Life cycle assessment as a decision-making tool for selecting building systems in heritage intervention: Case study of Roman Theatre in Itálica, Spain

This paper develops a method based on life cycle assessment (LCA) as a useful decision-making tool for analysing the most suitable building system for intervention in heritage sites. It focuses on a case study based on the Roman Theatre heritage site in Itálica (Spain), where several activities have taken place every two years since 2011 that require the addition of a reversible construction to support the lighting and electroacoustic elements, and improve the stage use. Based on the constraints on interventions in protected heritage settings, three suitable building options have been proposed: a standard system (option 1) and two innovative building systems (options 2 and 3). All three options are reversible, lightweight and quick assembly/disassembly systems. Option 1 is a standard aluminium system currently available on the market, while options 2 and 3 were originally created for this specific setting, using laminated wood beams and steel spatial lattices, respectively. All three lightweight construction systems that use the most common materials (aluminium, wood and steel) are compared. The LCA-based methodology aids in establishing the most suitable option for use in the construction of the case study. The LCA analysis includes the production, construction, deconstruction and end-of-life stages and two environmental indicators: global warming potential and cumulative energy demand. The results of the environmental impact of each option are compared, using the values obtained for option 1 (standard solution of frequent use) as references. In the case of option 3, the results demonstrate that the design decisions, supported by LCA, are determining factors in the choices made. The selected geometry, materials and construction system (production), assembly/disassembly process (construction/demolition) and recycling (end-of-life) reduce the environmental impact. Therefore, finally, option 3 was constructed. The results indicate that LCA can be of assistance in selecting the most suitable option for intervention at a heritage site.