb.
3

---------------------- Page: 7 ----------------------

SIST EN ISO 3746 : 2011
Dodatek ZA
(informativni)




Povezava med tem evropskim standardom in bistvenimi zahtevami Direktive
EU 2006/42/EC
Ta evropski standard je bil pripravljen v okviru mandata, ki sta ga Evropska komisija in Evropsko
združenje za prosto trgovino dala CEN, da bi zagotovila skladnost z bistvenimi zahtevami Direktive
novega pristopa 2006/42/EC o strojih.
Ko bo ta standard objavljen v Uradnem listu Evropskih skupnosti v okviru navedene direktive in bo kot
nacionalni standard privzet v vsaj eni državi članici, bo skladnost s točkami tega standarda, v obsegu
področja uporabe tega standarda, ustvarila domnevo o skladnosti z ustreznimi bistvenimi zahtevami te
direktive in pridruženimi predpisi EFTA.
OPOZORILO: Za proizvode, ki spadajo v področje uporabe tega standarda, se lahko uporabljajo tudi
druge zahteve in druge direktive EU.
4

---------------------- Page: 8 ----------------------

SIST EN ISO 3746 : 2011
Predgovor k mednarodnemu standardu
ISO (Mednarodna organizacija za standardizacijo) je svetovna zveza nacionalnih organov za standarde
(članov ISO). Mednarodne standarde ponavadi pripravljajo tehnični odbori ISO. Vsak član, ki želi
delovati na določenem področju, za katero je bil ustanovljen tehnični odbor, ima pravico biti zastopan v
tem odboru. Pri delu sodelujejo tudi mednarodne vladne in nevladne organizacije, povezane z ISO. V
vseh zadevah, ki so povezane s standardizacijo na področju elektrotehnike, ISO tesno sodeluje z
Mednarodno elektrotehniško komisijo (IEC).
Mednarodni standardi so pripravljeni v skladu s pravili, podanimi v 2. delu Direktiv ISO/IEC.
Glavna naloga tehničnih odborov je priprava mednarodnih standardov. Osnutki mednarodnih
standardov, ki jih sprejmejo tehnični odbori, se pošljejo vsem članom v glasovanje. Za objavo
mednarodnega standarda je treba pridobiti soglasje najmanj 75 odstotkov članov, ki se udeležijo
glasovanja.
Opozoriti je treba na možnost, da je lahko nekaj elementov tega dokumenta predmet patentnih pravic.
ISO ne prevzema odgovornosti za identifikacijo katerihkoli ali vseh takih patentnih pravic.
ISO 3746 je pripravil tehnični odbor ISO/TC 43, Akustika, pododbor SC1, Hrup.
Ta tretja izdaja razveljavlja in nadomešča drugo izdajo (ISO 3746:1995), ki je bila tehnično
spremenjena. Ta vključuje tudi tehnični popravek ISO 3746:1995/Cor.1:1995.
5

