Architecture, Building and Planning - Research Publications

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    Improving the uptake of hybrid life cycle assessment in the construction industry
    Crawford, RH ; Bontinck, PA ; Stephan, A ; Hajdu, M ; Skibniewski, E (Elsevier, 2017)
    With building-related greenhouse gas emissions(GHGE) having more than doubled since 1970, they represent one of the largest and most attractive opportunities for climate change mitigation. However, current focus has mainly been on reducing operational GHGE leaving building embodied GHGE (i.e. the GHG emissions associated with the extraction, manufacture and transportation of materials, and the building construction process itself) largely ignored. These embodied emissions have been estimated to represent between 10% to 97% of a buildings total life cycle GHGE. It is thus critical that decision-making in relation to buildings is based on a life cycle perspective. One of the main barriers to this approach is the uncertainty surrounding the financial implications of life cycle GHGE reduction strategies. Despite project cost being a key driver for decision-making, building developers, designers and owners have insufficient knowledge or appropriate tools to adequately consider these life cycle costs and balance them against GHGE savings. Several methods exist for quantifying the costs of a building, such as life cycle costing (LCC). However, LCC and life cycle GHGE assessments are often used in isolation. This study will address the urgent need to move towards integrating these assessments by developing a framework that can be used to ascertain the important relationships and trade-offs between financial and GHGE performance of various building-related GHGE reduction strategies. This framework can be used as part of the building decision-making process and help create a low carbon, affordable built environment.
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    Towards an automated approach for compiling hybrid life cycle inventories
    Crawford, RH ; Bontinck, P ; Stephan, A ; Wiedmann, T ; Ding, L ; Fiorito, F ; Osmond, P (Elsevier, 2017)
    There is an urgent need to reduce the environmental effects associated with the built environment. While a life cycle approach is considered essential for ensuring that these effects are not simply shifted from one life cycle stage to another, not all life cycle assessment methods provide the same level of detail. Three main approaches are currently used to compile a life cycle inventory capturing data on the inputs and outputs associated with a particular good or service: process, input-output and hybrid analysis. While process analysis is recognised for its specificity, it typically involves a truncation of the system boundary. Conversely, input-output analysis is systemically complete, but aggregates data at the economic sector or commodity level. Combining these two methods in a hybrid analysis has the potential to reduce their limitations, while maintaining their benefits. However, combining process and input-output data remains a highly manual and time-consuming process. The development of an automated approach for compiling life cycle inventories is a critical step in the uptake of hybrid analysis methods. This study aims to explore automating the hybridisation of process and input-output data using the Path Exchange method. Major practical barriers that usually prevent automating the integration of process and input-output data in hybrid life cycle inventories are discussed and a case study focusing on concrete is used for the purpose of illustrating the approach.
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    Embodied carbon in buildings: An Australian perspective
    Crawford, RH ; Stephan, A ; Schmidt, M ; Pomponi, F (Springer International Publishing, 2018-01-28)
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    The Australian industrial ecology virtual laboratory and multi-scale assessment of buildings and construction
    Baynes, TM ; Crawford, RH ; Schinabeck, J ; Bontinck, P-A ; Stephan, A ; Wiedmann, T ; Lenzen, M ; Kenway, S ; Yu, M ; Teh, SH ; Lane, J ; Geschke, A ; Fry, J ; Chen, G (Elsevier, 2018-04-01)
    As global population and urbanization increase, so do the direct and indirect environmental impacts of construction around the world. Low-impact products, buildings, precincts and cities are needed to mitigate the effects of building construction and use. Analysis of embodied energy and greenhouse gas (GHG) emissions across these scales is becoming more important to support this direction. The calculation of embodied impacts requires rigorous, flexible and comprehensive assessment tools. Firstly, we present the Australian Industrial Ecology Virtual Laboratory (IELab) as one such tool discussing its structure, function and wide scope of application. Secondly, we demonstrate its potential high level of resolution in a case study: assessing embodied GHG emissions in an aluminium-framed window by combining product-specific life-cycle inventory data. The input-output analysis at the core of the IELab is mathematically comprehensive in the assessment of direct and indirect impacts and the tool can be applied at a range of scales from building component, to precincts and cities, or to the entire construction industry. IELab uses a flexible formalism that enables consistent harmonisation of diverse datasets and tractable updating of input data. The emissions and energy database supporting IELab has detailed data, aligning with economic accounts and data on labour, water, materials and waste that enrich assessment across other dimensions of sustainability. IELab is a comprehensive, flexible and robust assessment tool well positioned to respond to the challenge of assessing and aiding the design of a low-impact built environment.
