ISO/TS 19425:2024

Reciprocating internal combustion engines — Measurement method for air cleaners — Sound power level of combustion air inlet noise and insertion loss using sound pressure

This document specifies the measurement method and requirements for combustion air inlet noise of air cleaners which are installed on reciprocating internal combustion engines, including laboratory measurement (engineering method and survey method) and site measurement (survey method). This document applies to all air cleaners installed on reciprocating internal combustion engines (reciprocating internal combustion engine is referred to as engine hereafter, except for specific explanations) falling within the field of application of ISO 3046-1 and/or other air induction installation.

Moteurs alternatifs à combustion interne — Méthode de mesure du bruit des purificateurs d'air — Niveau de puissance sonore du bruit d'entrée d'air de combustion et de perte d'insertion utilisant une pression sonore

General Information

• Status: Published
• Publication Date: 04-Jul-2024
• ICS: 27.020 - Internal combustion engines
• Technical Committee: ISO/TC 70 - Internal combustion engines
• Drafting Committee: ISO/TC 70 - Internal combustion engines
• Current Stage: 6060 - International Standard published
• Start Date: 05-Jul-2024
• Due Date: 31-Oct-2024
• Completion Date: 05-Jul-2024

Relations

• Revises: ISO/TS 19425:2015 - Reciprocating internal combustion engines — Measurement method for air cleaners — Sound power level of combustion air inlet noise and insertion loss using sound pressure
• Effective Date: 05-Nov-2022

Standards Content (Sample)

Technical
Specification
ISO/TS 19425
Second edition
Reciprocating internal combustion
2024-07
engines — Measurement method
for air cleaners — Sound power
level of combustion air inlet noise
and insertion loss using sound
pressure
Moteurs alternatifs à combustion interne — Méthode de mesure
du bruit des purificateurs d'air — Niveau de puissance sonore du
bruit d'entrée d'air de combustion et de perte d'insertion utilisant
une pression sonore
Reference number
© ISO 2024
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test environment . 5
4.1 General .5
4.2 Criterion for background noise.5
4.3 Criterion for acoustic adequacy of test environment .6
5 Instrumentation . 6
5.1 General .6
5.2 Calibration .6
5.3 Application .7
6 Installation and operation conditions . 7
6.1 General .7
6.2 Installation condition .7
6.3 Operation condition .8
7 Measurement . 9
7.1 General .9
7.2 Measurement uncertainty .9
7.3 Characteristic source dimension .10
7.4 Measurement radius .10
7.5 Measurement surface and area .10
7.6 Microphone arrays .10
8 Calculation .12
8.1 General . 12
8.2 Calculation of sound power level. 12
8.2.1 Mean time-averaged sound pressure levels . 12
8.2.2 Corrections for background noise . 13
8.2.3 Corrections for environmental . 13
8.2.4 Surface time-averaged sound pressure levels .14
8.2.5 Sound power levels .14
8.3 Calculation of insertion loss .14
9 Information to be recorded .15
10 Test report .16
Annex A (normative) Qualification procedures for the acoustic environment . 17
Annex B (normative) Calculation of A-weighted sound power levels from frequency band levels .20
Annex C (normative) Sound power level under reference meteorological conditions .22
Bibliography .23

iii
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 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. 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.html.
This document was prepared by Technical Committee ISO/TC 70, Air-borne noise.
This second edition cancels and replaces the first edition (ISO 19425:2015), which has been technically
revised.
The main changes are as follows:
— the terms and definitions have been revised and sources have been added (see Clause 3);
— the criterion for background noise has been changed (see 4.2);
— the application has been changed (see 5.3);
— the installation condition has been changed (see 6.2);
— the operation condition has been changed (see 6.3);
— the measurement radius has been changed (see 7.4).
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
Technical Specification ISO/TS 19425:2024(en)
Reciprocating internal combustion engines — Measurement
method for air cleaners — Sound power level of combustion
air inlet noise and insertion loss using sound pressure
1 Scope
This document specifies the measurement method and requirements for combustion air inlet noise of
air cleaners which are installed on reciprocating internal combustion engines, including laboratory
measurement (engineering method and survey method) and site measurement (survey method).
This document applies to all air cleaners installed on reciprocating internal combustion engines
(reciprocating internal combustion engine is referred to as engine hereafter, except for specific explanations)
falling within the field of application of ISO 3046-1 and/or other air induction installation.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 3046-1, Reciprocating internal combustion engines — Performance — Part 1: Declarations of power, fuel
and lubricating oil consumptions, and test methods — Additional requirements for engines for general use
ISO 3046-3, Reciprocating internal combustion engines — Performance — Part 3: Test measurements
ISO 6926, Acoustics — Requirements for the performance and calibration of reference sound sources used for
the determination of sound power levels
IEC 60942, Electroacoustics — Sound calibrators
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1, Electroacoustics — Sound level meters—Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in ISO 3046-1, ISO 3046-3, ISO 6926,
IEC 60942, IEC 61260 and IEC 61672-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
sound pressure
p
difference between instantaneous pressure and static pressure
Note 1 to entry: It is expressed in pascals.
[SOURCE: ISO 80000-8:2007, 8-9.2]

