Adaptation of the ISO/DIS 11551 to absorptance measurement of low thermal conductors

The ISO/DIS 11551 is valid only for materials with high thermal conductivity. The application of this standard to the calorimetric measurements of sample with low thermal conductivity like glass results in large deviations between the measured and the actual values of absorptance. These deviations depend on the applied methods of analysis and on several parameters. In this paper the influence of irradiation time and detection place is presented. Those influences are described theoretically and compared with the experimentally results, where a good agreement were achieved. It will be shown that by using a modified standard the absorptance measurement of samples with low thermal conductivity is possible.