Ranges are marked with "–". Heat Transfer Engineering . The image below illustrates application of the insulative material in a typical home construction. Various Insulation Material Thermal Conductivity Chart. K) at 10 °C. These data allow describing the foam structure from which a finite element model is derived to predict the thermal conductivity of the foam. The results are compared with experimental values measured by a new guarded hot plate apparatus adapted for the range of thermal conductivity values of interest. In general, thermal insulation is primarily based on the very low thermal conductivity of gases . Extruded polystyrene foam (XPS) consists of closed cells and offers improved surface roughness, higher stiffness and reduced thermal conductivity. ASTM C578 Standard Specification for Rigid Cellular Polystyrene Thermal Insulation addresses the physical properties and performance characteristics of EPS foam as it relates to thermal insulation in construction applications. R-values per inch given in SI and Imperial units (Typical values are approximations, based on the average of available results. Thermal Conductivity of Expanded Polystyrene. Typical thermal conductivity values for polyurethane foams are between 0.022 and 0.035W/m∙K. Thermal conductivity is defined as the amount of heat (in watts) transferred through a square area of material of given thickness (in metres) due to a difference in temperature.The lower the thermal conductivity of the material the greater the material’s ability to resist heat transfer, and hence the greater the insulation’s effectiveness. Insulation Material Thermal Conductivity Chart . Polystyrene foams are good thermal insulators and are therefore often used as building insulation materials.