Lightweight envelopes: ethylene tetra-fluoro-ethylene foil in architecture

Abstract

The fluoropolymer ethylene tetra-fluoro-ethylene (ETFE) in the form of thin foil is being used increasingly in architecture, in innovative building envelopes, either as a single-layer or, more commonly, as multi-layer inflated cushions. With foil thicknesses ranging from 100 to 300 µm, three-layer cushions typically weigh less than 1ṡ0 kg/m2. This paper reviews the main characteristics of ETFE foil that affect its use in architecture and discusses how developments in material technology and systems over the 30 years that the material has been used in permanent building envelopes have expanded the scope for architectural applications. Current state-of-the-art is illustrated through case studies of recently completed projects such as the north-light-like, multi-layer cushion, roof at the Dolce Vita Tejo shopping mall, Amadora, Portugal (2009); the external cushion cladding of the Media-TIC building, Barcelona (2010); and the single-layer façade of the Unilever Building in Hamburg (2009). It is concluded that there remain interesting possibilities for performance enhancement of ETFE foil-covered building envelopes that are able to adapt to provide desired thermal/optical performance as components in intelligent building skins and expand ETFE foil's fitness for use in more extreme climatic zones.