SIST EN ISO 3745:2009

Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)

This International Standard specifies methods for measuring the sound pressure levels on a measurement surface enveloping a noise source in anechoic and hemi-anechoic rooms, in order to determine the sound power level or sound energy level produced by the noise source. It gives requirements for the test environment and instrumentation, as well as techniques for obtaining the surface sound pressure level from which the sound power level or sound energy level is calculated, leading to results which have a grade 1 accuracy. The methods specified in this International Standard are suitable for measurements of all types of noise. The noise source can be a device, machine, component or sub-assembly. The maximum size of the source under test depends on the radius of the hypothetical sphere (or hemisphere) used as the enveloping measurement surface.

Akustik - Bestimmung der Schallleistungspegel von Geräuschquellen aus Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme Räume und Halbräume (ISO 3745:2003)

Diese Internationale Norm legt Verfahren zur Messung der Schalldruckpegel auf einer die Geräuschquelle einhüllenden
Messfläche (Hüllfläche) in reflexionsarmen Räumen und Halbräumen fest, um den Schallleistungs- oder
Schallenergiepegel der Geräuschquelle zu bestimmen. Sie enthält Anforderungen an die Prüfumgebung und die
Messgeräte sowie Verfahren zur Ermittlung des Messflächen-Schalldruckpegels, aus dem der Schallleistungsbzw.
Schallenergiepegel berechnet wird. Die Ergebnisse haben die Genauigkeitsklasse 1.
Die in dieser Internationalen Norm festgelegten Verfahren sind für die Messung aller Geräuscharten geeignet.
Die Geräuschquelle kann ein Gerät, eine Maschine, ein Bauteil oder eine Baugruppe sein. Die maximale Größe der
zu untersuchenden Geräuschquelle hängt von dem Radius der gedachten Kugel (oder Halbkugel) ab, die als einhüllende
Messfläche verwendet wird.

Acoustique - Détermination des niveaux de puissance acoustique émis par les sources de bruit à partir de la pression acoustique - Méthodes de laboratoire pour les salles anéchoïques et semi-anéchoïques (ISO 3745:2003)

L'ISO 3745:2003 spécifie des méthodes permettant de mesurer les niveaux de pression acoustique sur une surface de mesurage enveloppant une source de bruit, en salles anéchoïque et semi-anéchoïque, de façon à déterminer le niveau de puissance acoustique ou le niveau d'énergie acoustique produit par la source de bruit. Elle fournit des exigences relatives à l'environnement et à l'instrumentation d'essai, de même que des techniques d'obtention du niveau de pression acoustique surfacique à partir duquel le niveau de puissance acoustique ou le niveau d'énergie acoustique est calculé, menant à des résultats présentant une précision de classe 1.
Les méthodes spécifiées dans l'ISO 3745:2003 s'appliquent aux mesurages de tous types de bruit.
La source de bruit peut être un dispositif, une machine, un composant ou un sous-ensemble. La taille maximale de la source soumise à l'essai dépend du rayon de la sphère fictive (ou de l'hémisphère) utilisée comme surface de mesurage enveloppant la source.

Akustika - Ugotavljanje ravni zvočnih moči virov hrupa - Precizijska metoda za gluhe in polgluhe prostore (ISO 3745:2003)

General Information

• Status: Withdrawn
• Public Enquiry End Date: 09-Jun-2009
• Publication Date: 12-Oct-2009
• Withdrawal Date: 19-Jun-2012
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• ICS: 91.120.20 - Acoustics in building. Sound insulation
• Technical Committee: AKU - Acoustics
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 20-Jun-2012
• Due Date: 13-Jul-2012
• Completion Date: 20-Jun-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: 98/37/EC - Machinery
• Mandate: M/BC/CEN/88/13 - Standardization request to CEN/CENELEC relating to machinery
• Ref Project: EN ISO 3745:2009 - Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)

