Architecture, Building and Planning - Research Publications

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    Towards a comprehensive framework for integrating embodied environmental flow assessment into the structural design of tall buildings
    Helal, J ; STEPHAN, A ; Crawford, R (ANZAScA, 2021)
    Urgent changes are needed in the construction industry to meet short term mitigation goals for climate change. Traditionally, operational environmental flows have been the primary focus of regulations and current attempts to improve the environmental performance of buildings. However, studies have revealed that embodied environmental flows are often underestimated and rarely considered. Embodied environmental flows are particularly significant in the structural systems of tall buildings due to the substantial influence of wind and earthquake loads on structural material requirements.
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    Life Cycle Energy Analysis of a House in UAE
    Rauf, A ; Attoye, DE ; Crawford, R ; TABET AOUL, KA ; SHAFIQ, MT ; ATTOYE, DE (ZEMCH Network, 2022)
    In the United Arab Emirates (UAE) about 70% of total energy produced is consumed by building sector, and this compares with the global average of about 40%. Energy usage in buildings has often been discussed from the standpoint of operational energy, mainly used for purposes of heating or cooling. In recent times the discussion on building energy consumption has also raised the need for investigating the energy embodied in the construction of buildings and manufacturing of their constituent materials and components. This reorientation of energy consciousness in the construction industry is of critical importance in efforts to reduce the environmental impacts of the built environment. In United Arab Emirates, significant efforts have been made in recent times to reduce the operational energy consumption; however, embodied energy consumption is nearly unaddressed. The challenge this paper addresses is the need to review not only the operational (OPE) energy of a building but also its initial (IEE) and recurrent embodied energy (REE). The aim of this paper, therefore, is to calculate the energy consumption of a residential building over its life in UAE, and to identify the significance of embodied energy. A case study residential building in the UAE was selected as a representative example of government-built homes for UAE citizens for the purpose of this investigation. Using an input-output hybrid approach to calculate the energy required at the time of its construction and REE value calculated over a period of 50 years, the study compares the IEE, OPE and REE for the case study to extrapolate comparative data. Results from this study suggest the importance of including the initial and recurrent embodied energy of buildings in building life cycle energy analyses, which in this case represented 18% and 17% of the life cycle energy of the building. The anticipated merit of this study to building professionals is an appreciation and holistic consideration of the life cycle embodied energy of building design towards promoting a reduction in total building energy consumption.
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    Greenhouse gas emissions performance of cross laminated timber construction using hybrid life cycle assessment
    Cadorel, X ; Crawford, R ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020)
    Numerous studies have investigated the environmental benefits of cross laminated timber (CLT) construction in comparison to conventional construction, typically using a life cycle assessment (LCA). Yet, there is a need for further in-depth analysis of the environmental performance of CLT construction using a more comprehensive approach, in order to provide a more realistic estimation of the potential for CLT construction to reduce greenhouse gas (GHG) emissions associated with buildings. This research aims to fill this knowledge gap by conducting a streamlined life cycle assessment to quantify embodied GHG emissions, using hybrid coefficients from the EPiC Database, for a real case study; a five storey multi- residential CLT building about to be constructed in Melbourne, Australia. The new knowledge will provide some of the critical knowledge that is currently lacking in relation to the life cycle GHG emissions performance of CLT construction and the potential for this form of construction to reduce GHG emissions associated with the construction industry.
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    Comparative study of the life cycle embodied greenhouse gas emissions of panelised prefabricated residential walling systems in Australia
    Ghafoor, S ; Crawford, R ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020)
    Residential buildings account for 17% of global greenhouse gas (GHG) emissions. With detached housing accounting for over 70% of all of Australia’s residential dwellings, and a projected doubling of population in the next 40 years, these houses represent a significant opportunity for GHG emissions reduction. Prefabrication can improve the environmental performance of buildings through lower resource input, reduction in waste and improved quality. However, little research exists on whether it reduces embodied GHG emissions, an increasingly significant proportion of a building’s life cycle GHG emissions. The aim of this study was to compare the embodied GHG emissions associated with the construction of detached residential housing in Australia using panelised prefabricated external wall systems. This study used a Path Exchange hybrid life cycle inventory approach to quantify the construction-related embodied GHG emissions of a typical detached house with three external wall assembly variations: cross laminated timber (CLT), structural insulated panels (SIPs) and prefabricated timber framed panels. Compared to conventional brick veneer construction, the prefabricated timber framed panel was the only one that lowered embodied GHG emissions (by 7%). The SIPs resulted in the highest embodied GHG emissions for the house (6% higher than the brick veneer option). The use of prefabrication may not always reduce GHG emissions associated with house construction. In reducing the initial embodied GHG emissions, while the construction process accounts for around 30% of these emissions, the key focus should be on selecting materials with low GHG emissions intensity.
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    Design for Dematerialisation: an approach for reducing a building’s embodied environmental flows
    Skillington, K ; Crawford, R ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020)
    The building sector must rapidly adopt measures to reduce its significant contribution to global environmental degradation. However, recent efforts in pursuing improved environmental outcomes in the building sector have disproportionately focused on building operation, overlooking the increasingly significant construction-related life cycle stages. The environmental effects associated with these life cycle stages are often locked-in during the design of a building. As such, design stakeholders must have an appreciation of design approaches that affect a buildings’ construction-related or embodied environmental flows. Design for Dematerialisation (DfD) is one such approach, however from the perspective of the building sector it is not well understood. Informed by research from allied disciplines, this study addresses this gap and ascertains that DfD is a design approach that targets reduced material and resource inputs whilst pursuing optimal functionality/performance. Implemented in early design decision making, DfD requires rethinking the whole building design from a life cycle perspective, questioning necessity, and testing alternatives to satisfy user need. Drivers and barriers affecting adoption are discussed, and the paper concludes with recommendations to further develop DfD research and practice – namely the need to empirically assess built examples of the approach to better support its implementation.
