Building Envelope: the study case of the innovative technology ETFE (ethylene tetrafluoroethylene)

ETFE is a fluorine-based thermoplastic polymer, a material capable of withstanding high levels of thermal and corrosive stresses. Due to its performance, it is resistant to wear and has a long service life (about 20 years). Excellent is also the thermal insulation which is guaranteed depending on the needs. The possible use of external photosensors makes the entire structure autonomous and sensitive to climate change or, depending on the needs, the individual elements are inflated or deflated to ensure the required thermal transmittance. The building metaphorically "breathes": when the sun's rays are intense, the envelope becomes opaque and, during the winter, due to a higher internal temperature, the bearings regain their transparency, allowing the sun's rays to penetrate. In terms of light transmission, it allows 95% of the sun's rays to filter inside with considerable energy savings. Excellent results also in mechanical behaviour, fire resistance and it is totally recyclable. Already applied in many projects, its technical characteristics allow an interesting use for architectural envelopes, also thanks to the aesthetic impact given by lightness, transparency and low cost compared to traditional glass constructions. Thanks to the ease of processing, it is possible to create particular or expensive shapes, large surfaces with minimum weight at low costs. The exploration of some projects made with ETFE and of new applications such as the one hypothesized in the case study of Taormina, allows us to draw up a first evaluation of the effectiveness of these solutions, allowing us to define a sequence of Laboratory Tests at the BUILDING IL FUTURO Lab. then carried out on an experimental basis which will give rise to a proposal for an international standard to certify safe solutions as is already the case for metal and glass curtain walls through the AAMA and ASTM standards.