---------------------- Page: 9 ----------------------

SIST EN ISO 3746 : 2011
Uvod
[2] [6]
Ta mednarodni standard je eden v seriji ISO 3741 do ISO 3747 , ki opisuje metode za določanje
zvočne moči in zvočne energije virov hrupa, vključno s stroji, opremo in njihovimi podsestavi.
[1].
Smernice za izbiro ene od teh metod se najdejo v standardu ISO 3740 Izbor je odvisen od okolja,
razpoložljive preskusne opreme in zahtevane natančnosti izmerjene ravni zvočne moči ali ravni
zvočne energije. Morda bo treba izdelati navodila za izvajanje meritev za posamezni vir hrupa, da bi
izbrali primerno akustično merilno ploskev in razpored mikrofonov izmed vseh možnih v vsakem od
[1] [6]
standardov ISO 3740 do ISO 3747 , in da bi opredelili zahteve za postavitev preskušane enote,
njeno obremenitev in obratovalne pogoje, pod katerimi je treba določati ravni zvočne moči ali ravni
zvočne energije. Zvočna moč, ki jo oddaja določen vir v preskusnem okolju, se izračuna iz povprečja
kvadratov zvočnega tlaka, ki se izmeri na hipotetični merilni ploskvi, ki obdaja vir, in površine te
ploskve. Zvočna energija za posamezno operacijo stroja se izračuna iz te zvočne moči in časa trajanja
te operacije.
Ta mednarodni standard določa metode podajanja rezultatov, skladno z ISO 12001:1996, razred
točnosti 3 (informativni razred), ko se meritve izvajajo znotraj industrijskih stavb ali na prostem.
Idealno bi bilo, da bi preskušani vir namestili na zvočno odbojno ravnino na prostem. Za vire, ki so
običajno nameščeni na tla strojnih delavnic, se določijo popravki za nezaželene odboje od sosednjih
objektov, sten in stropa ter za preostali hrup ozadja, ki se tam pojavlja.
Metode, opisane v tem mednarodnem standardu, dovoljujejo določanje ravni zvočne moči in zvočne
energije z uporabo frekvenčnega A-vrednotenja.
[5]
V primerih, ko je potrebna večja natančnost, se lahko uporabi ISO 3744, ISO 3745 ali ustrezen del
[14]-[16]
standarda ISO 9614 . Če ustrezna merila za merilno okolje, ki so predpisana s tem mednarodnim
[2]
standardom, niso izpolnjena, potem se je mogoče sklicevati na drugega iz serije ISO 3741 do
[6] [14]-[16]
ISO 3747 ali na ustrezni del standarda ISO 9614 .
6

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SIST EN ISO 3746 : 2011
Akustika – Določanje ravni zvočnih moči in ravni zvočne energije virov hrupa z
zvočnim tlakom – Informativna metoda z merilno ploskvijo, sklenjeno okrog
vira hrupa nad odbojno ravnino
1 Področje uporabe
1.1 Splošno
Ta mednarodni standard opisuje metode za določanje ravni zvočne moči ali ravni zvočne energije vira
hrupa na podlagi ravni zvočnega tlaka, izmerjenih na ploskvi, ki obdaja vir hrupa (stroj ali oprema) v
preskusnem okolju, na katerega se zahteve nanašajo. Z uporabo teh meritev se izračuna raven
zvočne moči (ali v primeru hrupa poka ali prehodnega zvočnega pojava, raven zvočne energije), ki jo
proizvede vir hrupa, z uporabo frekvenčnega A-vrednotenja.
OPOMBA: Različno oblikovane merilne ploskve lahko dajo različne ocene o ravni zvočne moči določenega vira hrupa, zato
ustrezno pripravljeno navodilo za izvajanje meritev (glej ISO 12001) podaja podrobno informacijo o izbiri te
ploskve.
1.2 Vrste hrupa in virov hrupa
Metode, opisane v tem mednarodnem standardu, so primerne za vse vrste hrupa (stabilne, nestabilne,
spremenljive, posamezni izbruhi zvočne energije itn.), kot je opredeljeno v ISO 12001.
Ta mednarodni standard se uporablja za vse vrste in velikosti vira hrupa (npr. stacionarne ali počasi
premikajoče se naprave, inštalacije, stroje, sestavne dele ali podsestave), če se le lahko zagotovijo
pogoji za meritve.
OPOMBA: Pogoji za merjenje, ki so navedeni v tem mednarodnem standardu, so lahko nepraktični za zelo visoke in zelo
dolge vire, kot so dimniki, cevovodi, transporterji in kompleksni industrijski obrati z več virov hrupa. V takih
primerih se lahko v navodilih za določanje emitiranega hrupa specifičnih virov predvidijo alternativne metode.
1.3 Preskusno okolje

Preskusna okolja, ki se uporabljajo za izvajanje meritev v skladu s tem mednarodnim standardom, so
lahko v zaprtih prostorih ali na prostem, z eno ali več zvočno odbojnih ravnin na ali blizu površine, na
katero je preskušani vir nameščen.
1.4 Merilna negotovost

