BS EN 4705:2020 pdf free.Aerospace series – Measurement methods regarding the lifetime behaviour of light units in a standardized aircraft-related environment.
BS EN 4705 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一LED colour and brightness ranking1 EN 13032-4, Light and lighting 一Measurement and presentation of photometric data of lamps and luminaires一Part 4: LED lamps, modules and luminaires  IES LM-80-08, Approved Method: Measuring Lumen Maintenance of LED Light Sources2. 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: 一IEC Electropedia: available at http:/ /www.electropedia.org/ 一ISO Online browsing platform: available at http:/ /www.iso.org/obp 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.The brightness decreases during lifetime. When it decreases below a defined limit the light unit does not fulfil the specification and the light unit shall be considered as faulty. The definition of the limit depends on the user case of the light unit.BS EN 4705 pdf download.