To efficiently evolve towards 0-impact buildings it is important to investigate which are the act... more To efficiently evolve towards 0-impact buildings it is important to investigate which are the actions in order of priority. The latter can be defined as measures which lead to the highest reduction of the impact for the smallest increase in cost. This paper elaborates on the reduction potential of different environmental impacts of buildings throughout their life cycle based on a set of case studies. The case studies concern typical dwellings in the Belgian context. A life cycle assessment is used for the evaluation of the impacts, while a life cycle cost analysis is applied to determine the financial cost. The impacts are translated into a single score expressed in monetary values. This should be interpreted as an external cost which is not accounted for to date.no ISBNstatus: publishe
In construction, the focus of research and policy on sustainability broadened from reducing the e... more In construction, the focus of research and policy on sustainability broadened from reducing the energy consumption of a building in use, to a comprehensive sustainability strategy considering the building's entire life cycle. However, the implementation of life cycle thinking (and its operational counterpart the circular economy) in combination with an objective sustainability evaluation is still in its infancy. Therefore, the aim of this study is twofold. First, it is illustrative for the quantified assessment of the potential environmental and financial benefits and burdens of introducing circular design alternatives for internal wall assemblies to the Belgian market. Second, it reviews the methodological implications on the results of a consequential life cycle assessment (LCA) and a life cycle costing (LCC), acknowledging the time dependence and closed-loop nature of those circular design alternatives. That aim is achieved through a multi-model setup. Evaluating the design alternatives through various methodological assumptions and service life models, allows understanding the relevance and robustness of the results by acknowledging the corresponding uncertainty. demountable and reusable walls, but highlights at the same time the need for a comprehensive sustainability assessment before responsible conclusions can be drawn.
The transition from a linear to a circular economy is essential to reduce the environmental burde... more The transition from a linear to a circular economy is essential to reduce the environmental burden of our society. A key issue is to prevent a shift of the environmental burdens and take the consequences of a decision into account, for example based on a consequential life cycle assessment (LCA). However, limited practical guidance is available on how to implement consequential LCA in the context of the construction sector. Therefore, the aim of this study is twofold. First, to quantify the potential environmental and burdens of introducing circular design alternatives for internal wall assemblies to the Belgian market. Second, to review the methodological implications on the results of a consequential LCA with a particular focus on consistently identifying marginal suppliers and substitution routes, acknowledging the time dependence and closed-loop nature of the design alternatives. In total seven wall assemblies are assessed over a period of 60 years, with a refurbishment every 15 year. The results show that a low life cycle impact can be achieved for assemblies that are designed to be used again and have a higher initial impact, such as a plywood boarding connected reversibly to a demountable metal frame substructure, as well as for assemblies with no possibilities for direct reuse that have a low initial impact, such as a drywall system with a wooden substructure. Further, regarding the methodological scenarios on marginal supplier identification, the range of possible outcomes is however much larger for the demountable wall assemblies than for the conventional ones.
International Journal of Life Cycle Assessment, Nov 16, 2020
Purpose To reduce the environmental impact of the building sector, environmental targets consider... more Purpose To reduce the environmental impact of the building sector, environmental targets considering the full life cycle of buildings can be supportive. In recent years various benchmarks based on Life Cycle Assessment (LCA) have been developed as part of regulations, labelling systems, sustainability rating tools and research studies. The objective of this paper is to critically analyse 23 existing benchmarking systems focusing on the benchmark methodology but also on the benchmark applications and communication. Methods The critical literature review consists of two parts. In a first part, the choices related to the assessment method, functional equivalent, definition of benchmark values, benchmark scope, benchmark applications and benchmark communication are compared. In the second part, benchmark values are compiled from literature and statistically analysed. Results and discussion The comparative analysis allows to identify the main approaches and methods used in benchmarking systems. For each evaluation aspect, the strengths and weaknesses of the various approaches are highlighted. The statistical analysis provides insight in the spread of benchmark values. Important variations are found between the literature sources which can be explained by differences in benchmark approach, scope, system boundaries and applications. Conclusions Based on the comparative analysis, recommendations are formulated for the development of LCA benchmarks for the building sector. The results of the statistical analysis furthermore provide reference values which can be used for the validation of future benchmarks. For global warming, the statistical values for the full life cycle impacts (i.e. embodied and operational impacts) range from about 15 up to 35 kg CO2 eq./m².a.
ABSTRACT Assisted by designers and contractors, dwelling owners have historically based their dec... more ABSTRACT Assisted by designers and contractors, dwelling owners have historically based their decisions (including the choice of building services) on investment costs. Given the increasing interest in the environmental dimension of the built environment, it is also important to include environmental impact in the decisionmaking process. This paper focuses on the life cycle environmental impact and financial costs of heating and ventilation alternatives for new dwellings in Belgium. Insight into the environmental impact and financial costs of correctly dimensioned configurations over the entire life cycle could enable better choices. Commonly used alternatives are considered, as well as more advanced ones. These are compared and the optima are determined, identifying the best choice within a limited budget. The analysis indicates that, in addition to energy-efficiency measures regarding the building skin, a well-designed heating and ventilation system plays an important role in reducing financial costs and environmental impact over the lifespan of a dwelling. Different heating and ventilation solutions are likely to be selected when initial and life cycle costs are juxtaposed with environmental, financial and total costs. Nevertheless, preferences based on total costs generally coincide with those based on financial costs.