Navede se informacija o negotovosti ravni zvočne moči in ravni zvočne energije, določena v skladu s
tem mednarodnim standardom za opravljene meritve z uporabo frekvenčnega A-vrednotenja.
Negotovost se določa v skladu z ISO 12001:1996, razred točnosti 3 (informativni razred).
2 Zveza s standardi
Za uporabo tega dokumenta so nujno potrebni naslednji referenčni dokumenti. Za datirana sklicevanja
se uporablja samo navedena izdaja. Za nedatirana sklicevanja se uporablja zadnja izdaja navedenega
dokumenta (vključno z vsemi dopolnili).
ISO 3744 Akustika – Ugotavljanje ravni zvočnih moči virov hrupa z merjenjem zvočnega
tlaka – Inženirska metoda v pretežno prostem polju nad odbojno ravnino
ISO 5725 (vsi deli) Točnost (pravilnost in natančnost) merilnih metod in rezultatov
ISO 12001:1996 Akustika – Emisija hrupa naprav in opreme – Pravila za oblikovanje in pripravo
pravil za merjenje hrupa (ISO 12001:1996)
ISO/IEC Vodilo 98-3 Merilna negotovost – 3. del: Vodilo za izražanje merilne negotovosti
(GUM:1995)
IEC 60942:2003 Elektroakustika – Kalibratorji za zvokomere
IEC 61672-1:2002 Elektroakustika – Merilniki zvočne jakosti – 1. del: Specifikacije
7

---------------------- Page: 11 ----------------------

SIST EN ISO 3746 : 2011
3 Izrazi in definicije
Za namene tega dokumenta se uporabljajo naslednje definicije.
3.1
zvočni tlak
p
razlika med trenutnim tlakom in statičnim tlakom
OPOMBA 1: Povzeto po ISO 80000-8:2007[23], 8-9.2.
OPOMBA 2: Zvočni tlak je izražen v paskalih.
3.2
raven zvočnega tlaka
L
p
desetkratni logaritem z osnovo 10 razmerja kvadrata zvočnega tlaka, p, in kvadrata referenčne
vrednosti, p , izraženo v decibelih
0
(1)

kjer je referenčna vrednost, p , 20 µPa
0
[22]
[ISO/TR 25417:2007 , 2.2]
OPOMBA 1: Če se uporabi posebno frekvenčno in časovno vrednotenje, kot je določeno v IEC 61672-1, in/ali posebni
frekvenčni pasovi, je to treba označiti z ustreznimi indeksi; npr. L pomeni A-vrednotena raven zvočnega tlaka.
pA
[23]
OPOMBA 2: Ta definicija je tehnično v skladu z ISO 80000-8:2007 , 8-22.
3.3
časovno povprečena raven zvočnega tlaka
L
p,T
desetkratni logaritem z osnovo 10 razmerja časovno povprečenega kvadrata zvočnega tlaka, p, v
časovnem intervalu T (ki se začne pri t in konča pri t ) in kvadrata referenčne vrednosti, p , izraženo v
1 2 0
decibelih
(2)


kjer je referenčna vrednost, p , 20 µPa
0
OPOMBA 1: V splošnem se indeks "T" opusti, ker se časovno povprečena raven zvočnega tlaka praviloma določa v
določenem časovnem intervalu merjenja.
OPOMBA 2: Časovno povprečene ravni zvočnega tlaka so pogosto A-vrednotene, v tem primeru se označijo z L , oz.
pA,T
običajno skrajšano na L .
pA
OPOMBA 3: Povzeto po ISO/TR 25417:2007 [22], 2.3.
3.4
časovno integrirana raven zvočnega tlaka posameznega dogodka
L
E
desetkratni logaritem z osnovo 10 razmerja integrala kvadrata zvočnega tlaka, p, nekega izoliranega
posameznega zvočnega dogodka (zvok poka ali prehodni zvok) v določenem časovnem intervalu T (ki
se začne pri t in konča pri t ) in referenčne vrednosti, E , izraženo v decibelih
1 2 0
8