3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure (3.1), p, to the square of
a reference value, p
p
L =10lg
p
p
where the reference value, p , is 20 μPa
Note 1 to entry: If specific frequency and time weightings, as specified in IEC
...

FINAL DRAFT
Technical
Specification
ISO/DTS 19425
ISO/TC 70
Reciprocating internal combustion
Secretariat: SAC
engines — Measurement method
Voting begins on:
for air cleaners — Sound power
2024-04-11
level of combustion air inlet noise
Voting terminates on:
and insertion loss using sound
2024-06-06
pressure
Moteurs alternatifs à combustion interne — Méthode de mesure
du bruit des purificateurs d'air — Niveau de puissance sonore du
bruit d'entrée d'air de combustion et de perte d'insertion utilisant
une pression sonore
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/DTS 19425:2024(en) © ISO 2024

FINAL DRAFT
ISO/DTS 19425:2024(en)
Technical
Specification
ISO/DTS 19425
ISO/TC 70
Reciprocating internal combustion
Secretariat: SAC
engines — Measurement method
Voting begins on:
for air cleaners — Sound power
level of combustion air inlet noise
Voting terminates on:
and insertion loss using sound
pressure
Moteurs alternatifs à combustion interne — Méthode de mesure
du bruit des purificateurs d'air — Niveau de puissance sonore du
bruit d'entrée d'air de combustion et de perte d'insertion utilisant
une pression sonore
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 2024
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/DTS 19425:2024(en) © ISO 2024

ii
ISO/DTS 19425:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test environment . 5
4.1 General .5
4.2 Criterion for background noise.5
4.3 Criterion for acoustic adequacy of test environment .6
5 Instrumentation . 6
5.1 General .6
5.2 Calibration .6
5.3 Application .7
6 Installation and operation conditions . 7
6.1 General .7
6.2 Installation condition .7
6.3 Operation condition .8
7 Measurement . 9
7.1 General .9
7.2 Measurement uncertainty .9
7.3 Characteristic source dimension .10
7.4 Measurement radius .10
7.5 Measurement surface and area .10
7.6 Microphone arrays .10
8 Calculation .12
8.1 General . 12
8.2 Calculation of sound power level. 12
8.2.1 Mean time-averaged sound pressure levels . 12
8.2.2 Corrections for background noise . 13
8.2.3 Corrections for environmental . 13
8.2.4 Surface time-averaged sound pressure levels .14
8.2.5 Sound power levels .14
8.3 Calculation of insertion loss .14
9 Information to be recorded .15
10 Test report .16
Annex A (normative) Qualification procedures for the acoustic environment . 17
Annex B (normative) Calculation of A-weighted sound power levels from frequency band levels .20
Annex C (normative) Sound power level under reference meteorological conditions .22
Bibliography .23

iii
ISO/DTS 19425:2024(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 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. 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.html.
This document was prepared by Technical Committee ISO/TC 70, Air-borne noise.
This second edition cancels and replaces the first edition (ISO 19425:2015), which has been technically
revised.
The main changes are as follows:
— the terms and definitions have been revised and sources have been added (see Clause 3);
— the criterion for background noise has been changed (see 4.2);
— the application has been changed (see 5.3);
— the installation condition has been changed (see 6.2);
— the operation condition has been changed (see 6.3);
— the measurement radius has been changed (see 7.4).
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
FINAL DRAFT Technical Specification ISO/DTS 19425:2024(en)
Reciprocating internal combustion engines — Measurement
method for air cleaners — Sound power level of combustion
air inlet noise and insertion loss using sound pressure
1 Scope
This document specifies the measurement method and requirements for combustion air inlet noise of
air cleaners which are installed on reciprocating internal combustion engines, including laboratory
measurement (engineering method and survey method) and site measurement (survey method).
This document applies to all air cleaners installed on reciprocating internal combustion engines
(reciprocating internal combustion engine is referred to as engine hereafter, except for specific explanations)
falling within the field of application of ISO 3046-1 and/or other air induction installation.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 3046-1, Reciprocating internal combustion engines
...

