EN ISO 9921:2003

Ergonomics - Assessment of speech communication (ISO 9921:2003)

ISO 9921:2003 specifies the requirements for the performance of speech communication for verbal alert and danger signals, information messages, and speech communication in general. Methods to predict and to assess the performance in practical applications are described and examples are given.

Ergonomie - Beurteilung der Sprachkommunikation (ISO 9921:2003)

Diese Internationale Norm legt die Anforderungen an die Leistungsfähigkeit der Sprachkommunikation für sprachliche Warnungen und Gefahrensignale, Mitteilungen und an die allgemeine Sprachkommunikation fest. Es werden Verfahren für die Vorhersage und Beurteilung der subjektiven und der objektiven Leistungs-fähigkeit unter praktischen Anwendungsbedingungen beschrieben und Beispiele dafür angegeben.
Für das Erreichen einer optimalen Leistung in besonderen Anwendungsbereichen können drei Stufen in Betracht kommen:
a) Festlegung des Anwendungsbereichs und Definition der entsprechenden Leistungskriterien;
b) Gestaltung eines Kommunikationssystems und Vorhersage der Leistungsfähigkeit;
c) Beurteilung der Leistungsfähigkeit für Einsatzbedingungen.
Die Verwendung von akustischen Warnsignalen an Stelle von Sprache ist nicht Inhalt dieser Internationalen Norm, sondern wird in ISO 7731 behandelt.

Ergonomie - Evaluation de la communication parlée (ISO 9921:2003)

L'ISO 9921:2003 spécifie les exigences de performance en communication parlée relatives aux signaux oraux d'alerte et de danger, aux messages d'information et à la communication parlée en général. Des méthodes de prédiction et d'évaluation de la performance, subjectives et objectives, sont décrites dans des applications pratiques avec des exemples à l'appui.

Ergonomija – Ocena govorne komunikacije (ISO 9921:2003)

General Information

• Status: Published
• Publication Date: 14-Oct-2003
• ICS: 13.180 - Ergonomics
• Technical Committee: CEN/TC 122 - Ergonomics
• Drafting Committee: CEN/TC 122/WG 11 - Ergonomics of the Physical Environment
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 10-Jun-2008
• Completion Date: 10-Jun-2008
• Ref Project: SIST EN ISO 9921:2004 - Ergonomics - Assessment of speech communication (ISO 9921:2003)

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2004
Ergonomija – Ocena govorne komunikacije (ISO 9921:2003)
Ergonomics - Assessment of speech communication (ISO 9921:2003)
Ergonomie - Beurteilung der Sprachkommunikation (ISO 9921:2003)
Ergonomie - Evaluation de la communication parlée (ISO 9921:2003)
Ta slovenski standard je istoveten z: EN ISO 9921:2003
ICS:
13.180 Ergonomija Ergonomics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 9921
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2003
ICS 13.180
English version
Ergonomics - Assessment of speech communication (ISO
9921:2003)
Ergonomie - Evaluation de la communication parlée (ISO Ergonomie - Beurteilung der Sprachkommunikation (ISO
9921:2003) 9921:2003)
This European Standard was approved by CEN on 1 October 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9921:2003 E
worldwide for CEN national Members.

CORRECTED  2003-12-03
Foreword
This document (EN ISO 9921:2003) has been prepared by Technical Committee ISO/TC 159
"Ergonomics" in collaboration with Technical Committee CEN/TC 122 "Ergonomics", 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 April 2004, and conflicting national
standards shall be withdrawn at the latest by April 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 9921:2003 has been approved by CEN as EN ISO 9921:2003 without any
modifications.
INTERNATIONAL ISO
STANDARD 9921
First edition
2003-10-15
Ergonomics — Assessment of speech
communication
Ergonomie — Évaluation de la communication parlée

Reference number
ISO 9921:2003(E)
©
ISO 2003
ISO 9921:2003(E)
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ii © ISO 2003 — All rights reserved

ISO 9921:2003(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Descriptions of speech communications. 3
4.1 General. 3
4.2 Speaker. 3
4.3 Transmission channel. 3
4.4 Listener. 3
5 Performance of speech communications. 3
5.1 General. 3
5.2 Alert and warning situations. 4
5.3 Person-to-person communications. 4
5.4 Public address in public areas . 4
5.5 Personal communication systems. 5
5.6 Summary of recommended minimum performance. 5
6 Assessment and prediction. 5
6.1 General. 5
6.2 Subjective assessment methods . 5
6.3 Objective assessment and prediction methods . 6
Annex A (normative) Speaker and listener characteristics . 7
Annex B (informative) Subjective speech-intelligibility tests . 9
Annex C (informative) Speech transmission index, STI . 12
Annex D (informative) Overview of the means of communication and related parameters . 14
Annex E (normative) Speech interference level, SIL . 18
Annex F (informative) Intelligibility ratings for speech communications. 19
Annex G (normative) Definition of symbols . 22
Annex H (informative) Examples of applications of predictive intelligibility methods . 23
Bibliography . 28

ISO 9921:2003(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9921 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5, Ergonomics
of the physical environment.
This first edition of ISO 9921 cancels and replaces ISO 9921-1:1996.

iv © ISO 2003 — All rights reserved

ISO 9921:2003(E)
Introduction
The aim of standardization in the field of the ergonomic assessment of speech-communication is to
recommend the levels of speech-communication quality required for conveying comprehensive messages in
different applications. The quality of speech communication is assessed for the following cases:
 warning of hazard;
 warning of danger;
 information messages for work places, public areas, meeting rooms, and auditoria.
For some applications, direct communication between humans is considered while, in others, the use of
electro-acoustic systems (e.g. PA systems) or personal communication equipment (e.g. telephone, intercom)
will be the most convenient means of informing and instructing or exchanging information.
The use of auditory warning symbols other than speech is not included in this International Standard but is
covered by ISO 7731.
Acoustical danger and warning signals are in general omni-directional and therefore may be universal in many
situations. Auditory warnings are of great benefit in situations where smoke, darkness or other obstructions
interfere with visual warnings.
It is essential that, in the case of verbal messages, a sufficient level of intelligibility is achieved, in the
coverage area. If this cannot be achieved, non-voice warning signals (see ISO 7731, IEC 60849 and [4] in the
Bibliography) or visual warning signals (see ISO 11429) may be preferable.
If acoustical signals are too loud, hearing damage or environmental problems may occur (e.g. noise nuisance
to dwellings near railway platforms, road traffic, airports, etc.). Good design can minimize these negative
aspects. In addition, prediction methods with sufficient accuracy are useful for consultants, suppliers and end-
users and may thus reduce costs of necessary adjustments after installation of a system.
The communications might be directly between humans, through public address or intercom systems or by
pre-recorded messages. In general, text-to-speech systems are not recommended because of the low
intelligibility of these systems.
It is recognized that, in a general-purpose document, simple to apply and easily available tools for prediction
and assessment should be described, as well as more sophisticated advanced technological methodologies.

INTERNATIONAL STANDARD ISO 9921:2003(E)

Ergonomics — Assessment of speech communication
1 Scope
This International Standard specifies the requirements for the performance of speech communication for
verbal alert and danger signals, information messages, and speech communication in general. Methods to
predict and to assess the subjective and objective performance in practical applications are described and
examples are given.
In order to obtain optimal performance in a specific application, three stages can be considered:
a) specification of the application and definition of the corresponding performance criteria;
b) design of a communication system and prediction of the performance;
c) assessment of the performance for in situ conditions.
The use of auditory warning signals other than speech is not included in this International Standard but is
covered by ISO 7731.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited ap
...