---------------------- Page: 12 ----------------------

SIST EN ISO 3746 : 2011
(3)
2 −10 2
kjer je referenčna vrednost, E , (20 µPa) s = 4 ×10 Pa s
0
OPOMBA 1: Ta vrednost se lahko dobi z enačbo , kjer je T = 1 s.
0
OPOMBA 2: Če se ta vrednost uporablja za merjenje zvočne imisije, se običajno imenuje "ekspozicijska zvočna raven" (glej
[22]
ISO/TR 25417:2007 ).
3.5
časovni interval merjenja
T
del ali večkratnik časa obratovanja ali obratovalnega cikla vira hrupa, ki se preskuša, za katerega se
določa časovno povprečena raven zvočnega tlaka
OPOMBA: Časovni interval merjenja je izražen v sekundah.
3.6
odbojna ravnina
zvočno odbojna ravna površina, na kateri je vir hrupa med preskušanjem
3.7
frekvenčno območje, ki nas zanima
frekvenčno območje oktavnih pasov z nominalnimi centralnimi frekvencami od 125 Hz do 8 000 Hz
3.8
referenčni boks
hipotetični pravilni paralelepiped, postavljen na odbojno ravnino(-e), na kateri je preskušani vir hrupa,
ki popolnoma obdaja vir, vključno z vsemi pomembnejšimi komponentami, ki sevajo zvok, in tudi s
preskusno mizo, na kateri je nameščen vir
OPOMBA: Če je potrebno, se lahko uporabi najmanjša možna preskusna miza zaradi združljivosti z meritvami emisije
[18] [21]
zvočnega tlaka na mestu opazovalca skladno z npr. serijo ISO 11201 do ISO 11204 .
3.9
značilna dimenzija vira
d
0
razdalja od izhodišča koordinatnega sistema do najbolj oddaljenega kota referenčnega boksa
OPOMBA: Značilna dimenzija vira je izražena v metrih.
3.10
merilna razdalja
d
razdalja od referenčnega boksa do merilne ploskve na paralelepipedu
OPOMBA: Merilna razdalja je izražena v metrih.
3.11
merilni polmer
r
polmer polkrogle, merilne površine polkrogle ali četrtine polkrogle
OPOMBA: Merilni polmer je izražen v metrih.

9

---------------------- Page: 13 ----------------------

SIST EN ISO 3746 : 2011
3.12
merilna ploskev
hipotetična površina ploskve, S, na kateri so položaji mikrofona za merjenje ravni zvočnega tlaka, ki
obdaja vir preskušanega hrupa in je postavljena na odbojno ravnino(-e), na kateri je nameščen vir
3.13
hrup ozadja
hrup od vseh virov, razen od vira hrupa, ki se preskuša
OPOMBA: Hrup ozadja vključuje prispevke zvoka v zraku, strukturalnega hrupa kot posledice vibracij in električnega hrupa
v instrumentariju.
3.14
popravek hrupa ozadja
K
1
popravek se nanaša na povprečno (energijsko povprečje) časovno povprečene ravni zvočnega tlaka v
vseh položajih mikrofona na merilni ploskvi, s katerim se upošteva vpliv hrupa ozadja
OPOMBA 1: Popravek hrupa ozadja se izraža v decibelih.
.
OPOMBA 2: Popravek hrupa ozadja je frekvenčno odvisen, popravek v primeru A-vrednotenja se označi s K
1A
3.15
okoljski popravek
K
2
popravek se nanaša na povprečje (energijsko povprečje) časovno povprečene ravni zvočnega tlaka v
vseh položajih mikrofona na merilni površini, s katerim se upošteva vpliv odbitega ali absorbiranega
zvoka
OPOMBA 1: Okoljski popravek se izraža v decibelih.
OPOMBA 2: Okoljski popravek je frekvenčno odvisen, popravek v primeru A-vrednotenja se označi s K .
2A
OPOMBA 3: V splošnem je okoljski popravek odvisen od površine merilne ploskve in K se običajno povečuje s S.
2A
3.16
ploskovna časovno povprečena raven zvočnega tlaka
L
p
pomeni povprečje (energijsko povprečje) časovno povprečenih ravni zvočnega tlaka v vseh položajih
mikrofona ali skeniranja po merilni ploskvi s popravki zaradi hrupa ozadja, K , in okoljskega popravka,
1
K
2
OPOMBA: Časovno povprečna raven zvočnega tlaka po merilni ploskvi je izražena v decibelih.
3.17
časovno integrirana raven zvočnega tlaka posameznega dogodka po merilni ploskvi
L
E
pomeni povprečje (energijsko povprečje) časovno integriranih ravni zvočnega tlaka posameznega
dogodka v vseh položajih mikrofona ali skeniranja po merilni ploskvi s popravkom zaradi hrupa ozadja,
K , in okoljskega popravka, K
1 2

