EN ISO 3740:2019

Acoustics - Determination of sound power levels of noise sources - Guidelines for the use of basic standards (ISO 3740:2019)

ISO 3740:2019 gives guidance for the use of a set of twelve basic International Standards (see Tables 1, 2 and 3) describing various methods for determining sound power levels from all types of machinery, equipment and products. It provides guidance on the selection of one or more of these standards, appropriate to any particular type of sound source, measurement environment and desired accuracy. The guidance given applies to airborne sound. It is for use in the preparation of noise test codes (see ISO 12001) and also in noise emission testing where no specific noise test code exists. Such standardized noise test codes can recommend the application of particular basic International Standard(s) and give detailed requirements on mounting and operating conditions for a particular family to which the machine under test belongs, in accordance with general principles given in the basic standards.
ISO 3740:2019 is not intended to replace any of the details of, or add any additional requirements to, the individual test methods in the basic International Standards referenced.
NOTE 1    Two quantities which complement each other can be used to describe the noise emission of machinery, equipment and products. One is the emission sound pressure level at a specified position and the other is the sound power level. The International Standards which describe the basic methods for determining emission sound pressure levels at work stations and at other specified positions are ISO 11200 to ISO 11205 (References [20] to [25]).
NOTE 2    The sound energy level mentioned in ISO 3741 to ISO 3747 is not addressed in this document as it is not mentioned in any legal requirement. Its application is limited to very special cases of a single burst of sound energy or transient sound defined in ISO 12001.

Akustik - Bestimmung der Schallleistungspegel von Geräuschquellen - Leitlinien zur Anwendung der Grundnormen (ISO 3740:2019)

Dieses Dokument gibt Leitlinien für die Verwendung einer Gruppe von zwölf grundlegenden Internationalen Normen (siehe Tabellen 1, 2 und 3), die verschiedene Verfahren zur Bestimmung von Schallleistungspegeln von allen Arten von Maschinen, Geräten und Produkten beschreiben. Sie gibt Leitlinien zur Auswahl einer oder mehrerer dieser Normen, die für eine bestimmte Art von Schallquelle, Messumgebung und gewünschte Genauigkeit geeignet sind. Die Leitlinien gelten für Luftschall. Sie dient zur Verwendung bei der Erstellung von maschinenspezifischen Geräuschmessnormen (siehe ISO 12001) und auch bei Geräuschemissions¬prüfungen, wenn keine maschinenspezifische Geräuschmessnorm existiert. Solche maschinenspezifischen Geräuschmessnormen können die Anwendung bestimmter grundlegender Internationaler Norm(en) empfehlen und detail¬lierte Anforderungen an die Aufstellungs  und Betriebsbedingungen für eine bestimmte Art, zu der die zu überprüfende Maschine gehört, geben, entsprechend den allgemeinen Grundsätzen, die in den Grundnormen angegeben sind.
Dieses Dokument ist weder dafür vorgesehen, die Einzelheiten der einzelnen Prüfverfahren in den zitierten internationalen Grundnormen zu ersetzen, noch zusätzliche Anforderungen hinzuzufügen.
ANMERKUNG 1   Zur Beschreibung der Geräuschemission von Maschinen, Geräten und Produkten können zwei Größen verwendet werden, die sich gegenseitig ergänzen. Die eine Größe ist der Emissions Schalldruckpegel an einem fest¬gelegten Ort, und die andere ist der Schallleistungspegel. Die Internationalen Normen, die die grundlegenden Verfahren zur Bestimmung der Emissions Schalldruckpegel an Arbeitsplätzen und an anderen festgelegten Orten beschreiben, sind ISO 11200 bis ISO 11205. (Literaturhinweise [20] bis [25]).
ANMERKUNG 2   Der in ISO 3741 bis ISO 3747 genannte Schallenergiepegel wird in diesem Dokument nicht behandelt, da er in keiner gesetzlichen Anforderung erwähnt wird. Seine Anwendung beschränkt sich auf ganz besondere Fälle, wie ein einzelner Schallenergieausstoß oder transienter Schall nach ISO 12001.

