Análisis de ciclo de vida de la edificación y su huella ecológica sobre el territorio

Laburpena

Introduction :The consumption of natural resources on the Earth is bringing to scarcity in the existing sources, and the consequences of it are unpredictable. The building sector is one of the largest consumers of resources, and produces environmental impacts that bring to the environment degradation and the ecosystem variation. The building metabolism generates input and output flows that the environment must absorb. The study of this metabolism can help to know and evaluate those impacts, with the objective to be reduced. The main objective of this study is the implementation of two sustainability tools for environmental assessment: life cycle assessment and ecological footprint. With them, it is intended to analyze their possibilities of implementation to the building sector, and to develop the methodology and criteria for the estimation of the generated flows. Theoretical Development :The study is limited to the activity in the building sector in Spain during 2009, in the different stages of the life cycle. It is divided in two parts, according to the tool implemented. Firstly, the implementation of the life cycle assessment is developed. In this way, the present experience is studied about regulation, other implementations and research that are carried on. Then, the methodology is defined for our particular case, and finally the interpretation of results is shown, for methodology as well as for the obtained results. Secondly, the implementation of the ecological footprint is carried on, with the same structure as before. Finally, a comparative analysis is developed for both tools. The life cycle assessment is based on the standards UNE-EN ISO 14040 y 14044:2006, and the Evaluation for Construction Works according to the CEN/TC 350 European Committee. The results about life cycle assessment show a larger influence of the use stage, closely followed by the construction materials production. The stages of demolition and waste management are the ones with the least influence. Also, the construction stage has a short influence. Generally, the data analysis shows acceptable sensitive results. But they are significant in some cases, such as the period of time, with the possibility of variation in the final results. About the ecological footprint, there is not any methodology defined for the building sector implementation. The initial criteria are mainly extracted from the proposal of Global Footprint Network and the interpretation that M. Calvo Salazar makes in his study about ecological footprint in construction for the Andalucian Government (2010). The previous study about life cycle assessment simplifies much this implementation. The results obtained show very high productive land consumption, about 60.1 square meters per new floor square meter. The methodology analysis of these environmental tools lets distinguish the advantages and drawbacks of the implementation to the building sector, as well as the criteria and possibilities they can offer to the environmental assessment of this sector. The life cycle assessment develops a complete study about inputs and outputs to the system, whereas the ecological footprint resumes the results in one figure, translating them into productive land. It is easier to express, to understand and to communicate, but it leaves elements outside the environmental evaluation. Also, the aspects that are evaluated in the ecological footprint make reference to territorial units. It can help to urban planning and land use management, whereas the life cycle assessment helps to other kind of evaluations in the activity of the product system. Finally, as an example, it is developed a study about the impact of energetic refurbishment in the CO2 emissions during the building use stage, based on the implementation of these environmental tools. The study is developed in Alicante and Palermo, according to the reality that happens in each place. The study of different refurbishing processes in the building life cycle lets establish the most interesting ones to be able to achieve the European Union goals in CO2 reduction for 2020. In the Spanish case, it is necessary to change the energetic systems, at present based on electricity, to less carbon producer sources. In the Italian case, this transition is made to natural gas, so the main interest is put on the refurbishment of the building covering. Besides, the energetic refurbishment rate must be improved in Spain in the following years. Conclusions :This study goes in depth with the use of these sustainability tools implemented in buildings. It shows the possibilities of environmental analysis and the establishment of environmental criteria for decision making. The development of these methodologies and their comparison, as well as the analysis of the obtained results, confirms the viability and the large interest that generates this implementation to the building sector.