Conceptual Building Information Modelling Framework for Whole‐house Refurbishment based on LCC and LCA

The UK government aims at achieving 80% CO2 emission reduction by 2050 which requires collective efforts across all the UK industry sectors. In particular, the housing sector has a large potential to contribute to achieving the aim because the housing sector alone accounts for 27% of the total UK CO2 emission, and furthermore, 87% of the housing which is responsible for current 27% CO2 emission will still stand in 2050. Therefore, it is essential to improve energy efficiency of existing housing stock built with low energy efficiency standard. In order for this, a whole‐house needs to be refurbished in a sustainable way by considering the life time financial and environmental impacts of a refurbished house. However, the current refurbishment process seems to be challenging to generate a financially and environmentally affordable refurbishment solution due to the highly fragmented nature of refurbishment practice and a lack of knowledge and skills about whole‐house refurbishment in the construction industry. In order to generate an affordable refurbishment solution, diverse information regarding costs and environmental impacts of refurbishment measures and materials should be collected and integrated in right sequences throughout the refurbishment project life cycle among key project stakeholders. Consequently, various researchers increasingly study a way of utilizing Building Information Modelling (BIM) to tackle current problems in the construction industry because BIM can support construction professionals to manage construction projects in a collaborative manner by integrating diverse information, and to determine the best refurbishment solution among various alternatives by calculating the life cycle costs and lifetime CO2 performance of a refurbishment solution. Despite the capability of BIM, the BIM adoption rate is low with 25% in the housing sector and it has been rarely studied about a way of using BIM for housing refurbishment projects. Therefore, this research aims to develop a BIM framework to formulate a financially and environmentally affordable whole‐house refurbishment solution based on the Life Cycle Costing (LCC) and Life Cycle Assessment (LCA) methods simultaneously. In order to achieve the aim, a BIM feasibility study was conducted as a pilot study to examine whether BIM is suitable for housing refurbishment, and a BIM framework was developed based on the grounded theory because there was no precedent research. After the development of a BIM framework, this framework was examined by a hypothetical case study using BIM input data collected from questionnaire survey regarding homeowners’ preferences for housing refurbishment. Finally, validation of the BIM framework was conducted among academics and professionals by providing the BIM framework and a formulated refurbishment solution based on the LCC and LCA studies through the framework. As a result, BIM was identified as suitable for housing refurbishment as a management tool, and it is timely for developing the BIM framework. The BIM framework with seven project stages was developed to formulate an affordable refurbishment solution. Through the case study, the Building Regulation is identified as the most affordable energy efficiency standard which renders the best LCC and LCA results when it is applied for whole‐house refurbishment solution. In addition, the Fabric Energy Efficiency Standard (FEES) is recommended when customers are willing to adopt high energy standard, and the maximum 60% of CO2 emissions can be reduced through whole‐house fabric refurbishment with the FEES. Furthermore, limitations and challenges to fully utilize BIM framework for housing refurbishment were revealed such as a lack of BIM objects with proper cost and environmental information, limited interoperability between different BIM software and limited information of LCC and LCA datasets in BIM system. Finally, the BIM framework was validated as suitable for housing refurbishment projects, and reviewers commented that the framework can be more practical if a specific BIM library for housing refurbishment with proper LCC and LCA datasets is developed. This research is expected to provide a systematic way of formulating a refurbishment solution using BIM, and to become a basis for further research on BIM for the housing sector to resolve the current limitations and challenges. Future research should enhance the BIM framework by developing more detailed process map and develop BIM objects with proper LCC and LCA Information

DFAHP multicriteria risk assessment model for redeveloping derelict public buildings

Reusing abandoned public buildings is a positive strategy in sustainable urban development. An appropriate assessment method is needed to reduce the risks of redeveloping derelict public properties. The Delphi method is an optimal group decision-making technique; whereas the analytical hierarchy process (AHP) method is useful for solving multicriteria decision-making problems. In addition, fuzzy logic manages artificial uncertainty and ambiguity, where an explicit number or ratio can express the level of preference. This study uses the Delphi method, fuzzy logic, and AHP (DFAHP) as a risk assessment model to redevelop derelict public buildings. The DFAHP provides an objective reference for investment decisions and is beneficial in reducing the risk of the public sector investing in the reuse of abandoned public buildings, in aiding in reuse cases that revitalize urban economic development, and in appreciating the value of sustainable city development

Visualising urban energy use: the use of LiDAR and remote sensing data in urban energy planning

