Raw Materials

EPS 650 FF


Fire retardant expanded polystyrene EPS 650 FF is manufactured by the suspension polymerization of styrene monomer. The polymerization is generally carried out in a batch process and it contains a fire retarding additive in the formulation.

EPS 650 FF is an expandable polystyrene grade supplied in freeflowing beads, containing pentane (CFC free) as a foaming agent and additives to retard ignitability.


EPS 650 FF grade is used for articles with large shape molding, block molding with medium density for thermal insulation in construction industry.

EPS 650 FF has retarded ignitability and the moldings made from it will conform to the requirement of DIN 53438 class K1 and K2 as well as DIN 4102 class M1 according to the French Ministerial Decree of 30.06.83, relative to the fire behavior of material.


EPS 650 FF is processed in three steps: pre-expansion, maturation and molding. EPS 650 FF is heated by steam at 100°C in a pre-expander. The foaming agent present in the polystyrene beads, vaporizes and mixes with steam. The gas mixture so produced subsequently softens the beads and expands them to 30-40 times the initial size. Then in maturation the foaming agent and steam condense in the cells of the pre-foamed beads causing partial vacuum, which is compensated by the diffusion of air into the beads. The maturation period could be between 3 and 24 hours. In the molding process the matured pre-foamed beads can further be processed by direct steam to the desired shape molding.


Handling and Health Safety

EPS 650 FF presents no toxic hazard when handled under normal conditions. Excessive exposure to high concentration of pentane should be avoided. EPS 650 FF is not intended to be used where there is possibility of contact with food.


EPS 650 FF is supplied in 0.5 MT semi bulk cardboard containers (Octabins).

Storage and Fire Precautions

EPS 650 FF grade contains flammable foaming agent, pentane, which can form explosive mixture with air. Hence, expandable polystyrene should be stored in closed containers below 20°C. Storage and processing areas should be adequately floor ventilated. Source of ignition like smoking, sparks, welding and naked flame should be strictly avoided.
Should fire occur, the processor should use dry powder or carbon dioxide extinguishers, particularly in the area of hot wire cutting machines. MSDS is available on request.
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