• Energy Research

Currently, Uruguay is developing several measures to reduce the environmental impact of human activities and CO2 emissions. In 2015 more than 90% of electricity was produced by renewable sources. Despite this fact, the construction, transport and building sectors are still responsible for more than 60% of CO2 emissions. Reducing building environmental impacts is becoming an increasing challenge. Life Cycle Assessment (LCA) is recognized as a method that can help to reduce environmental impacts of the building sector. It can be used as an early stage decision-making tool to assess environmental impacts design choices. The present paper developed a method based on LCA which integrates Building Information Modeling (BIM) to assess building envelope alternatives. The method is validated by the application in a single-family house - the most popular typology - in Uruguay, considering three envelope alternatives, including frequent and non-frequent materials. Results focused on comparing the embodied impacts, transport, and operational energy consumptions of each scenario. The results evidence that the developed method can help during the building design process, especially to define dimension and thickness of materials.

Life Cycle Assessment (LCA) is increasingly used for decision-making in the design process of buildings and neighbourhoods. Therefore, visualisation of LCA results to support interpretation and decision-making becomes more important. The number of building LCA tools and the published literature has increased substantially in recent years. Most of them include some type of visualisation. However, there are currently no clear guidelines and no harmonised way of presenting LCA results. In this paper, we review the current state of the art in visualising LCA results to provide a structured overview. Furthermore, we discuss recent and potential future developments. The review results show a great variety in visualisation options. By matching them with common LCA goals we provide a structured basis for future developments. Case studies combining different kinds of visualisations within the design environment, interactive dashboards, and immersive technologies, such as virtual reality, show a big potential for facilitating the interpretation of LCA results and collaborative design processes. The overview and recommendations presented in this paper provide a basis for future development of intuitive and design-integrated visualisation of LCA results to support decision-making. Building and Environment, 190 ISSN:0360-1323 ISSN:0360-1323

Waste generated by the Construction Sector represents an environmental problem in many countries. To achieve increasingly eco-efficient waste management, Life Cycle Assessment (LCA) provides an objective method for the quantification of the potential impact that waste management exerts on the environment. Traditionally, LCA has focused on the evaluation of non-prevention scenarios once the waste is generated, mainly by showing the benefits of recycling vs. disposal. Consequently, the literature has hardly addressed the positive environmental impacts caused by waste prevention, that is, the reduction at source, which constitutes the preferred option of any waste management hierarchy. Therefore, this study proposes a model to simulate the environmental performance of the prevention vs. the non-prevention of construction waste production. The model is applied to an urban system of residential buildings in Spain. The results provide evidence of the environmental benefits achieved with the prevention scenario. The prevention scenario reduces the construction waste generated in the non-prevention scenarios by up to 57%. Furthermore, it allows a potential reduction of up to 4.6 and 171.1 times the impact caused by the disposal scenario; and up to 1.7 and 8.3 times those of the recycling scenario. The model can be implemented in other contexts with other reference buildings, and enables the environmental benefits of reduction strategies to be studied, thereby providing a tool to guide and support decision-making during the building design stage. Moreover, the results obtained can help professionals and policymakers to incorporate effective construction waste prevention measures in waste prevention plans and programs.

Abstract Wood and other bio-based building materials are often perceived as a good choice from a climate mitigation perspective. This article compares the life cycle assessment of the same multi-residential building from the perspective of 16 countries participating in the international project Annex 72 of the International Energy Agency to determine the effects of different datasets and methods of accounting for biogenic carbon in wood construction. Three assessment methods are herein considered: two recognized in the standards (the so-called 0/0 method and –1/+1 method) and a variation of the latter (–1/+1* method) used in Australia, Canada, France, and New Zealand. The 0/0 method considers neither fixation in the production stage nor releases of biogenic carbon at the end of a wood product’s life. In contrast, the –1/+1 method accounts for the fixation of biogenic carbon in the production stage and its release in the end-of-life stage, irrespective of the disposal scenario (recycling, incineration orlandfill). The -1/+1 method assumes that landfills offer only a temporary sequestration of carbon. In the –1/+1* variation, landfills and recycling are considered a partly permanent sequestration of biogenic carbon and thus fewer emissions are accounted for in the end-of-life stage. We examine the variability of the calculated life cycle-based greenhouse gas emissions calculated for a case study building by each participating country, within the same assessment method and across the methods. The results vary substantially. The main reasons for deviations are whether or not landfills and recycling are considered a partly permanent sequestration of biogenic carbon and a mismatch in the biogenic carbon balance. Our findings support the need for further research and to develop practical guidelines to harmonize life cycle assessment methods of buildings with bio-based materials.

