ISO 13347-4

Fans — Determination of fan sound power levels under standardized laboratory conditions — Part 4: Sound intensity method

ISO 13347-4:2004 applies to industrial fans as defined in ISO 5801 and ISO 13349. It is limited to the determination of airborne sound emission for the specified set-ups. Vibration is not measured, nor is the sensitivity of airborne sound emission to vibration effects determined. The sizes of the fan, which can be tested in accordance with ISO 13347-4:2004, are limited only by the practical aspects of the test installations. ISO 13347-4:2004 determines sound power by using sound intensity measurements on a measurement surface which encloses the sound source. It provides guidelines on the acoustical environment, ambient noise, measurement surface, and number of measurements. The test set-ups are generally designed to represent the physical orientation of a fan installed in accordance with ISO 5801 and also used in ISO 13347-2.

Ventilateurs industriels — Détermination des niveaux de puissance acoustique des ventilateurs dans des conditions de laboratoire standardisées — Partie 4: Méthode de l'intensité acoustique

L'ISO 13347-4:2004 est applicable aux ventilateurs industriels tels que définis dans l'ISO 5801 et l'ISO 13349. Elle se limite à la détermination de l'émission de son aérien pour les installations spécifiées. Les vibrations ne sont pas mesurées et la sensibilité de l'émission de son aérien aux effets des vibrations n'est pas déterminée. La taille du ventilateur qu'il est possible de soumettre à l'essai conformément à l'ISO 13347-4:2004 est uniquement limitée par les aspects pratiques des installations d'essai. L'ISO 13347-4:2004 fournit une détermination de la puissance acoustique au moyen de mesurages de l'intensité acoustique, sur une surface de mesurage qui enveloppe la source sonore. Elle fournit également des principes directeurs relatifs à l'environnement acoustique, au bruit ambiant, à la surface de mesurage et au nombre de mesurages. Les installations d'essai sont généralement conçues de façon à représenter l'orientation physique réelle d'un ventilateur conformément à l'ISO 5801 ainsi qu'à l'ISO 13347-2.

General Information

• Status: Not Published
• ICS: 17.140.20 - Noise emitted by machines and equipment
• ICS: 23.120 - Ventilators. Fans. Air-conditioners
• Technical Committee: ISO/TC 117 - Fans
• Drafting Committee: ISO/TC 117/WG 13 - Jet fans
• Current Stage: 6000 - International Standard under publication
• Start Date: 14-Jun-2025
• Completion Date: 14-Jun-2025

Relations

• Revises: ISO 13347-4:2004 - Industrial fans — Determination of fan sound power levels under standardized laboratory conditions — Part 4: Sound intensity method
• Effective Date: 23-Sep-2023

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/FDIS 13347-4
ISO/TC 117
Fans — Determination of fan sound
Secretariat: BSI
power levels under standardized
Voting begins on:
laboratory conditions —
2025-04-18
Part 4:
Voting terminates on:
2025-06-13
Sound intensity method
Ventilateurs — Détermination des niveaux de puissance
acoustique des ventilateurs dans des conditions de laboratoire
normalisées —
Partie 4: Méthode de l'intensité acoustique
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 13347-4:2025(en) © ISO 2025

FINAL DRAFT
ISO/FDIS 13347-4:2025(en)
International
Standard
ISO/FDIS 13347-4
ISO/TC 117
Fans — Determination of fan sound
Secretariat: BSI
power levels under standardized
Voting begins on:
laboratory conditions —
Part 4:
Voting terminates on:
Sound intensity method
Ventilateurs — Détermination des niveaux de puissance
acoustique des ventilateurs dans des conditions de laboratoire
normalisées —
Partie 4: Méthode de l'intensité acoustique
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 SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 13347-4:2025(en) © ISO 2025