OPOMBA: Časovno integrirana raven zvočnega tlaka posameznega dogodka na merilni ploskvi je izražena v decibelih.
3.18
zvočna moč
P
je produkt zvočnega tlaka, p, in komponente hitrosti delcev, u , usmerjene v vsaki točki pravokotno na
n
merilno ploskev, in integrirana po tej ploskvi
[23]
[ISO 80000-8:2007 , 8-16]
OPOMBA 1: Zvočna moč je izražena v vatih.
10

---------------------- Page: 14 ----------------------

SIST EN ISO 3746 : 2011
OPOMBA 2: To je količina energije v enoti časa, v kateri vir oddaja energijo zvoka v zraku.
3.19
raven zvočne moči
L
W
desetkratni logaritem z osnovo 10 razmerja zvočne moči vira, P, in referenčne vrednosti, P , izraženo
0
v decibelih
(4)

kjer je referenčna vrednost, P , 1 pW
0
OPOMBA 1: Če se uporabi posebno frekvenčno vrednotenje, kot je določeno v IEC 61672-1, in/ali posebni frekvenčni
pasovi, potem je to treba označiti z ustreznimi indeksi; npr. L označuje A-vrednoteno raven zvočne moči.
WA
[23]
OPOMBA 2: Ta definicija je tehnično v skladu z ISO 80000-8:2007 , 8-23.
[22]
[ISO/TR 25417:2007 , 2.9]
3.20
zvočna energija
J
integral zvočne moči, P, v določenem časovnem intervalu trajanja T (ki se začne pri t in konča pri t )
1 2
(5)

OPOMBA 1: Zvočna energija je izražena v joulih.
OPOMBA 2: Količina, ki je še posebej pomembna pri nestacionarnih, prekinjajočih zvočnih dogodkih.
[22]
[ISO/TR 25417:2007 , 2.10]
3.21
raven zvočne energije
L
J
je desetkratni logaritem z osnovo 10 razmerja zvočne energije, J, in referenčne vrednosti, J , izraženo
0
v decibelih
(6)

kjer je referenčna vrednost, J , 1 pJ
0
OPOMBA: Če se uporabi posebno frekvenčno vrednotenje, kot je določeno v IEC 61672-1, in/ali posebni frekvenčni
pasovi, je to treba označiti z ustreznimi indeksi; npr. L označuje A-vrednoteno raven zvočne energije.
JA
[22]
[ISO/TR 25417:2007 , 2.11]
4 Preskusno okolje
4.1 Splošno
Preskusna okolja, ki se uporabljajo za meritve v skladu s tem mednarodnim standardom, so prostor ali
ravna površina na prostem, ki je ustrezno izolirana od hrupa v okolju (glej 4.2) in ki izpolnjuje
zahtevane pogoje, podane v 4.3.
Okoljskim razmeram z negativnim vplivom na mikrofone, ki se uporabljajo pri meritvah (npr. močna
električna ali magnetna polja, veter, zadevanje toka zraka od vira hrupa, ki se preskuša, visoke ali
11

