The desire for the construction industry to move towards lifecycle carbon emissions analysis

A significant reduction in carbon emissions is a global mission and the construction industry has an indispensable role to play as a major carbon dioxide (CO2) generator. Over the years, various building environmental assessment (BEA) models and concepts have been developed to promote environmentally responsible design and construction. However, limited attention has been placed on assessing and benchmarking the carbon emitted throughout the lifecycle of building facilities. This situation could undermine the construction industry’s potential to reduce its dependence on raw materials, recognise the negative impacts of producing new materials, and intensify the recycle and reuse process. In this paper, current BEA approaches adopted by the construction industry are first introduced. The focus of these models and concepts is then examined. Following a brief review of lifecycle analysis, the boundary in which a lifecycle carbon emission analysis should be set for a construction project is identified. The paper concludes by highlighting the potential barriers of applying lifecycle carbon emissions analysis in the construction industry. It is proposed that lifecycle carbon emission analysis can be integrated with existing BEA models to provide a more comprehensive and accurate evaluation on the cradle-to-grave environmental performance of a construction facility. In doing so, this can assist owners and clients to identify the optimum solution to maximise emissions reduction opportunities.

A conceptual framework for future-proofing the energy performance of buildings

This paper presents a review undertaken to understand the concept of 'future-proofing' the energy performance of buildings. The long lifecycles of the building stock, the impacts of climate change and the requirements for low carbon development underline the need for long-term thinking from the early design stages. 'Future-proofing' is an emerging research agenda with currently no widely accepted definition amongst scholars and building professionals. In this paper, it refers to design processes that accommodate explicitly full lifecycle perspectives and energy trends and drivers by at least 2050, when selecting energy efficient measures and low carbon technologies. A knowledge map is introduced, which explores the key axes (or attributes) for achieving a 'future-proofed' energy design; namely, coverage of sustainability issues, lifecycle thinking, and accommodating risks and uncertainties that affect the energy consumption. It is concluded that further research is needed so that established building energy assessment methods are refined to better incorporate future-proofing. The study follows an interdisciplinary approach and is targeted at design teams with aspirations to achieve resilient and flexible low-energy buildings over the long-term. © 2012 Elsevier Ltd.

A generic model of Exergy Assessment of the Environmental Impact for the Building Lifecycle

A generic model of Exergy Assessment is proposed for the Environmental Impact of the Building Lifecycle, with a special focus on the natural environment. Three environmental impacts: energy consumption, resource consumption and pollutant discharge have been analyzed with reference to energy-embodied exergy, resource chemical exergy and abatement exergy, respectively. The generic model of Exergy Assessment of the Environmental Impact of the Building Lifecycle thus formulated contains two sub-models, one from the aspect of building energy utilization and the other from building materials use. Combined with theories by ecologists such as Odum, the paper evaluates a building's environmental sustainability through its exergy footprint and environmental impacts. A case study from Chongqing, China illustrates the application of this method. From the case study, it was found that energy consumption constitutes 70–80% of the total environmental impact during a 50-year building lifecycle, in which the operation phase accounts for 80% of the total environmental impact, the building material production phase 15% and 5% for the other phases.

Towards a holistic modelling framework for embodied carbon and waste in the building lifecycle

As the building industry proceeds in the direction of low impact buildings, research attention is being drawn towards the reduction of carbon dioxide emission and waste. Starting from design and construction to operation and demolition, various building materials are used throughout the whole building lifecycle involving significant energy consumption and waste generation. Building Information Modelling (BIM) is emerging as a tool that can support holistic design-decision making for reducing embodied carbon and waste production in the building lifecycle. This study aims to establish a framework for assessing embodied carbon and waste underpinned by BIM technology. On the basis of current research review, the framework is considered to include functional modules for embodied carbon computation. There are a module for waste estimation, a knowledge-base of construction and demolition methods, a repository of building components information, and an inventory of construction materials’ energy and carbon. Through both static 3D model visualisation and dynamic modelling supported by the framework, embodied energy (carbon), waste and associated costs can be analysed in the boundary of cradle-to-gate, construction, operation, and demolition. The proposed holistic modelling framework provides a possibility to analyse embodied carbon and waste from different building lifecycle perspectives including associated costs. It brings together existing segmented embodied carbon and waste estimation into a unified model, so that interactions between various parameters through the different building lifecycle phases can be better understood. Thus, it can improve design-decision support for optimal low impact building development. The applicability of this framework is anticipated being developed and tested on industrial projects in the near future.

