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Informal document No . GRE-65-29 (65th GRE, 28-31 March 2011, agenda item 14(d)). GRE-65-04 ’ s Justification HE Yuntang China Automotive Technology and Research Centre UNOG , Geneva , 31 March 2011. Point 1.
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Informal document No. GRE-65-29 (65th GRE, 28-31 March 2011, agenda item 14(d)) GRE-65-04’s JustificationHE YuntangChina Automotive Technology and Research CentreUNOG,Geneva, 31March2011
Point 1 Three new samples (lenses or samples of material) shall be exposedto radiation from a source having a spectral energy distribution similar to that of a black body at a temperature between 5,500 K and 6,000 K. daylight spectral energy distribution described in CIE Publication No. 85:1989, Table 4.
Point 1:reason The spectral energy distribution of sun light described in CIE Publication No. 85:1989, Table 4 is much more accurate than that described with Black body temperature. SAE J2527 Figure c2 Daylight filter VS. Sunlight spectral power distribution
Point 2 Reduce radiations with wave lengths smaller than 295 nm and greater than 2,500 nm,and the minimum and maximum levels of the relative spectral irradiance in the UV wavelength range are given in Table 1. Table 1 – Relative spectral irradiance of xenon-arc lamps with daylight filters
Point-2: reason Threshold UV Wavelengths • For degradation of polymer material, UV range is severer than visible and IR range. • UV table from ‘CIE Publication No. 85:1989, Table 4
Point-3 The samples shall be exposed to an energetic illumination of 1,200 W/m2 ±200 W/m2an light source with irradiance of 0.68±0.02W/m2 at 340nm,for a period such that the luminous energy that they receive is equal to 4,500 MJ/m2±200 MJ/m2the radiation energy that they receive is equal to 2,550±75kJ/m2.
Point-3: reason • UV is more severe than visible and IR light, exposure of the sample under 50 W/m2 of UV or IR light for 1000 hours will have totally different result. • It will be more accurate to set the irradiance of the light source base on UV version instead of total irradiance/illumination
Point-4 In order to ensure a regular exposure, the samples shall revolve around the source of radiation at a speed between 1 and 5 r/minthe irradiance at any position in the area used for specimen exposure shall be at least 80 % of the maximum irradiance.
Point-4: reason • Hardware based, limiting the use of test equipment • Performance based description is accepted by ISO 4892 Rotating Drum Xenon Arc Tester Cross Section