ii
ISO/FDIS 13347-4:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and Definitions, symbols and units . 2
3.1 Terms and definitions .2
3.2 Symbols — Fan sound power levels .3
3.3 Other symbols .3
4 Instruments and methods of test . 4
4.1 General .4
4.2 Reference sound source (RSS) . .5
4.3 Calibration and field check .5
4.4 Performance verification .6
4.5 Test method .6
5 Equipment and installation categories . 6
5.1 Test environment .6
5.1.1 Background noise .6
5.1.2 Nearby reflecting surfaces .7
5.1.3 Reverberation control . . .7
5.2 Fan installation .7
5.2.1 Installation categories . . .7
5.2.2 Aerodynamic performance .8
5.2.3 Mounting methods .8
5.2.4 Duct length .8
5.2.5 Fan total sound testing (installation category E) .9
5.2.6 Fan inlet total sound testing .11
5.2.7 Fan outlet total sound testing .14
5.2.8 Fan casing-radiated sound testing . 15
5.3 Measurement surface . 15
5.4 Reference sound source (RSS) . .18
6 Test method .18
6.1 General .18
6.2 Sampling of sound on the measurement surface .18
6.3 Number of measurements .19
6.4 Observations .19
6.4.1 Point of operation .19
6.4.2 Background sound level .19
6.4.3 Sound intensity .19
6.4.4 Field indicators and qualification requirements . 20
6.4.5 Test conditions . 20
6.4.6 Information to be recorded . 20
7 Calculations .22
7.1 Surface average level . 22
7.2 Reference sound source adjustment, R . 23
W
7.3 Sound power level, L . 23
W
8 Report and results.24
8.1 Uncertainty of results .24
8.2 Presentation of results .24
8.3 Results . .24
8.4 Minimum information to be reported .24
Annex A (informative) Indicators for use in case of difficulty .26

iii
ISO/FDIS 13347-4:2025(en)
Annex B (normative) Alternative procedure for testing of large fan equipment .27
Annex C (normative) Radiation of sound by fan casing .28
Bibliography .30

iv
ISO/FDIS 13347-4:2025(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may invol
...

INTERNATIONAL STANDARD
Style Definition
...
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ISO/DISFDIS 13347-4:2024(en)
Section start: New page, Width: 21 cm, Height: 29.7
cm, Header distance from edge: 1.27 cm, Footer
ISO/TC 117
distance from edge: 1.27 cm
Formatted: English (United Kingdom)
Secretariat: BSI
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First edition
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Formatted: English (United Kingdom)
2024-07-18
Date: 2025-04-02
Fans — Determination of fan sound power levels under standardized
laboratory conditions —
Formatted: Regular, French (Switzerland)
Part 4:
Formatted: Cover Title_A2
Sound intensity method
Formatted: French (Switzerland)
Ventilateurs industriels — Détermination des niveaux de puissance acoustique des ventilateurs dans des
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conditions de laboratoire normalisées —
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Partie 4: Méthode par intensité acoustique
and Asian text, Adjust space between Asian text and
numbers
Partie 4: Méthode de l'intensité acoustique
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FDIS stage
ISO/DIS 13347-4:2024(en)
DRAFT International Standard
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
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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: + 41 22 749 01 11
Formatted: French (Switzerland)
EmailE-mail: [e-mail]
Formatted: French (Switzerland)
Website: www.iso.orgwww.iso.org
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Published in Switzerland
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ISO/DISFDIS 13347-4:20242025(en)
Formatted: Font: Bold, English (United Kingdom)
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Formatted: HeaderCentered, Left
Contents Page
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Formatted: Font: Bold
Foreword . iv
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Introduction . vi
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1 Scope . 1
stops: Not at 0.71 cm + 17.2 cm
2 Normative references . 1
3 Terms and Definitions, symbols and units . 2
4 Instruments and methods of test . 5
5 Equipment and installation categories . 7
6 Test method . 22
7 Calculations . 26
8 Report and results . 28
Annex A (informative) Indicators for use in case of difficulty . 31
Annex B (normative) Alternative procedure for testing of large fan equipment . 32
Annex C (normative) Radiation of sound by fan casing . 33
Bibliography . 35

1 Scope . 1
2 Normative references . 1
3 Definitions, symbols and units . 2
4 Instruments and methods of test . 5
5 Equipment and installation categories . 7
6 Test method . 18
7 Calculations . 22
8 Report and results . 24
Annex A (normative) Indicators for use in case of difficulty . 26
Annex B (normative) Alternative procedure for testing of large fan equipment . 27
Annex C (normative) Radiation of sound by fan casing . 28

