TECHNICAL DATA Delta Insulation Systems P: +61 07 3271 2170 E: info@deltainsulationsystems.com W: www.deltainsulationsystems.com.au A: 49 Bernoulli Street, Darra Qld. 4076 ABN: 12 122 760 552 Page 2 of 4 What is Expanded Polystyrene (EPS) EPS is a closed cell lightweight cellular plastics material produced from polystyrene. The material has been modified by the addition of flame retardant additives. Polystyrene literally translated is “polymerised styrene”. That is, the single styrene molecules are chemically joined together to form a large molecule which is called the polymer. Styrene is produced from benzene and ethylene, and polymerisation is accomplished in the presence of catalysts, usually organic peroxides. The expandable form is produced as small beads containing a blowing agent. The Manufacturing Process Pre-Expansion The small expandable beads are subjected to steam, which causes the thermoplastic polystyrene to soften. Increasing vapour pressure caused by the blowing agent causes the beads to expand to up to 40 times their original volume. It is this prefoam stage which determines the final density of the expanded polystyrene block. Aging After pre-expansion the prefoam is transferred via to fluidized drying bed to large silos for aging. This process is designed to allow for the replacement of expanding agent by air in the cells of the bead. Aging also allows for stabilization and cooling of the prefoam. Moulding Once conditioned by aging, the prefoam is blown into a mould where further steaming causes the expanded beads to fuse into a block. Drying To provide dimensionally stable dry blocks it is necessary to pass them through a temperature controlled oven. This process also ensures that any residual blowing agent has been removed. Finishing For most customers the manufacturing process is not complete until the EPS blocks have been cut into various shapes. This process is mainly carried out using a hot wire cutting machine that gives a fine finish to the product and enables very fine cutting tolerances to be achieved. Australian Standard Australian Standard 1366, Part 3 – 1992 Physical Properties of Rigid Cellular Polystyrene – sets out minimum properties for six classes (see table 1) and methods for determination and compliance. Flexibility in production allows EPS to be produced to this standard or to other requirements that specialized applications may demand. Quality Control To ensure compliance with customer requirements our Quality Assurance process monitors and tests various key properties. Acoustic Properties As EPS has a closed cell structure it offers only a limited absorption of airborne sound. Structure borne sound, transmitted though such structures as walls, may be effectively isolated by the use of floating floor systems. For this type of insulation EPS with the required dynamic stiffness can be obtained by compressing the sheets by 50 to 60 percent and then allowing them to recover to 80 or 90 percent of their original thickness. Table 1 Physical Properties of EPS, according to AS 1366, Part 3 – 1992 Physical Property Unit Class Test Method L SL S M H VH Nominal Density (kg/m3) 11 13.5 16 19 24 28 N/a Compressive stress at 10% deformation (min) kPa 50 70 85 105 135 165 AS2498.3 Cross-breaking strength (min) kPa 95 135 165 200 260 320 AS2498.4 Rate of water vapour transmission (max) measured parallel to rise at 23°C μg/m2s 710 630 580 520 460 400 AS2498.5 Dimensional stability of length, width, thickness (max) at 70°C, dry condition 7 days % 1.0 1.0 1.0 1.0 1.0 1.0 AS2498.6 Thermal resistance (min) at a mean temperature of 25°C (50mm sample) M2K/W 1 1.13 1.17 1.20 1.25 1.28 AS2464.5 or AS2464.6 Flame propagation characteristics: - median flame duration; max - eighth value; max - median volume retained; - eighth value; min. S S % % 2 3 15 12 2 3 18 15 2 3 22 19 2 3 30 27 2 3 40 37 2 3 50 47 AS2122.1
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