RSTIB Thermal conductivity is the time rate of stable state heat flow through a unit area of 1 m-thick material in a direction perpendicular to the iso thermal planes that is induced by a unit temperature difference across the sample [2]. The thermal conductivity, k-value,is the property of a material to conduct heat. Hence, knowledge of the thermal conductivity values allows quantitative comparison to be made between the effectiveness of different thermal insulation materials [43].