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    The effect of data age on the assessment of a building’s embodied energy
    Crawford, R ; Stephan, A ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020)
    Data used to quantify the embodied energy of a building, known as life cycle inventory (LCI) data, varies widely in temporal relevance. The energy associated with construction material production and building construction changes regularly due to improvements in manufacturing and construction processes, and energy mix and intensity. Older LCI data may not be representative of the current industry. Due to the time and costs involved in compiling LCIs, many studies rely on outdated data, yet no studies have considered the effect of data age on the analysis of a building’s embodied energy. A reliable embodied energy value is critical to ensure energy reduction efforts have been effective. This study compares the life cycle embodied energy of a typical Australian house using data from a 2010 and 2019 LCI database, compiled using an identical technique. The 2019 data lead to a 27.7% decrease in life cycle embodied energy. This reveals that the age of data may have a considerable effect on the value of a building’s embodied energy, indicating that LCI data should be regularly updated to respond to changes in manufacturing and construction processes as well as energy mix and intensity.
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    The effect of COVID-19 on household energy demand
    Crawford, RH ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020-01-01)
    The emergence and global spread of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) at the beginning of 2020 changed the way we live our lives, including how and where we undertook our everyday activities. Strict lockdown rules, put in place to limit the spread of the virus, saw activity centres, workplaces and schools deserted, and homes become places of work and education. This shift led to a reduction in energy demand for many businesses. However, much of this energy demand transferred to households with most householders occupying their houses for most of the day, leading to increased use of heating, cooling, lighting and appliances, such as computers. This study analyses the total energy usage data for a household in Melbourne, Australia to explore the possible effect of the COVID-19-related lockdown on the household’s energy demand. Energy usage data was sourced from energy bills and the electricity distributor. Data associated with the period where all householders were working and studying solely at home (March to June 2020) were compared to six years of historical energy usage data for the same time period. The analysis shows a 26% increase in household energy demand. This also hasimplications for household finances.
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    The life cycle embodied energy and greenhouse gas emissions of an Australian housing development: comparing 1997 and 2019 hybrid life cycle inventory data
    Allende, A ; Stephan, A ; Crawford, R ; Ghaffarianhoseini, A ; Ghaffarianhoseini, A ; Nasmith, N (The Architectural Science Association (ANZAScA), 2020)
    Data used to conduct a life cycle assessment, called a life cycle inventory (LCI), is rarely scrutinised and its effects on the results of an environmental assessment is understudied. Hybrid analysis is the most comprehensive technique to compile an LCI. It combines bottom-up industrial process data and top-down macroeconomic input-output data. This study compares two hybrid LCIs of construction materials, using the same technique, developed in 1997 and 2019. This paper evaluates the effect of LCI data on the life cycle embodied energy and greenhouse gas emissions of a recent housing development in Melbourne, Australia. The case study development consists of six different apartment buildings (~14,000m² gross floor area; 555 inhabitants) that have an improved environmental performance compared to business-as-usual. Results show that the 2019 LCI lead to a decrease in the life cycle embodied energy and greenhouse gas emissions over 50 years, from 39.1 GJ/m² to 32.2 GJ/m² (-17.6%) and from 2,338 kgCO2e/m² to 2,218 kgCO2e/m² (-5.1%), respectively. The embodied energy and greenhouse gas emissions ranking of some materials changed by up to five positions, while at the assembly level the top five assemblies did not change much. This analysis provides rare insights into the effects of hybrid LCI data on the life cycle assessment of built environment assets and implications for design.
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    EPiC: Introducing a database of hybrid environmental flow coefficients for construction materials
    Crawford, RH ; Stephan, A ; Prideaux, F (IOP Publishing, 2020-11-20)
    Abstract As worldwide consumption of materials continues to rise, there is growing pressure on material, energy and water resources and an increase in waste production and greenhouse gas emissions. A much more sustainable approach to the procurement of built assets is crucial to avoid exacerbating existing environmental pressures. Product and process-based environmental data is an important element in understanding how current and future built assets perform. This paper analyses environmental flow data for a range of construction materials contained within the Environmental Performance in Construction (EPiC) Database, a new, open access repository of hybrid environmental flow coefficients for construction materials. The structural paths of 131 construction materials are analysed to identify trends and contributors to embodied water, energy and greenhouse gas (GHG) emissions coefficients. The disaggregation and analysis of material coefficients shows the complexity of the material supply chains and provides insight into the key inputs and outputs resulting from the production of construction materials.
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    Tiny house, tiny footprint? The potential for tiny houses to reduce residential greenhouse gas emissions
    Crawford, RH ; Stephan, A (IOP Publishing, 2020-11-20)
    Abstract While considerable improvements to the energy efficiency of housing have been achieved over recent decades, the residential sector still represents a significant and increasing proportion of global greenhouse gas emissions. This is exacerbated by an increasing global population and living standards, demand for larger houses, and smaller household size. Tiny houses have emerged as a potential solution to this issue. While research exists on the environmental benefits of smaller housing, there is little on that of tiny houses. This study quantifies the life cycle GHG emissions of a tiny house, and their potential to reduce residential GHG emissions. A hybrid analysis and a dynamic energy modelling tool were used to quantify embodied and operational GHG emissions, respectively, for a tiny house located in Australia. The study shows that a tiny house may result in a 70% reduction in per capita GHG emissions over its life compared to a traditional Australian house. This indicates the potential of tiny houses to be a useful option for reducing GHG emissions in the building sector.