Thermal performance

In short, no. Steel conducts energy 1,700 times faster than insulation, and concrete does not insulate. Energy loss attributed to the effect of steel and concrete thermal bridges can be greater than 70%.

Heat flows from a warm region to a cool region. As stated earlier, steel and concrete passing through the insulation create thermal bridges with high rates of heat transfer. In an insulated wall with thermal bridges, energy will tend to flow in paths parallel to the insulation until it reaches the bridges and is conducted rapidly from the warm side to the cold side of the wall. Because the energy effectively flows from a large area surrounding each thermal bridge, the total affected area is much larger than the cross-sectional area of the bridge itself.

Yes. Significant research has recently been conducted at the Oak Ridge National Laboratory in Knoxville, TN using guarded hot box testing. Full-scale examples of many popular construction methods, including insulated concrete sandwich panels, have been tested. The test data verify that one can predict the thermal bridging effect with mathematic equations such as the Modified Isothermal Planes Analysis Method published in the ASHRAE Handbook of Fundamentals.

Only the composite connectors should tie the two wythes of concrete together. The insulation should extend to all edges and the top and bottom of the panel – eliminating all steel and concrete connections. Solid concrete sections not only produce thermal bridging but the also restrain the significant independent movement of the two concrete layers due to temperature change.