Relations

• Replaced By: SIST EN ISO 3745:2012 - Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms (ISO 3745:2012)
• Effective Date: 01-Jul-2012
• Replaces: SIST EN ISO 3745:2004 - Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)
• Effective Date: 01-Nov-2009
• Replaces: SIST EN ISO 3745:2004/AC:2006 - Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and hemi-anechoic rooms (ISO 3745:2003)
• Effective Date: 01-Nov-2009
• Replaces: SIST EN ISO 3745:2004 - Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 3745:2009
01-november-2009
1DGRPHãþD
SIST EN ISO 3745:2004
SIST EN ISO 3745:2004/AC:2006
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLYLURYKUXSD3UHFL]LMVNDPHWRGD]D
JOXKHLQSROJOXKHSURVWRUH,62
Acoustics - Determination of sound power levels of noise sources using sound pressure -
Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)
Akustik - Bestimmung der Schallleistungspegel von Geräuschquellen aus
Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme Räume
und Halbräume (ISO 3745:2003)
Acoustique - Détermination des niveaux de puissance acoustique émis par les sources
de bruit à partir de la pression acoustique - Méthodes de laboratoire pour les salles
anéchoïques et semi-anéchoïques (ISO 3745:2003)
Ta slovenski standard je istoveten z: EN ISO 3745:2009
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
91.120.20 $NXVWLNDYVWDYEDK=YRþQD Acoustics in building. Sound
L]RODFLMD insulation
SIST EN ISO 3745:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3745:2009

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SIST EN ISO 3745:2009
EUROPEAN STANDARD
EN ISO 3745
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2009
ICS 17.140.01 Supersedes EN ISO 3745:2003
English Version
Acoustics - Determination of sound power levels of noise
sources using sound pressure - Precision methods for anechoic
and semi-anechoic rooms (ISO 3745:2003)
Acoustique - Détermination des niveaux de puissance Akustik - Bestimmung der Schallleistungspegel von
acoustique émis par les sources de bruit à partir de la Geräuschquellen aus Schalldruckmessungen - Verfahren
pression acoustique - Méthodes de laboratoire pour les der Genauigkeitsklasse 1 für reflexionsarme Räume und
salles anéchoïques et semi-anéchoïques (ISO 3745:2003) Halbräume (ISO 3745:2003)
This European Standard was approved by CEN on 13 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 3745:2009: E
worldwide for CEN national Members.

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SIST EN ISO 3745:2009
EN ISO 3745:2009 (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 3745:2009
EN ISO 3745:2009 (E)
Foreword
The text of ISO 3745:2003 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 3745:2009 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 January 2010, and conflicting national standards shall be withdrawn at
the latest by January 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 3745:2003.
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 3745:2003 has been approved by CEN as a EN ISO 3745:2009 without any modification.
3

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SIST EN ISO 3745:2009
EN ISO 3745:2009 (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 3745:2009
EN ISO 3745:2009 (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 3745:2009

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SIST EN ISO 3745:2009


INTERNATIONAL ISO
STANDARD 3745
Second edition
2003-12-01


Acoustics — Determination of sound
power levels of noise sources using
sound pressure — Precision methods for
anechoic and hemi-anechoic rooms
Acoustique — Détermination des niveaux de puissance acoustique
émis par les sources de bruit à partir de la pression acoustique —
Méthodes de laboratoire pour les salles anéchoïques et semi-
anéchoïques




Reference number
ISO 3745:2003(E)
©
ISO 2003

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
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©  ISO 2003
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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ii © ISO 2003 — All rights reserved

