What is EPS?

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Expanded Polystyrene, or EPS for short, is an economical, versatile, lightweight, rigid, plastic foam insulation material produced from solid beads of polystyrene. The end product is made up of fine spherical cells that comprise 98% air.

EPS has a very high strength to weight ratio that, dependant on the density, offers exceptional compressive and flexural strength and dimensional stability characteristics. It can be moulded or shaped to meet almost any design requirement.

Who needs EPS?

Architects, civil engineers, marine engineers, builders, concreters, packaging companies, creative designers, et al;
Insulation, building applications (including cladding and concreting), road and bridge works, flotation, protective packaging, theming (creative works in theme parks and on buildings). Your imagination really is the limit.

EPS Properties

National Polystyrene Systems (NPS) EPS range comprises block moulded and shape moulded expanded polystyrene products. NPS block foam is manufactured to AS1366 Part 3 ~ 1992 and contains a flame retardent.

The minimum physical properties specified in this standard are the minimum requirements to which NPS foam complies, however if physical properties outside this standard are required, a tailor made class of NPS foam can be designed to meet these requirements. The nominal densities used to manufacture expanded polystyrene are as listed in the standard; however the physical properties may be achieved using other densities, depending on raw material and other variables. The table below lists the minimum physical properties of NPS foam as it compares to AS1366 Part3 ~ 1992.

Flotation Properties

The density of NPS expanded polystyrene foam is low compared to water, with a nominal density range from 13 to 28 kg/m3 compared with water at 1000 kg/m3. The water buoyancy per cubic meter of NPS Foam is determined by subtracting its kg/m3 density from 1000. The result is the weight in kilograms, which a cubic meter of NPS Foam can support when fully submerged in water.

Chemical Properties

NPS expanded polystyrene foam is resistant to virtually all aqueous media, including diluted acids and alkalis. It is also resistant to water-miscible alcohol such as methanol, ethanol and I-Propanol, and also to silicone oils. NPS Foam has limited resistance to paraffin oil, vegetable oils, diesel fuel, and Vaseline. These substances may attack the surface of NPS Foam after long term contact. NPS Foam is not resistant to hydrocarbons, chlorinated hydrocarbons, ketones and esters. Paint containing thinners and solutions of synthetic adhesives fall into this category, and this should be taken into account in any painting or bonding operations. Anhydrous acids such as glacial acetic acid and fuming sulfuric acid destroy NPS Foam.

Resistance to Fungi and Bacteria

Fungus attack has not been observed on NPS expanded polystyrene foam and it does not support bacterial growth. Surface spoilage (in the form of spilt soft drink, sugar, etc) can however supply the nutrient for fungal or bacterial growth.

Toxicity

The heat of combustion of solid polystyrene polymer is 40,472 kJ/kg – Combustion products are carbon dioxide, water, soot (carbon), and to a lesser extent carbon monoxide.
A CSIRO report comments that the toxicity of gases associated with the burning of expanded polystyrene is no greater than that associated with timber. Toxicity of thermal decomposition products of EPS appears to be no greater than for wood and decidedly less than other conventional building products i.e.

Polystyrene CO=0.09 plus CO2=0.01 Total=0.10
White Pine CO=0.09 plus CO2=0.003 Total=0.09

Flammability Properties

Expanded polystyrene products used in building and construction, contain a Flame Retardant (FR) and when properly cured, FR EPS is not an ignitability risk.

Expanded polystyrene (F Grade) contains a fire retardant additive to inhibit accidental ignition from small fire sources.
Please refer to the table below for a comparison of expanded polystyrene with other common building materials.