ETFE has freed architecture from the weight of glass. From the Allianz Arena in Munich to the Water Cube in Beijing, this transparent ‘air bubble’ allows immense spans to be covered with minimal support structures, creating living, dynamic envelopes.
ETFE is extruded into very thin films (generally 100 to 300 microns). On its own, a film has no flexural rigidity. The structural genius of the system lies in its pneumatic nature. Multiple layers (two, three or four) are heat-welded along the edges to form a closed ‘cushion’, then inserted into an aluminium frame. A continuous system of pumps supplies filtered air at very low pressure between the chambers. This overpressure transforms the limp films into a pre-tensioned and hyper-rigid element, capable of bearing immense snow loads and elastically deforming under extreme wind gusts without tearing.
Unlike glass which screens most ultraviolet, ETFE is almost totally permeable to UV rays — essential for botanical greenhouses. Chemically similar to Teflon, ETFE has a very low coefficient of friction: it is literally non-stick. Rainwater does not wet the surface but slides away in perfect droplets (Lotus Effect), automatically removing smog, dust and dirt, reducing façade cleaning costs almost to zero.
Standards
European and international references applicable.
Physical properties
Usage environment
ETFE cushions are a living system that ‘breathes’. They require small inflation units connected to the power grid. However, since the system is airtight, the fans do not need to generate a continuous flow but only compensate for micro-losses and thermal variations. Energy consumption for covering thousands of square metres is equivalent to that of a single incandescent light bulb. CRITICAL: the air must be rigorously dehumidified to prevent internal condensation.