The role of the client to enable circular economy in the building sector

Whilst there is an increasing recognition of the circular economy concept within the building sector, opportunities for its implementation at project level remain largely underexploited. Research has shown that challenges to its uptake include limited knowledge and awareness among stakeholders; a fragmented supply chain; an unclear business model and financial case; and a lack of incentives to implement circular economy in building projects. Whilst these challenges are present across the construction supply chain, clients have a pivotal role in addressing them and driving the shift towards circular economy from project inception to completion. As such, clients can progress a number of enabling factors for the uptake of circular economy, including the implementation of innovative business models, whole life thinking, information sharing, facilitating supply chain collaboration and establishing a clear vision. This paper focuses on the role of the client in enabling a circular economy within the building sector by analyzing data obtained from a supply chain workshop on the critical success factors for implementing the circular economy. Supporting actions of the construction supply chain are also discussed. The results indicate that whilst a client can be influential in applying circular economy principles with a resulting reduction in material usage and waste generation through setting suitable conditions within the procurement process such as requirements for material efficiency, support from the construction supply chain is required to enable this to happen

Circular technologies in construction

The report emphasizes the importance of standardisation in promoting circular construction and the circular economy. It discusses the need for future standardisation and pre-normative research for circular construction in terminology, metrology, such as indicators, performance characterisation, compatibility and operability assessments. Several opportunities for synergies are uncovered, such as collaboration between the New European Bauhaus and circular construction. The report presents a gap analysis carried out by CEN/TC350 on circularity in the construction sector and emphasizes the importance to overcome cradle-to-grave construction frameworks. Strategies to bridge these gaps include enhancing standardisation, collaboration, and innovation. Four strategic areas could benefit from standardisation: a) frameworks and indicators to measure circularity, b) quality assurance of reused and recycled material, end-of-waste criteria, c) design for circularity, adaptability and disassembly, and d) building information. The report also highlights the need for clear objectives, focused standards, cost-effectiveness, common future scenarios, resource indicators, and practical implementation aspects to advance circularity in the construction industry. The recommendations provided aim to guide future standardisation activities, aligning with circular principles to drive industry competitiveness and environmental stewardship. Taking first steps towards a standardisation roadmap, the study highlights specific areas that CEN/TC 350 may consider in their future work programme and suggests high priority topics based on discussions with stakeholders.JRC.S.4 - Scientific Development Programme

The Origins of AGN Obscuration: The 'Torus' as a Dynamical, Unstable Driver of Accretion

Multi-scale simulations have made it possible to follow gas inflows onto massive black holes (BHs) from galactic scales to the accretion disk. When sufficient gas is driven towards the BH, gravitational instabilities generically form lopsided, eccentric disks that propagate inwards. The lopsided stellar disk exerts a strong torque on the gas disk, driving inflows that fuel rapid BH growth. Here, we investigate whether the same gas disk is the 'torus' invoked to explain obscured AGN. The disk is generically thick and has characteristic ~1-10 pc sizes and masses resembling those required of the torus. The scale heights and obscured fractions of the predicted torii are substantial even in the absence of strong stellar feedback providing the vertical support. Rather, they can be maintained by strong bending modes and warps excited by the inflow-generating instabilities. Other properties commonly attributed to feedback processes may be explained by dynamical effects: misalignment between torus and host galaxy, correlations between local SFR and turbulent gas velocities, and dependence of obscured fractions on AGN luminosity or SFR. We compare the predicted torus properties with observations of gas surface density profiles, kinematics, scale heights, and SFR densities in AGN nuclei, and find that they are consistent. We argue that it is not possible to reproduce these observations and the observed column density (N_H) distribution without a clumpy gas distribution, but allowing for clumping on small scales the predicted N_H distribution is in good agreement with observations from 10^20-27 cm^-2. We examine how N_H scales with galaxy and AGN properties, and find that AGN feedback may be necessary to explain some trends with luminosity and/or redshift. The torus is not merely a bystander or passive fuel source for accretion, but is itself the mechanism driving accretion.Comment: 20 pages, 10 figures, accepted to MNRAS (matches accepted version

Understanding and predicting construction waste

For the last 12 years, Building Research Establishment (BRE) has been working on developing better data in terms of the amount and type of waste being produced as a result of construction activity. The means of collecting and aggregating these data have been refined over the years to arrive at the current large-scale and long-term benchmarking exercise being undertaken by way of BRE’s site waste management planning tool – Smartwaste Plan. Concurrently, a 3 year project ‘Understanding and predicting construction waste’ has been funded by Defra to develop robust reporting procedures and detailed waste benchmarks. A further objective is to demonstrate the use of such benchmarks as a means of predicting the amount and type of waste likely to be produced as a result of construction activity on a local and regional basis. This is potentially useful in working out gaps in suitable resource management facilities or under/over capacity relating to reprocessing specific waste materials. Interim results from these activities, conclusions and future/ongoing work are summarised in this paper. A range of performance indicators for waste arisings from new build construction were produced for a variety of different project types and for different waste types. These performance indicators have been use to produce benchmarks for standard, good and best practice. </jats:p

