EN ISO 24550:2019

Ergonomics - Accessible design - Indicator lights on consumer products (ISO 24550:2019)

This document specifies design requirements and recommendations for indicator lights, mainly LED sourced, on consumer products for use by older people and people with visual disabilities. It does not consider the needs of persons who are blind.
Indicator lights include those that inform users visually about the conditions, changes in functional status and settings, and malfunction of products. They convey information by light on/off, time-modulated intensity, blinking, colour, luminance level, and layout.
This document addresses household and home appliances. It excludes electronic displays presenting characters and graphics, machinery, and appliances in special use for professional, technical, and industrial applications.

Ergonomie - Zugängliche Gestaltung - Kontrollleuchten an Konsumgütern (ISO 24550:2019)

Dieses Dokument legt Anforderungen und Empfehlungen für die Gestaltung von Kontrollleuchten, zumeist mit LED-Lichtquelle, an Konsumgütern für den Gebrauch durch ältere Menschen und Menschen mit Sehbehinderungen fest. Es berücksichtigt nicht die Bedürfnisse von Menschen, die blind sind.
Kontrollleuchten umfassen Leuchten, die Benutzer optisch über die Zustände, Veränderungen des Funktionsstatus und der Einstellungen sowie Fehlfunktionen von Produkten informieren. Sie vermitteln Informationen durch ihr Aufleuchten oder Erlöschen, zeitliche Modulation ihrer Lichtstärke, Blinken, Farbe, unterschiedliche Leuchtdichten und durch ihre Anordnung.
Dieses Dokument bezieht sich auf Geräte für den Hausgebrauch. Es bezieht sich nicht auf elektronische Anzeigeeinrichtungen zur Darstellung von Zeichen und Graphiken, Maschinen, und Geräte, die speziell in beruflichen, technischen und industriellen Anwendungen verwendet werden.

Ergonomie - Conception accessible - Voyants lumineux sur les produits de consommation (ISO 24550:2019)

Le présent document spécifie des exigences et des recommandations de conception des voyants lumineux, principalement à base de LED, sur les produits de consommation courante destinés à être utilisés par des personnes âgées et des personnes malvoyantes. Il ne prend pas en compte les besoins des personnes non voyantes.
Les voyants lumineux englobent les voyants qui informent visuellement les utilisateurs sur les conditions, les changements d'état fonctionnel et les réglages, ainsi que sur le dysfonctionnement des produits. Ils fournissent des informations par leur état allumé/éteint, par la modulation de leur intensité dans le temps, leur clignotement, leur couleur, leur niveau de luminance et leur configuration.
Le présent document concerne les produits et appareils électroménagers. Il exclut les écrans électroniques affichant des caractères et des graphiques, les machines et les appareils pour usages spéciaux destinés à des applications professionnelles, techniques et industrielles.

Ergonomija - Dostopno načrtovanje - Indikatorji svetil za proizvode (ISO 24550:2019)

General Information

• Status: Published
• Publication Date: 19-Nov-2019
• Withdrawal Date: 30-May-2020
• ICS: 11.180.15 - Aids for deaf and hearing impaired people
• ICS: 13.180 - Ergonomics
• Technical Committee: CEN/TC 122 - Ergonomics
• Drafting Committee: CEN/TC 122/WG 11 - Ergonomics of the Physical Environment
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 20-Nov-2019
• Completion Date: 20-Nov-2019
• Ref Project: SIST EN ISO 24550:2020 - Ergonomics - Accessible design - Indicator lights on consumer products (ISO 24550:2019)

Overview

EN ISO 24550:2019 - Ergonomics: Accessible design - Indicator lights on consumer products (adopted by CEN) specifies design requirements and recommendations for indicator lights (mainly LED-sourced) on household and home appliances to improve accessibility for older people and people with visual disabilities. The standard covers visual signalling by on/off, time‑modulated intensity, blinking, colour, luminance and layout. It excludes full electronic displays (characters/graphics), industrial/professional machinery and the needs of people who are blind.

Key topics and technical requirements

• Modes of lighting: Defines recognisable modes such as light-on, light-off, blinking and gradual luminance changes - each mode should convey a distinct meaning to users.
• Colour use: Colours must be noticeable relative to surroundings; multiple colours in one product must be discriminable. Colour must not be the sole means of differentiation.
• Luminance and visibility: Guidance on adequate luminance levels and contrast to ensure visibility for people with reduced vision and in various ambient lighting conditions.
• Size and small-field effects: Defines a small indicator light as an emitting area with visual angle < 20' (≈ 3 mm at 50 cm) and explains how apparent brightness and colour perception change for small lights.
• Temporal characteristics: Addresses perceptible temporal luminance differences and blinking frequencies to avoid ambiguous or uncomfortable signals.
• Location and layout: Recommendations for consistent placement and grouping of indicator lights on control panels to support quick interpretation.
• Alternative presentations and marking: Encourages alternate or redundant information channels (e.g., tactile marks, text labels, audio cues) and clear marking of the indicator meaning.
• Conformance: Describes conformance expectations and references normative documents that inform implementation.