Acoustique - Détermination des niveaux de puissance acoustique émis par les sources de bruit - Lignes directrices pour l'utilisation des normes de base (ISO 3740:2019)

L'ISO 3740 :2019 donne des lignes directrices concernant l'utilisation d'une série de douze Normes internationales (voir Tableaux 1, 2 et 3) de base décrivant différentes méthodes de détermination des niveaux de puissance acoustique émis par des machines, des équipements et des produits de tous types. Il fournit des recommandations pour le choix de l'une ou de plusieurs de ces normes appropriées à un type donné de source sonore, l'environnement de mesurage et l'exactitude attendue. Les lignes directrices présentées s'appliquent au bruit aérien. Elles sont destinées à la préparation des codes d'essai acoustiques (voir l'ISO 12001) ainsi qu'aux mesurages de l'émission sonore en l'absence de code spécifique d'essai acoustique. De tels codes d'essai acoustiques normalisés peuvent prescrire l'application de certaines Normes internationales de base et fournir des exigences détaillées relatives aux conditions de montage et de fonctionnement de la famille spécifique à laquelle appartient la machine soumise à essai, conformément aux principes généraux figurant dans les normes de base.
L'ISO 3740 :2019 n'a pas pour objet de remplacer des informations données dans les Normes internationales de base auxquelles il est fait référence ou de leur ajouter des exigences.
NOTE 1    On peut utiliser deux grandeurs qui se complètent pour décrire l'émission sonore des machines, des équipements et des produits. L'une de ces grandeurs est le niveau de pression acoustique d'émission à une position spécifiée et l'autre est le niveau de puissance acoustique. Les normes ISO 11200 à ISO 11205 (Références [20] à [25]) sont des Normes internationales qui décrivent les méthodes de base permettant de déterminer les niveaux de pression acoustique d'émission aux postes de travail et à d'autres positions spécifiées.
NOTE 2    Le niveau d'énergie acoustique mentionné dans les normes ISO 3741 à ISO 3747 n'est pas traité dans le présent document, car il n'est mentionné dans aucune exigence réglementaire. Son application est limitée à des cas très particuliers d'impulsion isolée d'énergie acoustique ou de son transitoire définis dans l'ISO 12001).

Akustika - Ugotavljanje ravni zvočnih moči virov hrupa - Smernice za uporabo temeljnih standardov (ISO 3740:2019)

Ta dokument podaja smernice za uporabo dvanajst temeljnih mednarodnih standardov (glej preglednice 1, 2 in 3), ki opisujejo različne metode za ugotavljanje ravni zvočnih moči vseh vrst strojev, opreme in izdelkov. Podaja smernice za izbiro enega ali več standardov, ki ustrezajo kateri koli določeni vrsti vira hrupa, merilnega okolja in želene natančnosti.
Podane smernice veljajo za zvok v zraku. Uporablja se pri pripravljanju oznak preskusa hrupa (glej standard ISO 12001) in tudi pri preskusih emisij hrupa, kadar posebna oznaka preskusa hrupa ne obstaja. Takšne standardizirane oznake preskusa hrupa lahko priporočijo uporabo posebnih temeljnih mednarodnih standardov in podajajo zahteve glede priključitve in delovanja za posamezno vrsto strojev, ki ji pripada preskušani stroj, v skladu s splošnimi načeli, podanimi v temeljnih standardih.
Ta dokument ni namenjen za zamenjavo nobenih podrobnosti ali dodajanje dodatnih zahtev posameznim preskusnim metodam v temeljnih mednarodnih standardih.
OPOMBA 1: Za opis emisije hrupa strojev, opreme in izdelkov je mogoče uporabiti dve količini, ki druga drugo dopolnjujeta. Prva je raven emisije zvočnega tlaka v določenem položaju, druga pa je raven zvočne moči. Mednarodni standardi, ki opisujejo osnovne metode za ugotavljanje ravni emisij zvočnega tlaka v delovnih postajah in drugih določenih položajih, so standardi od ISO 11200 do ISO 11205 (sklici od [20] do [25]).
OPOMBA 2: Raven zvočne energije, omenjena v standardih od ISO 3741 do ISO 3747, ni obravnavana v tem dokumentu, saj ni omenjena v nobeni zakonski zahtevi. Njena uporaba je omejena na zelo posebne primere enega samega izbruha zvočne energije ali prehodnega zvoka, opredeljene v standardu ISO 12001.

