The basic components of the Concrete-Foam-Concrete Panel with Steel Connectors are 2-in. thick layer of extruded polystyrene insulation installed between two 3-in. thick layers of concrete. These three layers are held together by #5 gauge Galvanized Steel C- clips installed on a 12-in. grid. For this panel, the guarded box covered about 82% of thermally bridged area. Because thermal bridges were relatively uniform distributed through the whole area of the tested panel, the tested area can be considered as a relatively good representation of the whole panel.
Thermal conductivities of the panel concrete and extruded polystyrene foam were tested by ORNL BTC Laboratory using hot plate apparatus - ASTM C 518-91. Thermal conductivity of foam at mean temp. 50 deg. F was k a = 0.2 Btu-in./hft 2F. Thermal conductivity of concrete was k a = 9.09 Btu-in./hft 2F.