Ergonomics - Danger signals for public and work areas - Auditory danger signals (ISO 7731:2003)

ISO 7731:2003 specifies the physical principles of design, ergonomic requirements and the corresponding test methods for danger signals for public and work areas in the signal reception area and gives guidelines for the design of the signals. It may also be applied to other appropriate situations.
ISO 7731:2003 does not apply to verbal danger warnings (e.g. shouts, loudspeaker announcements). ISO 9921 covers verbal danger signals.
Special regulations such as those for a public disaster and public transport are not affected by this International Standard.

Ergonomie - Gefahrensignale für öffentliche Bereiche und Arbeitsstätten - Akustische Gefahrensignale (ISO 7731:2003)

Ergonomie - Signaux de danger pour lieux publics et lieux de travail - Signaux de danger auditifs (ISO 7731:2003)

L'ISO 7731:2003 spécifie les principes physiques de conception, les exigences ergonomiques et les méthodes d'essai correspondantes applicables aux signaux de danger pour les lieux publics et les lieux de travail dans la zone de réception du signal. Elle donne également des recommandations relatives à la conception de ces signaux. Elle peut également s'appliquer à d'autres situations appropriées.
L'ISO 7731:2003 ne s'applique pas aux avertissements de danger verbaux (tels que des cris ou des annonces par haut-parleurs). Les signaux de danger verbaux sont traités dans l'ISO 9921.
Les réglementations particulières telles que celles applicables aux transports publics ou aux catastrophes touchant le public ne sont pas concernées par l'ISO 7731:2003.

Ergonomija - Signali za nevarnost na javnih in delovnih območjih - Zvočni signali za nevarnost (ISO 7731:2003)

General Information

Status
Published
Publication Date
23-Sep-2008
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
24-Sep-2008
Completion Date
24-Sep-2008

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SLOVENSKI STANDARD
SIST EN ISO 7731:2008
01-december-2008
1DGRPHãþD
SIST EN ISO 7731:2006

(UJRQRPLMD6LJQDOL]DQHYDUQRVWQDMDYQLKLQGHORYQLKREPRþMLK=YRþQLVLJQDOL

]DQHYDUQRVW ,62

Ergonomics - Danger signals for public and work areas - Auditory danger signals (ISO

7731:2003)

Ergonomie - Gefahrensignale für öffentliche Bereiche und Arbeitsstätten - Akustische

Gefahrensignale (ISO 7731:2003)

Ergonomie - Signaux de danger pour lieux publics et lieux de travail - Signaux de danger

auditifs (ISO 7731:2003)
Ta slovenski standard je istoveten z: EN ISO 7731:2008
ICS:
13.180 Ergonomija Ergonomics
13.320 Alarmni in opozorilni sistemi Alarm and warning systems
SIST EN ISO 7731:2008 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 7731:2008
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SIST EN ISO 7731:2008
EUROPEAN STANDARD
EN ISO 7731
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2008
ICS 13.180; 13.320 Supersedes EN ISO 7731:2005
English Version
Ergonomics - Danger signals for public and work areas -
Auditory danger signals (ISO 7731:2003)
Ergonomie - Signaux de danger pour lieux publics et lieux
de travail - Signaux de danger auditifs (ISO 7731:2003)
This European Standard was approved by CEN on 25 August 2008.

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 CEN 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 CEN Management Centre has the same status as the

official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,

Romania, Slovakia, Slovenia, 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

© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7731:2008: E

worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 7731:2008
EN ISO 7731:2008 (E)
Contents Page

Foreword..............................................................................................................................................................3

Annex ZA (informative) Relationship between this European Standard and the Essential

Requirements of EU Directive 98/37/EC ..............................................................................................4

Annex ZB (informative) Relationship between this European Standard and the Essential

Requirements of EU Directive 2006/42/EC .........................................................................................5

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SIST EN ISO 7731:2008
EN ISO 7731:2008 (E)
Foreword

The text of ISO 7731:2003 has been prepared by Technical Committee ISO/TC 159 “Ergonomics” of the

International Organization for Standardization (ISO) and has been taken over as EN ISO 7731:2008 by

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 March 2009, and conflicting national standards shall be withdrawn at

the latest by December 2009.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 7731:2005.

