1.foam board. XPS is an extruded polystyrene insulation manufactured through a plastic extrusion process. The resulting boards are almost 100% closed cell, strong, highly moisture resistant and easy to cut and shape. 2.1 Technical data sheet of the XPS foam board Density Kg/m3 36~40 Thermal conductivity, 90 days, 10°C W/mK 0.027~0.03 Compressive strength at 10% deflection or yield, (vertical) kPa ≥300 Tensile strength kPa ≥300 Water absorption Vol-% <=1.00% Capillarity nil nil Coefficient of linear thermal expansion mm/mK 0.07 Temperature limits °C -50°C, +75°C