This paper explores the potential for using remotely sensed data from a combination of commercial and open-sources, to improve the functionality, accuracy of energy-use calculations and visualisation of carbon emissions. We present a study demonstrating the use of LiDAR (Light Detection And Ranging) data and aerial imagery for a mixed-use inner urban area within the North East of England and how this can improve the quality of input data for modelling standardised energy uses and carbon emissions. We explore the scope of possible input data for both (1) building geometry and (2) building physics models from these sources. We explain the significance of improved data accuracy for the assessment of heat-loss parameters, orientation, and shading and renewable energy micro-generation. We also highlight the limitations around the sole use of remotely sensed data and how these concerns can be partially addressed through combinations with (1) open-source property data, such as age, occupancy, tenure and (2) existing stakeholder data sets, including building services and measured performance. We set out some of the technical challenges; addressed through data approximation (considering data quality and metadata protocols) and a combination of automated or manual processing; in the use, adaptation, and transferability of this data. We elucidate how the output can be visualised and be supported by many of industry-standard CAD, GIS, and BIM software applications hence, broadening the scope for realworld applications. We demonstrate the support of commercial interest and potential drawing evidence from primary market research regarding the principal applications, functionality, and output. In summary, we conclude on the benefits in the use of remotely sensed data for improved accuracy in energy use and carbon emission calculations, the need for semantic integration of mixed data sources and the importance of output visualisation

Decision support and risk management system for competitive bidding in refurbishment work

This study is concerned with the management of risks in competitive bidding for refurbishment work (lump sum contracts). It investigates the main difficulties and risks faced by contractors when they are making decisions in competitive bidding as a result of the general lack of information both inside and outside a contractor's organisation. A decision support and risk management system model is developed which provides a systematic and objective approach to risk management in competitive bidding for refurbishment work. The model provides a framework whereby both quantitative (tender bid records) and qualitative (risk perception of contractors) information may be obtained to support the decisions of contractors during tendering. The research adopts a combination of both Archival and Opinion research methodologies to build up two main databases consisting of tender bid records and information on the risk perception of contractors during tendering. From the analysis, a decision support and risk management system is developed consisting of six modules namely: (i) Module 1 - Databases of tender bid records and Repertory grid data, (ii) Module 2 - General information of bidding characteristics, (iii) Module 3 - Contractor's analysis, (iv) Module 4 - Competitor's analysis, (v) Module 5 - Bidding models, and (vi) Module 6 - Risk management system. This study has demonstrated that past tender bid records of contractors may be organised in a systematic way to provide invaluable strategic information to enhance the understanding of contractors with respect to their competitive bidding environments, their own bidding performance and the bidding behaviour of their competitors, thereby enabling contractors to manage risks more effectively and efficiently

the Case of Germany’s Building Policy

This paper analyzes the degree of climate policy integration (CPI) in Germany’s building policy. The basic assumption of CPI is that the cross- sectoral and multi-level challenge of climate change necessitates the integration of climate concerns into non-environmental policy fields (horizontally) and across different levels of governance (vertically). There are at least three dimensions in which CPI can be analyzed, namely a conceptual, a procedur-al, and an output/outcome dimension. We use this distinction and analyze the current sta-tus of CPI in Germany’s building policy, an area highly relevant for climate change mitiga-tion. In all three dimensions, CPI appears to be at a fairly low level, leaving much room for improvement in terms of prioritization, coordination, and coherence. It seems as if politi-cal commitment to climate change mitigation has a rather low impact on everyday policy-making, i.e. when decisions on trade-offs, resources, and reallocations have to be made. In the absence of a comprehensive strategy, current German building policy does not reflect the need for coherent and long-term climate policymaking. What is the role of federalism in this regard? In section 2, we outline that federalism might impact both positively and negatively on the prospects of CPI, and that there is no uniform relationship between the two. In the specific case of building policy, a number of negative effects of federalism – incoherence, veto players, enforcement deficits – seem to material-ize. Even though coordination between federal and Länder level is deemed necessary, real-ity shows that it happens only to a very limited extent. The Länder partly opposing more ambitious policies, a stronger integration and are varying considerably regarding the im-plementation of federal policies. On the other hand, potential advantages from federalism for CPI are limited in the field of building policy. Baden-Wuerttemberg’s pioneering role in setting standards for renewable heating systems certainly inspired federal legislation, but so far that is mainly restricted to new constructions. The lacking horizontal CPI across departments in particular as well as the lack of coordina-tion across levels of decision making leads to an argument for more and better coordina- tion between all actors involved, be they federal or state actors. Coordination needs to be firmly embedded in the whole policy cycle, starting with joint target-setting, continuing with agreement on adequate policy instruments, and concluding with an evaluation of ef-fects. Strategic capacities, e.g. dedicated institutions or budgets would be needed to maintain the topic on the agenda as an issue of high priority even after changes in government. The finding however, indicates that the low hanging fruits of energy demand and ef-ficiency have not received similar attention as the supply of (renewable) energy