 Properties of EPS
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) www.bsi-global.co.uk
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 |
| Product Type |
EPS 70 |
EPS100 |
EPS150 |
EPS200 |
EPS250 |
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| MECHANICAL PROPERTIES |
| Compressive stress @10% compression (kPa) |
70 |
100 |
150 |
200 |
250 |
| Compressive stress@1% strain (kPa) |
20 |
45 |
70 |
90 |
100 |
| Bending strength (kPa) |
115 |
150 |
200 |
250 |
350 |
| |
| MOISTURE PROPERTIES |
| Vapour resistivity (MNs/gm) |
145 |
200 |
238 |
238 |
238 |
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| THERMAL PROPERTIES |
| Thermal Conductivity (λ) (W/mK at 10°C) |
0.038 |
0.036 |
0.035 |
0.034 |
0.034 |
 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 www.eumeps.org
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
Standards
| 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 |
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