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| 2. |
- Francart, Nicolas, 1993-
(författare)
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Buildings in municipal climate change mitigation strategies : towards life cycle thinking
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fulfilling climate targets requires ambitious changes. The building sector is a large contributor to emissions of greenhouse gases (GHG), but also offers opportunities for climate change impact reductions. This thesis aims at supporting strategic decisions to reach climate change mitigation targets in the building sector, based on knowledge about what factors contribute significantly to climate impact from buildings in a life cycle perspective and how practitioners can influence these factors. More specifically, a first point of investigation concerns what aspects play a key importance in buildings’ climate impact, and what climate change mitigation strategies for the building sector should focus on. A quantitative analysis of backcasting scenarios for 2050 was performed using a spreadsheet model to estimate GHG emissions for the building sector. The parameters were adjusted to ensure that a GHG emission quota was reached in every scenario. This provided an illustration of four very different ways the building sector could contribute to the fulfillment of a global climate change mitigation target. The results were used to discuss what aspects of buildings were particularly important for target fulfillment. These aspects include a low-carbon energy mix, a reduction of GHG emissions from construction materials and an optimized use of space. A second point of investigation concerns how municipalities can influence practices through the use of environmental requirements in construction, in particular requirements based on a life cycle approach. A survey of Swedish municipalities was used to assess their current practices and knowledge level regarding mitigating climate change impact from construction, as well as the influence of a municipality’s size on these practices. It was followed up by semi-structured interviews investigating barriers to the use of environmental requirements in construction. Barriers were identified regarding in-house skills, access to data, resources, ambiguities regarding the law and guidance from national authorities. A stepwise strategy was suggested to overcome these barriers and successfully implement environmental requirements. Therefore, the thesis as a whole provides insight on how municipalities could use environmental requirements in construction to influence current practices in the building sector, so that the changes needed to fulfill the 1.5℃ target are implemented.
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| 3. |
- Francart, Nicolas, 1993-
(författare)
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Decision support for the implementation of low-carbon measures in the building sector
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The building sector is responsible for about a fifth to a third of global greenhouse gas (GHG) emissions. Therefore, a successful mitigation of GHG emissions over the entire life cycle of buildings is particularly important to achieve climate targets such as the Paris Agreement. This requires measures at multiple levels and from multiple actors, including broad roadmaps for the building sector, policies and regulations, certification and green procurement criteria, and new practices among property owners, architects, developers and manufacturers. Such initiatives are sometimes supported by the introduction of tools and methods to quantitatively assess environmental performance. Life cycle assessment (LCA) is one such tool, used in certification and increasingly in procurement and regulation. To reliably steer towards lower environmental impacts, environmental performance assessment tools need to be precise, accurate and well-adapted to the decision contexts in which they will be used. While a tool like LCA can provide valuable decision support, some methodological issues remain unresolved, and its effect in real decision situations remains understudied.This thesis aims to support decisions and initiatives to mitigate environmental impacts in the building sector, with a particular focus on fulfilling ambitious climate targets. The thesis addresses two facets of this overarching issue. First, it investigates challenges to the implementation of relevant sustainable practices, at various levels and in various decision contexts. Second, the thesis considers to what extent environmental performance assessments could steer towards low environmental impacts (and in particular low global warming potential (GWP)).The thesis is based on a combination of quantitative and qualitative approaches. At a strategic level, a quantitative model of buildings’ GWP linked to four backcasting future scenarios is used to spotlight issues for the fulfilment of ambitious climate targets. This helps challenging existing paradigms and images of the future about how buildings are constructed and operated. At a more operational level, multiple qualitative studies explore barriers to specific practices to mitigate environmental impacts, and the roles played by environmental performance assessments. An interview- and workshop study explores important factors for the adoption of space sharing, as a way of optimizing the use of indoor space. A survey- and interview study highlights challenges to the use of requirements by Swedish municipalities to promote low-GWP construction. A third interview study shows how various artefacts mediate work with sustainable design in housing projects. Finally, the thesis addresses more directly the accuracy of environmental performance assessments, and investigates how choices of data and method related to maintenance and replacement affect LCA results, exemplified for façade materials.The modelling of buildings’ GWP in backcasting scenarios helps challenge current paradigms by drawing attention to some less-discussed issues, such as reducing embodied emissions (including by avoiding new construction) as well as the demand for indoor space. Space sharing can help optimizing the use of indoor space, but several factors limit its adoption. It requires different practices among building users and property managers, including different business models and performance metrics considering occupancy. Ambiguities in national legislation and municipal plans regarding the status of shared and multifunctional buildings also hinder space sharing initiatives (e.g. unclear rights and responsibilities of tenants and property owners, conflicting requirements for fire safety or ventilation, etc.). Similarly, the thesis highlights important regulatory ambiguities regarding to what extent municipalities can set requirements to promote low-GWP construction. Environmental performance requirements in construction also entail barriers related to limited in-house skills, access to data, time and