EN 4705:2020

SLOVENSKI STANDARD
01-april-2020
Aeronavtika - Merilne metode v zvezi z obnašanjem svetlobnih enot v njihovi
življenjski dobi v standardiziranem letalskem okolju
Aerospace series - Measurement methods regarding the lifetime behaviour of light units
in a standardized aircraft-related environment
Luft- und Raumfahrt - Messverfahren zur Bestimmung der Lebenszeit von Leuchten in
einem standardisierten luftfahrzeugnahen Umfeld
Série aérospatiale - Méthodes de mesure du comportement lié à la durée de vie des
systèmes d’éclairage dans un environnement normalisé destiné aux aéronefs
Ta slovenski standard je istoveten z: EN 4705:2020
ICS:
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
91.160.01 Razsvetljava na splošno Lighting in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 4705
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 49.095
English Version
Aerospace series - Measurement methods regarding the
lifetime behaviour of light units in a standardized aircraft-
related environment
Série aérospatiale - Méthodes de mesure du Luft- und Raumfahrt - Messverfahren zur Bestimmung
comportement lié à la durée de vie des systèmes der Lebenszeit von Leuchten in einem standardisierten
d'éclairage dans un environnement normalisé destiné luftfahrzeugnahen Umfeld
aux aéronefs
This European Standard was approved by CEN on 14 July 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4705:2020 E
worldwide for CEN national Members.

Contents
Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviations . 5
4 Definition of lifetime . 7
4.1 General . 7
4.2 Light unit fails . 7
4.3 The brightness of the light unit falls below a defined limit . 8
4.4 The chromaticity of the light unit is out of a defined limit . 8
5 Failure mode identification . 8
5.1 General . 8
5.2 Brightness degradation calculation selection . 8
5.3 Colour degradation . 8
6 Operating the light unit . 9
6.1 General . 9
6.2 Installation orientation . 10
6.3 Installation condition . 10
6.4 Ambient temperature . 10
6.5 Power supply . 11
7 Light measurement . 11
7.1 General . 11
7.2 Measurement method . 11
7.3 Measurement uncertainty of long term stability . 12
7.4 Determination of the start value . 12
7.5 Measurement intervals . 12
Bibliography . 13

European foreword
This document (EN 4705:2020) has been prepared by the Aerospace and Defence Industries
Association of Europe - Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this Standard has
received the approval of the National Associations and the Official Services of the member countries of
ASD, prior to its presentation to CEN.
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 August 2020, and conflicting national standards shall
be withdrawn at the latest by August 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 organisations 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.
Introduction
The light output of all light sources decreases over time and also the chromaticity coordinates may
change. Because of a longer lifetime of modern light sources, like LEDs, a brightness decrease or a
chromaticity locus shift can be expected more often than a complete failure of the light source.
This document is applicable to all kind of aircraft cabin light sources including those with means for
ageing compensation.
1 Scope
This document describes the measurement method for the lifetime behaviour of aircraft cabin light
units in a standardized aircraft-related environment.
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.
EN 4706, Aerospace series — LED colour and brightness ranking
EN 13032-4, Light and lighting — Measurement and presentation of photometric data of lamps and
luminaires — Part 4: LED lamps, modules and luminaires
IES LM-80-08, Approved Method: Measuring Lumen Maintenance of LED Light Sources
3 Terms, definitions and abbreviations
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
 IEC Electropedia: available at http://www.electropedia.org/
 ISO Online browsing platform: available at http://www.iso.org/obp
3.1
light-emitting diode
LED
solid state device embodying a p-n junction, emitting optical radiation when excited by an electric
current
3.2
luminance
photometric measure of the luminous intensity per unit area of light travelling in a given direction
Note 1 to entry: The unit is cd/m .
3.3
illuminance
photometric measure of the total luminous flux incident on a surface, per unit area
Note 1 to entry: The unit is lx.
3.4
colour space
description model to define light colours in a two-dimensional (colour without intensity, e.g. xy space
CIE 1931) or three-dimensional space, (colour and intensity, e.g. Yxy CIE 1931)

1 Published as ASD-STAN Prestandard at the date of publication of this standard by AeroSpace and Defence
Industries Association of Europe – Standardization (ASD-STAN) (www.asd-stan.org).
2 Published by Illumination Engineering Society (IES), 120 Wall Street, Floor 17, New York NY 10005-4001, USA
3.5
CIE 1931 colour space
description of a two-dimensional colour space for light colours
Note 1 to entry: In the CIE 1931 diagram the colour coordinates x and y describe the chromaticity locus in the
diagram. For this document the CIE 1931 2° observer is applicable.
3.6
chromaticity coordinate
two-dimensional data representation of the colour in the corresponding colour space, e.g. x and y for the
CIE 1931
3.7
MacAdam ellipse
area in the corresponding colour space (e.g. CIE 1931) in which all colours have the same visual
impression to an observer as the colour in the centre of this area
Note 1 to entry: The borderline of the ellipse represents the just noticeable colour difference. Based on
experimental data, originally 25 MacAdam ellipses were defined in the CIE 1931 colour space. In the experiment
an observer had a given colour and was able to modify the chromaticity locus of a second colour. The chromaticity
loci, where the observer determined a difference between the two colours were recorded. When all these points
were plotted in the CIE 1931 diagram, they created an ellipse around the chromaticity locus of the given colour.
The size and the orientation of the ellipses are different for different colours.
[SOURCE: D. L. MacAdam]
3.8
Standard Deviation of Colour Matching
SDCM
for a given target chromaticity locus, the metric of the distance between light colours at photopic light
level, that describes approximately the perceptual distance between two chromaticity loci as a multiple
of the MacAdam ellipses for these chromaticity loci
Note 1 to entry: n SDCM means that the distance between the two chromaticity loci is n-times the radius of the
appropriate MacAdam ellipse in that direction. The centre of the ellipse is given by the chromaticity locus of the
specified colour. Two chromaticity loci on opposite points of the MacAdam ellipse have a distance of (2 n) SDCM.
The SDCM calculation between two chromaticity loci may be non-linear, dependent on the selected colour space.
Therefore distances are limited to less than 10 SDCM.
Note 2 to entry: For this document the calculated data from the MacAdam ellipses has been used.
3.9
chromaticity coordinate distance
R
perceived chromaticity coordinate distance between any chromaticity loci and the target chromaticity
locus in the corresponding colour space which is expressed in SDCM values
Note 1 to entry: The maximum chromaticity coordinate distance between any two chromaticity loci is the full
diameter 2 × R of the corresponding n-times scaled MacAdam ellipse:
R is the function which describes the radius of an n-times scaled MacAdam ellipse:
𝑅𝑅=𝑛𝑛⋅SDCM
Figure 1 shows the chromaticity coordinate distance in a n SDCM ellipse.
Key
1 Target chromaticity locus
2 Colour 1
3 Colour 2
4 Colour 3
5 Limit R = n × SDCM
X Chromaticity coordinate x
Y Chromaticity coordinate y
Figure 1 — Chromaticity coordinate distance in a n SDCM ellipse
4 Definition of lifetime
4.1 Ge
...