---------------------- Page: 15 ----------------------

SIST EN ISO 3746 : 2011
nizke temperature), se je treba izogibati. Glede škodljivosti okoljskih razmer je treba slediti navodilom
proizvajalcev merilnih instrumentov.
Na prostem je treba poskrbeti za minimiziranje negativnih učinkov vremenskih razmer (npr.
temperatura, vlažnost, veter, padavine) na širjenje zvoka in na nastajanje hrupa v frekvenčnem
območju, ki nas zanima, ali na hrup ozadja v času meritev.
Na višinah nad 1500 m je treba ravni zvočne moči in ravni zvočne energije korigirati na referenčne
meteorološke razmere v skladu z ISO 3744.
Če odbojna površina ni ravna podlaga ali ni sestavni del površine preskusnega prostora, je treba
posebej zagotoviti, da ta ravnina ne oddaja nobenega občutnega zvoka zaradi vibracij.
4.2 Kriteriji za hrup ozadja
A-vrednotene ravni zvočnega tlaka zaradi hrupa ozadja, povprečene za vse položaje mikrofona ali
skeniranja po merilni ploskvi, morajo biti vsaj 3 dB pod povprečno ravnjo zvočnega tlaka, ki ga povzroča
preskušani vir hrupa med obratovanjem, če se meri v prisotnosti tega hrupa ozadja (glej 8.3.2).
4.3 Kriterij za akustično ustreznost okoljskega preskusa
Dodatek A določa postopke za določanje velikosti okoljskega popravka, K , s katerim se upošteva
2A
odstopanja preskusnega okolja od idealnih razmer. Meritve so veljavne in v skladu s tem
mednarodnim standardom le, če je K ≤ 7dB.
2A
[6] [14] [15]
OPOMBA 1: Če okoljski popravek K presega 7dB, se lahko uporabljajo ISO 3747 , ISO 9614-1 ali ISO 9614-2 .
2A
OPOMBA 2: V nekaterih posebnih primerih je ravna podlaga preskuševališča le delno odbojna (npr. vrtne kosilnice, nekatere
vrste strojev za zemeljska dela). V takih primerih ustrezna navodila za izvajanje meritev hrupa podrobno
opisujejo naravo ravnine, na kateri je vir nameščen, in nakažejo možne posledice za merilno negotovost.
5 Instrumentarij
5.1 Splošno
Merilni sistemi, ki vključujejo mikrofone, kable in vetrobransko peno, če se uporablja, morajo
izpolnjevati zahteve IEC 61672-1:2002, razred 2.
Instrumenti razreda 2 so primerni za nespremenljivi hrup, čeprav je na splošno priporočljivo uporabljati
instrumente razreda 1.
5.2 Umerjanje
Pred vsako serijo meritev in po njej je treba umeriti vsakega od mikrofonov s pomočjo kalibratorja
zvoka, ki izpolnjuje zahteve IEC 60942:2003, razred 1, z namenom, da se preveri kalibracija celotnega
merilnega sistema pri eni ali več frekvencah v frek
...

SLOVENSKI STANDARD
oSIST prEN ISO 3746:2006
01-februar-2006
$NXVWLND'RORþDQMHUDYQL]YRþQLKPRþLLQ]YRþQHHQHUJLMHYLURYKUXSD]
PHUMHQMHP]YRþQHJDWODND,QIRUPDWLYQDPHWRGD]PHULOQRSORVNYLMRVNOHQMHQR
RNURJYLUDKUXSDQDGRGERMQRUDYQLQR,62',6
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Survey method using an enveloping measurement
surface over a reflecting plane (ISO/DIS 3746:2005)
Akustik - Ermittlung der Schallleistungs- und der Schallenergiepegel von
Geräuschquellen aus Schalldruckmessungen - Hüllflächenverfahren der
Genauigkeitsklasse 3 über einer reflektierenden Ebene (ISO/DIS 3746:2005)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux
d'énergie acoustique a partir de la pression acoustique - Méthode de contrôle employant
une surface de mesure enveloppante au-dessus d'un plan réfléchissant (ISO/DIS
3746:2005)
Ta slovenski standard je istoveten z: prEN ISO 3746
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
oSIST prEN ISO 3746:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD
DRAFT
prEN ISO 3746
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2005
ICS Will supersede EN ISO 3746:1995
English Version
Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure - Survey
method using an enveloping measurement surface over a
reflecting plane (ISO/DIS 3746:2005)
Acoustique - Détermination des niveaux de puissance
acoustique et des niveaux d'énergie acoustique à partir de
la pression acoustique - Méthode de contrôle employant
une surface de mesure enveloppante au-dessus d'un plan
réfléchissant (ISO/DIS 3746:2005)
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, 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
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 3746:2005: E
worldwide for CEN national Members.