This document has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association, and supports essential requirements of EC Directive(s).

For relationship with EC Directive(s), see informative Annexes ZA and ZB, which are integral parts of this

document.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland and the United Kingdom.
Endorsement notice

The text of ISO 7731:2003 has been approved by CEN as a EN ISO 7731:2008 without any modification.

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SIST EN ISO 7731:2008
EN ISO 7731:2008 (E)
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC

This European Standard has been prepared under a mandate given to CEN by the European Commission

and the European Free Trade Association to provide a means of conforming to Essential Requirements of the

New Approach Directive 98/37/EC on machinery, amended by 98/79/EC.

Once this standard is cited in the Official Journal of the European Communities under that Directive and has

been implemented as a national standard in at least one Member State, compliance with the normative

clauses of this standard given in Table ZA.1 confers, within the limits of the scope of this standard, a

presumption of conformity with the relevant Essential Requirements of that Directive and associated EFTA

regulations.

Table ZA.1 — Correspondence between this European Standard and Directive 98/37/EC,

amended by 98/79/EC

Clause(s)/sub-clause(s) of this EN Essential Requirements (ERs) Qualifying remarks/Notes

of Directive 98/37/EC, amended
by 98/79/EC
All clauses Annex I: 1.2.2, 1.7.0, 3.6.1 -

WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within

the scope of this standard.
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SIST EN ISO 7731:2008
EN ISO 7731:2008 (E)
Annex ZB
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC

This European Standard has been prepared under a mandate given to CEN by the European Commission

and the European Free Trade Association to provide a means of conforming to Essential Requirements of the

New Approach Directive 2006/42/EC on machinery.

Once this standard is cited in the Official Journal of the European Communities under that Directive and has

been implemented as a national standard in at least one Member State, compliance with the normative

clauses of this standard given in Table ZB.1 confers, within the limits of the scope of this standard, a

presumption of conformity with the relevant Essential Requirements of that Directive and associated EFTA

regulations.

Table ZB.1 — Correspondence between this European Standard and Directive 2006/42/EC

Clause(s)/sub-clause(s) of this EN Essential Requirements (ERs) Qualifying remarks/Notes

of Directive 2006/42/EC
All clauses Annex I: 1.1.6, 1.2.2, 1.7.1, -
1.7.1.2, 1.7.2, 3.6.1

WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within

the scope of this standard.
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SIST EN ISO 7731:2008
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SIST EN ISO 7731:2008
INTERNATIONAL ISO
STANDARD 7731
Second edition
2003-11-01
Ergonomics — Danger signals for public
and work areas — Auditory danger
signals
Ergonomie — Signaux de danger pour lieux publics et lieux
de travail — Signaux de danger auditifs
Reference number
ISO 7731:2003(E)
ISO 2003
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
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ii © ISO 2003 — All rights reserved
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope...................................................................................................................................................... 1

2 Normative references ........................................................................................................................... 1

3 Terms, definitions and symbols .......................................................................................................... 1

4 Safety requirements.............................................................................................................................. 3

4.1 General................................................................................................................................................... 3

4.2 Recognition ........................................................................................................................................... 3

4.2.1 Introduction ........................................................................................................................................... 3

4.2.2 Audibility................................................................................................................................................ 3

4.2.3 Distinctiveness...................................................................................................................................... 3

4.2.4 Unambiguity .......................................................................................................................................... 3

4.2.5 Moving sources..................................................................................................................................... 3

4.3 Review of the signal.............................................................................................................................. 4

4.4 Recommended maximum level of the danger signal ........................................................................ 4

5 Test methods......................................................................................................................................... 4

5.1 Measurement equipment...................................................................................................................... 4

5.2 Objective acoustic measurements...................................................................................................... 4