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 2
4 Measurement uncertainty. 5
5 Test room requirements. 6
5.1 General. 6
5.2 Criterion for adequacy of the test room . 7
5.3 Criterion for background noise . 7
5.4 Criterion for temperature. 7
5.5 Humidity correction . 7
6 Instrumentation . 7
6.1 General. 7
6.2 Calibration. 8
7 Installation and operation of source under test.8
7.1 General. 8
7.2 Source location . 8
7.3 Source mounting. 8
7.4 Auxiliary equipment. 9
7.5 Operation of source under test . 9
8 Measurement of sound pressure levels for the determination of sound power level . 10
8.1 General. 10
8.2 Measurement surface . 10
8.3 Microphone positions. 11
8.4 Conditions of measurement. 12
8.5 Data to be obtained. 13
8.6 Correction for background sound pressure levels . 13
8.7 Calculation of surface sound pressure level . 14
9 Measurement of single-event sound pressure levels for the determination of sound
energy level . 15
10 Calculation of sound power level and sound energy level. 16
10.1 Sound power level . 16
10.2 Sound energy level . 17
11 Information to be recorded . 17
11.1 General. 17
11.2 Sound source under test. 18
11.3 Acoustic environment . 18
11.4 Instrumentation . 18
11.5 Acoustic data. 18
12 Information to be reported . 19
Annex A (normative) General procedures for qualification of anechoic and hemi-anechoic rooms . 20
Annex B (normative) Alternative qualification procedure for anechoic and hemi-anechoic rooms
for the determination of sound power levels of specific noise sources. 26
© ISO 2003 — All rights reserved iii

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
Annex C (normative) Array of microphone positions in a free field.28
Annex D (normative) Array of microphone positions in a free field over a reflecting plane .29
Annex E (normative) Coaxial circular paths of microphones in a hemi-free field .31
Annex F (normative) Meridional paths of microphones in a hemi-free field .32
Annex G (normative) Spiral paths of microphones in a hemi-free field.34
Annex H (normative) Calculation of A-weighting sound power level from one-third-octave-band
sound power levels .35
Annex I (normative) Calculation of directivity index and directivity factor .37
Annex J (informative) Measurement uncertainty.38
Annex K (informative) Guidelines for the design of test rooms.41
Bibliography.43

iv © ISO 2003 — All rights reserved

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SIST EN ISO 3745:2009
ISO 3745:2003(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 3745 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This second edition cancels and replaces the first edition (ISO 3745:1977), which has been technically revised.
© ISO 2003 — All rights reserved v

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
Introduction
0.1 This International Standard is one of the ISO 3740 series, which specifies various methods for
determining the sound power levels of machines, equipment and other sub-assemblies. When selecting one
of the methods of the ISO 3740 series, it is necessary to select the most appropriate for the conditions and
purpose of the test. General guidelines to assist in the selection are provided in ISO 12001 and ISO 3740. The
ISO 3740 series gives only general principles regarding the operating and mounting conditions of the source
under test. Reference should be made to the noise test code for a specific type of machine or equipment, if
available, for specifications on mounting and operating conditions.
0.2 This International Standard specifies a laboratory method for determining the sound power radiated by
sources using an anechoic test room or a hemi-anechoic test room having specified acoustical characteristics.
The method specified in this International Standard is only applicable to indoor measurements in specialized
test rooms.
0.3 This International Standard specifies a laboratory method for the determination of not only sound power
levels but also sound energy levels of sound sources. For a single burst of sound energy or transient sound,
the sound power level cannot be defined and so it is necessary to adopt the sound energy level in order to
specify the emitted sound with such a time history. The application of sound energy levels will be considered
in the future revision of other standards of the ISO 3740 series.
0.4 In this International Standard, the sound power level or sound energy level for reference meteorological
conditions is determined. This is required especially for grade 1 measurements.

vi © ISO 2003 — All rights reserved

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SIST EN ISO 3745:2009
INTERNATIONAL STANDARD ISO 3745:2003(E)

Acoustics — Determination of sound power levels of noise
sources using sound pressure — Precision methods for
anechoic and hemi-anechoic rooms
1 Scope
This International Standard specifies methods for measuring the sound pressure levels on a measurement
surface enveloping a noise source in anechoic and hemi-anechoic rooms, in order to determine the sound
power level or sound energy level produced by the noise source. It gives requirements for the test
environment and instrumentation, as well as techniques for obtaining the surface sound pressure level from
which the sound power level or sound energy level is calculated, leading to results which have a grade 1
accuracy.
The methods specified in this International Standard are suitable for measurements of all types of noise.
The noise source can be a device, machine, component or sub-assembly. The maximum size of the source
under test depends on the radius of the hypothetical sphere (or hemisphere) used as the enveloping
measurement surface.
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 7574-1:1985, Acoustics — Statistical methods for determining and verifying stated noise emission values
of machinery and equipment — Part 1: General considerations and definitions
ISO 7574-4:1985, Acoustics — Statistical methods for determining and verifying stated noise emission values
of machinery and equipment — Part 4: Methods for stated values for batches of machines
ISO 9613-1:1993, Acoustics — Attenuation of sound during propagation outdoors — Part 1: Calculation of the
absorption of sound by the atmosphere
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
1)
GUM:1993 , Guide to the expression of uncertainty in measurement. BIPM/IEC/IFCC/ISO/IUPAC/IUPAP/
OIML (ISBN 92-67-10188-9)

