ISO/FDIS 13472-2

Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 2: Spot method for reflective surfaces

ISO 13472-2:2010 specifies a test method for measuring in situ the sound absorption coefficient of road surfaces for the one-third-octave-band frequencies ranging from 250 Hz to 1 600 Hz under normal incidence conditions. For special purposes, the frequency range can be changed by modifying the dimensions of the system. The test method is intended for: a) determination of the sound absorption coefficient of semi-dense to dense road surfaces (and, if of interest, also the complex acoustical impedance); b) determination of the sound absorption properties of test tracks in accordance with standards such as ISO 10844 and test surfaces defined in national and international type approval regulations for road vehicles and vehicle tyres; c) verification of the compliance of the sound absorption coefficient of a road surface with design specifications or other requirements.

Acoustique — Mesurage in situ des propriétés d'absorption acoustique des revêtements de chaussées — Partie 2: Méthode ponctuelle pour les surfaces réfléchissantes

General Information

• Status: Not Published
• ICS: 17.140.30 - Noise emitted by means of transport
• ICS: 93.080.20 - Road construction materials
• Technical Committee: ISO/TC 43/SC 1 - Noise
• Drafting Committee: ISO/TC 43/SC 1 - Noise
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 26-Feb-2025
• Due Date: 26-Feb-2025
• Completion Date: 26-Feb-2025

Relations

• Revises: ISO 13472-2:2010 - Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 2: Spot method for reflective surfaces
• Effective Date: 06-Jun-2022

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 43/SC 1
Acoustics — Measurement of sound
Secretariat: DIN
absorption properties of road
Voting begins on:
surfaces in situ —
2025-02-26
Part 2:
Voting terminates on:
2025-04-23
Spot method for reflective surfaces
Acoustique — Mesurage in situ des propriétés d'absorption
acoustique des revêtements de chaussées —
Partie 2: Méthode ponctuelle pour les surfaces réfléchissantes
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
FINAL DRAFT
International
Standard
ISO/TC 43/SC 1
Acoustics — Measurement of sound
Secretariat: DIN
absorption properties of road
Voting begins on:
surfaces in situ —
Part 2:
Voting terminates on:
Spot method for reflective surfaces
Acoustique — Mesurage in situ des propriétés d'absorption
acoustique des revêtements de chaussées —
Partie 2: Méthode ponctuelle pour les surfaces réfléchissantes
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
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle of the method . 3
4.1 Measurement principle .3
4.2 Signal analysis . .4
4.3 In situ fixture .5
5 Test equipment . 5
5.1 Components of the test system .5
5.2 Sound source .5
5.3 Test signal .5
5.4 Impedance tube .5
5.4.1 Tube diameter .5
5.4.2 Tube length and microphone positions .6
5.4.3 Microphones .6
5.5 In situ test fixture between impedance tube and test surface .7
5.6 Signal processing system .7
5.7 Thermometer and barometer .7
6 Measurement and analysis procedure . 7
6.1 Stabilizing the system .7
6.2 Calibration of the system .7
6.3 Reference measurement .8
6.4 Measurement of a road surface .8
6.5 Data analysis .8
6.6 One-third octave band absorption spectrum .9
7 Positioning of the equipment . 9
7.1 Location of the measurement positions .9
7.1.1 Test surfaces such as those meeting ISO 10844 requirements .9
7.1.2 Regular roads .9
7.2 Temperature .9
8 Measurement and analysis procedure . 9
9 Measurement uncertainty .10
10 Test report .11
Annex A (informative) Correction on base of reference measurement .13
Annex B (informative) Measurement uncertainty . 14
Annex C (informative) Alternative procedures to improve accuracy . 17
Annex D (informative) In situ test fixture .20
Annex E (informative) Example of a test report .22
Bibliography .25