---------------------- Page: 2 ----------------------
prEN ISO 3746:2005 (E)




Foreword

This document (prEN ISO 3746:2005) 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 3746:1995.

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 3746:2005 has been approved by CEN as prEN ISO 3746:2005 without any
modifications.

2

---------------------- Page: 3 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 3746
ISO/TC 43/SC 1 Secretariat: DS
Voting begins on: Voting terminates on:
2005-11-24 2006-04-24
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 — Survey
method using an enveloping measurement surface over a
reflecting plane
Acoustique — Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique à partir
de la pression acoustique — Méthode de contrôle employant une surface de mesure enveloppante au-dessus
d'un plan réfléchissant
[Revision of second edition (ISO 3746:1995 and ISO 3746:1995/Cor 1:1995)]
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, 2005

---------------------- Page: 4 ----------------------
ISO/DIS 3746
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ii ISO 2005 – All rights reserved

---------------------- Page: 5 ----------------------
ISO/DIS 3746
Contents Page
Foreword .iv
Introduction.v
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.5
4.1 General .5
4.2 Criterion for background noise.5
4.3 Criterion for acoustic adequacy of test environment.5
5 Instrumentation .6
5.1 General .6
5.2 Calibration.6
6 Definition, location, installation and operation of noise source under test.6
6.1 General .6
6.2 Auxiliary equipment .6
6.3 Noise source location .7
6.4 Installation and mounting conditions .7
6.5 Operation of source during test.7
7 Reference box and measurement surface.8
7.1 Reference box.8
7.2 Measurement surface.8
8 Determination of sound power levels and sound energy levels .11
8.1 Determination of environmental correction.11
8.2 Microphone positions on the measurement surface.11
8.3 Determination of sound power levels .12
8.4 Determination of sound energy levels of a noise .14
9 Measurement uncertainty.15
10 Information to be recorded.16
10.1 General.16
10.2 Noise source under test.17
10.3 Test environment.17
10.4 Instrumentation.17
10.5 Acoustical data.17
11 Information to be reported.18
Annex A (normative) Determination of the environmental correction .19
Annex B (normative) Microphone arrays on a hemispherical measurement surface .21
Annex C (normative) Microphone arrays on a parallelepiped measurement surface .26
Annex D (informative) Guidance on the development of information on measurement uncertainty .31
Bibliography.38

© ISO 2005 – All rights reserved iii

---------------------- Page: 6 ----------------------
ISO/DIS 3746
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
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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 3746 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1.
This third edition cancels and replaces the second edition (ISO 3746:1995), which has been technically
revised.
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ISO/DIS 3746
Introduction
0.1 This International Standard is one of the series ISO 3740 to ISO 3747, that specifies methods to
determine the emitted sound power level and sound energy level of noise sources including machinery,
equipment and their sub-assemblies. Guidelines to select one of those methods are provided in ISO
3740:2001. 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 a survey grade of accuracy (grade 3) as defined in ISO 12001
when performed 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 method specified in this International Standard permits the determination of the sound power level
and the sound energy level with frequency weighting ‘A’ applied.
0.4 For applications where greater accuracy is required, reference can be made to ISO 3744, ISO 3745 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.
0.5 This International Standard cancels and replaces ISO 3746:1995.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 3746

Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure — Survey
method using an enveloping measurement surface over a
reflecting plane
1 Scope
1.1 General
This International Standard specifies methods determining the sound power levels of a noise source from
sound pressure levels measured on a surface enveloping a noise source (machinery or equipment) in a test
environment for which requirements are given. The sound power level (or, in the case of noise bursts or
transient noise emission, the sound energy level) produced by the noise source, 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.
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 with frequency weighting A applied. The
uncertainty conforms with that of the survey grade of accuracy (grade 3) defined in ISO 12001.
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ISO/DIS 3746
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 3744, 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 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 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 International Standard, 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 = 10 lg dB (1)
p
2
p
0
-5
The reference value, p , is 20 µPa (2 × 10 Pa).
0
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, expressed in
decibels
T
 2 
1 p (t)
 