1) Corrected and reprinted in 1995.
© ISO 2003 — All rights reserved 1

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
instantaneous sound pressure
p(t)
value at a particular instant in time of the fluctuating pressure that is superimposed on the atmospheric static
pressure due to the presence of a sound wave, and existing at a given point in space, in a stated frequency
band
NOTE It is expressed in pascals.
3.2
sound pressure
p
in space, the root mean square pressure determined over a specified time interval of the instantaneous sound
pressure
NOTE It is expressed in pascals.
3.3
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the time-mean-square of the instantaneous sound
−5
pressure to the square of the reference sound pressure p [p = 20 µPa (2 × 10 Pa)]
0 0
2
p
L = 10 lg dB (1)
p
2
p
0
NOTE 1 Sound pressure levels are expressed in decibels.
NOTE 2 The frequency weighting or the width of the frequency band used and the time weighting should be indicated.
EXAMPLE The A-weighted sound pressure level with time weighting S is L .
pAS
3.3.1
time-averaged sound pressure level
L
peq,T
sound pressure level of a steady or fluctuating sound over the measurement time interval T: ten times the
logarithm to the base 10 of the ratio of the time-mean-square of the instantaneous sound pressure, during a
stated time interval, to the square of the reference sound pressure
T
2

pt
()
1

L = 10 lg dt dB (2)
pTeq,
∫ 2
T
p
0
0

NOTE In general, the subscripts “eq” and “T” are omitted since time-averaged sound pressure levels are necessarily
determined over a certain measurement time interval.
3.3.2
measurement time interval
time interval for which the time-averaged sound pressure level is determined
2 © ISO 2003 — All rights reserved

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
3.4
measurement surface
hypothetical surface of area S, enveloping the source, on which the measurement positions are located
NOTE In the case of a hemi-anechoic room, the measurement surface terminates on the reflecting plane.
3.5
surface sound pressure level
L
pf
energy-average of the time-averaged sound pressure levels at all the microphone positions on the
measurement surface, with the background noise correction K (3.18) applied
1
N

1 0,1 L
pi
L = 10 lg10 dB (3)
pf ∑
N

i=1
where
L is the surface sound pressure level, in decibels;
pf
L is the sound pressure level corrected for background noise resulting from the ith microphone
pi
position, in decibels;
N is the number of microphone positions.
NOTE It is expressed in decibels.
3.6
sound power
W
rate at which airborne sound energy is radiated by a source
NOTE It is expressed in watts.
3.7
sound power level
L
W
ten times the logarithm to the base 10 of the ratio of the sound power radiated by the sound source under test
−12
to the reference sound power W [W = 1 pW (10 W)]
0 0
W
L = 10 lg dB (4)
W
W
0
NOTE 1 It is expressed in decibels.
NOTE 2 The frequency weighting or the width of the frequency band used should be indicated.
3.8
single-event sound pressure level
L
pE
sound pressure level of a single burst of sound or transient sound, given by the formula
t
2
2
pt
()

Lt= 10 lg d dB (5)
pE
∫
2

pT
00
t

1

© ISO 2003 — All rights reserved 3

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
where
p(t) is the instantaneous sound pressure;
p = 20 µPa
0
t − t is a stated time interval long enough to encompass all significant sound of a stated event;