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    Towards a design framework for the structural systems of tall buildings that considers embodied greenhouse gas emissions
    Helal, J ; Stephan, A ; Crawford, RH ; Cruz, PJS (CRC Press, 2019-07-29)
    During the 1960s, the Bangladeshi-American structural engineer and architect Fazlur Rahman Khan proposed an influential design framework for the structural systems of tall buildings titled premium-for-height. Khan argued that the challenge of a structural engineer is to design structural systems that minimise the increase in structural material weight per gross floor area with increasing building height. However, in meeting the challenges of climate change and urbanisation, minimising the embodied environmental flows of tall buildings must also be a priority in structural design frameworks. This paper proposes to expand the premium-for-height framework for tall buildings by considering the embodied greenhouse gas emissions of structural systems using a hybrid life cycle inventory analysis method. Advanced structural analysis and a comprehensive consideration of building parameters are also proposed. To demonstrate the use and potential of the framework, embodied greenhouse gas emissions of six case study tall buildings are analysed. The results arediscussed and recommendations are made to improve the reliability of the more comprehensive framework.
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    A comprehensive database of environmental flow coefficients for construction materials: closing the loop in environmental design
    Crawford, RH ; Stephan, A ; Prideaux, F ; Agrawal, A (The Architectural Science Association, 2019)
    Life cycle assessment is increasingly used to quantify and reduce the environmental effects of buildings. Embodied environmental effects, resulting from material production and replacement as well as construction, are typically quantified using coefficients from readily available databases. However, most existing databases of embodied environmental coefficients for construction materials suffer from limitations, such as inconsistency in the life cycle inventory method used or system boundary incompleteness. This paper introduces a new database of hybrid environmental flow coefficients for construction materials, covering flows of energy, water and greenhouse gas emissions for over 100 common construction materials. The hybrid approach used combines bottom-up industrial process data and top-down macroeconomic input-output data, making it more comprehensive than process analysis and more accurate and specific than input-output analysis alone. A case study building is used to demonstrate the importance of using hybrid coefficients for improving environmental performance. This study shows that the use of process coefficients can lead to a significant underestimation of the total environmental effects associated with the construction of a building, by up to 64%. This has considerable implications for decision-making relating to building design, including the focus of improvement efforts. This database of coefficients will enable building professionals to more effectively analyse and improve the environmental performance of buildings. This will also help inform the focus of environmental policy and improve the implementation of life cycle thinking in environmental design.
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    Environmental Performance in Construction (EPiC) Database: a database of embodied environmental flow coefficients
    Crawford, RH ; Stephan, A ; Prideaux, F (The University of Melbourne, 2019)
    The EPiC Database contains environmental flow coefficients for over 250 common construction materials and products. Developed using complete, transparent and consistent methods, the EPiC coefficients can be used to assess the embodied energy, water and greenhouse gas emissions of construction projects, assisting with design, construction and whole of life decision-making. The EPiC database is the result of a four-year multi-institutional research project, led by internationally recognised experts in modelling embodied environmental flows. Their combined 30+ years of experience in the field is testimony to their commitment to improving the environmental performance of construction.
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    Use of an Object-Oriented System for Optimizing Life Cycle Embodied Energy and Life Cycle Material Cost of Shopping Centres
    Weththasinghe, K ; Stephan, A ; Francis, V ; Tiwari, P ; Littlewood, J ; Howlett, RJ ; Capozzoli, A ; Jain, LC (Springer London, 2019)
    Shopping centres are an integral part and a critical component of urban cities in most economies. Typically, the shorter refurbishment cycle and frequent tenant replacements in shopping centres cause excessive use of building materials over its service life. This drastic use of resources, consequently, increase life cycle embodied energy (LCEE) and life cycle material cost (LCMC) of shopping centres. Therefore, careful selection of materials is vital to reduce the negative environmental impacts and material costs. Current research on the implications of material choices on LCEE and LCMC of shopping centres are insubstantial and decisions makers are left with limited information to make better selections. Therefore, selection of energy efficient, cost-effective and environmentally responsive materials and assemblies has been a critical process for the professionals who are involved in decision-making. This paper proposes the use of object-oriented programming (OOP) to develop a mathematical model to develop combinations of building assemblies with minimum LCEE and LCMC of shopping centres through material selection. The model is based for sub-regional shopping centres in Australia, yet can be applied for any similar property type with modifications to databases and model architecture. However, scope of this paper is limited to the development of model architecture with detailed explanations on databases and computing core development. Even though, the detailed presentation of development of OOP structure pro-vides proper insight to the mathematical core for future application.