General Information

• Status: Published
• Publication Date: 29-Jun-2019
• Withdrawal Date: 29-Sep-2019
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: CEN/TC 211 - Acuostics
• Drafting Committee: CEN/TC 211 - Acuostics
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 27-Mar-2019
• Completion Date: 27-Mar-2019
• 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)
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Ref Project: SIST EN ISO 3740:2019 - Acoustics - Determination of sound power levels of noise sources - Guidelines for the use of basic standards (ISO 3740:2019)

Relations

• Replaces: EN ISO 3740:2000 - Acoustics - Determination of sound power levels of noise sources - Guidelines for the use of basic standards (ISO 3740:2000)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 3740:2019
01-julij-2019
Nadomešča:
SIST EN ISO 3740:2001
Akustika - Ugotavljanje ravni zvočnih moči virov hrupa - Smernice za uporabo
temeljnih standardov (ISO 3740:2019)

Acoustics - Determination of sound power levels of noise sources - Guidelines for the

use of basic standards (ISO 3740:2019)

Akustik - Bestimmung der Schallleistungspegel von Geräuschquellen - Leitlinien zur

Anwendung der Grundnormen (ISO 3740:2019)

Acoustique - Détermination des niveaux de puissance acoustique émis par les sources

de bruit - Lignes directrices pour l'utilisation des normes de base (ISO 3740:2019)

Ta slovenski standard je istoveten z: EN ISO 3740:2019
ICS:
17.140.01 Akustična merjenja in Acoustic measurements and
blaženje hrupa na splošno noise abatement in general
SIST EN ISO 3740:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3740:2019
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SIST EN ISO 3740:2019
EN ISO 3740
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2019
EUROPÄISCHE NORM
ICS 17.140.01 Supersedes EN ISO 3740:2000
English Version
Acoustics - Determination of sound power levels of noise
sources - Guidelines for the use of basic standards (ISO
3740:2019)

Acoustique - Détermination des niveaux de puissance Akustik - Bestimmung der Schallleistungspegel von

acoustique émis par les sources de bruit - Lignes Geräuschquellen - Leitlinien zur Anwendung der

directrices pour l'utilisation des normes de base (ISO Grundnormen (ISO 3740:2019)

3740:2019)
This European Standard was approved by CEN on 8 February 2019.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3740:2019 E

worldwide for CEN national Members.
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SIST EN ISO 3740:2019
EN ISO 3740:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 3740:2019
EN ISO 3740:2019 (E)
European foreword

This document (EN ISO 3740:2019) 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

DIN.

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 September 2019, and conflicting national standards

shall be withdrawn at the latest by September 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 3740:2000.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 3740:2019 has been approved by CEN as EN ISO 3740:2019 without any modification.

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SIST EN ISO 3740:2019
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SIST EN ISO 3740:2019
INTERNATIONAL ISO
STANDARD 3740
Third edition
2019-02
Acoustics — Determination of
sound power levels of noise sources
— Guidelines for the use of basic
standards
Acoustique — Détermination des niveaux de puissance acoustique
émis par les sources de bruit — Lignes directrices pour l'utilisation
des normes de base
Reference number
ISO 3740:2019(E)
ISO 2019
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Sound power level ............................................................................................................................................................................................... 7

4.1 Basic information .................................................................................................................................................................................. 7

4.2 Reasons for the determination of sound power levels ......................................................................................... 7

4.3 Basic procedures for determining sound power levels ....................................................................................... 7

4.4 Quality of determined sound power levels ..................................................................................................................... 8

4.5 Noise emission declaration .......................................................................................................................................................... 8

5 Selection of the most appropriate method in the set of standards .................................................................. 9

5.1 Methods and quantities to be measured and determined................................................................................. 9

5.2 Considerations affecting the selection of a measurement method ............................................................ 9

5.3 Test environment ...............................................................................................................................................................................17

5.4 Selection of basic standards appropriate for measurements in laboratory rooms

and special test rooms ...................................................................................................................................................................17

5.4.1 General...................................................................................................................................................................................17

5.4.2 Acoustical requirements on the sound field in laboratories and special

test rooms ...........................................................................................................................................................................17

5.4.3 Background noise limitation ..............................................................................................................................17

5.5 Selection of basic standards appropriate for in-situ measurements ....................................................18

5.5.1 General...................................................................................................................................................................................18

5.5.2 Hemi-anechoic sound field check ...................................................................................................................19

5.6 Determination of high-frequency sound power levels ......................................................................................20

Annex A (informative) Basic International Standards specifying methods for determining

sound power levels of machines, equipment and products — Main facts and

requirements.........................................................................................................................................................................................................21

Annex B (informative) Acoustical test environments ......................................................................................................................23

Annex C (informative) Measurement uncertainty ...............................................................................................................................25

Annex D (informative) Case studies ...................................................................................................................................................................28

Bibliography .............................................................................................................................................................................................................................34

© ISO 2019 – All rights reserved iii
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SIST EN ISO 3740:2019
ISO 3740:2019(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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.