2 1
T = 1 s
0
NOTE 1 It is expressed in decibels.
NOTE 2 Other standards refer to this quantity as “sound exposure level”.
3.9
sound energy
E
sound energy of a single burst of sound or transient sound radiated by the sound source
T
E = Wt()dt (6)
∫
0
NOTE It is expressed in joules.
3.10
sound energy level
L
J
ten times the logarithm to the base 10 of the ratio of the sound energy, E (in joules), radiated by the sound
−12
source under test to the reference sound energy, E [E = 1 pJ (10 J)]
0 0
E
L = 10 lg dB (7)
J
E
0
NOTE 1 It is expressed in decibels.
NOTE 2 The frequency weighting or the width of the frequency band used should be indicated.
3.11
free field
sound field in a homogeneous, isotropic medium, free of boundaries
NOTE In practice, it is a field in which reflections at the boundaries are negligible over the frequency range of interest.
3.12
anechoic room
room in which a free field is obtained
3.13
free field over a reflecting plane
hemi-free field
sound field in a homogeneous, isotropic medium in the half-space above an infinite, rigid plane surface
3.14
hemi-anechoic room
room in which a free field over a reflecting plane is obtained
4 © ISO 2003 — All rights reserved

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SIST EN ISO 3745:2009
ISO 3745:2003(E)
3.15
frequency range of interest
one-third-octave bands having centre frequencies from 100 Hz to 10 000 Hz
NOTE For special purposes, the range may be extended or reduced at either end, provided the test room and
instrument accuracy are satisfactory for use over the extended or reduced frequency range.
3.16
measurement radius
r
radius of a spherical or hemi-spherical measurement surface
3.17
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 instr
...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Akustik - Bestimmung der Schallleistungspegel von Geräuschquellen aus Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme Räume und Halbräume (ISO 3745:2003)Acoustique - Détermination des niveaux de puissance acoustique émis par les sources de bruit à partir de la pression acoustique - Méthodes de laboratoire pour les salles anéchoïques et semi-anéchoïques (ISO 3745:2003)Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for anechoic and semi-anechoic rooms (ISO 3745:2003)17.140.01Acoustic measurements and noise abatement in generalICS:Ta slovenski standard je istoveten z:FprEN ISO 3745kSIST FprEN ISO 3745:2009en01-junij-2009kSIST FprEN ISO 3745:2009SLOVENSKI
STANDARD



kSIST FprEN ISO 3745:2009



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMFINAL DRAFTFprEN ISO 3745March 2009ICS 17.140.01Will supersede EN ISO 3745:2003
English VersionAcoustics - Determination of sound power levels of noisesources using sound pressure - Precision methods for anechoicand semi-anechoic rooms (ISO 3745:2003)Acoustique - Détermination des niveaux de puissanceacoustique émis par les sources de bruit à partir de lapression acoustique - Méthodes de laboratoire pour lessalles anéchoïques et semi-anéchoïques (ISO 3745:2003)Akustik - Bestimmung der Schallleistungspegel vonGeräuschquellen aus Schalldruckmessungen - Verfahrender Genauigkeitsklasse 1 für reflexionsarme Räume undHalbräume (ISO 3745:2003)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 3745:2009: EkSIST FprEN ISO 3745:2009



FprEN ISO 3745:2009 (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 3745:2009



FprEN ISO 3745:2009 (E) 3 Foreword The text of ISO 3745:2003 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 3745:2009 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 3745:2003. 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 3745:2003 has been approved by CEN as a FprEN ISO 3745:2009 without any modification. kSIST FprEN ISO 3745:2009



FprEN ISO 3745:2009 (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 3745:2009