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iii
ISO/FDIS 13347-4:2025(en)
Formatted: HeaderCentered
Formatted: Font: Bold
Foreword Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
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 document 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).
Formatted: English (United Kingdom)
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 117, Fans.
This fourth edition cancels and replaces the third edition (ISO 13347-4:2004), which has been technically
Formatted: English (United Kingdom)
revised. It also incorporates the Technical Corrigendum ISO 13347-4:2004/Cor 1:2006.
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The main changes are as follows:
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— — the inclusion of acoustic methods for installation category E fans;
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— — symbols have been harmonized with those used in ISO 5801 and other ISO standards as listed in
Normativeas normative references [2][2];
— — closer alignment with the superordinate ISO 9614 series relating to sound intensity measurement;
— — editorial corrections have been incorporatedrevisions.
A list of all parts in the ISO 13347 series can be found on the ISO website.
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ICS 17.140.20; 23.120
Price based on 25 pages
iv
ISO/DISFDIS 13347-4:20242025(en)
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Formatted: HeaderCentered, Left
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Any feedback or questions on this document should be directed to the user’s national standards body. A
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complete listing of these bodies can be found at www.iso.org/members.html.
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Field Code Changed
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v
ISO/FDIS 13347-4:2025(en)
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Introduction
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This document establishes a method for determining the sound power level of a fan. The method is
reproducible in all laboratories which are qualified according to the requirements of this document.
The method specified in this document employs standard sound measurement instrumentation. The test set-
ups are generally designed to represent the physical orientation of a fan as installed, in accordance with
ISO 5801 or ISO 13350.
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Since sound power levels are considered independent of the acoustic environment around the fan, a good
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comparison can be made between two or more fans proposed for any specific air performance condition.
Moreover, these values establish an accurate base for estimating the acoustical outcome of the fan installation
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in terms of sound pressure levels. A successful estimate of sound pressure levels requires extensive
information on the fan and the environment in which it is to be located.
It is often advantageous for the equipment user to employ acoustical consultation to ensure that all factors
which affect the final sound pressure levels are considered. More detailed information on the complexity of
this situation may be found in acoustic textbooks.
This document has been developed in response to the need for a reliable and accurate enveloping surface
method for determining the sound power levels of fan equipment. Where possible, it has been based on
existing National standards and combines state-of-the-art with practical considerations.
NOTE: The Bibliography of this document hasbibliography contains further references for those wishing to explore
this subject in greater detail [1](see References [1] to [7].[7]).
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ICS 17.140.20; 23.120
Price based on 25 pages
vi
ISO/DIS 13347-4:2024(en)
DRAFT International Standard
Fans — Determination of fan sound power levels under standardized
laboratory conditions —
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Part 4: Adjust space between Asian text and numbers
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Sound intensity method
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Fans — Determination of fan sound power levels under standardized
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laboratory conditions —
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Part 4:
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Sound intensity method
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1 Scope
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This document specifies a method to measure sound power by using sound intensity measurements on a
measurement surface which encloses the sound source. ItThis document provides guidelines on the acoustical Formatted: Default Paragraph Font
environment, ambient noise, measurement surface, and number of measurements. The installation categories
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are generally designed to represent the physical orientation of a fan installed in accordance with ISO 5801,
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ISO 13350 and also defined in ISO 13349-1.
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This document appliesis applicable to fans as defined in ISO 5801 and ISO 13349-1. ItThis document is limited Adjust space between Asian text and numbers, Tab
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
to the determination of airborne sound emission for the specified installation categories. Vibration is not
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
measured, nor is the sensitivity of airborne sound emission to vibration effects determined.
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The sizes of the fan, which can be tested in accordance with this document are limited only by the practical
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...

PROJET FINAL
Norme
internationale
ISO/FDIS 13347-4
ISO/TC 117
Ventilateurs industriels —
Secrétariat: BSI
Détermination des niveaux
Début de vote:
de puissance acoustique des
2025-04-18
ventilateurs dans des conditions de
Vote clos le:
laboratoire standardisées —
2025-06-13
Partie 4:
Méthode de l'intensité acoustique
Fans — Determination of fan sound power levels under
standardized laboratory conditions —
Part 4: Sound intensity method
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
Numéro de référence
ISO/FDIS 13347-4:2025(fr) © ISO 2025

