Vejledning 3 - Isoleringssystemer / Expanded polystyrene (EPS)

Expanded polystyrene (EPS)

Insulation made of man-made materials

Expanded polystyrene (EPS) is from the family of polystyrene products, made from cellular plastic.

The raw material for polystyrene is crude oil. During manufacturing polystyrene balls are expanded, as the expansion agent pentane is used and water vapour and heat is applied. The obtained spheres are then merged together to form the boards, therefore EPS has partly open structure of pores.

Typical final product is EPS boards. Since the pores of insulation material are filled with air, this insulation material is used in non-load bearing applications. The perforation and cutting can be done at the construction site without losing the thermal properties of the material.

Usually EPS boards are white, but the more innovative have grey colour because of graphite additives; these additives are applied to improve the insulation performance.

Thermal properties are dependent on temperature, moisture and mass density of the material. Typical values for thermal conductivity is 0.030 – 0.040 W/(mK), while reference standard EN 13163:2012 is 0.034 – 0.037 W/(m K) for dry material at 10 °C. Thermal conductivity of EPS increases 33 % (from 0.036 W/(m K) to 0.054 W/(m K)) in the case the moisture content in the insulation material increases from 0 vol% to 10 vol%.