FprEN ISO 3745:2009 (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 3745:2009



kSIST FprEN ISO 3745:2009



Reference numberISO 3745:2003(E)© ISO 2003
INTERNATIONAL STANDARD ISO3745Second edition2003-12-01Acoustics — Determination of sound power levels of noise sources using sound pressure — Precision methods for anechoic and hemi-anechoic rooms Acoustique — Détermination des niveaux de puissance acoustique émis par les sources de bruit à partir de la pression acoustique — Méthodes de laboratoire pour les salles anéchoïques et semi-anéchoïques
kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
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ISO 2003 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 • CH-1211 Geneva 20 Tel.
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ii © ISO 2003 — All rights reserved
kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) © ISO 2003 — All rights reserved iii Contents Page Foreword.v Introduction.vi 1 Scope.1 2 Normative references.1 3 Terms and definitions.2 4 Measurement uncertainty.5 5 Test room requirements.6 5.1 General.6 5.2 Criterion for adequacy of the test room.7 5.3 Criterion for background noise.7 5.4 Criterion for temperature.7 5.5 Humidity correction.7 6 Instrumentation.7 6.1 General.7 6.2 Calibration.8 7 Installation and operation of source under test.8 7.1 General.8 7.2 Source location.8 7.3 Source mounting.8 7.4 Auxiliary equipment.9 7.5 Operation of source under test.9 8 Measurement of sound pressure levels for the determination of sound power level.10 8.1 General.10 8.2 Measurement surface.10 8.3 Microphone positions.11 8.4 Conditions of measurement.12 8.5 Data to be obtained.13 8.6 Correction for background sound pressure levels.13 8.7 Calculation of surface sound pressure level.14 9 Measurement of single-event sound pressure levels for the determination of sound energy level.15 10 Calculation of sound power level and sound energy level.16 10.1 Sound power level.16 10.2 Sound energy level.17 11 Information to be recorded.17 11.1 General.17 11.2 Sound source under test.18 11.3 Acoustic environment.18 11.4 Instrumentation.18 11.5 Acoustic data.18 12 Information to be reported.19 Annex A (normative)
General procedures for qualification of anechoic and
hemi-anechoic rooms.20 Annex B (normative)
Alternative qualification procedure for anechoic and hemi-anechoic rooms for the determination of sound power levels of specific noise sources.26 kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) iv © ISO 2003 — All rights reserved Annex C (normative)
Array of microphone positions in a free field.28 Annex D (normative)
Array of microphone positions in a free field over a reflecting plane.29 Annex E (normative)
Coaxial circular paths of microphones in a hemi-free field.31 Annex F (normative)
Meridional paths of microphones in a hemi-free field.32 Annex G (normative)
Spiral paths of microphones in a hemi-free field.34 Annex H (normative)
Calculation of A-weighting sound power level from one-third-octave-band sound power levels.35 Annex I (normative)
Calculation of directivity index and directivity factor.37 Annex J (informative)
Measurement uncertainty.38 Annex K (informative)
Guidelines for the design of test rooms.41 Bibliography.43
kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) © ISO 2003 — All rights reserved v 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 3745 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. This second edition cancels and replaces the first edition (ISO 3745:1977), which has been technically revised. kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) vi © ISO 2003 — All rights reserved Introduction 0.1 This International Standard is one of the ISO 3740 series, which specifies various methods for determining the sound power levels of machines, equipment and other sub-assemblies. When selecting one of the methods of the ISO 3740 series, it is necessary to select the most appropriate for the conditions and purpose of the test. General guidelines to assist in the selection are provided in ISO 12001 and ISO 3740. The ISO 3740 series gives only general principles regarding the operating and mounting conditions of the source under test. Reference should be made to the noise test code for a specific type of machine or equipment, if available, for specifications on mounting and operating conditions. 0.2 This International Standard specifies a laboratory method for determining the sound power radiated by sources using an anechoic test room or a hemi-anechoic test room having specified acoustical characteristics. The method specified in this International Standard is only applicable to indoor measurements in specialized test rooms. 0.3 This International Standard specifies a laboratory method for the determination of not only sound power levels but also sound energy levels of sound sources. For a single burst of sound energy or transient sound, the sound power level cannot be defined and so it is necessary to adopt the sound energy level in order to specify the emitted sound with such a time history. The application of sound energy levels will be considered in the future revision of other standards of the ISO 3740 series. 0.4 In this International Standard, the sound power level or sound energy level for reference meteorological conditions is determined. This is required especially for grade 1 measurements.
kSIST FprEN ISO 3745:2009



