ISO/DTS 16755-1
(Main)Acoustics — Non acoustic factors influencing the perception, interpretation and response to environmental sounds — Part 1: Definition and conceptual framework
Acoustics — Non acoustic factors influencing the perception, interpretation and response to environmental sounds — Part 1: Definition and conceptual framework
This Technical Specification will provide a definition, a conceptual framework and a categorisation framework for non-acoustic factors (sometimes also referred to as “contextual factors”). These factors have a material influence on the measurement, reporting and assessment of self-reported health outcomes attributable to noise and soundscape studies, as well as on the planning, design and management of soundscape and noise interventions. If Part I is adopted, the following parts would be proposed to complete the standard series: – Part 2: Data collection and reporting – Part 3: Data analysis – Part 4: Interpretation
Acoustique — Facteurs non acoustiques influençant la perception, l'interprétation et la réponse aux sons de l'environnement — Partie 1: Définition et cadre conceptuel
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FINAL DRAFT
Technical
Specification
ISO/TC 43/SC 1
Acoustics — Non acoustic factors
Secretariat: DIN
influencing the perception,
Voting begins on:
interpretation and response to
2025-02-12
environmental sounds —
Voting terminates on:
2025-04-09
Part 1:
Definition and conceptual
framework
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Reference number
FINAL DRAFT
Technical
Specification
ISO/TC 43/SC 1
Acoustics — Non acoustic factors
Secretariat: DIN
influencing the perception,
Voting begins on:
interpretation and response to
environmental sounds —
Voting terminates on:
Part 1:
Definition and conceptual
framework
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
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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 Conceptual framework of non-acoustic factors . 1
4.1 General .1
4.2 Categories of non-acoustic factors .2
Annex A (informative) Non-acoustic factors categories . 4
Bibliography . 5
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.
A list of all parts in the ISO/TS 16755 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
Many countries already have regulations in place concerning the acceptability of environmental noise
exposure, while others are likely to do so in the future. Such regulations often take into account relationships
between noise exposure and noise-induced health outcomes, including long-term annoyance and sleep
disturbance.
International standards have been developed for the measurements of certain characteristics of
[1]
environmental sound. Two examples are ISO 1996-1 , which contains details specifications about basic
quantities and procedures, measurement of sound and guidance on the application of these data to set noise
[2]
limits, and ISO 20906 , which specifies criteria for unattended monitoring of aircraft sound in the vicinity
of airports.
Other standards focus on the effects of sound on humans. Long-term annoyance is an important health
effect attributable to environmental noise, both as a health outcome in its own right, but also as a potential
[3] [4]
risk factor to other clinical health outcomes. ISO/TS 15666 provides a standardised specification for
the assessment of noise annoyance by social and socio-acoustic surveys. This specification has enabled a
more robust consolidation of the international evidence on noise annoyance, by ensuring consistency in the
[3]
definition and measurements of this specific health endpoint .
It is generally accepted that human reaction to environmental sound is determined partly by the acoustic
characteristics of the physical stimulus, and partly by factors that frame the sound exposure within a
[5]to[9]
broader context. Such factors are often referred to as non-acoustic factors in the noise and health
literature.
In recent years there has been a growing interest in the soundscape approach. Whilst the term “soundscape”
has seen widespread academic and popular adoption in various fields and applications (including urban,
[10]
underwater and ecological contexts), the most relevant definition for the purposes of this document is
the ISO 12913-1 definition, which places an emphasis on how sound in an environment is experienced by a
person and/or people in context. According to ISO 12913-1 assessing soundscape in context includes:
“the interrelationships between person and activity and place, in space and time. The context may influence
soundscape through (1) the auditory sensation, (2) the interpretation of the auditory sensation, and (3) the
[11]
responses to the acoustic environment.” .
[11]to[13]
There is clear overlap between the concept of the “context” as discussed in the ISO 12913 series and
the term “non-acoustic factors” as used by the noise and health community. Therefore identifying, measuring
and assessing non-acoustic factors is an important process of measuring and assessing soundscape in
[5][7]
accordance with ISO 12913 series as well as assessing non-acoustic factors in noise and health research
[8][30][31]
.
