EN 4731:2018

Aerospace series - Spectral quality of LED luminaires used with photoluminescent marking systems

This document defines a measure for the spectral quality of LED luminaires in terms of the ratio of the amount of visual light emitted by the luminaire versus the amount effective for charging photoluminescent products contained in that spectrum.
Fulfilment of this document by a LED luminaire will ensure general compatibility of the luminaire with photoluminescent marking systems.
This document alone does not provide any means of compliance to fulfil any airworthiness requirements.
For a specific aircraft installation, the spectral power distribution and illuminance at the photoluminescent marking systems are relevant.

Luft- und Raumfahrt - Spektrale Qualität von LED Leuchten zur Verwendung mit langnachleuchtenden Markierungssystemen

Dieses Dokument definiert eine Maßzahl für die spektrale Qualität von LED-Leuchten in Bezug auf das Verhältnis zwischen der Menge des abgegebenen sichtbaren Lichts und dem für die Aufladung langnach-leuchtender Produkte wirksamen Anteil dieses Spektrums.
Entspricht eine LED-Leuchte diesem Dokument stellt dies eine allgemeine Kompatibilität der Leuchte mit langnachleuchtenden Markierungssystemen sicher.
Dieses Dokument allein liefert kein Mittel zur Erfüllung jeglicher Anforderungen an die Lufttüchtigkeit.
Für spezifische Einbauten an Luftfahrzeugen sind die spektrale Leistungsverteilung und die Beleuchtungsstärke am Einbauort der langnachleuchtenden Markierungssysteme relevant.

Série aérospatiale - Qualité spectrale des luminaires à diodes électroluminescentes appliquées aux systèmes de marquage photoluminescents

Le présent document définit une mesure de la qualité spectrale des luminaires à diodes électroluminescentes en termes de rapport entre la quantité de lumière visuelle émise par le luminaire et la quantité efficace pour charger les produits photoluminescents contenus dans ce spectre.
Le respect du présent document par un luminaire à diodes électroluminescentes assure la compatibilité générale du luminaire avec les systèmes de marquage photoluminescents.
Le présent document à lui seul ne fournit aucun moyen de se conformer aux exigences de navigabilité.
Pour l’installation spécifique d'un aéronef, la distribution spectrale de puissance et l'éclairement des systèmes de marquage photoluminescents sont pertinents.

Aeronavtika - Spektralna kakovost LED-svetilk, ki se uporabljajo s fotoluminiscenčnimi sistemi označevanja

Ta evropski standard opredeljuje meritev spektralne kakovosti LED-sijalk v smislu razmerja med količino vidne svetlobe, ki jo odda svetilka, in dejansko količino svetlobe, potrebno za polnjenje fotoluminiscenčnih izdelkov tega spektra.
Izpolnjevanje tega evropskega standarda za LED-sijalke bo zagotovila splošno skladnost svetilk s sistemi za fotoluminiscenčno označevanje.
Ta evropski standard sam po sebi ne vsebuje nobenega načina usklajevanja za izpolnjevanje zahtev glede plovnosti.
Za posebne letalske instalacije je pomembna porazdelitev spektralne moči in osvetljenost sistemov za fotoluminiscenčno označevanje.

General Information

• Status: Published
• Publication Date: 15-May-2018
• Withdrawal Date: 29-Nov-2018
• ICS: 29.140.99 - Other standards related to lamps
• ICS: 49.095 - Passenger and cabin equipment
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 12/WG 4 - Displays, projection and interior lighting
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 16-May-2018
• Completion Date: 16-May-2018
• Ref Project: SIST EN 4731:2018 - Aerospace series - Spectral quality of LED luminaires used with photoluminescent marking systems

Overview

EN 4731:2018 (CEN) defines a quantitative measure of the spectral quality of LED luminaires intended to charge photoluminescent marking systems used in aerospace interiors. The standard establishes a repeatable test method and a single metric - the excitation coefficient (Ce) - that relates the portion of a luminaire’s emitted light that is effective for charging common photoluminescent pigments (based on strontium aluminate) to the luminaire’s perceived visual light output.

Key topics and technical requirements

• Excitation coefficient (Ce): Ce = EA / (EA + EV), where EA is the approximated weighted excitation irradiance and EV is the photometrically weighted irradiance. Ce ranges from 0 to 1 and rates spectral charging effectiveness.
• Measurement method:
  • Record spectral irradiance Eλ(λ) from 360 nm to 780 nm in 1 nm steps with an instrument optical bandwidth ≤ 5 nm.
  • Compute EVλ(λ) = Eλ(λ) · V(λ) using the CIE photopic luminosity function (CIE 018.2:1983).
  • Use the approximated excitation spectrum Aλ(λ) for typical SrAl2O4 pigments (Aλ(λ) ≈ −(1/130)·λ + 3.7692 for 360–490 nm) to compute EAλ(λ) = Eλ(λ) · Aλ(λ).
  • Integrate EV over 360–780 nm and EA over 360–490 nm, then calculate Ce.
• Classification and labelling:
  • Ce classes: A (Excellent) Ce > 0.140; B (Good) 0.100 < Ce ≤ 0.140; C (Limited) 0.060 < Ce ≤ 0.100; D (Poor) 0 < Ce ≤ 0.060.
  • Product data sheets must show Ce with three decimals. For multi-colour luminaires, the colour scenario parameters used to derive Ce must be provided (minimum comparison case: S4000 per EN 4706).
• Scope limits: EN 4731:2018 ensures spectral compatibility with photoluminescent marking systems but is not by itself an airworthiness compliance method. For installations, local spectral power distribution and illuminance at the marking surface remain essential.