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 43, Acoustics, Subcommittee SC 1, Noise.
This second edition cancels and replaces the first edition (ISO 13472-2:2010), which has been technically
revised.
The main changes are as follows:
— mandatory choice of the transfer function formulation and quality requirements for the coherence
function;
— an alternative microphone arrangement and application of alternating transfer functions are presented
to cancel the distortion due to destructive interference at the microphone positions.
A list of all parts in the ISO 13472 series can be found on the ISO website.
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
Introduction
This method provides a means to evaluate the sound absorption characteristics of a road surface without
damaging the surface. The field of application is limited to low absorption surfaces such as those in
accordance with ISO 10844 and similar surfaces. Due to air leakage the method is not reliable if the measured
sound absorption coefficient exceeds 0,15. Surfaces with a sound absorption coefficient of 0,10 or below are
considered reflective.
The method in this document is based on propagation of the test signal from the source to the road surface
and back to the receiver through an impedance tube with a diameter of 80 mm to 100 mm. The tube covers
2 2
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ISO /TC 43/SC 1
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Secretariat: DIN
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Date: 2025-01-18-xx
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Acoustics — Measurement of sound absorption properties of road
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surfaces in situ — —
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Spot method for reflective surfaces
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ISO/DIS FDIS 13472--2:2024(E2025(en) Formatted: Font: 11 pt, Bold
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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, spacing: single
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
Commented [eXtyles1]: The reference "ISO 2025" is to a
at the address below or ISO’s member body in the country of the requester.
withdrawn standard
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ISO copyright office
CP 401 • Ch. de Blandonnet 8
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CH--1214 Vernier, Geneva
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Phone: + 41 22 749 01 11
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EmailE-mail: [e-mail]
between Latin and Asian text, Adjust space between
Website: www.iso.orgwww.iso.org
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Published in Switzerland Formatted: French (France)
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ii © ISO 2024 2025 – All rights reserved
ii
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Contents
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Foreword . vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle of the method . 3
4.1 Measurement principle . 3
4.2 Signal analysis . 4
4.3 In situ fixture . 5
5 Test equipment . 5
5.1 Components of the test system . 5
5.2 Sound source . 5
5.3 Test signal . 5
5.4 Impedance tube . 5
5.5 In situ test fixture between impedance tube and test surface . 7
5.6 Signal processing system . 7
5.7 Thermometer and barometer . 7
6 Measurement and analysis procedure . 7
6.1 Stabilizing the system . 7
6.2 Calibration of the system . 8
6.3 Reference measurement . 8
6.4 Measurement of a road surface . 8
6.5 Data analysis . 9
6.6 One-third octave band absorption spectrum . 9
7 Positioning of the equipment . 9
7.1 Location of the measurement positions . 9
7.2 Temperature. 10
8 Measurement and analysis procedure . 10
9 Measurement uncertainty . 11
10 Test report . 12
Annex A (informative) Correction on base of reference measurement . 14
Annex B (informative) Measurement uncertainty . 15
Annex C (informative) Alternative procedures to improve accuracy . 18
Annex D (informative) In situ test fixture . 21
Annex E (informative) Example of a test report . 23
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Bibliography . 27

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Foreword . v
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Introduction . vi
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1 Scope . 1
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© ISO 2025 – All rights reserved
iii
ISO/DIS FDIS 13472--2:2024(E2025(en) Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold
2 Normative references . 1
Formatted: Font: 11 pt, Bold
Formatted: HeaderCentered, Space After: 0 pt, Line
3 Terms and definitions . 1
spacing: single
4 Principle of the method . 2
4.1 Measurement principle . 2
4.2 Signal analysis . 4
4.3 In situ fixture . 5
5 Test equipment . 5
5.1 Components of the test system . 5
5.2 Sound source . 5
5.3 Test signal . 5
5.4 Impedance tube . 5
5.4.1 Tube diameter . 5
5.4.2 Tube length and microphone positions . 6
5.4.3 Microphones . 6
5.5 In situ test fixture between impedance tube and test surface . 7
5.6 Signal processing system . 7
5.7 Thermometer and barometer . 7
6 Measurement and analysis procedure . 7
6.1 Stabilizing the system . 7
6.2 Calibration of the system . 7
6.3 Reference measurement . 8
6.4 Measurement of a road surface . 8
6.5 Data analysis . 8
7 Positioning of the equipment . 9
7.1 Location of the measurement positions . 9
7.1.1 Test surfaces such as those meeting ISO 10844 requirements . 9
7.1.2 Regular roads . 9
7.2 Condition of the road surface . 9
7.3 Temperature. 9
8 Measurement and analysis procedure .
...