ETFE Foil is becoming an increasingly common component of cladding systems for buildings around the globe. Its growing popularity has been fuelled by success on high profile projects such as The Eden Project UK and more recently in Beijing where it featured on the Water Cube. It is currently being proposed as the roofing system for a number of prestigious projects in New Zealand such the Central Otago sports stadium and The Base mall in Hamilton.
The cladding system consists of pneumatic cushions comprising two to five layers of the modified copolymer Ethylene Tetra Flouro Ethylene. Each layer of the ETFE foil is formed as an extruded sheet, restrained around the perimeter by an aluminum extrusion, which in turn is supported off the main building frame. It can be used either horizontally or vertically to form the entire cladding system for a building.
The cushions are inflated by a small inflation unit to give the foil structural stability and high insulation properties. The system is closed volume and so once the cushions are at operational pressure they only require topping up.
- A lightweight cost-effective alternative to glass, combining high degrees of transparency with good thermal properties.
- The flexible nature of foil means the system can accommodate much larger spans, requiring significantly lighter support steelwork, and can achieve complex forms that are difficult to realise in glass.
- A light flexible cladding system that minimises mass contributions under seismic events, and can accommodate the potentially higher deflections experienced in ductile structures without catastrophic failure.
- The standard units can provide U values in excess of standard triple glazing when used horizontally, and can be further increased with the introduction of additional layers.
- The foil can be surface treated in a number of ways to reduce solar gain whilst maintaining its transparency.
- The material has been in existence for over 36 years, and no signs of aging, em-brittlement or discoloration have been observed.
- ETFE is not classified as a fragile roof. This coupled with its PTFE-like properties means it is essentially self-cleansing and negates the need for external gantries.
- The system has low embodied energy and requires low energy input under normal operation.