EN 842:1996+A1:2008

Safety of machinery - Visual danger signals - General requirements, design and testing

This European Standard describes criteria for the perception of visual danger signals in the area that people are intended to perceive and to react to such a signal. It specifies the safety and ergonomic requirements and the corresponding physical measurements and subjective visual check. It also provides guidance for the design of the signals to be clearly perceived and differentiated as described in 5.3 of EN 292-2:1991.
This European Standard does not apply to danger indicators:
-   Presented in either written or pictorial form;
-   Transmitted by data display units.
This European Standard does not apply to special regulations such as those for public disaster and public transport.

Sicherheit von Maschinen - Optische Gefahrensignale - Allgemeine Anforderungen, Gestaltung und Prüfung

Diese Europäische Norm beschreibt Kriterien für die Wahrnehmung von optischen Gefahrensignalen in dem Bereich, in dem Menschen dafür bestimmt sind, diese Signale zu erkennen und auf sie zu reagieren. Sie legt die sicherheitstechnischen und ergonomischen Anforderungen und die entsprechenden physikalischen Messungen und die subjektive Sichtprüfung für optische Gefahrensignale fest. Sie bietet außerdem Hilfestellung für die Gestaltung von Signalen, die klar erkannt und unterschieden werden müssen, wie es in
EN 292-2:1991, 5.3 gefordert wird.
Diese Europäische Norm gilt nicht für Gefahrenhinweise:
   die entweder in schriftlicher oder in bildlicher Form gegeben werden;
   die über Bildschirmgeräte übertragen werden.
Diese Europäische Norm ist nicht anwendbar auf spezielle Regelungen wie die des öffentlichen Katastrophenschutzes und des öffentlichen Verkehrs.

Sécurité des machines - Signaux visuels de danger - Exigences générales, conception et essais

La présente norme européenne décrit les critères applicables à la perception de signaux visuels de danger dans
la zone où des personnes sont censées percevoir et réagir à un tel signal.
La présente norme européenne prescrit les exigences en matière d'ergonomie et de sécurité et les mesurages
physiques et le contrôle visuel subjectif pour les signaux visuels de danger. Elle fournit également des indications
pour la conception des signaux, afin qu'ils soient clairement perçus et différenciés comme cela est prescrit au 5.3
de l'EN 292-2:1991.
La présente norme européenne n’est pas applicable aux indicateurs de danger
- présentés sous forme écrite ou picturale ;
- transmis par des unités d'affichage de données.
La présente norme européenne n’est pas applicable aux réglementations particulières, telles que celles concernant
les catastrophes d'ordre public ou les transports en commun.

Varnost strojev - Vidni signali za nevarnost - Splošne zahteve, načrtovanje in preskušanje

General Information

• Status: Published
• Publication Date: 23-Sep-2008
• Withdrawal Date: 27-Dec-2009
• ICS: 13.110 - Safety of machinery
• 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: 20-Sep-2022
• Completion Date: 14-Apr-2025
• Directive: 2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Directive: 98/37/EC - Machinery
• Mandate: M/079 - Mandate to CEN and CENELEC for standardization in the field of machines
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Ref Project: SIST EN 842:1998+A1:2008 - Safety of machinery - Visual danger signals - General requirements, design and testing

Relations

• Merged From: EN 842:1996 - Safety of machinery - Visual danger signals - General requirements, design and testing
• Effective Date: 18-Jan-2023

Overview

EN 842:1996+A1:2008 - Safety of machinery - Visual danger signals - General requirements, design and testing - is a CEN standard that defines ergonomic and safety criteria for visual danger signals used around machinery. It specifies how visual warning and emergency signals should be designed, measured and subjectively checked so that people in the intended signal reception area can reliably detect, discriminate and react to the signal. The standard is aligned with the EU machinery safety framework and complements other signalling standards.

