ETFE in focus: Today’s future
The benefits of glass have long been known. From weaponry, tableware and ornaments to windows and facades, its qualities of transparency and durability remain highly sought after and endlessly versatile – particularly within the modern built environment.
The journey taken to get to the stage we’re at – with seemingly infinite glazing options available – has been a significant one. And it’s not over yet.
In the late 20th century, two fluoropolymer plastics began to change the face of facades – fluorinated ethylene propylene (FEP) and ethylene tetrafluoroethylene (ETFE). Both presented a disruptive opportunity – a new, lighter and more adaptable version of glass.
Following rigorous testing, trial and error, FEP eventually lost the membrane material fight to ETFE, as it became more opaque and brittle over time. On the other hand, ETFE lasted – and still does.
Playing the long game
But it’s not just its longevity that has enabled ETFE to stand the test of time – its advantages are abundant. When it comes to light, the benefits aren’t just apparent in the material’s weight. Radiation from the sun doesn’t damage ETFE at all, whilst the membrane’s molecular make-up means that although nearly all harmful UVB rays are blocked, most of the Vitamin D-boosting UVA beams are able to shine through.
These enviable properties make this the perfect material for certain applications – including roofs for stadiums, leisure facilities, retail parks, school recreational areas and agricultural habitats.
Despite its wide-ranging qualities and uses, ETFE won’t be stealing the millennia-long reign of glass anytime soon. However, it’s not a case of competition where these two materials are concerned – rather, a lot can be gained from working with both.
ETFE and glass, not ETFE vs. glass
Although alike in appearance and designed for similar applications, ETFE and glass are two very different products. Their development may have followed a comparable trajectory – with obstacles relating to access, maintenance, light transmittance, insulation, leaks and external damage having largely been overcome through years of diligent engineering – but each is best suited to varying tasks and environments.
When it comes to making the vision of an architect a reality, due attention must therefore be paid to the context of the structure, to ensure the most suitable product is chosen to achieve the desired results. What is the space going to be used for? Where will the structure be located? How important is light quality? What type of visual impact needs to be achieved? And fundamentally, which material best suits these aesthetic and functional requirements? Answering these key questions ultimately helps determine whether glass, ETFE or a combination of both is the best choice.
The cost of ETFE compared to glass is always an interesting subject. Yes, it is lighter, meaning less materials for the structure, but it all depends on the design. If this is parametric and all the shapes are different, then prices will undoubtedly be driven up. That’s why value engineering (VE) the design and cost expectations of clients is essential – to ensure the right balance is reached and the most suitable material chosen for the application.
Understanding ETFE structures
ETFE isn’t a tensile fabric as many assume – but it is a membrane. It doesn’t fall under the NBS H90 category of tensile fabric coverings as it has its own H80 specification, and its application history is actually more closely linked to glass.
Most structures have a steel framework, with a pneumatic or stressed skin façade – the ETFE part – which sits or hangs off it. The material has very different forces to glass, and so must be engineered accordingly – for instance, if the ETFE pillows become deflated, the integrity of the structure must not be compromised as a result. It must also be designed to hold extra loads – including workmen and water weight – particularly at the perimeter edge, in case a disaster occurs.
What role can ETFE play in modern structures?
Through notable success in stadium structures, retail complexes and recreational facilities, ETFE has won a definitive place in the architectural world. Its use in leisure parks is now unrivalled because of its light-boosting, insulating and durability properties. The natural stack ventilation triggered by the convecting heat enables the space to consistently replenish itself with fresh air, ensuring the quality is always at a high standard – much like a greenhouse. Vegetation needs great air quality – just visit the Eden Project or Center Parcs to find out!
So, ETFE undeniably has a huge role to play in our built environment, but its advantages have the potential to reach much further afield. As with the examples above, it’s certainly likely that within the agricultural arena, ETFE will establish itself as a viable alternative for greenhouses in the coming years.
The product’s ability to allow more natural light to permeate is a definite advantage for outdoor and agricultural environments. Plus, as with glass, it’s possible to control the sun’s short-wave light transmittance through ETFE with solar gain, and light transmittance frit patterns to absorb and reflect the light. This means that light levels and temperature can be controlled to the optimal conditions required for the cultivation of produce.
What does the future hold for ETFE?
The future of the relatively youthful material is a very optimistic one. Just like with glass, constant development is taking place to improve clarity, strength and aesthetics. By combining real-world requirements with scientific advancements, the resulting systems are increasingly more robust, versatile and adapted to better withstand the challenges of the environment.
ETFE’s advantages are certainly extensive, especially when structures are designed with foresight for the surrounding space. A further key benefit is that it is very ‘green’, and with growing attention surrounding sustainability, ETFE’s renown in the architectural world is only set to rise.