resources. Using such requirements would first require bridging skill and data gaps. Similar barriers are highlighted regarding the use of LCA in public housing projects. In such projects, artefacts such as national regulations, local development plans and internal requirements of the housing organization enforce a certain level of work with sustainable design while limiting the range of design options. Other artefacts simplify the design work and provide standardized default options. In such cases, design choices that strongly influence environmental performance are taken upstream of the project, when these criteria, requirements and default options are developed.The thesis highlights ways in which quantitative assessments of environmental performance could directly influence building design and management, e.g. through the introduction of environmental performance criteria in regulation and procurement. Besides challenges related to skill, data, time and resources mentioned above, the thesis draws attention to the variability of LCA results due to choices of method and data sources. In the particular case of maintenance and replacement processes, the choice of reference study period (RSP) influences the relative significance of these processes, and longer RSPs favor more durable products. Discrepancies exist between different sources for service life data, indicating a need for more reliable data. The use of a round-up or annualized number of replacements makes little difference in average, but can lead to different outcomes in specific cases. This shows a need to carefully harmonize methodological choices as LCA becomes used more and more broadly in procurement and building regulation.Furthermore, the thesis also draws attention to more complex effects of environmental performance assessments in housing projects. Widespread certification systems can become de-facto definitions of sustainability for actors, influencing design even in projects that are not certified. Environmental performance assessments can hide or reveal certain aspects of sustainability. Widely used assessment tools can act as “black boxes”, where criteria for what constitutes a sustainable building are hidden and no longer contested. This process helps operationalize sustainability in building projects. However, it can lead to some important aspects being disregarded. For instance, conventional energy performance metrics are often normalized for floor area, ignoring occupancy and space efficiency. On the other hand, quantitative assessments can also highlight important aspects of the multifaceted issue of sustainability. The thesis exemplifies this by using a quantitative model of buildings’ GWP to draw attention to key mitigation strategies, and by reviewing energy metrics highlighting occupancy and space efficiency.
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| 4. |
- Francart, Nicolas, 1993-, et al.
(författare)
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Demands, default options and definitions : How artefacts mediate sustainability in public housing projects in Sweden and Cyprus
- 2022
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Ingår i: Energy Research & Social Science. - : Elsevier BV. - 2214-6296 .- 2214-6326. ; 92
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable building design practices are influenced by requirements, guidelines, criteria for green procurement and certification, assessment tools such as life cycle assessment, etc. This study investigates how such artefacts support or define aspirations towards sustainability, through case studies of public housing projects in Sweden and Cyprus. The study first illustrates how constraints mediated by artefacts set boundaries to the range of available sustainable design options. On one hand, fulfilling sustainability requirements conveyed in regulations, certifications and directives is a major driver of designers' involvement with sustainable design. On the other hand, cost calculations, procurement laws and development plans exclude certain design options. Moreover, default solutions and standardised design guidelines within the organisation streamline and simplify the design process, indirectly determining what sustainable design options are considered. However, these demands and default options are also bent and adapted on a case-by-case basis. The ways in which sustainable design arises from the interplay between artefacts and actors' agency differed significantly between the Swedish and Cypriot cases. Swedish actors' operational definition of sustainability is strongly codified and enforced through inter-connected artefacts. The Miljo center dot byggnad certification is often a de facto definition of sustainability used by actors to set sustainability criteria and targets. Environmental databases for construction products act as black boxes, implicitly determining what aspects of sustainability are addressed in design decisions. Conversely, Cypriot designers' work with sustainability depends to a larger extent on their motivation, experience and ability to convince their peers.
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| 5. |
- Francart, Nicolas, 1993-, et al.
(författare)
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Environmental Sustainability Building Criteria for an Open Classification System
- 2019
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Ingår i: Cold Climate HVAC 2018. - Cham : Springer Nature. ; , s. 1005-1016
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Konferensbidrag (refereegranskat)abstract
- Existing classification systems linked to the environmental performance of buildings provide limited added value for practitioners. A survey among Swedish construction entrepreneurs showed that there is a real demand for better formulated criteria and clearer guidance. At the same time, critical investigation of requirements based on fixed average values for primary energy factors (such as in the EU Environmental Performance of Buildings Directive) shows that they are insufficient to provide guidance towards environmental sustainability building practices. They fail to take into account a number of methodological issues, including seasonal and hourly variability of energy supply and demand, and the future evolution of energy mixes. This is illustrated in the case of Sweden. The outline of an Open Classification System, currently under development, is then presented. This system focuses on methodological transparency and validity, as well as ease of use for practitioners. It addresses specifically issues where other existing systems were found to be lacking, and its methodology will be assessed to ensure that it provides optimal guidance towards environmentally sustainable practices. The system is based on three criteria: the energy resource index and global warming potential, calculated with attributional and consequential life cycle approaches, and a heat loss factor to assess the building's energy performance independently from the supply side.