L = 10lg dt dB (2)
p,T
∫
2
T 
p
 0 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
A
p ,T
usually abbreviated to L .
pA
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ISO/DIS 3746
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
reflecting plane
reflecting planar surface on which the noise source under test is located
3.7
frequency range of interest
the range of octave bands with nominal midband frequencies from 125 Hz to 8000 Hz
3.8
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 6.3)
3.9
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
3.10
measurement distance
d
distance from the reference box to a parallelepiped measurement surface, expressed in metres
3.11
measurement radius
r
radius of a hemispherical measurement surface, expressed in metres
3.12
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
3.13
background noise
noise from all sources other than the noise source under test
NOTE Background noise may include contributions from airborne sound, structure-borne vibration, and electrical
noise in the instrumentation.
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ISO/DIS 3746
3.14
background noise correction
K
1
correction applied to the mean (energy-average) of the time-averaged sound pressure levels at all the
microphone positions on the measurement surface, to account for the influence of background noise,
expressed in decibels
NOTE The background noise correction is frequency dependent, and in the case of A-weighting is denoted K .
1A
3.15
environmental correction
K
2
correction applied to the mean (energy-average) of the time-averaged sound pressure levels at all the
microphone positions on the measurement surface, to account for the influence of reflected or absorbed
sound, expressed in decibels
NOTE 1 The environmental correction is frequency dependent, and in the case of A-weighting is denoted K .
2A
NOTE 2 In general, the environmental correction depends on the area of the measurement surface and usually K
2
increases with S.
3.16
surface time-averaged sound pressure level
L
p
mean (energy average) of the time-averaged sound pressure levels at all the microphone positions on the
measurement surface, with the background noise correction, K , and the environmental correction, K , applied,
1 2
expressed in decibels
3.17
surface single-event sound pressure level
L
E
mean (energy average) of the single-event sound pressure levels at all the microphone positions on the
measurement surface, with the background noise correction, K , and the environmental correction, K , applied,
1 2
expressed in decibels
3.18
sound power
W
rate per unit time at which airborne sound energy is radiated by a source, expressed in watts
3.19
sound power level
L
W
ten times the logarithm to the base 10 of the ratio of the sound power of a source, W, to a reference value, W ,
0
expressed in decibels
W
L = 10lg dB (4)
W
W
0
-12
The reference value, W , is 1 pW (10 W).
0
NOTE The frequency weighting is indicated in the symbol, so the A-weighted sound power level is L .
WA
3.20
sound energy
J
energy of a single burst of sound or transient sound emitted by a source, expressed in joules
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ISO/DIS 3746
3.21
sound energy level
L
J
ten times the logarithm to the base 10 of the ratio of the sound energy of a source, J, to a reference value, J ,
0
expressed in decibels
J
L = 10lg dB (5)
J
J
0
-12
The reference value, J , is 1 pJ (10 J).
0
NOTE The frequency weighting is indicated in the symbol, so the A-weighted sound energy level is L .
A
J
4 Test environment
4.1 General
The test environments that are applicable for measurements according to this International Standard are a
room or a flat outdoor area which is adequately isolated from background noise (see 4.2) and which meets the
qualification requirements of 4.3.
Environmental conditions having an adverse effect on the microphones used for the measurements (for
example, strong electric or magnetic fields, wind, impingement of air discharge from the noise source being
tested, high or low temperatures) shall be avoided. The instructions of the manufacturers of the measuring
instrumentation regarding adverse environmental conditions shall be followed.
In an outdoor area, care shall be taken to minimize the effects of adverse meteorological conditions (for
example, temperature, humidity, wind, precipitation) on the sound propagation and on the sound generation
over the frequency range of interest or on the background noise during the course of the measurements.
At altitudes exceeding 1500 m sound power levels and sound energy levels shall be corrected to reference
meteorological conditions according to ISO 3744.
NOTE When a reflecting surface is not a ground plane or is not an integral part of a test room surface, particular care
should be exercised to ensure that the plane does not radiate any appreciable
...