Investigation of thickness and density dependence of thermal conductivity of expanded polystyrene insulation materials

Analysis of thermal conductivity of different insulation materials is very important in applications for passive and nearly zero houses. This paper presents the measurements results of the thermal conductivities of expanded polystyrene (EPS) insulation materials, with different thicknesses and air pore content. The measurements were achieved on pure (white) as well as graphite-enhanced (grey) EPS slabs, with a Holometrix type 2000 series heat flow meter after desiccating them in a Venticell 111 type drying apparatus to changeless weight. The densities of the white samples were varied from 10 to 26 kg/m3 (EPS types 30–200 and grey), furthermore both the white ones and the grey (14 kg/m3) samples with three different thicknesses (5, 8, 10 cm) were tested. In addition, experimental results for the density dependence of thermal conductivity at low densities are given. Thermal conductivity measurements of different white slabs in combination with grey slabs were executed also and the changes in the thermal conductivity values are presented.