Expanded polystyrene (EPS)
Expanded polystyrene (EPS) is a rigid and tough, closed-cell foam with a normal density range of 11 to 32 kg/m3. It is usually white and made of pre-expanded polystyrene beads, each of which is made of thin-walled, air-filled bubbles of polystyrene. EPS is used for food containers, molded sheets for building insulation, and packing material for cushioning fragile items inside boxes. Due to its technical properties such as low weight, rigidity, and formability, EPS can be used in a wide range of applications.
|Polystyrene beads||EPS foam||EPS foam concrete|
EPS thermal conductivity
Thermal conductivity is measured according to EN 12667. Typical values range from 0.032 to 0.038 W/(m·K) depending on the density of the EPS board.
EPS water vapor diffusion
Water vapor diffusion resistance (μ) of EPS is around 30–70.
|Expanded polystyrene EPS||EPS foam|
EPS oxygen index
ICC-ES (International Code Council Evaluation Service) requires EPS boards used in building construction meet ASTM C578 requirements. One of these requirements is that the oxygen index of EPS as measured by ASTM D2863 be greater than 24 volume %. Typical EPS has an oxygen index of around 18 volume %; thus, a flame retardant is added to styrene or polystyrene during the formation of EPS.
EPS flame retardant
The boards containing a flame retardant when tested in a tunnel using test method UL 723 or ASTM E84 will have a flame spread index of less than 25 and a smoke-developed index of less than 450. ICC-ES requires the use of a 15-minute thermal barrier when EPS boards are used inside of a building.
|Expanded polystyrene EPS sandwich concrete||Pre expanded polystyrene EPS concrete boards|