The basic components of the Concrete-Foam-Concrete Panel with Steel and Concrete Connections 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 and eight 8 x 8-in. solid-concrete penetrations through the insulation. As shown on the enclosed drawing, the guarded box completely covered 4 concrete penetrations during the hotbox test.
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.