One example of a biodome would be the Eden Project in the United Kingdom which includes the largest biodome greenhouse in the world. There are three biodomes at the Eden Project: one with a tropical climate, one with a mediterranean, and one that is a local temperate biodome.
Large biodomes are architectural wonders, while the designs have much in common and take from the geodesic domes patented by Buckminister Fuller in 1954, there have been more recent innovations in building materials that have made the enormous light-friendly roofs in biodomes and other architectural projects possible.
The Eden Project's biodomes are constructed with tubular steel frames with hexagonal external cladding panels made from the thermoplastic ethylene tetrafluoroethylene (ETFE) replacing the use of glass, too heavy a material to use.
According to Interface Magazine,"ETFE foil is essentially a plastic polymer related to Teflon and is created by taking the polymer resin and extruding it into a thin film. It is largely used as a replacement for glazing due to its high light transmission properties. Transparent windows are created either by inflating two or more layers of foil to form cushions or tensioning into a single skin membrane."
Plastic ArchitectureEthylene tetrafluoroethylene (ETFE) has opened up new architectural design options when used as a building material. ETFE was originally invented by DuPont in the 1930s as an insulation material for the aeronautics industry. Its use as a building material was brought about during the 1980s by German engineer and inventor, Stefan Lehnert.
Lehnert, an avid yachtsman and three-time winner of the Admirals Cup, was researching ETFE for use as a possible material for sails. For that purpose, ETFE was not successful, however Lehnert continued to research the material and developed ETFE-based building materials suitable for roof and cladding solutions. These cladding systems, based on plastic cushions filled with air, have since pushed the boundaries of architecture and allowed the creation of highly innovative structures such as the Eden Project or the Beijing National Aquatics Center in China.
Vector FoiltecIn 1981, Lehnert founded Vector Foiltec in Bremen, Germany. The company manufactures Texlon ETFE cladding systems. Texlon being the trademarked name for ETFE foil.
According to Vector Foiltec's history, "Chemically, ETFE is constructed by substituting a fluorine atom in PTFE (Teflon) with an ethylene monomer. This retains some of PTFE's qualities such as its non-stick self cleaning properties, as in non-stick pans, whilst increasing its strength, and in particular, its resistance to tearing. Vector Foiltec invented drop bar welding, and used ETFE to construct a small cable structure, originally made from FEP, which had failed due to the low tear resistance of the material. ETFE provided the perfect substitute, and the Texlon® cladding system was born."
Vector Foiltec's first project was for a zoo. The zoo looked into the possibility to implement a new concept whereby visitors would pass through the zoos in small confined pathways while the animals would be, according to Stefan Lehnert, almost living in broad areas“…almost in freedom.” The zoo, the Burger´s Zoo in Arnheim, hence also looked for transparent roofs, which were to cover a large area and at the same time would allow the passage of UV rays. The Burger´s zoo project eventually became the very first project of the firm in 1982.
Stefan Lehnert has been nominated for a 2012 European Inventor Award for his work with ETFE. He has also been called the inventor of the biodome.