Expanded Polystyrene is a closed-cell, resilient, lightweight rigid cellular plastics material produced in a range of densities between 10 kg/m3 and 35 kg/m3.
EPS is manufactured in 4 Stages starting with very small beads of Raw EPS much like grains of sand; the first step is to expand these tiny beads into larger EPS foam beads (Bean Bag Bead). This process is known as Pre expansion, in which an expanding/blowing agent, usually pentane (already within the tiny beads) when in the presence of steam softens the polystyrene balls and the increasing vapour pressure of the pentane causes the beads to expand up to 50 times their original volume.
This process can be controlled to expand the beads to a very large size often used for packaging with a much lighter density. Through to much higher density foam by only expanding to a smaller size bead, these higher density products are often used in building and construction.
Step 2 Conditioning, after pre-expansion the beads are carried through large pipes and ducting to large hoppers for ageing. The time of ageing is needed to cool and stabilise the beads, allowing for the infusion of air to replace the expanding pentane within the bead.
Step 3 Moulding, after conditioning the beads are pressure fed into a mould where they are further expanded and fused together by steam heating and conform to the shape of the mould usually a large block.
Step 4 Finishing, The freshly moulded blocks of Expanded Polystyrene are passed through temperature-controlled ovens to remove moisture and residual pentane, this helps greatly to ensure block size is constant and dimensional stability and dryness is achieved.
Now we can process the Expanded Polystyrene Blocks into a myriad of products using Industry-specific hotwire machines that cut and shape these large Blocks.
Starting Block Size 5000mm x 1200mm x 600mm
All EPS is manufactured to AS1366 Part 3 in which the physical properties of EPS are tabled and graded into 6 different densities
Please find all EPS specific tables, graphs and technical information attached in this brochure
Recommended Readings:
Moisture Gain and its Thermal Conequences for Common Roof Insulations
What is Expanded Polystyrene
It is a lightweight cellular material consisting of fine spherical shaped particles which are comprised of 98% air and 2% polystyrene. This air is trapped within several closed hollow cells in each particle.
Does EPS have a capillary action?
No, EPS does not have a capillary action. EPS is ideally suited when the insulation material is in contact with the ground.
EPS is said to breath. What does this mean?
The breathability characteristic of EPS refers to its ability to allow any absorbed moisture to escape when condition change. It therefore reduces any tendency towards the formation of vapor dams.
In applications where high humidity and temperature differentials are likely, a water vapor barrier such as plastic sheeting should be used. The vapor barrier is best installed on the warm side of the structural component, with the warm side of the structural component, with the insulation as near as possible to the cold side.
Does age effect the thermal performance of EPS?
No, EPS consists of 98% air and 2% polystyrene, and nothing else. Because of its cellular structure of EPS is dimensionally stable and will not settle over time. EPS used and installed correctly does not deteriorate with age and as such is able to deliver constant R-values for the life of the building.
Is EPS resistant to chemicals?
It depends. It is resistant to virtually all aqueous media including dilute acids and alkalis and to methanol, ethanol and silicone oils. See the table of chemicals resistance int his brochure.
It has limited resistance to paraffin oil, vegetable oils, diesel fuel and Vaseline, which may attack the surface of EPS after long-term contact.
It is not resistant to hydrocarbons, ketones, esters, paints containing thinners, and solutions of synthetic adhesives.
Is EPS degraded by ultraviolet light?
Prolonged exposure to sunlight will cause a slight discoloration (yellowing) of PES insulation and cause some surface embrittlement.
Even so, the thermal insulation properties will not be affected unless exposure results in loss of thickness of the EPS boards, although the friable surface can make bonding difficult. For this reason, EPS insulation should be covered to protect it from UV light if it is to be stored in the open for extended periods.
Is EPS subject to Australian Standards?
Yes. Manufacturers when stating the class of EPS and therefore its physical characteristics are required to manufacture to AS 1366, 3, 1992. As such, he properties of EPS required for a application are guaranteed. Where the densities exceed the AS1366 – 3 – 1992 grade levels Queensland Polystyrene Specialists has measured the properties and provides specification sheets for these high-density grades.
R-Value
R-value is the thermal resistance rating that is most commonly used to measure the building and the material’s ability to resist the transfer of heat. R-value is the most important characteristic that needs to be defined with it comes to insulating buildings, housing, flooring, and roofing. The following r-value equation is;
 | = | R value |
 | = | temperature difference between the warmer surface and colder surface of a barrier |
 | = | heat flux through the barrier |
R-Value Table
Sheet Thickness | 25mm | 50mm | 75mm | 100mm |
| R-value | 0.69 | 1.39 | 2.08 | 2.78 |