5.2.1 General................................................................................................................................................... 4

5.2.2 Weighted measurements...................................................................................................................... 4

5.2.3 Measurements made in the frequency domain.................................................................................. 4

5.2.4 Measurement of the auditory signal with ambient noise present.................................................... 5

5.3 Subjective test method......................................................................................................................... 5

6 Design criteria for auditory danger signals........................................................................................ 5

6.1 General................................................................................................................................................... 5

6.2 Sound-pressure level............................................................................................................................ 5

6.3 Spectral characteristics........................................................................................................................ 6

6.4 Temporal characteristics...................................................................................................................... 6

6.4.1 Temporal distribution of the danger signal........................................................................................ 6

6.4.2 Temporal distribution of the frequencies ........................................................................................... 6

6.4.3 Duration of the danger signals ............................................................................................................ 7

6.5 Information required from suppliers................................................................................................... 7

Annex A (normative) Definitions of symbols................................................................................................... 8

Annex B (normative) Calculation of effective masked threshold.................................................................. 9

Annex C (normative) Listening test................................................................................................................10

Annex D (informative) Examples of danger signals...................................................................................... 11

Bibliography ..................................................................................................................................................... 17

© ISO 2003 — All rights reserved iii
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SIST EN ISO 7731:2008
ISO 7731:2003(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 7731 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5, Ergonomics

of the physical environment.

This second edition cancels and replaces the first edition (ISO 7731:1986), which has been technically revised.

iv © ISO 2003 — All rights reserved
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
Introduction

This International Standard specifies criteria applicable to the recognition of auditory danger signals,

especially in cases where there is a high level of ambient noise. It covers auditory danger signals, desigated in

the text of this standard by the use of the phrase “danger signals”, which apply to emergency signals and

warning signals (see Table 1).

Auditory danger signals can also be found in the following International Standards:

 ISO 8201 dealing with emergency evacuation signals;
 ISO 11429 dealing with auditory and visual danger signals.
Various types of danger signals and their responses are described in Table 1.
It should be noted that ISO 11429 covers this subject in greater detail.
Table 1 — Various types of danger signals
Type of danger signal Response
Auditory emergency evacuation signal Leave the danger zone immediately
Auditory emergency signal Take urgent action for rescue or protection
Auditory warning signal Take preventative or preparatory action

Correctly designed signals can reliably call attention to a hazard or a dangerous situation, even when hearing

protection is worn, without causing fright.
© ISO 2003 — All rights reserved v
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SIST EN ISO 7731:2008
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SIST EN ISO 7731:2008
INTERNATIONAL STANDARD ISO 7731:2003(E)
Ergonomics — Danger signals for public and work areas —
Auditory danger signals
1 Scope

This International Standard specifies the physical principles of design, ergonomic requirements and the

corresponding test methods for danger signals for public and work areas in the signal reception area and

gives guidelines for the design of the signals. It may also be applied to other appropriate situations.

The relevance given in the definitions as to the difference between an auditory emergency signal, auditory

emergency evacuation signal and an auditory warning signal should be noted. The emergency evacuation

signal is covered in ISO 8201.

This International Standard does not apply to verbal danger warnings (e.g. shouts, loudspeaker

announcements). ISO 9921 covers verbal danger signals.

Special regulations such as those for a public disaster and public transport are not affected by this

International Standard.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.

NOTE Definitions of symbols referred to in this International Standard are given in Annex A.

3.1
ambient noise

all sounds in the signal reception area not produced by the danger-signal transmitter

3.2
danger signals

depending on the degree of urgency and the possible effect of the danger on people, a distinction is made

between three types of auditory danger signals: an auditory emergency signal, an auditory emergency

evacuation signal and an auditory warning signal
3.2.1
auditory emergency signal

signal marking the onset and, if necessary, the duration and the end of a dangerous situation

© ISO 2003 — All rights reserved 1
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
3.2.2
auditory emergency evacuation signal

signal indicating the beginning or the actual occurrence of an emergency involving the possibility of injury and

instructing the person(s) to immediately leave the danger zone in the recognized manner