Applications and users

• Aircraft lighting designers and OEMs specifying cabin LED luminaires to ensure compatibility with photoluminescent emergency markings.
• Lighting manufacturers and test laboratories measuring spectral power distribution and reporting Ce for product datasheets.
• Certification engineers, safety managers and procurement teams who need to compare luminaires for effective charging of photoluminescent escape path marking systems.
• Maintenance planners verifying cabin lighting performance against spectral charging requirements.

Related standards

• EN 4706 - Aerospace series: LED colour and brightness ranking (referenced for multi-colour settings)
• CIE 018.2:1983 - The basis of physical photometry (photopic luminosity function V(λ))

Keywords: EN 4731:2018, spectral quality, LED luminaires, photoluminescent marking systems, excitation coefficient Ce, spectral irradiance, spectral power distribution, strontium aluminate, aerospace lighting.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2018
$HURQDYWLND6SHNWUDOQDNDNRYRVW/('VYHWLONNLVHXSRUDEOMDMRV
IRWROXPLQLVFHQþQLPLVLVWHPLR]QDþHYDQMD
Aerospace series - Spectral quality of LED luminaires used with photoluminescent
marking systems
Luft- und Raumfahrt - Spektrale Qualität von LED Leuchten zur Verwendung mit
langnachleuchtenden Markierungssystemen
Série aérospatiale - Qualité spectrale des diodes électroluminescentes appliquées aux
systèmes de marquage photoluminescents
Ta slovenski standard je istoveten z: EN 4731:2018
ICS:
29.140.40 Svetila Luminaires
49.060 /HWDOVNDLQYHVROMVND Aerospace electric
HOHNWULþQDRSUHPDLQVLVWHPL equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 4731
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2018
EUROPÄISCHE NORM
ICS 29.140.99; 49.095
English Version
Aerospace series - Spectral quality of LED luminaires used
with photoluminescent marking systems
Série aérospatiale - Qualité spectrale des luminaires à Luft- und Raumfahrt - Spektrale Qualität von LED
diodes électroluminescentes appliquées aux systèmes Leuchten zur Verwendung mit langnachleuchtenden
de marquage photoluminescents Markierungssystemen
This European Standard was approved by CEN on 20 November 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4731:2018 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 Spectral quality . 7
Annex A (informative) Approximated excitation spectrum . 10
A.1 General . 10
A.2 Approximated excitation spectrum Aλ(λ) for typical photoluminescent pigments
based on strontium aluminate . 10
Annex B (informative) Examples of different light spectra . 11
B.1 Example for a single colour LED luminaire . 11
B.2 Example for a multi-colour LED luminaire (white primary mixed with blue primary) . 12
B.3 Example for a multi-colour LED luminaire (all RGBW primaries are mixed) . 13
B.4 Example for a bi-colour LED luminaire (white and amber primaries are mixed) . 14
B.5 Example for a bi-colour LED luminaire (white and amber primaries are mixed) . 15

European foreword
This document (EN 4731:2018) 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 November 2018, and conflicting national standards
shall be withdrawn at the latest by November 2018.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
Photoluminescent marking systems are commonly used in passenger airplanes to provide visual
guidance in emergency events. Those marking systems need to be charged by ambient light during
cabin preparation and/ or aircraft operation as to be operational if, at any phase of a flight, an
emergency occurs.
While the certification regulations require photoluminescent marking system to be sufficiently charged
solely by cabin interior lighting, i.e. without accounting for daylight entering the cabin through
windows, only certain portions of the visual light spectrum emitted by a cabin interior luminaire are
stored by the photoluminescent pigment and thus contribute to charging.

1 Scope
This document defines a measure for the spectral quality of LED luminaires in terms of the ratio of the
amount of visual light emitted by the luminaire versus the amount effective for charging
photoluminescent products contained in that spectrum.
Fulfilment of this document by a LED luminaire will ensure general compatibility of the luminaire with
photoluminescent marking systems.
This document alone does not provide any means of compliance to fulfil any airworthiness
requirements.
For a specific aircraft installation, the spectral power distribution and illuminance at the
photoluminescent marking systems are relevant.
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
CIE 018.2:1983, The basis of physical photometry
3 Terms, definitions and abbreviations
For the purposes of this document, the following terms, definitions and abbreviations 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
single colour LED luminaire
luminaire using one or more LEDs as source of light whereas the luminaire is designed to operate in a
single colour mode only
3.3
multiple colour LED luminaire
luminaire using two or more LEDs as source of light whereas the LEDs are of at least two different
primary wavelengths and the luminaire is designed to operate in two or more colour modes by
controlling the light output of the different primaries independently
3.4
spectral irradiance
Eλ(λ)
function that relates the spectral irradiance Eλ of a light source to the wavelength λ
Note 1 to entry: The function’s unit is [W/m²/nm].
3.5
photopic luminosity function
V(λ)
function that relates the average spectral sensitivity of human visual perception of brightness at
photopic light levels to the wav
...