This third edition cancels and replaces the second edition (ISO 3740:2000), which has been technically

revised. The main change compared to the previous edition is as follows:

— All of the basic standards covered by this document with the exception of the ISO 9614 series

have been revised.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
Introduction

For many users of machinery, equipment and products, the control of noise is a major issue which

requires effective exchange of acoustical information. In this context, the main flow of information goes

from the manufacturer to the purchaser, installer or user of the machines and products to describe the

generated sound. In particular, information on source airborne noise emission is desired. Therefore,

the sound power level, as the major parameter characterising airborne noise emission of sound sources,

needs to be determined by measurement.

However, such measurements are only useful if the conditions under which they are carried out are

specified; they yield defined acoustical quantities, and they are taken with standardized instruments.

Sound power levels are used for
— declaration of the noise emitted under defined conditions,
— verification of declared values,
— comparison of the noise emitted by machinery of various types and sizes,
— comparison with limits specified in a purchasing contract or a regulation,
— engineering work to control the noise emission of machinery,
— prediction of noise exposure of workers in indoor or outdoor work shops,
— prediction of noise in the environment.

International Standards describing basic methods for determining sound power level are

— ISO 3741 to ISO 3747 (sound power level determination using sound pressure level measurements),

— ISO 9614-1 to ISO 9614-3 (sound power level determination using sound intensity measurements),

— ISO/TS 7849-1 and ISO/TS 7849-2 (sound power level determination using vibration measurements).

These standards specify different methods for determination of sound power level and the achievable

accuracy, characterized by the standard deviation of reproducibility of the method. Operating and

mounting conditions, and the uncertainty associated with these conditions, are dealt with only in a

very general manner. Specific and detailed requirements on the machinery or equipment under test

are given in noise test codes prepared by machinery specific standards committees. They not only

provide the necessary detailed information on the operating, installation and mounting conditions but

also identify basic measurement standards that can be used and how a noise emission declaration and

verification is made.

The standards mentioned above differ in their range of applications and their requirements with regard

to the test environment. In practice, procedures that do not require special laboratory environments and

additionally meet class 2 accuracy are particularly advantageous, especially to meet legal requirements.

These include the procedures in standards ISO 3744, ISO 3747 and methods in ISO 9614-2.

To help technical committees in drafting noise test codes or to assist manufacturers of machines and

equipment in determining the sound power level if a noise test code is not currently available, ISO 3740

introduces the set of twelve International Standards describing various methods for determining sound

power levels of machinery, equipment and products taking into account the broad variety of practical

situations for the sources under test (types of machinery, equipment and products), test environments,

measurement instruments and the accuracy desired.

Some machinery, equipment and products emit high-frequency noise, which can be broad-band noise,

narrow-band noise or discrete tones. ISO 9295 specifies four methods for the determination of sound

power levels emitted by machinery, equipment and products in the frequency range covered by the

16 kHz octave band. In 5.6, ISO 9295 is briefly described.
© ISO 2019 – All rights reserved v
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SIST EN ISO 3740:2019
ISO 3740:2019(E)

More detailed definitions than those specified in this document can be found in ISO 3741, ISO 3743-1,

ISO 3743-2, ISO 3744, ISO 3745, ISO 3746 and ISO 3747, in ISO 9614-1 to ISO 9614-3, ISO/TS 7849-1, ISO/

TS 7849-2, and in noise test codes for specific types of machinery, equipment and products.

vi © ISO 2019 – All rights reserved
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SIST EN ISO 3740:2019
INTERNATIONAL STANDARD ISO 3740:2019(E)
Acoustics — Determination of sound power levels of noise
sources — Guidelines for the use of basic standards
1 Scope

This document gives guidance for the use of a set of twelve basic International Standards (see Tables 1,

2 and 3) describing various methods for determining sound power levels from all types of machinery,

equipment and products. It provides guidance on the selection of one or more of these standards,

appropriate to any particular type of sound source, measurement environment and desired accuracy.