NOTE The auditory emergency evacuation signal is the subject of ISO 8201.
3.2.3
auditory warning signal

signal indicating the possibility or actual occurrence of a dangerous situation requiring appropriate measures

for the elimination or control of the danger

NOTE The auditory warning signal may also provide information concerning the conduct and courses of action to be

taken.
3.3
effective masked threshold

level of auditory danger signal just audible over the ambient noise, taking account of the acoustic parameters

of both the ambient noise in the signal reception area and the listening deficiencies (hearing protection,

hearing loss and other masking effects)
3.4
octave
bandwidth of a filter which comprises a frequency range of a factor of two

NOTE That is to say, the cut-off frequency f is twice the lower f as specified in IEC 61260; e.g. for an octave-band

2 1

centred on 500 Hz, the lower frequency is 353 Hz ( 500 / 2 ), the upper frequency is 707 Hz ( 500 2 ).

3.5
1/3 octave
fractional-octave-band filter
bandwidth of a filter which comprises a frequency range of a factor of 2
3 3

NOTE 1 That is to say, the cut-off frequency f is 2 times the lower f (i.e. f = 2 f as specified in IEC 61260).

2 1 2 1

NOTE 2 A bandpass filter has a narrower frequency range than an octave filter. The octave filter can be subdivided into

three 1/3 octave-bands.
3.6
reverberation time

time interval required for the sound-pressure level to decrease by 60 dB, after the emission by the source is

stopped
3.7
signal reception area
area in which persons are intended to recognize and react to a signal

NOTE This International Standard does not deal with problems that might occur if the danger signals are heard from

outside the signal reception area.
3.8
spectral content
overall frequency content of a signal, or of the ambient noise
2 © ISO 2003 — All rights reserved
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
4 Safety requirements
4.1 General

The nature of the danger signal shall be such that people in the reception area can hear and react to the

signal as intended. If persons with hearing impairment (deafness) or hearing protection (helmets, ear plugs,

etc.) are likely to be present, special care should be taken. The characteristics of the audible signal shall be

adapted to take account of the characteristics relevant to the situation.
4.2 Recognition
4.2.1 Introduction

The reliable recognition of a danger signal requires that the signal be clearly audible, be sufficiently different

from other sounds in the environment and have an unambiguous meaning.

In order of priority, any emergency evacuation signal shall take precedence over all other danger signals and

danger signals shall take precedence over all other auditory signals.
4.2.2 Audibility

4.2.2.1 The danger signal shall be clearly audible. The effective masked threshold shall be distinctly

exceeded. If relevant, the probability of hearing loss in the recipient population may be assessed and taken

into account. If hearing protectors are worn, their levels of attenuation shall be known and introduced into the

assessment.

To ensure its audibility, the A-weighted sound-pressure level of the danger signal shall not be lower than

65 dB at any position in the signal reception area.
In addition, at least one of the criteria in 4.2.2.2 to 4.2.2.4 shall be met.

4.2.2.2 For measurements of the A-weighted sound-pressure level [method a) in 5.2.2.1], the difference

between the two A-weighted sound-pressure levels of the signal and the ambient noise shall be greater than

15 dB (L − L > 15 dB).
S, A N, A

4.2.2.3 For measurements of the octave-band sound-pressure level [method b) in 5.2.3.1], the sound-

pressure level of the signal in one or more octave-bands shall exceed the effective masked threshold by at

least 10 dB in the octave-band under consideration (L − L > 10 dB).
Si, oct Ti, oct

4.2.2.4 For measurements of the 1/3 octave-band sound-pressure level [method c) in 5.2.3.2], the sound-

pressure level of the signal in one or more 1/3 octave-bands shall exceed the effective masked threshold by

13 dB in the 1/3 octave-band under consideration (L − L > 13 dB).
Si, 1/3oct Ti, 1/3oct
4.2.3 Distinctiveness

Parameters of the danger signal (signal level, frequency spectrum, temporal pattern, etc.) shall be designed to

stand out from all other sounds in the reception area and shall be distinctly different from any other signals.

