Browsing by Author "Roucour, Jean"

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    Glazing solar parameters evaluated by ISO, CEN and ASTM Standard procedures
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1996) Polato, Pietro; Daneo, Antonio; Roucour, Jean; Conti, Angelo
    The solar behaviour of glazing for architectural or automotive applications is generally characterized by (near) normal incidence spectrophotometry The spectral transmittance and reflectance curves are integrated in the solar range using a global or direct solar irradiance curve at sea level as a weighting function. These solar curves can be obtained taking into account the effects of the atmosphere on the extraterrestrial solar radiation and comparing the computed spectra with the measured spectral irradiance values on the earth surface. However, the theoretical global and direct solar curves depend on the model used to simulate the atmospheric behaviour (type of model and values assumed for the atmospheric parameters). Moreover, solar irradiance measurements made at ground level were limited in accuracy, at least in the past. For these reasons different solar curves were standardized by ISO, CEN and ASTM. Glass samples representative of commercial production are considered in this paper and a comparison is performed among t he values obtained for the solar parameters following international. European and American Standards .
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    Interlaboratory comparison of solar range transmittance and reflectance of coated and uncoated flat glass
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1994) Nicoletti, Fabiano; Polato, Pietro; Roucour, Jean
    Transmittance and reflectance measurements on glass for architectural applications using commercial spectrophotometers may be affected by errors resulting from an improperly operated instrument, an inappropriate calibration, etc. Discrepancies between the values of parameters such as light reflectance and solar factor measured on the same glass product by different laboratories can be very pronounced. In order to avoid disputes among glass producers and complaints from glass users the interlaboratory reproducibility and the accuracy of the measurements must be improved. A n intercomparison was organized by Technical Committee 10 "Optical Properties of Glass" of the International Commission on Glass among 15 laboratories and one metrological institute on transmittance and reflectance measurements on commercial coated and uncoated glasses. Good reproducibility and accuracy in transmittance measurements ( ± 0 . 6 %) have been achieved even with each laboratory using its own instrumental procedures. In the case of reflectance, a preliminary round robin performed using the same instruments gave very large discrepancies in the spectral and integrated values. Reproducibility and accuracy of the same order of magnitude as in the transmittance measurements were obtained when each laboratory used a standardized procedure and the same reference standards, the latter having optical characteristics similar to the samples.
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    Interlaboratory comparison of ultraviolet transmittance and reflectance of coated and uncoated flat glass : Report of the International Commission on Glass Technical Committee 10 "Optical Properties of Glass"
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1998) Polato, Pietro; Roucour, Jean; Simons, José
    Glass manufacturers generally characterize the ultraviolet behaviour of flat glass (glass for building or automotive applications) by normal incidence spectrophotometry. Intercomparisons have been organized by Technical Committee 10 of the International Commission on Glass among its members and one metrological Institute on spectrophotometric evaluations of ultraviolet transmittance and reflectance on uncoated and coated glasses. Spectral transmittance and reflectance were measured in the 280 to 380 nm ränge and parameters like UV transmittance and UV reflectance were computed following a procedure recommended by a European Standard. The purpose of these round robins was to assess the interlaboratory reproducibility and accuracy of the spectral measurements and of the computed values obtained by integration of the experimental data in the ultraviolet ränge. UV transmittance and UV reflectance were then evaluated for the selected samples using two new different ultraviolet radiation tables proposed by the International Organization for Standardization to evaluate the difference in the results obtained by applying the different Standard procedures. Finally, measurements were also performed in the first part of the visible ränge and a "Krochmann Damage Factor" was evaluated for the considered samples.