Expandable polymeric beads

Expandable polymeric beads or Expandable Polystyrene beads are moulding materials which come in the form of beads. The composition is polystyrene and a blowing agent which is  hydrocarbon . (blowing  agent is n-pentane, i-pentane and c-pentane).

Expandable polymeric beads containing blowing agent will expand when exposed to heat. These expandable polymeric beads are used for many applications like insulation, thermal packing, trays, toys, coffee cups food containers etc.

English: Structure of n-pentane Deutsch: Struk...

Hazards of Expandable Polymeric Beads

Fire! Fire is the hazard associated with this. Since this product contains hydrocarbon blowing agent (typically pentane) handling and storing of this product must take into consideration of any possible source of ignition. While stored Expandable polymeric beads will keep releasing a small amount of hydrocarbon vapors and the rate of release will increase when exposed to heat. Pentane vapors are heavier than air hence storage area must have good ventilation to remove any vapor trapped in low areas. Recommended storage is below 20 deg C in a well-ventilated area.


Generally Expandable Polymeric Beads are transported in fibreboard boxes or flexible IBCs. IMDG Code list this under UN 2211 , POLYMERIC BEADS, EXPANDABLE , Class 9 with instruction for segregation as for Class 3 ( Flammable Liquids )*. IMDG Code 36th Amendment which will be published in 2012 may contain the requirement of hermetically sealed packaging and IBCs which meet certain performance standards when transported in Closed Cargo Transport unit as proposed by European Chemical Industry Council to IMO.

Some shipping lines may require additional warning label apart from Placards. This label should be placed on the door and may read “ WARNING : MAY CONTAIN EXPLOSIVE ATMOSPHERE, KEEP IGNITION SOURCES AWAY” or may even ask to ship it as one-door-off. However one-door-off operation will require additional approval for the said container as per CSC ( International Convention for Safe Containers) as one-door-off on normal containers will change allowable stacking load and transverse racking test force.

* Category E. Shaded from radiant heat and protected from sparks and open flame.  When stowed under-deck, mechanical ventilation shall be in accordance with SOLAS regulation II-2/19 (II-2/54) for flammable liquids with flashpoint below 23°C c.c. Segregation as for class 3 but “Separated from” class 1 except division 1.4S.