(See Clause 6.)
4.2.4 Unambiguity
The meaning of the danger signal shall be unambiguous.
4.2.5 Moving sources

The characteristics of a danger signal from a moving signal source shall be recognizable, regardless of the

speed or movement direction of the source.
© ISO 2003 — All rights reserved 3
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
4.3 Review of the signal

The effectiveness of the danger signal shall be reviewed at both regular intervals and whenever a new signal

(whether a danger signal or not) or a change in the ambient noise occurs, or any other relevant changes are

made.
4.4 Recommended maximum level of the danger signal

If the A-weighted sound-pressure level of the ambient noise in the signal reception area exceeds 100 dB, the

use of additional visual, rather than solely auditory, danger signals is recommended (e.g. visual danger

signals according to ISO 11428 and ISO 11429). In any case, the maximum signal level should not exceed

118 dB(A) in the signal reception area.
5 Test methods
5.1 Measurement equipment

Measurements should be made with equipment conforming to IEC 61672 and IEC 61260.

For measuring the ambient noise and the signal, the maximum reading with time weighting “Slow” shall be

used. Calculations shall be based on the samples taken from a representative number of measurements.

5.2 Objective acoustic measurements
5.2.1 General

Compliance with the following requirements shall be adequate for the auditory danger signal. (See 4.2.2.)

5.2.2 Weighted measurements
5.2.2.1 A-weighted measurements [method a)]
Measure the A-weighted sound-pressure level of the ambient noise (L ).
N, A
Measure the A-weighted sound-pressure level of the danger signal (L ).
S, A
Calculate L − L and check compliance with the requirements given in 4.2.2.2.
S, A N, A
5.2.3 Measurements made in the frequency domain
5.2.3.1 Octave-band measurements [method b)]
Measure the octave-band sound-pressure levels of the ambient noise (L ).
Ni, oct
Determine the effective masked threshold (L ), according to Annex B.
Ti, oct
Measure the octave-band sound-pressure levels of the danger signal (L ).
Si, oct

Calculate ( L − L ) and check compliance with the requirements given in 4.2.2.3.

Si, oct Ti, oct
5.2.3.2 Third octave-band measurements [method c)]
Measure the 1/3 octave-band sound-pressure levels of the ambient noise (L ).
Ni, 1/3oct
Calculate the effective masked threshold (L ), according to Annex B.
Ti, 1/3oct
4 © ISO 2003 — All rights reserved
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SIST EN ISO 7731:2008
ISO 7731:2003(E)
Measure the 1/3 octave-band sound-pressure levels of the danger signal (L ).
Si, 1/3oct
Calculate (L − L ) and check compliance with the requirements given in 4.2.2.4.
Si, 1/3oct Ti, 1/3oct

NOTE 1 By using methods b) or c), the difference between the signal-to-noise ratios can be smaller than in 5.2.2.1,

method a).
NOTE 2 Methods b) and c) require more sophisticated measurement efforts.

NOTE 3 All other criteria according to Clause 6 also apply to the methods of measurement.

5.2.4 Measurement of the auditory signal with ambient noise present

Generally, the auditory signal is measured with the ambient noise absent, i.e. the source of ambient noise (e.g.

machinery) shall be switched off during the measurement. If this is not possible (permanent ambient noise

which would be measured along with the auditory signal), alternative methods of measurement should be

employed, taking into account reduced accuracy.
5.3 Subjective test method

It is preferable to carry out objective acoustic measurements. In their absence, a subjective listening test may

be used.
Details of the method for a listening test shall comply with Annex C.
6 Design criteria for auditory danger signals
6.1 General
When designing auditory danger signals the following are relevant:
 the sound-pressure level;
 spectral characteristics;
 temporal characteristics.
6.2 Sound-pressure level

Danger signals are deemed to be clearly audible in the signal reception area if their A-weighted sound-

pressure levels exceed the soun
...

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