Key topics and technical requirements

• Scope & exclusions
  • Applies to visual danger signals intended to convey imminent or actual hazardous situations.
  • Does not apply to written/pictorial indicators or data-display transmissions, nor to special public-disaster or public-transport regulation.
• Types of signals
  • Visual warning signal (imminent danger): colour = yellow / yellow‑orange.
  • Visual emergency signal (immediate action required): colour = red.
• Detectability
  • For luminous area sources: luminance ratio (contrast) between signal and background - warning ≥ 5× background; emergency ≥ 10× background (i.e., at least twice a warning).
  • For point sources: detectability expressed via pupillary illuminance versus background luminance (physical measurement procedures included).
  • Flashing lights are required for emergency signals; recommended flash frequency ~2–3 Hz with similar ON/OFF intervals.
• Discriminability
  • Signals must be distinguishable by at least two characteristics (e.g., colour, location, temporal pattern, intensity).
  • Relative positioning rules (e.g., red above yellow) to avoid ambiguity.
• Placement & field of vision
  • Signals must be located within defined signal reception areas and positioned so at least one signal is visible from any point where reactions are required (guidance on vertical/horizontal fields of vision and recommended zones).
• Other ergonomic factors
  • Glare control, minimum effective distance, effects of transmissivity (fog, smoke), and duration requirements.
• Verification
  • Includes both physical measurements and subjective visual checks for validation.

Applications and users

• Who uses EN 842:
  • Machine designers and manufacturers
  • Safety engineers and ergonomists
  • Control-panel and HMI designers
  • Plant managers and maintenance teams
  • Compliance officers preparing CE documentation
• Practical uses:
  • Designing emergency/warning lighting for machinery and plants
  • Specifying signal colours, intensities and locations to meet ergonomic safety criteria
  • Testing and validating visual signalling systems during commissioning and periodic safety reviews

Related standards

• EN 292-2 (EN 292 series / EN 292-2:1991) - technical principles for machinery safety
• EN 60073, EN 61310-1, ISO 3864 - colour coding and signalling conventions
• EN 981 - auditory/visual signal systems
• ISO 11428 - international equivalent on visual danger signals
• Informative alignment with EU Machinery Directives (see Annex ZA/ZB in EN 842)

Using EN 842 helps ensure visual danger signals are ergonomically effective, unambiguous and verifiable - essential for reducing reaction time and improving workplace safety around machinery.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2008
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Safety of machinery - Visual danger signals - General requirements, design and testing
Sicherheit von Maschinen - Optische Gefahrensignale - Allgemeine Anforderungen,
Gestaltung und Prüfung
Sécurité des machines - Signaux visuels de danger - Exigences générales, conception et
essais
Ta slovenski standard je istoveten z: EN 842:1996+A1:2008
ICS:
13.110 Varnost strojev Safety of machinery
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 842:1996+A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2008
ICS 13.110 Supersedes EN 842:1996
English Version
Safety of machinery - Visual danger signals - General
requirements, design and testing
Sécurité des machines - Signaux visuels de danger - Sicherheit von Maschinen - Optische Gefahrensignale -
Exigences générales, conception et essais Allgemeine Anforderungen, Gestaltung und Prüfung
This European Standard was approved by CEN on 30 November 1995 and includes Amendment 1 approved by CEN on 14 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 842:1996+A1:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Definitions .4
4 Safety and ergonomic requirements .5
4.1 General.5
4.2 Detectibility.5
4.3 Discriminability .9
4.4 Glare.9
4.5 Distance .9
4.6 Duration .10
5 Physical measurements.10
6 Subjective visual check .10
Annex A (informative) Bibliography .11
Annex ZA (informative) !!!!Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/EC, amended by 98/79/EC"""" .12
Annex ZB (informative) !!!!Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC"""".13