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    A model for streamlining and automating path exchange hybrid life cycle assessment
    Stephan, A ; Crawford, RH ; Bontinck, PA (Springer Verlag, 2019-02)
    Purpose: Life cycle assessment (LCA) is inherently complex and time consuming. atypically involves the collection of data for dozens to hundreds of individual processes. More comprehensive LCI methods, such as input-output analysis and hybrid analysis can include data for billions of individual transactions or transactions/processes, respectively. While these two methods are known to provide a much more comprehensive overview of a product’s supply chain and related environmental flows, they further compound the complex and time-consuming nature of an LCA. This has limited the uptake of more comprehensive LCI methods, potentially leading to ill-informed environmental decision-making. A more accessible approach for compiling a hybrid LCI is needed to facilitate its wider use. Methods: This study develops a model for streamlining a hybrid LCI by automating various components of the approach. The model is based on the path exchange hybrid analysis method and includes a series of inter-related modules developed using object-oriented programming in Python. Individual modules have been developed for each task involved in compiling a hybrid LCI, including data processing, structural path analysis and path exchange or hybridisation. Results and discussion: The production of plasterboard is used as a case study to demonstrate the application of the automated hybrid model. Australian process and input-output data are used to determine a hybrid embodied greenhouse gas emissions value. Full automation of the node correspondence process, where nodes relating to identical processes across process and input-output data are identified, remains a challenge. This is due to varied dataset coverage, different levels of disaggregation between data sources and lack of detail of activities and coverage for specific processes. However, by automating other aspects of the compilation of a hybrid LCI, the comprehensive supply chain coverage afforded by hybrid analysis is able to be made more accessible to the broader LCA community. Conclusions: This study shows that it is possible to automate various aspects of a hybrid LCI in order to address traditional barriers to its uptake. The object-oriented approach used enables the data or other aspects of the model to be easily updated to contextualise an analysis in order to calculate hybrid values for any environmental flow for any variety of products in any region of the world. This will improve environmental decision-making, critical for addressing the pressing global environmental issues of our time.
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    Towards a comprehensive energy assessment of residential buildings. A multi-scale life cycle energy analysis framework
    STEPHAN, A ( 2013)
    Buildings are directly responsible for 40% of the final energy consumption in most developed economies and for much more if indirect requirements are considered. This results in huge impacts which affect the environmental balance of our planet. However, most current building energy assessments focus solely on operational energy overlooking other energy consumptions such as embodied and transport energy. Embodied energy comprises the energy requirements for building materials production, construction and replacement. Transport energy represents the amount of energy required for the mobility of building users. Decisions based on partial assessments might result in an increased energy demand during other life cycle stages or at different scales of the built environment. Recent studies have shown that embodied and transport energy demands often account for more than half of the total lifecycle energy demand of residential buildings. Current assessment tools and policies therefore overlook more than 50% of the life cycle energy consumption. This thesis presents a comprehensive life cycle energy analysis framework for residential buildings. This framework takes into account energy requirements at the building scale, i.e. the embodied and operational energy demands, and at the city scale, i.e. the embodied energy of nearby infrastructures and the transport energy of its users. This framework is implemented through the development, verification and validation of an advanced software tool which allows the rapid analysis of the life cycle energy demand of residential buildings and districts. Two case studies, located in Brussels, Belgium and Melbourne, Australia, are used to investigate the potential of the developed framework. Results show that each of the embodied, operational and transport energy requirements represent a significant share of the total energy requirements and associated greenhouse gas emissions of a residential building, over its useful life. All the scales of the built environment and the different life cycle stages should therefore be taken into consideration in order to reduce energy use in the built environment. Also, results have demonstrated that current building energy efficiency regulations may paradoxically lead to an increase in energy use. The use of the developed tool will allow building designers, town planners and policy makers to reduce the energy demand and greenhouse gas emissions of residential buildings by selecting measures that result in overall savings. This will ultimately contribute to reducing the environmental impact of the built environment.