Case study on the whole life carbon cycle in buildings

Global temperatures are expected to rise by between 1.1 and 6.4oC this century, depending, to a large extent, on the amount of carbon we emit to the atmosphere from now onwards. This warming is expected to have very negative effects on many peoples and ecosystems and, therefore, minimising our carbon emissions is a priority. Buildings are estimated to be responsible for around 50% of carbon emissions in the UK. Potential reductions involve both operational emissions, produced during use, and embodied emissions, produced during manufacture of materials and components, and during construction, refurbishments and demolition. To date the major effort has focused on reducing the, apparently, larger operational element, which is more readily quantifiable and reduction measures are relatively straightforward to identify and implement. Various studies have compared the magnitude of embodied and operational emissions, but have shown considerable variation in the relative values. This illustrates the difficulties in quantifying embodied, as it requires a detailed knowledge of the processes involved in the different life cycle phases, and requires the use of consistent system boundaries. However, other studies have established the interaction between operational and embodied, which demonstrates the importance of considering both elements together in order to maximise potential reductions. This is borne out in statements from both the Intergovernmental Panel on Climate Change and The Low Carbon Construction Innovation and Growth Team of the UK Government. In terms of meeting the 2020 and 2050 timeframes for carbon reductions it appears to be equally, if not more, important to consider early embodied carbon reductions, rather than just future operational reductions. Future decarbonisation of energy supply and more efficient lighting and M&E equipment installed in future refits is likely to significantly reduce operational emissions, lending further weight to this argument. A method of discounting to evaluate the present value of future carbon emissions would allow more realistic comparisons to be made on the relative importance of the embodied and operational elements. This paper describes the results of case studies on carbon emissions over the whole lifecycle of three buildings in the UK, compares four available software packages for determining embodied carbon and suggests a method of carbon discounting to obtain present values for future emissions. These form the initial stages of a research project aimed at producing information on embodied carbon for different types of building, components and forms of construction, in a simplified form, which can be readily used by building designers in optimising building design in terms of minimising overall carbon emissions. Keywords: Embodied carbon; carbon emission; building; operational carbon.

A semiotic framework for information representation of energy consumption in office buildings

Taking a perspective from a whole building lifecycle, occupier's actions could account for about 50% of energy. However occupants' activities influence building energy performance is still a blind area. Building energy performance is thought to be the result of a combination of building fabrics, building services and occupants' activities, along with their interactions. In this sense, energy consumption in built environment is regarded as a socio-technical system. In order to understand how such a system works, a range of physical, technical and social information is involved that needs to be integrated and aligned. This paper has proposed a semiotic framework to add value for Building Information Modelling, incorporating energy-related occupancy factors in a context of office buildings. Further, building information has been addressed semantically to describe a building space from the facility management perspective. Finally, the framework guides to set up building information representation system, which can help facility managers to manage buildings efficiently by improving their understanding on how office buildings are operated and used.

Concepts, models and analyses of electronic demolition of buildings

The demolition of building structures produces enormous amounts of waste materials. In most current demolition projects, a great number of demolished materials are directly sent to landfill after their primary usage due to the difficulties in finding their next usage immediately. At the same time, because of limited supply of second-hand materials, new and high quality materials are used in construction projects whose design standards can be fitted using the secondary or used materials. However, this is an inefficient method to reduce waste because off the flow nature of the current waste-exchange systems and the demolition procedure. The recent concept using deconstruction rather than destruction for demolishing a constructed facility fails to achieve widespread understanding or acceptance due to various practical limitations. In this paper, for the purpose of envisaging the deconstruction implementations in practice and promoting cascading usages of construction materials, the concept of electronic demolition (e-Demotion, eDemolition) is put forward for the first time. E-demolition is a virtual demolition approach by which the demolition information, progress and outputs are operated before the physical demolition. Furthermore, the authors set up the essential models to implement electronic demolition of buildings from the viewpoints of demolition progress, business, and information. Each model is demonstrated in accord with the conventional demolition practice and subject to the ideal deconstruction implementation. Following the electronic demolition of a real project, the physical demolition can be anticipated with a minimum of construction waste emission.

Lifecycle cost and CO2 emission comparison of conventional and rationalized bridges

The construction industry consumes a great deal of natural resources and energy in constructing, maintaining and demolishing their products such as buildings and bridges. These activities lead significant impacts on global and regional environments in addition to their economic expenses. In this research, the lifecycle cost (LCC) and lifecycle CO₂ (LCCO₂) emission of newly developed bridges, including the minimized girder, rationalized box-girder and rationalized truss bridges, are quantified and compared with those of the conventional I-girder, box-girder and truss bridges. It was found that the newly developed types of bridges have lower values in both LCC and LCCO₂ than the corresponding conventional bridges do. The effects of span lengths on LCC and LCCO₂ are studied for both conventional and rationalized bridges. The characteristics of LCC and LCCO₂ are investigated over the lifecycle of a bridge including its construction, maintenance and replacement stages.

