From the CST website:
The material proposed for the roof cladding is a transparent membrane technology, formally known as Texlon. Texlon comprises several layers of a space-age thermoplastic called ETFE that will be clamped to the roof structure and then filled with low pressure air to form large ‘cushions.’ The resulting ‘cushions’ are extremely strong and stable, and will allow large amounts of light – particularly in the photosynthetic UV light range – into the stadium, and therefore allow both the grass to grow naturally all year round and provide a sheltered venue.
ETFE is a close relative of the common compound PTFE – also known as Teflon and shares many of the same properties. In addition to having a ‘non-stick’ surface that will keep it clean, it has an extremely long lifespan and is not affected by salt water, acids, alkalis or other solvents present in the environment.
Items of interest:
- The stadium will be designed to withstand minimum 90 knot winds without damage, which is equivalent toa Category 2 hurricane
- Texlon ETFE cushions are custom designed and have been used in many public building-types, from airports to hospitals, galleries to youth hostels and, now for the first in the world, it is to be used to fully cover a multipurpose stadium
- Texlon ETFE weighs less than 3kg per square metre
- Texlon ETFE cushions are shatterproof
- A Texlon ETFE system will give roughly the same thermal insulation as double glazing
- ETFE has a melting temperature of approximately 260°C
- Texlon ETFE structures can be easily lit using a variety of methods (including projection and LEDs)
- For the different environments at this multipurpose stadium the simplest way to describe the acoustic effect of Texlon is to imagine that it is not there. The ETFE does not promote reverberation and does not reflect sound. The net effect would be as for an open air stadium.
- As ETFE does not degrade over time – the material can be fully recycled and re-extruded to form new cushions
- ETFE is made from a waste product from the mining industry and is not an oil-based product. It also requires very little heat in its manufacturing and is one of the most environmentally friendly materials available in the building industry
- Can easily be repaired or patched
- The Dunedin Multi Purpose Stadium will be the 3rd largest ETFE clad building in the world – the two others are the Beijing National Aquatic Centre and the Allianz Arena in Germany. It would be the largest ETFE clad building in the Southern Hemisphere