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| 6. |
- Francart, Nicolas, 1993-, et al.
(författare)
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How artefacts mediate sustainability in public housing projects
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The concept of “sustainable building”, in its various interpretations, is becoming increasingly important for policymakers, planners and building sector practitioners. The ways actors work with building sustainability are influenced by requirements, guidelines, criteria for green procurement and certification, assessment tools, internal documents of their company, etc. The present study investigates how such artefacts mediate building design, focusing on how they support or define aspirations towards environmental sustainability. This investigation is based on case studies of public housing projects in Sweden and Cyprus. First of all, the cases indicate that artefacts set boundaries to the range of available sustainable design options. On one hand, regulations, certification systems and directives internal or external to the housing company codify and enforce minimum demands regarding sustainability. Several actors mentioned that a major driver of their work with sustainable design was the need to fulfil requirements set in regulations, plans, directives or procurement documents. On the other hand, cost calculations, procurement laws and requirements in development plans also restrict the range of possible design options. Artefacts also streamline and simplify the design process. The use of predefined or default options, checklists, standardised technical specifications and databases implies that some key design choices are not made within the project itself, but outside of it, when these guidelines and standards are developed. However, these various requirements, constraints and standardised options are often bent and adapted on a case-by-case basis, showing a complex and interdependent relationship between artefacts and actors’ agency. Significant differences were apparent between the Swedish and Cypriot cases. In the Swedish cases, the ways actors understand and operationalise the concept of “sustainable building” is strongly reified, codified and enforced through various interconnected artefacts. The widespread Miljöbyggnad certification is often a de facto definition of sustainability and a reference for actors to set practical sustainability criteria. Third party environmental databases for construction products also create black boxes where environmental performance criteria are unchallenged and not immediately visible to the user. This reification was less noticeable in the Cypriot cases. Cypriot designers’ work with sustainability seemed to depend to a larger extent on their motivation, experience, knowledge, skills and ability to convince their peers. The paper ends with a discussion of implications for the implementation of environmental performance criteria and decision support tools such as life cycle assessment (LCA).
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| 7. |
- Francart, Nicolas, 1993-, et al.
(författare)
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Influence of methodological choices on maintenance and replacement in building LCA
- 2021
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Ingår i: The International Journal of Life Cycle Assessment. - : Springer Nature. - 0948-3349 .- 1614-7502. ; 26:11, s. 2109-2126
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Previous life cycle assessments (LCAs) of buildings and building components show a broad range of values for theimpact of maintenance and replacement, some highlighting these operations as major hotspots while others consider theminsignificant. This article highlights methodological aspects explaining this discrepancy. The influence of three aspects isinvestigated further in a case study of façade materials: the reference study period (RSP), service life data, and the use of around-up number of operations or annualized impacts.Methods A comparative LCA of seven façade alternatives is carried out as an illustrative case study. For each alternative,global warming potential (GWP) is calculated using three possible RSPs, four possible material service lives (one fromindustry practitioners and low, standard and high values from a generic database), and two possible calculation methods (round-up or annualized impacts).Results and discussion While the same façade alternative had the lowest GWP in all cases, different methodological choicessignificantly affected the GWP and respective ranking of other alternatives. Some alternatives showed a significant increasein GWP over longer RSPs, while others were still dominated by the impact of initial production after 200 years. In nearlyall cases, generic service life data lead to a higher GWP than data from industry practitioners. Major discrepancies werefound between generic and practitioner data in some cases, e.g., for the brick façade. In most cases, annualized impacts ledto a slightly lower (or equal) GWP than using a round-up number of operations. However, when a major operation happensshortly before the end of the RSP, the annualized method leads to considerably lower GWP.ConclusionsMaintenance and replacement are rarely significant over a 50-year RSP but sometimes become hotspots overlonger RSPs. Using round-up operations or annualized impacts does not make much difference in average, but leads to significantlydifferent results in specific cases. As building LCA enters certification and regulation, there is a need to harmonizesuch methodological choices, as they affect LCA results, hotspot identification, and recommendations. Discrepancies inservice life data also call for the gathering of reliable data.
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| 8. |
- Francart, Nicolas, 1993-, et al.
