Application and validation of eco-efficiency principles to assess the design of lightweight structures: case studies of ETFE building skins

Membrane and foil structural skins exploit minimal amounts of material to cover a space, compared to the common envelope materials, thanks also to the ability to be tensioned, by shaping themselves to the forces ways, with a few additional components. On the other hand, the environmental compatibility together with the thermal, optical, and acoustic performances are crucial factors during the designing phase. The paper aims to show the research updates on the Life Cycle Assessment (LCA) methodology applied to ETFE cushion building technology, with the final goal of validating a couple of design principles and sustainability criteria, which the authors stated after past research experiences on the membrane and foil structures evaluation in their building life cycle. The LCA design principles for those lightweight structures are: 1.Verification of the ratio Frame Perimeter/Covered Surface; 2.Verification of the ratio Fixing System (or Primary Structure)/Membrane; 3.Verification of the ratio Membrane Structure/Mechanical Load of the Structure. Their application will help to point out both advantages and disadvantages of membrane and foil structural skins and to correctly exploit the properties of those thin and flexible materials, during the design process. The aim of this work is to validate this sustainable design criteria and its repeatability through 5 different case studies of ETFE built structures, focusing mainly on the principles 1 and 2. Thanks to the results, benchmark range as designers’ reference will be carried out