Particularly if you’ve been looking into building with Structural Insulated Panels (SIPs), you’ve likely heard the term “EPS.” What’s that? It’s expanded polystyrene foam. Um … okay. What’s THAT?
A Little History & Chemistry
Polystyrene was discovered quite by accident. In 1839, a German apothecary named Eduard 
Simon distilled an oily substance from the resin of a sweetgum tree. He dubbed it ‘styrol.’ A few days later, he noticed the styrol had become a thickened jelly. He assumed (incorrectly) that oxidation occurred and called this new compound styroloxyd.
About six years later, chemists John Buddle Blyth and August Wilhelm von Hofmann showed the same transformation of styrol could occur without oxygen, and their final product was chemically identical to Simon’s styroloxyd.
Fast forward another 20 years: Marcelin Berthelot correctly identified the process which was occurring to form styroloxyd from styrol as a polymerization process. Some 80 years later, chemists realized heating styrol begins a chain reaction which produces macromolecules. Now, we know the substance as polystyrene. And you likely see or use it far more often than you think.
The Process
Small solid plastic particles of polystyrene are made from the monomer styrene. Polystyrene is normally a solid thermoplastic at room temperature that can be melted at a higher temperature and re-solidified for desired applications.
EPS is rigid, closed cell plastic resin made from petrochemicals derived from crude oil. The resin is incorporated with the blowing agent pentane. During the pre-expansion, steam softens the plastic resin causing the pentane to expand the plastic into beads at least 100 times their original size.
While the plastic is exposed to steam, the pentane continues to expand, therefore determining the expanded size of the bead. Before the pentane is displaced by air, the pre-expanded bead is placed into a mold of any shape (package inserts of many varieties or even the base for intricate signs!) or block. EPS foam is the correct term for any form of expanded polystyrene.
For our use at Enercept, the foam is delivered (from nearby Benchmark Foam) in large columns called billets. From those, production workers painstakingly cut the foam to required size.
Other EPS Facts:
- EPS does NOT contain CFC’s, HCFC’s, or formaldehyde
- EPS does NOT contribute to the growth of mold or mildew
- EPS is no more toxic than Douglas Fir wood under the worst- case fire scenario
- EPS is manufactured in accordance with
ASTM C578 - EPS is recyclable
Uses of EPS
Because of its properties — excellent thermal insulation, good damping properties and being extremely light weight — and its versatility, polystyrene foams are used for a variety of applications. From being used as building materials to white foam packaging, EPS has a wide range of applications. Even many surfboards and bicycle helmets use EPS as the foam core.
Expanded Polystyrene (EPS) is a lightweight, closed cell, rigid, plastic foam insulation material produced from solid beads of polystyrene.
Building and Construction
EPS is ideal for building and construction. Its durability, strength and light weight make it ideal for structural insulated panels (SIPs.) Such panels are often used for walls, roofs, facades and floors. EPS offers design flexibility, high R-Values for thermal insulation, superior dimensional stability, and resistance to moisture absorption and physical degradation. It’s also available in several compressive strengths to withstand load and back-fill forces.
EPS can be used as flotation material when building marinas and pontoons and is sometimes used as lightweight fill in road and railway construction.
Since EPS is inert in nature, it doesn’t result in any chemical reactions. Since it will not appeal to any pests (it has no nutritional value for them), it can be used easily in the construction industry. It is also closed cell, so when used as a core material it will absorb little water and in return, not promote mold or rotting.
So, now you know. EPS is a rigid polystyrene foam with a multitude of uses. It can also help make your next building project easy and energy efficient. Let us know if you’d like more information.
Our Mission: Our Commitment
When you build with Enercept SIPs we provide a building that will go up faster and will be warmer, tighter, stronger, quieter and more cost-effective than conventional construction. It is a commitment that others simply can’t beat!
