What is Expanded Polystyrene (EPS)?

Foamex expanded polystyrene (polymerised styrene) is a rigid cellular plastic foam material derived from petroleum and natural gas byproducts. Styrene is produced from benzene and ethylene, and is polymerised in the presence of catalysts, usually organic peroxides. The beads of resin are subjected to steam, which causes the thermoplastic polystyrene to soften and expand up to 40 times its original volume. Each small bead of polystyrene is fully sealed.

No chlorofluorocarbons (CFCs) are contained in, nor are they used in the manufacture of Foamex EPS.

Once conditioned by ageing, the EPS beads are blown into a mould, and steam is used in the forming process. The EPS product is then dried and finished by a number of processes, such as hot wire cutting or lamination.

Characteristics of Polystyrene

Foamex Polystyrene (EPS) is a durable, economical material with all of the following advantages;

FIRE PROPERTIES - Foamex blocks and sheets are manufactured from a fire retardant raw material and are not an undue fire hazard when correctly installed. The polystyrene will burn when in contact with a flame, like other organic building materials, but will self extinguish when the fire source is removed.

R-VALUE - Foamex Polystyrene is manufactured in seven grades to Australian Standard AS 1366 Part 3-1992. These grades relate to the density of the product, which affects their physical strength as well as the thermal resistance (R-Value). As the density increases so does the thermal resistance.

LONG TERM ‘R’ VALUE - Foamex Polystyrene’s cellular structure means it is stable and will not settle. Installed correctly without damage it will not deteriorate with age and will deliver constant R values for the life of the building.

WATER RESISTANCE - Expanded beads are a closed cell and do not absorb water. When molded into a block or shape tiny channels are formed between particles and when immersed these channels can fill with water. After prolonged saturation (one year or more) up to 6% water content by volume may exist in the expanded polystyrene. Even then EPS suffers little effect maintaining its shape, size, structure, cohesion and appearance.

Foamex Polystyrene exhibits no capillary action. This makes it suitable for use when in contact with the ground.

MATERIAL SAFETY DATA SHEET - FOAMEX STYROBOARD AND EXPANDED POLYSTYRENE PRODUCTS.PDF