The business case for incorporating sustainability in office buildings : the adaptive reuse of existing buildings

The effect of climate change and global warming has received increased attention in society with constant reminders about the importance of energy efficiency and sustainability in buildings. Whilst the focus is often placed on smaller items such as plastic bags, air conditioners and motor vehicles, the emphasis has recently shifted to structures in the built environment. Office buildings have been identified as contributing significantly to global warming during their building lifecycle with a substantial contribution to CO2 omissions. In response, building designs and construction techniques have evolved over time to improve energy efficiency and reduce CO2 omissions. Whilst property valuers, managers and analysts must remain up-to-date regarding changes, relatively little research has been conducted about whether and how increased sustainability, such as signified in a Green Star rating affects a property’s highest and best value and long-term lifecycle. This study investigates the degree to which sustainability is understood in the property marketplace, especially in relation to property values with the emphasis placed on a cost- benefit analysis from both an owner’s and tenant’s perspective. Whilst it may be argued that incorporating sustainability into a new office building is cost prohibitive on a financial cost-benefit analysis, often various minor steps can be taken to upgrade the sustainability of an existing building. This project examines recent trends in capital expenditure to increase the sustainability of offices and where Green Star ratings have been applied to establish whether any corresponding increase in value is evident. In order to develop a researchframework, a thorough literature review will be conducted of recent Australian and overseas studies. This will enable links between sustainability and office buildings to be highlighted, and vitally how they affect a property’s value in both the short and long-term.

User satisfaction in sustainable office buildings : a preliminary study

Energy efficiency was first mandated for commercial buildings in 2006 in Part J of The Building Code of Australia (BCA) and regulators are already implementing increased measures in 2010 (ABCB 2010). Further increases will follow as part of the co-ordinated effort to reduce building related greenhouse gas emissions. The introduction of the Energy Efficiency Disclosure Bill 2010 will establish a national scheme to promote the disclosure of information about the energy efficiency of office buildings as well as further highlighting the need for efficiency. Increased energy efficiency in the form of insulation, energy efficient light fittings, sophisticated Building Management Systems (BMS), micro-generation such as solar and wind turbines all result in measurable quantifiable reductions in operating costs for owners and tenants. However convincing all building owners about the sound business case for adopting sustainability measures has not been fully realised. To-date the adoption of cutting edge sustainable buildings in Australia is restricted to a few industry leaders, such as Investa and ISPT in Victoria for example. Sustainable building owners and tenants often benefit from reduced operating costs during the building lifecycle although the ‘intangible’ effect on businesses (e.g. employee productivity) is uncertain. This aspect has not been accurately quantified and has not been included as part of the measurement of sustainability in buildings.

This study will allow property stakeholders, including government policy-makers and investors/developers, to better understand the optimal type and level of sustainability to be incorporated into the built environment. In addition this knowledge will enable policymakers to make more informed decisions with regards to the likely impact of the legislative measures they propose in respect of sustainability and buildings in The Building Code of Australia (BCA) and other relevant legislation.

Implementation Feasibility of a Digital Nervous System for the Construction Industry: For Efficient and Effective Information Management across the Project Lifecycle

The construction industry has long been considered as highly fragmented and non-collaborative industry. This fragmentation sprouted from complex and unstructured traditional coordination processes and information exchanges amongst all parties involved in a construction project. This nature coupled with risk and uncertainty has pushed clients and their supply chain to search for new ways of improving their business process to deliver better quality and high performing product. This research will closely investigate the need to implement a Digital Nervous System (DNS), analogous to a biological nervous system, on the flow and management of digital information across the project lifecycle. This will be through direct examination of the key processes and information produced in a construction project and how a DNS can provide a well-integrated flow of digital information throughout the project lifecycle. This research will also investigate how a DNS can create a tight digital feedback loop that enables the organisation to sense, react and adapt to changing project conditions. A Digital Nervous System is a digital infrastructure that provides a well-integrated flow of digital information to the right part of the organisation at the right time. It provides the organisation with the relevant and up-to-date information it needs, for critical project issues, to aid in near real-time decision-making. Previous literature review and survey questionnaires were used in this research to collect and analyse data about information management problems of the industry – e.g. disruption and discontinuity of digital information flow due to interoperability issues, disintegration/fragmentation of the adopted digital solutions and paper-based transactions. Results analysis revealed efficient and effective information management requires the creation and implementation of a DNS.