The Life-cycle Assessment (LCA) method and the Environmental Product Declaration (EPD) each play a crucial role in reducing buildings’ embodied environmental impacts. EPDs provide the validated and geographically representative data necessary to conduct an LCA. However, the development of EPDs in the European context is still irregular. Countries such as Germany and France have many EPDs for construction products, while other countries, such as Spain, have a limited number of EPDs and more than one operator programme, which is pointed out in the literature as a possible limiting factor for comparing results. This study aimed to examine the use of construction product EPDs manufactured in Spain, to then use as a data source to conduct a building LCA. We analysed the comparability of the results among the different EPD programmes and investigated to what extent the use of Spainߣs geographically representative construction product EPDs can contribute to conducting a building LCA, including all the materials and products that compose a building, and covering all the building life-cycle stages (product, construction, use, and end-of-life). The results showed that plasterboard and thermal insulation products have the highest numbers of EPDs in different EPD programmes. The case study analysis showed that 20% of the construction products that compose a building can potentially use these EPDs as a data source to conduct a building LCA, and 89% of those product categories include at least the product, use, or end-of-life stage modules. Finally, recommendations and challenges to improve LCA development in the architecture, engineering, construction, and operation industries were included.

Existing studies provide evidence that buildings and the construction sector are the largest consumers of natural resources and carry the greatest responsibility for greenhouse gas emissions. In order to reverse this situation, future challenges involve utilising the lowest amount of resources possible. To this end, building refurbishment has become a crucial strategy, given its potential to improve operational energy efficiency and to extend the life span of existing building stock, thereby reducing the environmental impact while also providing social and economic benefits to our cities. Life cycle sustainability assessment (LCSA) has become one of the scientific community’s most widely recognised methodologies for the evaluation of the social, economic, and environmental dimensions (triple bottom line), as it assesses sustainability using quantitative metrics. However, the implementation of this methodology to support the refurbishment process at the project stage in building design tools, such as BIM, remains scarce. One of the main obstacles lies in the difficulties of accessing building information, given that the system boundaries only cover new materials and products. Hence, this study proposes a BIM plug-in developed to support multi-dimensional building material selection in the early design steps based on the LCSA of a building during the refurbishment stage and validates its application in a case study. The results show the viability of using this tool during the early design stages and demonstrate the consistency of the results for evaluating various material and product alternatives for the refurbishment of the envelope system of a multi-family residential building. This study contributes towards the integration of decision-making by providing real-time assessment of a building envelope.

Life Cycle Assessment (LCA) is globally recognized as one of the most complete methods for environmental assessment of buildings. Literature assumes that its applications in the building sector are prejudiced regarding complexity and difficulty. However, simplification is necessary, since it can facilitate LCA application in buildings. Moreover, growing interest on reducing environmental impact in the building sector, as well as the relevance of single-family houses on CO2 emissions have become key points on the wide spread of LCA. Therefore, this paper presents a research study about simplification in LCA recent studies applied to singlefamily houses. The review focuses on 20 cases that were analyzed according to ISO 14040, ISO 14044, EN 15978, and EN 15804 standards. The main objective was to identify the simplification strategies assumed in each paper, to clarify and to help to promote further developments on LCA. This paper examines system boundary definition, data sources, life cycle phases included, and environmental impact indicator calculated in case studies. Results show the variety of simplifications identified. They affect physical model definition, life cycle scenario definition and communication of results. In most cases, the functional unit was the complete building, the life cycle scenario definition included production, use and demolition phases, and the most considered environmental impact indicator was GWP. Finally, new challenges and recommendations were defined in order to establish common criteria to develop simplification strategies that allow results comparability in LCA of single-family houses.