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In this work an inexpensive instrument which is able to measure the thermal conductivity constants of building materials, especially the stone siding was built in our laboratory.
The function of this apparatus is based on thermal equilibrium on a flat surface. It is able to measure thermal conductivity constants of stones with the dimensions of 40 x 20 x 10 centimeter.
With this apparatus the thermal conductivity constant -for 20 different stone sidings from different regions in Iran was evaluated. The results were between 1.7 to 3 Kcal.m-1 hr-1 .dg-1.
Among the stones, .the Haj Hassan TRAVERTAN of Ghom and TRAVERTAN of Mahallat had the least thermal conductivity lowest.