EPS granules are the polystyrene containing easily boiling a component (pentane). EPS granules represent beaded granulated material which can be delivered the consumer, as passed separation division, and without division into fractions. At use drizzle granulated material the made foam granules of polystyrene have the identical sizes, in case of application, not drizzle granulated material foam polystyrene granules will have considerable divergences of the sizes (0,5-12 mm). Process of foaming EPS of granules can be divided into two stages: 1. Preliminary foaming. 2. Drying (staying) the made foam granules, for their further use.