The guidance given applies to airborne sound. It is for use in the preparation of noise test codes (see

ISO 12001) and also in noise emission testing where no specific noise test code exists. Such standardized

noise test codes can recommend the application of particular basic International Standard(s) and give

detailed requirements on mounting and operating conditions for a particular family to which the

machine under test belongs, in accordance with general principles given in the basic standards.

This document is not intended to replace any of the details of, or add any additional requirements to,

the individual test methods in the basic International Standards referenced.

NOTE 1 Two quantities which complement each other can be used to describe the noise emission of machinery,

equipment and products. One is the emission sound pressure level at a specified position and the other is the

sound power level. The International Standards which describe the basic methods for determining emission

sound pressure levels at work stations and at other specified positions are ISO 11200 to ISO 11205 (References

[20] to [25]).

NOTE 2 The sound energy level mentioned in ISO 3741 to ISO 3747 is not addressed in this document as it is

not mentioned in any legal requirement. Its application is limited to very special cases of a single burst of sound

energy or transient sound defined in ISO 12001.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
emission

airborne sound radiated by a well-defined noise source (e.g. the machine under test) under

specified operating and mounting conditions

Note 1 to entry: Emission values may be incorporated into a product noise declaration, product label and/or

product specification. The basic noise emission quantities are the sound power level of the source itself and the

emission sound pressure levels at the work station and/or at other specified positions (if any) in the vicinity of

the source.

[SOURCE: ISO 12001:1996, 3.3, modified — Note 1 to entry "product noise declaration" added.]

© ISO 2019 – All rights reserved 1
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
3.2
sound power

through a surface, product of the sound pressure, p, and the component of the particle velocity, u , at a

point on the surface in the direction normal to the surface, integrated over that surface

Note 1 to entry: Sound power is expressed in watts.

Note 2 to entry: The quantity relates to the rate at which airborne sound energy is radiated by a source.

[SOURCE: ISO 80000-8:2007, 8-16, modified — Notes 1 and 2 to entry added.]
3.3
sound power level

ten times the logarithm to the base 10 of the ratio of the sound power, P (3.2), of a source to a reference

value, P , expressed in decibels
L =10lg dB
where the reference value, P , is 1 pW

Note 1 to entry: If a specific frequency weighting 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 power level.

Note 2 to entry: This definition is technically in accordance with ISO 80000-8:2007, 8-23.

Note 3 to entry: lg ( ) = lg ( ) in all relevant parts of the standard.
[SOURCE: ISO/TR 25417:2007, 2.9, modified — Note 3 to entry added.]
3.4
structure vibration generated sound
airborne sound caused by structural vibration in the audible frequency range

Note 1 to entry: In the ISO/TS 7849 series, structure vibration generated sound is determined either from the

vibratory velocity or from the vibratory acceleration of the surface of the solid structure.

[SOURCE: ISO/TS 7849-1:2009, 3.1, modified — Expression "In the ISO/TS 7849 series" used for

clarification instead of "For the purpose of this part of ISO/TS 7849".]
3.5
sound pressure level

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
L =10lg dB
where the reference value, p , is 20 μPa
[SOURCE: ISO/TR 25417:2007, 2.2, modified — Notes 1 and 2 deleted.]
2 © ISO 2019 – All rights reserved
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
3.6
time-averaged sound pressure level
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

1 2
a reference value, p , expressed in decibels
 2 
pt dt
 
L =10lg dB
pT,
 
 
 
where the reference value, p , is 20 μPa

Note 1 to entry: In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily

determined over a certain measurement time interval.

Note 2 to entry: Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by

L , which is usually abbreviated to L .
pA,T pA
Note 3 to entry: Adapted from ISO/TR 25417:2007, 2.3.
[SOURCE: ISO 3744:2010, 3.3]
3.7
single event time-integrated sound pressure level

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 ending at t ), to a reference value, E , expressed in decibels

1 2 0
 
pt dt
 
 
L =10lg dB
 
 
 
2 −10 2
where the reference value, E , is (20 μPa) s = 4 × 10 Pa s
Note 1 to entry: This quantity can be obtained by
 T
L +10lg dB
pT,  
 0 
where T = 1 s.