ISO/DTS 19425:20XX (X)
ISO /TC 70/WG13
Secretariat: SAC
Date: 2024-01-2703-28
Reciprocating internal combustion engines — Measurement
method for air cleaners— — Sound power level of combustion air
inlet noise and insertion loss using sound pressure

DTS stage
Warning for WDs and CDs
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to
change without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.

A model manuscript of a draft International Standard (known as “The Rice Model”) is available at
https://www.iso.org/iso/model_document-rice_model.pdf

© ISO #### – All rights reserved

ISO #####-#:####(X)
Moteurs alternatifs à combustion interne — Méthode de mesure du bruit des purificateurs d'air — Niveau de
puissance sonore du bruit d'entrée d'air de combustion et de perte d'insertion utilisant une pression sonore
2 © ISO #### – All rights reserved

ISO /DTS 19425:20XX(X:(en)
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: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
© ISO #### 2024 – All rights reserved
iii
ISO /DTS 19425:20XX(X:(en)
Contents
Foreword . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test environment . 6
4.1 General . 6
4.2 Criterion for background noise . 6
4.3 Criterion for acoustic adequacy of test environment . 7
5 Instrumentation . 7
5.1 General . 7
5.2 Calibration . 7
5.3 Application . 8
6 Installation and operation conditions . 8
6.1 General . 8
6.2 Installation condition . 8
6.3 Operation condition . 10
7 Measurement . 10
7.1 General . 10
7.2 Measurement uncertainty . 10
7.3 Characteristic source dimension . 11
7.4 Measurement radius . 12
7.5 Measurement surface and area . 12
7.6 Microphone arrays . 12
8 Calculation . 15
8.1 General . 15
8.2 Calculation of sound power level . 16
8.2.1 Mean time-averaged sound pressure levels . 16
8.2.2 Corrections for background noise . 16
8.2.3 Corrections for environmental . 17
8.2.4 Surface time-averaged sound pressure levels . 17
8.2.5 Sound power levels . 17
8.3 Calculation of insertion loss . 18
9 Information to be recorded . 18
10 Test report . 19
Annex A (normative) Qualification procedures for the acoustic environment . 20
A.1 General . 20
A.2 Reverberation method . 20
A.3 Two-surface method . 21
A.4 Determination of the equivalent absorption area A with a reference sound source . 21
A.5 Approximate method for Measurements made with A-weighting . 22
A.6 A-weighted sound power levels . 23
A.7 Values of j and Aj for use in calculations . 23
Bibliography . 26

iv © ISO #### 2024 – All rights reserved
iv
ISO /DTS 19425:20XX(X:(en)
This template allows you to work with default MS Word functions and styles. You can use these if you want to
maintain the Table of Contents automatically and apply auto-numbering.
To update the Table of Contents please select it and press "F9".
Foreword . v
Introduction . vi
1 Scope (mandatory) . 1
2 Normative references (mandatory) . 1
3 Terms and definitions (mandatory) . 1
4 Test environment . 5
4.1 General . 5
4.2 Criterion for background noise . 5
4.3 Criterion for acoustic adequacy of test environment . 6
5 Instrumentation . 6
5.1 General . 6
5.2 Calibration . 6
5.3 Application . 7
6 Installation and operation conditions . 7
6.1 General . 7
6.2 Installation condition . 7
6.3 Operation condition . 8
7 Measurement . 8
7.1 General . 8
7.2 Measurement uncertainty . 9
7.3 Characteristic source dimension . 10
7.4 Measurement radius . 10
7.5 Measurement surface and area . 10
7.6 Microphone arrays . 10
8 Calculation . 12
8.1 General . 12
8.2 Calculation of sound power level . 12
8.2.1 Mean time-averaged sound pressure levels . 12
8.2.2 Corrections for background noise . 13
8.2.3 Corrections for environmental . 13
8.2.4 Surface time-averaged sound pressure levels . 14
8.2.5 Sound power levels . 14
8.3 Calculation of insertion loss . 14
9 Information to be recorded . 14
10 Test report . 15
Annex A (normative) Qualification procedures for the acoustic environment . 16
A.1 General . 16
A.2 Reverberation method .
...