Foreword
This document (EN 842:1996+A1:2008) has been prepared 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.
This document includes Amendment 1, approved by CEN on 2008-08-14.
This document supersedes EN 842:1996.
The start and finish of text introduced or altered by amendment is indicated in the text by tags ! ".
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association, and supports essential requirements of EU Directive(s).
!For relationship with EU Directive(s), see informative Annexes ZA and ZB, which are integral parts of this
document."
On the international level the International Standard ISO 11428 "Ergonomics – Visual danger signals –
General requirements, design and testing" has been prepared by WG 3 "Danger signs and speech
communication in noisy environments" of ISO/TC 159/SC 5 "Ergonomics of the physical environment". The
technical content of both the European Standard EN 842 and the International Standard ISO 11428 is
identical, however the limits of applicability of the standards to other technical fields are different.
Due to the different limits of applicability still existing on the European and international level direct
transformation of the International Standard into a European Standard is not possible. The reason is that EN
842 has been prepared in order to fulfil the essential safety and health requirements of annex 1 of the Council
Directive 89/392/EEC of 14 June 1989 on the approximation of the laws of the Member States relating to
machinery: Essential health and safety requirements relating to the design and construction of machinery (see
annex A of EN 292-2:1991/A1:1995) and that therefore the limits of applicability of the European Standard is
restricted to this Directive.
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 United Kingdom.

1 Scope
This European Standard describes criteria for the perception of visual danger signals in the area that people
are intended to perceive and to react to such a signal. It specifies the safety and ergonomic requirements and
the corresponding physical measurements and subjective visual check. It also provides guidance for the
design of the signals to be clearly perceived and differentiated as described in 5.3 of EN 292-2:1991.
This European Standard does not apply to danger indicators:
 Presented in either written or pictorial form;
 Transmitted by data display units.
This European Standard does not apply to special regulations such as those for public disaster and public
transport.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to
this European Standard only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
EN 292-2:1991/A1:1995, Safety of machinery - Basic concepts, general principles for design - Part 2:
Technical principles and specifications.
EN 60073, Coding of indicating devices and actuators by colours and supplementary means (IEC 73:1991).
EN 61310-1, Safety of machinery – Indicating, marking and actuating – Part 1: Requirements for visual,
auditory and tactile signals (IEC 1310-1:1995).
ISO 3864, Safety colours and safety signs.
3 Definitions
For the purposes of this standard the following definitions apply:
3.1
visual danger signal
visual signal indicating imminent onset, or actual occurrence of a dangerous situation, involving risk of
personal injury or equipment disaster, and requiring some human response to eliminate or control the danger
or requiring other immediate action.
A distinction is made between two types of visual danger signals: visual warning signal and visual emergency
signal.
3.1.1
visual warning signal
visual signal indicating the imminent onset of a dangerous situation requiring appropriate measures for the
elimination or control of the danger

3.1.2
visual emergency signal
visual signal indicating the beginning or the actual occurrence of a dangerous situation requiring immediate
action
3.2
signal reception area
area in which the signal is intended to be perceived and reacted upon
3.3
field of vision (visual field)
physical space visible to an eye in a given position (see also 3.1.10 of ISO 8995:1989)
3.4
danger signal light
light source intended to convey information about the existence of a dangerous situation by means of one or
1)
several characteristics, such as luminance colour, shape, location and temporal pattern
4 Safety and ergonomic requirements
4.1 General
The characteristics of the visual danger signal shall ensure that any person in the signal reception area can
detect, discriminate and react to the signal as intended. Visual danger signals shall be:
 Clearly seen under all possible lighting conditions;
 Clearly discriminated from general lighting and other visual signals;
 Allocated a specific meaning within the signal reception area.
Visual danger signals shall take precedence over all other visual signals.
Visual emergency signals shall take precedence over all visual warning signals.
Care shall be taken to review the effectiveness of the visual danger signals at regular intervals and whenever
a new signal (whether a danger signal or not) is introduced in the signal reception area.
NOTE 1 A visual danger signal should, if not contradicted by special reasons, be associated with an auditory danger
signal. When the danger signal is an emergency signal, auditory and visual signals should be presented together (see EN
981).
NOTE 2 It could be advantageous for visual danger signals to have a relatively low intensity test mode to indicate they
are functional but not in a warning mode.
4.2 Detectibility
1) 1) 1)
4.2.1 Luminance , illuminance and contrast

1) As defined in ISO 8995
...