Challenging the current approach to end of life of buildings using a life cycle assessment (LCA) approach

Life cycle thinking has been applied in the construction industry for more than 20 years for the environmental evaluation of construction products and processes. Life cycle assessment (LCA) is the tool that enables the quantification of environmental impacts using parameters appropriate to the various potential environmental impact categories. Standards have developed alongside to support this process, under the ISO 14000 series, ISO 21930 and 21931 for construction products, and lately European standards aimed at harmonising approaches to LCA in construction in Europe, specifically EN 15804 for product level assessments, and EN 15978 for building level assessments. EN 15978 provides a modular approach through which the environmental impacts are reported for different life cycle stages across the processes for the provision of the products and services used in the construction (A1 to A3), the delivery of the products and services to site and the actual construction process (A4 and A5), the use of the building including maintenance, repair and replacement, and energy and water use (B1 to B7), and the demolition/deconstruction and end-of-life management processes for the building (C1 to C4). There is also a further life cycle stage (D) which is aimed at evaluating the benefits or burdens resulting from any potential future reuse of components of the building which would otherwise have been disposed of as wastes from either the construction, use, or endof- life of the building. On the whole this represents a linear approach to assessing buildings, to which a paradigm shift will be needed to apply the principles and benefits posed by circular economy thinking to the construction sector. Part of the H2020 funded project BAMB (Building As Materials Bank) will be to develop a methodology to assess the potential circularity of a building and, in particular, will investigate the potential role of LCA in circular economy

Reuse of building products and materials – barriers and opportunities

BRE have been working with the reclamation sector in the UK for around 20 years to promote the reuse of end-of-life building products and materials in preference to recycling and recovery. Much of this has been dedicated to the promotion of pre-demolition and prerefurbishment audits to facilitate targets being set and markets for reusable resources sourced prior to work commencing. Against this backdrop the surveys undertaken to measure levels of reclamation in the UK over a 15 year period showed a significant decline. The cause of this decline was investigated and revealed a number of challenges which were affecting both the supply and demand for reclaimed products and materials. Many of the challenges to reuse are connected to the availability and robustness of data. Therefore, the work currently being undertaken as part of the H2020 funded project BAMB (Building As Material Banks) provides a great opportunity to address such gaps in buildings of the future. However, since the existing built environment will have a major impact on resource flows for many years, it is also important to consider approaches to improve data in this context also. Therefore, this presentation will summarise the challenges for reuse of building products and materials in existing and future buildings. It will then briefly describe the opportunities and solutions to address these challenges in the context of improved data access, management and evaluation. Finally, the BAMB research which should contribute to providing solutions will be explored

The role of the client to enable circular economy in the building sector

Whilst there is an increasing recognition of the circular economy concept within the building sector, opportunities for its implementation at project level remain largely underexploited. Research has shown that challenges to its uptake include limited knowledge and awareness among stakeholders; a fragmented supply chain; an unclear business model and financial case; and a lack of incentives to implement circular economy in building projects. Whilst these challenges are present across the construction supply chain, clients have a pivotal role in addressing them and driving the shift towards circular economy from project inception to completion. As such, clients can progress a number of enabling factors for the uptake of circular economy, including the implementation of innovative business models, whole life thinking, information sharing, facilitating supply chain collaboration and establishing a clear vision. This paper focuses on the role of the client in enabling a circular economy within the building sector by analyzing data obtained from a supply chain workshop on the critical success factors for implementing the circular economy. Supporting actions of the construction supply chain are also discussed. The results indicate that whilst a client can be influential in applying circular economy principles with a resulting reduction in material usage and waste generation through setting suitable conditions within the procurement process such as requirements for material efficiency, support from the construction supply chain is required to enable this to happen

The role of the client to enable circular economy in the building sector

Whilst there is an increasing recognition of the circular economy concept within the building sector, opportunities for its implementation at project level remain largely underexploited. Research has shown that challenges to its uptake include limited knowledge and awareness among stakeholders; a fragmented supply chain; an unclear business model and financial case; and a lack of incentives to implement circular economy in building projects. Whilst these challenges are present across the construction supply chain, clients have a pivotal role in addressing them and driving the shift towards circular economy from project inception to completion. As such, clients can progress a number of enabling factors for the uptake of circular economy, including the implementation of innovative business models, whole life thinking, information sharing, facilitating supply chain collaboration and establishing a clear vision. This paper focuses on the role of the client in enabling a circular economy within the building sector by analyzing data obtained from a supply chain workshop on the critical success factors for implementing the circular economy. Supporting actions of the construction supply chain are also discussed. The results indicate that whilst a client can be influential in applying circular economy principles with a resulting reduction in material usage and waste generation through setting suitable conditions within the procurement process such as requirements for material efficiency, support from the construction supply chain is required to enable this to happen