Practical applications and users

Who uses EN ISO 24550:2019:

• Product designers and UX/ergonomics specialists designing home appliances and consumer electronics.
• Manufacturers and component suppliers (LED indicators, control panels).
• Accessibility consultants, usability testers and compliance officers.
• Procurement teams and regulatory assessors seeking accessible-device criteria.

Practical benefits:

• Improves usability and safety for older adults and users with low vision.
• Reduces misinterpretation of operational status and faults.
• Helps manufacturers meet accessibility best practices and market expectations.

Related standards

• ISO/IEC Guide 71 - Accessibility in standards
• ISO 17049 - Braille on equipment and appliances
• CIE S 017 - International Lighting Vocabulary (luminance definitions)
• ISO/TR 22411 and ISO 24505 - Accessibility and colour guidance

Keywords: EN ISO 24550:2019, indicator lights, ergonomics, accessible design, LED indicators, consumer products, low vision, luminance, blinking frequency, colour contrast.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2020
Nadomešča:
SIST EN ISO 24500:2011
Ergonomija - Dostopno načrtovanje - Indikatorji svetil za proizvode (ISO
24550:2019)
Ergonomics - Accessible design - Indicator lights on consumer products (ISO
24550:2019)
Ergonomie - Zugängliche Gestaltung - Kontrollleuchten an Konsumgütern (ISO
24550:2019)
Ergonomie - Conception accessible - Voyants lumineux sur les produits de
consommation (ISO 24550:2019)
Ta slovenski standard je istoveten z: EN ISO 24550:2019
ICS:
11.180.15 Pripomočki za gluhe osebe in Aids for deaf and hearing
osebe z okvaro sluha impaired people
13.180 Ergonomija Ergonomics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 24550
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2019
EUROPÄISCHE NORM
ICS 11.180.15; 13.180
English Version
Ergonomics - Accessible design - Indicator lights on
consumer products (ISO 24550:2019)
Ergonomie - Conception accessible - Voyants lumineux Ergonomie - Zugängliche Gestaltung - Kontrollleuchten
sur les produits de consommation (ISO 24550:2019) an Konsumgütern (ISO 24550:2019)
This European Standard was approved by CEN on 25 October 2019.

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-CENELEC 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-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 24550:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 24550:2019) 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 May 2020, and conflicting national standards shall be
withdrawn at the latest by May 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
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,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 24550:2019 has been approved by CEN as EN ISO 24550:2019 without any modification.

INTERNATIONAL ISO
STANDARD 24550
First edition
2019-10
Ergonomics — Accessible design —
Indicator lights on consumer products
Ergonomie — Conception accessible — Voyants lumineux sur les
produits de consommation courante
Reference number
ISO 24550:2019(E)
©
ISO 2019
ISO 24550:2019(E)
© ISO 2019
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, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 24550:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Accessibility considerations related to indicator lights . 2
4.1 Modes of lighting condition . 2
4.2 Colour . 3
4.3 Luminance . 3
4.4 Size . 5
4.5 Temporal luminance difference and blinking light frequency . 5
4.6 Location . 6
4.7 Alternative presentation of indicator light information. 6
4.8 Marking of the indicator light meaning . 7
4.9 Other factors . 7
5 Conformance . 7
Bibliography . 8
ISO 24550:2019(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.
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 159, Ergonomics, Subcommittee SC 4,
Ergonomics of human-system interaction.
This first edition cancels and replaces ISO 24500:2010.
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 © ISO 2019 – All rights reserved

ISO 24550:2019(E)
Introduction
Indicator lights of consumer products provide important information to use products properly.
Although their importance is recognized widely, many difficulties exist in relation to indicator lights
such as insufficient on/off visibility, unclear implications of lighting modes, and discomforting glare are
reported by users, particularly by older persons or persons with visual disabilities. These claims result
from the lack of a relevant standard related to indicator lights design. This document is intended to
provide design requirements and recommendations for adequate brightness, colour, and use of blinking
lights of indicator lights considering the needs of older persons and persons with visual disabilities.
This document adopts the concepts of accessibility given in ISO/IEC Guide 71 and in ISO/TR 22411.
INTERNATIONAL STANDARD ISO 24550:2019(E)
Ergonomics — Accessible design — Indicator lights on
consumer products
1 Scope
This document specifies design requirements and recommendations for indicator lights, mainly LED
sourced, on consumer products for use by older people and people with visual disabilities. It does not
consider the needs of persons who are blind.
Indicator lights include those that inform users visually about the conditions, changes in functional
status and settings, and malfunction of products. They convey information by light on/off, time-
modulated intensity, blinking, colour, luminance level, and layout.
This document addresses household and home appliances. It excludes electronic displays presenting
characters and graphics, machinery, and appliances in special use for professional, technical, and
industrial applications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO/IEC Guide 71, Guide for addressing accessibility in standards
ISO 17049, Accessible design — Application of braille on signage, equipment and appliances
CIE S 017, ILV: International Lighting Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 71 and CIE S 017
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
consumer product
product that is intended to be acquired and used by an individual for personal rather than
professional use
[SOURCE: ISO/TS 20282-2:2013, 4.3]
3.2
indicator light
light which is associated with the operation of a product and is indicative of th
...