Expanded foam is such interesting stuff - don’t you think?
Is it an environmental friend or an environmental foe?
That depends so much on the application it is used for.
The key characteristic of expanded polystyrene foam (EPS) is that is mostly air. The typical density is less than one tenth that of most plastics, or timber for that matter.
Being mostly air means it makes very good insulation.
EPS is widely used in packaging including seafood and fruit packaging where its properties of light weight, insulation and moisture resistance are exploited to maximum effect. Being a good insulator also means it is also being used more and more in the building industry to reduce energy and resource use.
Being so light though means its best features work against it when comes to waste management.
The slightest puff of wind means any empty foam packaging blows away into the nearest water course. Which gives the product a bad reputation.
Being low density also means that EPS is quite expensive to dispose of in landfill so there is an incentive to recycle.
Low density also ruins the economics of recycling due to the cost of transport. It is not economical to transport air. To overcome this recyclers use machinery to squeeze the air out and increase the density to between 200 and 400 kg per m3. A much more economic proposition. Recent developments in this area are meaning there are more and more mobile EPS compaction machines around and increased recycled rates.
Unfortunately you can’t then convert this squashed EPS back into EPS so it mainly gets turned into recycled plastic products such as CD/DVD covers and sometimes into bollards and stakes. But at least it does get recycled.
Some EPS is recycled in its expanded form. It gets used in the building sector to make waffle pods – these are forms that help make concrete slabs more efficient. These can contain up to 30% recycled EPS. But due to the low density the challenge is finding enough waste EPS close to the waffle pod manufacturer.
EPS helps save energy in range of building applications including as insulated cladding. We have known for years that Australian houses should be better insulated so it’s good to see houses being built to be more like beer coolers.
So how do we optimise the environmental benefits?
It sounds like the construction sector would welcome increased recycled content in their products. If attention can be made to developing good logistics to efficiently transport EPS to facilities that can reprocess it we can have an energy saving industry based on recycled content materials. Energy saving insulation and building materials based on recycled content is about as good as it gets.
Who would have thought? - EPS as a green solution!