BS EN 4731:2018 pdf download

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BS EN 4731:2018 pdf download

BS EN 4731:2018 pdf download.Aerospace series – Spectral quality of LED luminaires used with photoluminescent marking systems
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 iluminance 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一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
3.11 excitation coefficient
quotient that results from dividing the approximated weighted excitation irradiance EA by the sum of approximated weighted excitation irradiance and the photometrically weighted irradiance EV
Note 1 to entry: Ce = EA/(EA+EV) Ce is element of {0 to 1}
Note 2 to entry: The excitation coefficient indicates the spectral quality of a light source in view of charging strontium aluminate pigments relative to its brightness as perceived by the human eye or measured with a luxmeter. The bigger Ce is, the more effective is the light source with respect to charging of photoluminescent material.
4 Spectral quality
4.1 Method for determination of Ce for a luminaire
4.1.1 Single colour LED luminaires
The excitation coefficient Ce for single colour LED luminaires shall be determined according to the following steps:
1. Record the luminaire’s spectral irradiance Eλ(1) in steps of 1 nanometer (1 nm) in a steady state condition with a spectrometer in the wavelength range of 360 nm to 780 nm and an optical bandwidth not greater than 5 nm;
2. Calculate the photometrically weighted spectral irradiance EVA(2) by multiplying the spectral irradiance EN[E) and photopic luminosity function V[2) in steps of every nanometer;
3. Calculate the approximated weighted spectral excitation irradiance EAA[1) by multiplying the spectral irradiance EA(I] and the approximated excitation spectrum AA(n) in steps of every nanometer;
4. Calculate the photometrically weighted irradiance EV within in the range of 360 nm to 780 nm;