Note 2 to entry: When used to measure sound immission, this quantity is usually called “sound exposure level”

(see ISO/TR 25417:2007).
[SOURCE: ISO 3744:2010, 3.4]
3.8
sound intensity
Ip=⋅u
where
© ISO 2019 – All rights reserved 3
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
p is the sound pressure, in Pa;
u is the sound particle velocity, in m/s.
Note 1 to entry: u and I are vectorial quantities.
3.9
vibratory velocity

root-mean square (RMS) value of the component of the velocity of a vibrating surface in the direction

normal to the surface

Note 1 to entry: In ISO/TS 7849-1, the vibratory velocity is applied with an A-weighting, denoted v .

[SOURCE: ISO 7849-1:2009, 3.3, modified — Former Note 1 to entry deleted, expression "In ISO/

TS 7849-1" used for clarification instead of "In this part of ISO/TS 7849" in former Note 2, now Note 1.]

3.10
vibratory velocity level

ten times the logarithm to the base 10 of the ratio of the square of the RMS value of the vibratory

velocity, v, to the square of a reference value, v , expressed in decibels:
L =10lg dB
where
v is the RMS value of the vibratory velocity, in metres per second;
v is the reference value for the velocity and is equal to 5 × 10 m/s.

Note 1 to entry: For airborne and structure vibration generated sound, the reference value, v = 50 nm/s has the

−5 −12

property that it leads, together with p = 2 × 10 Pa, to the reference value of the intensity level I = 1 × 10 W/

0 0
m and to a characteristic impedance of air of p /v = 400 Pa·s/m.
0 0

Note 2 to entry: In ISO/TS 7849-1, the vibratory velocity level is applied as A-weighted vibratory velocity level,

2 2

L , by substituting v for the A-weighted RMS v in ISO/TS 7849-1:2009, Formula (6).

vA A

Note 3 to entry: In ISO 1683, two reference values for the velocity level are mentioned: v = 10 m/s and

5 × 10 m/s. The latter is intended for cases of airborne and structure vibration generated sound and is therefore

used in ISO/TS 7849-1 and ISO/TS 7849-2. A choice of v = 10 m/s results in a vibratory velocity level which is

34 dB higher than the level used in both parts of ISO/TS 7849. Therefore, if v = 10 m/s is used, subtract 34 dB

from the right-hand sides of the first formula in 3.10.
3.11
radiation factor

factor expressing the efficiency of airborne sound power (3.2) radiation from the vibrating surface

Note 1 to entry: See ISO/TS 7849-1:2009, 4.4.1 to 4.4.4.
3.12
background noise
noise from all sources other than the noise source under test

Note 1 to entry: Background noise includes contributions from airborne sound, noise from structure-borne

vibration, and electrical noise in the instrumentation.
[SOURCE: ISO 3744:2010, 3.15]
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SIST EN ISO 3740:2019
ISO 3740:2019(E)
3.13
background noise level
sound pressure level (3.5) measured when the source under test is not operating
Note 1 to entry: It is expressed in decibels.
3.14
extraneous vibratory velocity level

vibratory velocity level (3.10) caused by all sources other than the source under test

Note 1 to entry: Extraneous vibratory velocity levels originate, for example, from coupled assemblies.

[SOURCE: ISO/TS 7849-1:2009, 3.9]
3.15
background noise correction

correction applied to the mean (energy average) of the time-averaged sound pressure levels (3.6) over

all the microphone positions on the measurement surface, to account for the influence of background

noise (3.12)
Note 1 to entry: Background noise correction is expressed in decibels.

Note 2 to entry: The background noise correction is frequency dependent; the correction of a frequency band is

denoted K , where f denotes the relevant center frequency, and that in the case of A-weighting is denoted K .

1f 1A
[SOURCE: ISO 3744:2010, 3.16]
3.16
environmental correction

correction applied to the mean (energy average) of the time-averaged sound pressure levels (3.6) over

all microphone positions on the measurement surface, to account for the influence of reflected or

absorbed sound
Note 1 to entry: Environmental correction is expressed in decibels.

Note 2 to entry: The environmental correction is frequency dependent; the correction in the case of a frequency

band is denoted K , where f denotes the
...