Multivariate regression analyses of socio-acoustic surveys suggest that known non-acoustic factors can
[6][14]to[17]
account for up to one third of the variance observed in noise annoyance reactions. These results
have been further replicated in soundscape studies, with multi-level regression analysis indicating that non-
acoustic factors can explain 35 % of the variance in pleasantness perception (i.e. the opposite dimension to
[18]
annoyance) and 18 % of the variance in eventfulness perception .
There is clear evidence that non-acoustic factors offer significant opportunities in a) understanding the
drivers of annoyance and soundscape appraisal and b) opening up new possibilities for reducing the health
burden attributable to the sound environment. In fact, several projects have already explored how non-
[19]
acoustic factors can be used to reduce noise annoyance (see for example the ANIMA project for aviation
[20]
noise and FAMOS project for road traffic noise). Consideration of non-acoustic factors in policy and
[21]
practice could also lead to more equitable health outcomes. In business terminology, non-acoustic factors
have the potential to significantly increase the return on investment in noise effects investigation and
[22]
mitigation and soundscape design. The WHO Environmental Noise Guidelines 2018 also acknowledge the
[23]
important contribution of non-acoustic factors, and recommend that :
v
“Future intervention studies … should use measures of moderators and confounders, including repeated meas-
urements of situational and personal variables such as activity interference, potential confounders such as
noise sensitivity, coping strategies and a range of other attitudinal variables.”
Despite the key role that non-acoustic factors play in both the health protection (noise control) and health
promotion/improvement (good acoustic quality and soundscape design) approaches, to date, there is no
standardised specification for the assessment of non-acoustic factors in social surveys and soundscape
assessments. For example, the definition and standardisation of non-acoustic factors fall outside scope of
ISO/TS 15666. This means that the extent to which non-acoustic factors are investigated in a particular
study is limited by the specialist expertise within the study group, and different studies tend to develop
project-specific survey instruments.
The aim of ISO/TS 16755 series is to help define, measure and interpret specific attributes of the context that
help to better understand the human interpretation of, and response to a sound environment. The objective
of this document is to harmonise the definition and conceptual framework for non-acoustic factors related
to noise and soundscape data collection activities, such as via social and socio-acoustic surveys, soundwalks,
questionnaires and guided interviews. This definition and conceptual framework form the foundation for
data collection, analysis and interpretation covered in subsequent parts of this document.
ISO/TS 16755 series applies to any sound in the acoustic environment (“acoustic environment” is defined in
ISO 12913-1:2014, 2.2).
When these specifications are met, it will be possible to identify, compare and pool survey results across
studies in a methodologically robust way, thereby strengthening the evidence base and ultimately leading
to a better understanding and application of non-acoustic factors to improve the health and quality of life
of citizens across the globe. The data generated by the application of this Technical Specification series
will be relevant to practitioners involved in all aspects of spatial planning and environmental public health
including policy makers, planners, developers, regulators, researchers and environmental public health
practitioners.
This document was developed with valuable input from the International Commission on Biological Effects
of Noise (ICBEN) Team 6 - Community response to noise and annoyance.
vi
FINAL DRAFT Technical Specification ISO/DTS 16755-1:2025(en)
Acoustics — Non acoustic factors influencing the perception,
interpretation and response to environmental sounds —
Part 1:
Definition and conceptual framework
1 Scope
This document provides a definition, a conceptual framework and a categorisation framework for non-
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Date: 2025-01-27xx
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interpretation and response to environmental sounds — —
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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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Website: www.iso.orgwww.iso.org
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ii © ISO 2025 – All rights reserved
ii
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Contents
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Foreword . iv
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Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Conceptual framework of non-acoustic factors . 1
4.1 General. 1
4.2 Categories of non-acoustic factors . 2
Annex A (informative) Non-acoustic factors categories . 4
Bibliography . 5
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Conceptual framework of non-acoustic factors . 1
4.1 General. 1
4.2 Categories of non-acoustic factors . 3
Annex A (informative) Non-acoustic factors categories . 4
Bibliography . 5
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© ISO 2025 – All rights reserved
iii
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Foreword
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ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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 documentsdocument should be noted. This document was drafted in accordance with the editorial rules
Commented [A2]: The URL www.iso.org/directives has
of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). 2 (see www.iso.org/directives).
been redirected to https://www.iso.org/directives. Please
verify the URL.
Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of this
Commented [A3]: The URL www.iso.org/patents has been
document may beinvolve the subjectuse of (a) patent(s). ISO takes no position concerning the evidence,
redirected to https://www.iso.org/patents. Please verify the
validity or applicability of any claimed patent rights. in respect thereof. As of the date of publication of this
URL.
document, ISO had not received notice of (a) patent(s) which may be required to implement this document.
Commented [A4]: The URL
However, implementers are cautioned that this may not represent the latest information, which may be
www.iso.org/iso/foreword.html has been redirected to
obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for
https://www.iso.org/iso/foreword.html. Please verify the
identifying any or all such patent rights. Details of any patent rights identified during the development of the
URL.
document will be in the Introduction and/or on the ISO list of patent declarations received (see
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www.iso.org/patents).
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Any trade name used in this document is information given for the convenience of users and does not
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constitute an endorsement.
Commented [A5]: Not found, but similar references exist
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
ISO/TS 16755 (all parts), Acoustics — Non acoustic factors
related to conformity assessment, as well as information about ISO's adherence to the World Trade
influencing the perception, interpretation and response to
environmental sounds
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.www.iso.org/iso/foreword.html.
Commented [A6]: Not found, but similar references exist
This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise, ISO/TS 16755 (all parts), Acoustics — Non acoustic factors
influencing the perception, interpretation and response to
Working Group WG 68, Non-acoustic factors.
environmental sounds
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influencing the perception, interpretation and response to environmental sounds:
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— Part 1- Definition and conceptual framework
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The following parts are proposed following the adoption of Part 1:
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— Data collection and reporting
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— Data analysis
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— Interpretation
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ISO/TS 16755 applies to any sound in the acoustic environment (“acoustic environment” is defined in ISO
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12913-1:2014 cl.2.2).
Formatted: Font: 10 pt
Formatted: Font: 10 pt
A list of all parts in the ISO/TS 16755 series can be found on the ISO website.
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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.www.iso.org/members.html.
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iv © ISO 2025 – All rights reserved
iv
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Formatted: Font: Bold
Introduction
Formatted: HeaderCentered, Left
This document is proposed for provisional application so that information and experience of its use in practice
may be gathered. Comments on the content of this document should be sent to the ISO Central Secretariat.
Many countries already have regulations in place concerning the acceptability of environmental noise
Formatted: Adjust space between Latin and Asian text,
exposure, while others are likely to do so in the future. Such regulations often take into account relationships
Adjust space between Asian text and numbers
between noise exposure and noise-induced health outcomes, including long-term annoyance and sleep
disturbance.
International standards have been developed for the measurements of certain characteristics of
[1][1]
environmental sound. Two examples are ISO 1996-1:2016, , which contains details specifications about
Formatted: Default Paragraph Font
basic quantities and procedures, measurement of sound, and guidance on the application of these data to set
Formatted: Default Paragraph Font
[2][2]
noise limits;, and ISO 20906:2009, , which specifies criteria for unattended monitoring of aircraft sound in
Formatted: Default Paragraph Font
the vicinity of airports.
Formatted: Default Paragraph Font
Other standards focus on the effects of sound on humans. Long-term annoyance is an important health effect
Formatted: Default Paragraph Font
attributable to environmental noise, both as a health outcome in its own right, but also as a potential risk factor
[3] [4] [3] [4]
to other clinical health outcomes. ISO/TS 15666:2021 . ISO/TS 15666 provides a standardised
specification for the assessment of noise annoyance by social and socio-acoustic surveys. This specification
has enabled a more robust consolidation of the international evidence on noise annoyance, by ensuring
[3] [3]
consistency in the definition and measurements of this specific health endpoint . .
It is generally accepted that human reaction to environmental sound is determined partly by the acoustic
characteristics of the physical stimulus, and partly by factors that frame the sound exposure within a broader
[5-9] [5]to[9]
context. . Such factors are often referred to as non-acoustic factors in the noise and health literature.
In recent years there has been a growing interest in the soundscape approach. Whilst the term “soundscape”
Formatted: Default Paragraph Font
has seen widespread academic and popular adoption in various fields and applications (including urban,
[10] [10]
underwater and ecological contexts), ), the most relevant definition for the purposes of this document is
Formatted: Default Paragraph Font
the ISO 12913-1 definition, which places
...
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