INTERNATIONAL STANDARD ISO 3745:2003(E) © ISO 2003 — All rights reserved 1 Acoustics — Determination of sound power levels of noise sources using sound pressure — Precision methods for anechoic and hemi-anechoic rooms 1 Scope This International Standard specifies methods for measuring the sound pressure levels on a measurement surface enveloping a noise source in anechoic and hemi-anechoic rooms, in order to determine the sound power level or sound energy level produced by the noise source. It gives requirements for the test environment and instrumentation, as well as techniques for obtaining the surface sound pressure level from which the sound power level or sound energy level is calculated, leading to results which have a grade 1 accuracy. The methods specified in this International Standard are suitable for measurements of all types of noise. The noise source can be a device, machine, component or sub-assembly. The maximum size of the source under test depends on the radius of the hypothetical sphere (or hemisphere) used as the enveloping measurement surface. 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 7574-1:1985, Acoustics — Statistical methods for determining and verifying stated noise emission values of machinery and equipment — Part 1: General considerations and definitions ISO 7574-4:1985, Acoustics — Statistical methods for determining and verifying stated noise emission values of machinery and equipment — Part 4: Methods for stated values for batches of machines ISO 9613-1:1993, Acoustics — Attenuation of sound during propagation outdoors — Part 1: Calculation of the absorption of sound by the atmosphere IEC 60942:2003, Electroacoustics — Sound calibrators IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave-band filters IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications GUM:19931), Guide to the expression of uncertainty in measurement. BIPM/IEC/IFCC/ISO/IUPAC/IUPAP/ OIML (ISBN 92-67-10188-9)
1) Corrected and reprinted in 1995. kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) 2 © ISO 2003 — All rights reserved 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 instantaneous sound pressure p(t) value at a particular instant in time of the fluctuating pressure that is superimposed on the atmospheric static pressure due to the presence of a sound wave, and existing at a given point in space, in a stated frequency band NOTE It is expressed in pascals. 3.2 sound pressure p in space, the root mean square pressure determined over a specified time interval of the instantaneous sound pressure NOTE It is expressed in pascals. 3.3 sound pressure level Lp ten times the logarithm to the base 10 of the ratio of the time-mean-square of the instantaneous sound pressure to the square of the reference sound pressure p0 [p0 = 20 µPa (2 × 10−5 Pa)] 22010lgdBppLp= (1) NOTE 1 Sound pressure levels are expressed in decibels. NOTE 2 The frequency weighting or the width of the frequency band used and the time weighting should be indicated. EXAMPLE The A-weighted sound pressure level with time weighting S is LpAS. 3.3.1 time-averaged sound pressure level Lpeq,T sound pressure level of a steady or fluctuating sound over the measurement time interval T: ten times the logarithm to the base 10 of the ratio of the time-mean-square of the instantaneous sound pressure, during a stated time interval, to the square of the reference sound pressure ()2eq,200110lgdTpTptLtTp=∫ dB (2) NOTE In general, the subscripts “eq” and “T” are omitted since time-averaged sound pressure levels are necessarily determined over a certain measurement time interval. 3.3.2 measurement time interval time interval for which the time-averaged sound pressure level is determined kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) © ISO 2003 — All rights reserved 3 3.4 measurement surface hypothetical surface of area S, enveloping the source, on which the measurement positions are located NOTE In the case of a hemi-anechoic room, the measurement surface terminates on the reflecting plane. 3.5 surface sound pressure level fpL energy-average of the time-averaged sound pressure levels at all the microphone positions on the measurement surface, with the background noise correction K1 (3.18) applied 0,1f1110lg10piNLpiLN==∑ dB (3) where fpL is the surface sound pressure level, in decibels; Lpi is the sound pressure level corrected for background noise resulting from the ith microphone position, in decibels; N is the number of microphone positions. NOTE It is expressed in decibels. 3.6 sound power W rate at which airborne sound energy is radiated by a source NOTE It is expressed in watts. 