Intercomparison of thermal conductivity measurements on an expanded glass granulate in a wide temperature range

The German expert group “AK-Thermophysik” of the Association of Thermal Analysis (GEFTA, Gesellschaft für Thermische Analyse e.V.) further initiated a round robin test for thermal conductivity in the year 2012. With this additional use of the expanded glass granulate material, more experience with transient methods and thermal conductivity values in the extended temperature range could be obtained. The thermal conductivity of expanded glass granulates was determined from −170 °C to 530 °C with different methods and apparatuses. Within this temperature range the thermal conductivity increases from about 0.030 W m−1 K−1 to 0.160 W m−1 K−1. The comparison with the reference curve of the VDI/Keymark indicates very good compliance within 4% for most cases.