The BPF Expanded Polystyrene Group
EPS is 98% air
EPS is 100% recyclable

EPS applications

Properties of EPS

Four retaining walls insulated with EPS expanded polystyrene airpop

For construction applications the properties of EPS are determined according to a set of harmonised European Standards or BS ENs. BS EN 13163 is the base standard for EPS (see below)

The low, stable, thermal conductivity of EPS is the reason for its important use in reducing the carbon dioxide (CO2) emissions in our buildings. This vital property is declared as a 90/90 value defined in BS EN 13163 to represent 90% of production with a statistical certainty of 90%.

Other properties, for example compressive strength or tensile strength, can be declared at a variety of levels independently of each other. However in reality the number of standard products is relatively small and a typical range of properties is shown in the table below:

Typical properties of white EPS

Mechanical properties

  • Compressive stress @10% compression (kPa)

    EPS 70 70   

    EPS 100100

    EPS 150150

    EPS 200200

    EPS 250250

  • Compressive stress @1% strain (kPa)

    EPS 70 20   

    EPS 10045

    EPS 15070

    EPS 20090

    EPS 250100

  • Bending strength (kPa)

    EPS 70 115   

    EPS 100150

    EPS 150200

    EPS 200250

    EPS 250350

Moisture properties

  • Vapour resistivity (MNs/gm)

    EPS 70 145   

    EPS 100200

    EPS 150238

    EPS 200238

    EPS 250338

Thermal properties

  • Thermal Conductivity (λ) (W/mK at 10°C)

    EPS 700.038

    EPS 1000.036

    EPS 1500.035

    EPS 2000.034

    EPS 2500.034

SIPS panels using EPS expanded polystyrene airpop as insulation

The table gives typical properties for the traditional white EPS. A detailed explanation of all properties can be found in The White Book published on line at

In recent years developments have taken place to introduce a grey product which has the advantage of a lower thermal conductivity giving a 20% improvement in thermal resistance.

A thermal conductivity of 0.030W/mK can be achieved for EPS 70 or 100.


  • BS EN 13163:2008

    Thermal insulation products for buildings. Factory made products of expanded polystyrene (EPS). Specification

  • BS EN 13499:2003

    Thermal insulation products for buildings. External insulation composite systems (ETICS) based on expanded polystyrene. Specification

  • BS EN 14933:2007

    Thermal insulation and light weight fill products for civil engineering applications. Factory made products of expanded polystyrene (EPS). Specification

  • BS EN 13172:2008

    Thermal insulation products. Evaluation of conformity

  • BS 6203

    Guide to fire characteristics and fire performance of expanded polystyrene materials (EPS and XPS) used in building applications

Pitched roof using EPS expanded polystyrene airpop as insulation