(författare)
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Investigation of maintenance and replacement of materials in building LCA
- 2020
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Ingår i: IOP Conference Series. - : IOP Publishing. ; , s. 032027-
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Konferensbidrag (refereegranskat)abstract
- Recent life cycle assessments (LCAs) of buildings highlight the importance of global warming potential from construction materials, in particular in energy-efficient buildings. It is therefore important to address the influence of methodological choices related to materials on LCA results. This paper focuses on scenarios for the maintenance and replacement of building elements. Methods: A literature review is carried out to summarize the state of the art regarding scenarios for maintenance and replacement in building LCA, their influence on LCA results and related methodological issues. Additionally, a case study is carried out to investigate whether assumptions about service lives in LCA could significantly influence the recommended design for a building's roof, using a Monte Carlo analysis considering service lives as stochastic variables. Results: The literature review reveals a broad range of impacts from maintenance and replacement in case studies. There is therefore no consensus about the relative impact of these processes. These differences can be partly explained by differences in scope (e.g. what elements are considered to be replaced and what kinds of processes are included), in methods for service life estimation and in future scenarios for the production and recycling of materials. Relative impacts from maintenance and replacement seem to be highest for energy efficient buildings with a long service life, and for elements such as carpets, paint, insulation, doors and windows. The case study of roofing materials exemplifies a case where assumptions about service lives could influence design decisions. Both the ranking of alternatives and the relative significance of maintenance and replacement processes depend on assumptions about service lives. An asphalt roof cover is preferred when considering only initial installation, but a clay tile roof cover is preferred over asphalt in roughly two thirds of the cases when considering maintenance and replacement. Metal roofs almost always had a poorer environmental performance under the assumptions considered. Conclusions: Results from the case study are compared with previous studies of maintenance and replacement processes, and methodological issues deserving further consideration are highlighted. In particular, the case study is used to discuss the issue of whether a modelling based on independent service lives for various building elements accurately reflects industrial practices. Moreover, the relevance of including maintenance and replacement in regulations and climate declarations for buildings is discussed.
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| 9. |
- Francart, Nicolas, 1993-, et al.
(författare)
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Sharing indoor space: stakeholders’ perspectives and energy metrics
- 2020
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Ingår i: Buildings and Cities. - : Ubiquity Press, Ltd.. - 2632-6655. ; , s. 70-85
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Tidskriftsartikel (refereegranskat)abstract
- The sharing of indoor space can improve space and energy efficiency. The drivers and barriers to space-sharing initiatives are investigated from the perspectives of building users and building sector practitioners, based on interviews and a workshop. The role of energy performance metrics in promoting space efficiency is further analysed through a literature review. From the users’ perspective, space sharing can be understood through the interplay between tangible aspects (e.g. concrete benefits derived from sharing), organisational aspects (e.g. common decision processes and conflict resolution) and social aspects (e.g. group identity and consensus on appropriate behaviours). From the perspective of architects and property owners, shareable spaces require features such as flexibility and multifunctionality. The design of such spaces is limited by regulatory issues (e.g. building regulations poorly accommodate shared facilities) and business-related issues. One such issue is that building performance metrics normalised based on floor area do not incentivise the efficient use of space. A review of complementary metrics is provided, covering parameters such as number of users, layout, time of use, etc. Each metric serves a particular purpose; therefore, a set of complementary metrics can be used to support decisions at different phases of the building’s life cycle. Practice relevanceImproving space efficiency (e.g. by sharing indoor space) is a key strategy to meet simultaneously the future demand for facilities in cities and fulfil environmental objectives such as a reduction of climate change impact in the building sector. A clearer understanding of the specificities of space sharing is provided from the perspectives of building users and practitioners. This will assist practitioners to understand the needs of other stakeholders. Regulatory and business-related barriers to space-sharing initiatives are highlighted as a first step towards overcoming these barriers. Guidance is provided on complementary energy performance metrics appropriate for space efficiency. These metrics can be used to support various decisions during the different stages of a building’s life cycle.
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| 10. |
- Frischknecht, R., et al.
(författare)
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Comparison of the environmental assessment of an identical office building with national methods
- 2019
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Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; , s. 012037-
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Konferensbidrag (refereegranskat)abstract
- The IEA EBC Annex 72 focuses on the assessment of the primary energy demand, greenhouse gas emissions and environmental impacts of buildings during production, construction, use (including repair and replacement) and end of life (dismantling), i.e. during the entire life cycle of buildings. In one of its activities, reference buildings (size, materialisation, operational energy demand, etc.) were defined on which the existing national assessment methods are applied using national (if available) databases and (national/regional) approaches. The "be2226" office building in Lustenau, Austria was selected as one of the reference buildings. TU Graz established a BIM model and quantified the amount of building elements as well as construction materials required and the operational energy demand. The building assessment was carried out using the same material and energy demand but applying the LCA approach used in the different countries represented by the participating Annex experts. The results of these assessments are compared in view of identifying major discrepancies. Preliminary findings show that the greenhouse gas emissions per kg of building material differ up to a factor of two and more. Major differences in the building assessments are observed in the transports to the construction site (imports) and the construction activities as well as in the greenhouse gas emissions of the operational energy demand (electricity). The experts document their practical difficulties and how they overcame them. The results of this activity are used to better target harmonisation efforts.
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