PROJET FINAL
ISO/FDIS 13347-4:2025(fr)
Norme
internationale
ISO/FDIS 13347-4
ISO/TC 117
Ventilateurs industriels —
Secrétariat: BSI
Détermination des niveaux
Début de vote:
de puissance acoustique des
2025-04-18
ventilateurs dans des conditions de
Vote clos le:
laboratoire standardisées —
2025-06-13
Partie 4:
Méthode de l'intensité acoustique
Fans — Determination of fan sound power levels under
standardized laboratory conditions —
Part 4: Sound intensity method
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSERVATIONS,
NOTIFICATION DES DROITS DE PROPRIÉTÉ DONT ILS
AURAIENT ÉVENTUELLEMENT CONNAISSANCE ET À
FOURNIR UNE DOCUMENTATION EXPLICATIVE.
DOCUMENT PROTÉGÉ PAR COPYRIGHT
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
© ISO 2025 INDUSTRIELLES, TECHNOLOGIQUES ET COM-MERCIALES,
AINSI QUE DU POINT DE VUE DES UTILISATEURS, LES
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE CONSIDÉRÉS
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
DU POINT DE VUE DE LEUR POSSI BILITÉ DE DEVENIR DES
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
NORMES POUVANT
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTATION
NATIONALE.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse Numéro de référence
ISO/FDIS 13347-4:2025(fr) © ISO 2025

ii
ISO/FDIS 13347-4:2025(fr)
Sommaire Page
Avant-propos .v
Introduction .vi
1 Domaine d'application . 1
2 Références normatives . 1
3 Termes et définitions, symboles et unités . 2
3.1 Termes et définitions .2
3.2 Symboles — Niveaux de puissance acoustique du ventilateur .3
3.3 Autres symboles .4
4 Appareillage et méthodes d'essai . 5
4.1 Généralités .5
4.2 Source sonore de référence (RSS) .5
4.3 Étalonnage et contrôle sur site .5
4.4 Vérification des performances .6
4.5 Méthode d'essai .6
5 Équipement et catégories d'installation . . 7
5.1 Environnement d'essai .7
5.1.1 Bruit de fond .7
5.1.2 Surfaces réfléchissantes avoisinantes .7
5.1.3 Contrôle de la réverbération .7
5.2 Installation du ventilateur .8
5.2.1 Catégories d'installation . .8
5.2.2 Essai aérodynamique .8
5.2.3 Méthodes de montage .9
5.2.4 Longueur du conduit .9
5.2.5 Essai acoustique global du ventilateur (catégorie d'installation E) .10
5.2.6 Essai acoustique total de l'aspiration du ventilateur . 12
5.2.7 Essai acoustique total du refoulement du ventilateur .14
5.2.8 Essai de son rayonné par l'enveloppe du ventilateur .16
5.3 Surface de mesure .16
5.4 Source sonore de référence (RSS) .18
6 Méthode d'essai .18
6.1 Généralités .18
6.2 Échantillonnage du son sur la surface de mesure .18
6.3 Nombre de mesurages .19
6.4 Observations .19
6.4.1 Point de fonctionnement .19
6.4.2 Niveau de bruit de fond. 20
6.4.3 Intensité acoustique . 20
6.4.4 Indicateurs de champ et exigences de qualification . 20
6.4.5 Conditions d'essai . 20
6.4.6 Informations à enregistrer .21
7 Calculs .23
7.1 Niveau moyen surfacique . 23
7.2 Ajustement de la source sonore de référence,R .24
W
7.3 Niveau de puissance acoustique, L .24
W
8 Rapport et résultats .25
8.1 Incertitude des résultats . 25
8.2 Présentation des résultats . 25
8.3 Résultats . 25
8.4 Informations minimales à consigner . 25
Annexe A (informative) Indicateurs à utiliser en cas de problème .27

iii
ISO/FDIS 13347-4:2025(fr)
Annexe B (normative) Mode opératoire de remplacement pour l'essai de systèmes de
ventilateurs de grande taille .28
Annexe C (normative) Son rayonné par l'enveloppe du ventilateur .30
Bibliographie .32

iv
ISO/FDIS 13347-4:2025(fr)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux
de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général
confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude a le droit de faire
partie du comité technique créé à cet effet. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec
la Commission électrotechnique internationale (IEC) en ce qui concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a
été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir
www.i
...