3.7 sound power level LW ten times the logarithm to the base 10 of the ratio of the sound power radiated by the sound source under test to the reference sound power W0 [W0 = 1 pW (10−12 W)] 010lgWWLW= dB (4) NOTE 1 It is expressed in decibels. NOTE 2 The frequency weighting or the width of the frequency band used should be indicated. 3.8 single-event sound pressure level LpE sound pressure level of a single burst of sound or transient sound, given by the formula ()212E20010lgddBtptptLtpT=∫ (5) kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) 4 © ISO 2003 — All rights reserved where p(t) is the instantaneous sound pressure; p0 = 20 µPa t2 − t1 is a stated time interval long enough to encompass all significant sound of a stated event; T0 = 1 s NOTE 1 It is expressed in decibels. NOTE 2 Other standards refer to this quantity as “sound exposure level”. 3.9 sound energy E sound energy of a single burst of sound or transient sound radiated by the sound source 0()dTEWtt=∫ (6) NOTE It is expressed in joules. 3.10 sound energy level LJ ten times the logarithm to the base 10 of the ratio of the sound energy, E (in joules), radiated by the sound source under test to the reference sound energy, E0 [E0 = 1 pJ (10−12 J)] J010lgdBELE= (7) NOTE 1 It is expressed in decibels. NOTE 2 The frequency weighting or the width of the frequency band used should be indicated. 3.11 free field sound field in a homogeneous, isotropic medium, free of boundaries NOTE In practice, it is a field in which reflections at the boundaries are negligible over the frequency range of interest. 3.12 anechoic room room in which a free field is obtained 3.13 free field over a reflecting plane hemi-free field sound field in a homogeneous, isotropic medium in the half-space above an infinite, rigid plane surface 3.14 hemi-anechoic room room in which a free field over a reflecting plane is obtained kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) © ISO 2003 — All rights reserved 5 3.15 frequency range of interest one-third-octave bands having centre frequencies from 100 Hz to 10 000 Hz NOTE For special purposes, the range may be extended or reduced at either end, provided the test room and instrument accuracy are satisfactory for use over the extended or reduced frequency range. 3.16 measurement radius r radius of a spherical or hemi-spherical measurement surface 3.17 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. 3.18 background noise correction K1i correction term to account for the influence of background noise on the measurements at each microphone position NOTE K1i is frequency dependent and is expressed in decibels. 3.19 directivity index DI measure of the extent to which a source radiates sound predominantly in one direction NOTE It is expressed in decibels. 4 Measurement uncertainty If a particular noise source were to be transported to each of a number of different laboratories, and if, at each laboratory, the sound power level of that source were to be determined in accordance with this International Standard, the results would show a scatter. The standard deviation of the measured levels could be calculated (see examples in ISO 7574-4:1985, B.2.1) and would vary with frequency. With few exceptions, these standard deviations would not exceed those listed in Table 1. The values given in Table 1 are standard deviations of reproducibility, σR, as defined in ISO 7574-1. The values of 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 expanded measurement uncertainty of determinations of sound power level or sound energy level, for a coverage probability of 95 % (coverage factor k = 2) as defined in the GUM, shall be taken to be two times the standard deviation of reproducibility, unless more specific knowledge is available (e.g. in the laboratory undertaking the measurements or in a noise test code for the particular family of noise sources). kSIST FprEN ISO 3745:2009



ISO 3745:2003(E) 6 © ISO 2003 — All rights reserved Table 1 — Estimated upper values of the standard deviations of reproducibility of sound power levels and sound energy levels determined in accordance with this International Standard Upper values of standard deviation of reproducibility, σR dB One-third-octave midband frequency Hz Anechoic room Hemi-anechoic room 50 to 80a 2,0 2,0 100 to 630 1,0 1,5 800 to 5 000 0,5 1,0 6 300 to 10 000 1,0 1,5 12 500 to 20 000b 2,0 2,0 A-weighted 0,5 0,5 a If the sound field is qualified according to Clause 5. b If the instrumentation allows and if correction is made for absorption of sound by the atmosphere.
NOTE 1 The standard deviations listed in Table 1 are associated with the test conditions and procedures defined in this International Standard and not with the noise source itself. They arise in part fro
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