Because of its scale and the role it plays in our lives, a healthy built environment is of vital ... more Because of its scale and the role it plays in our lives, a healthy built environment is of vital importance. As a part of material culture, buildings have to support human needs. But because of their static nature, obtained through design, most contemporary buildings and their components have a negative impact on their surroundings. The huge quantities of waste produced during demolition and the still rising emission of greenhouse gases created during use of the building, manufacture and waste treatment of its components are environmental indicators of an ineffi cient and unhealthy design. Moreover, a socioeconomic paradox has been created. Due to inadequate design many buildings are unable to adapt to (fast-changing) contemporary requirements. As a result many constructions are left to their fate and decay. This ineffi cient use of matter and space is in sharp contrast with a global need for affordable housing. In high density countries, such as Belgium, building plots are scarce and expensive. In addition to this, the UN Human Settlements Programme (UN-HABITAT) estimates that 600 million urban residents and 1 billion rural dwellers in developing countries live in inadequate housing. In this paper, three main methods that integrate the fourth dimension, i.e. time, into design are described: design for adaptability (construction reuse), design for deconstruction (component reuse) and design for dismantling (material reuse). These four-dimensional design strategies strive for a healthy built environment, by taking into account, as from the fi rst sketches, the wear and tear of artefacts and the changing and evolving circumstances that will affect them. The design of several construction kits, developed at the Vrije Universiteit Brussel, shows that the designer must pay attention to detailing. The key detailing principles and two design cases are further examined in this paper.
To efficiently evolve towards 0-impact buildings it is important to investigate which are the act... more To efficiently evolve towards 0-impact buildings it is important to investigate which are the actions in order of priority. The latter can be defined as measures which lead to the highest reduction of the impact for the smallest increase in cost. This paper elaborates on the reduction potential of different environmental impacts of buildings throughout their life cycle based on a set of case studies. The case studies concern typical dwellings in the Belgian context. A life cycle assessment is used for the evaluation of the impacts, while a life cycle cost analysis is applied to determine the financial cost. The impacts are translated into a single score expressed in monetary values. This should be interpreted as an external cost which is not accounted for to date.no ISBNstatus: publishe
In construction, the focus of research and policy on sustainability broadened from reducing the e... more In construction, the focus of research and policy on sustainability broadened from reducing the energy consumption of a building in use, to a comprehensive sustainability strategy considering the building's entire life cycle. However, the implementation of life cycle thinking (and its operational counterpart the circular economy) in combination with an objective sustainability evaluation is still in its infancy. Therefore, the aim of this study is twofold. First, it is illustrative for the quantified assessment of the potential environmental and financial benefits and burdens of introducing circular design alternatives for internal wall assemblies to the Belgian market. Second, it reviews the methodological implications on the results of a consequential life cycle assessment (LCA) and a life cycle costing (LCC), acknowledging the time dependence and closed-loop nature of those circular design alternatives. That aim is achieved through a multi-model setup. Evaluating the design alternatives through various methodological assumptions and service life models, allows understanding the relevance and robustness of the results by acknowledging the corresponding uncertainty. demountable and reusable walls, but highlights at the same time the need for a comprehensive sustainability assessment before responsible conclusions can be drawn.
The transition from a linear to a circular economy is essential to reduce the environmental burde... more The transition from a linear to a circular economy is essential to reduce the environmental burden of our society. A key issue is to prevent a shift of the environmental burdens and take the consequences of a decision into account, for example based on a consequential life cycle assessment (LCA). However, limited practical guidance is available on how to implement consequential LCA in the context of the construction sector. Therefore, the aim of this study is twofold. First, to quantify the potential environmental and burdens of introducing circular design alternatives for internal wall assemblies to the Belgian market. Second, to review the methodological implications on the results of a consequential LCA with a particular focus on consistently identifying marginal suppliers and substitution routes, acknowledging the time dependence and closed-loop nature of the design alternatives. In total seven wall assemblies are assessed over a period of 60 years, with a refurbishment every 15 year. The results show that a low life cycle impact can be achieved for assemblies that are designed to be used again and have a higher initial impact, such as a plywood boarding connected reversibly to a demountable metal frame substructure, as well as for assemblies with no possibilities for direct reuse that have a low initial impact, such as a drywall system with a wooden substructure. Further, regarding the methodological scenarios on marginal supplier identification, the range of possible outcomes is however much larger for the demountable wall assemblies than for the conventional ones.
International Journal of Life Cycle Assessment, Nov 16, 2020
Purpose To reduce the environmental impact of the building sector, environmental targets consider... more Purpose To reduce the environmental impact of the building sector, environmental targets considering the full life cycle of buildings can be supportive. In recent years various benchmarks based on Life Cycle Assessment (LCA) have been developed as part of regulations, labelling systems, sustainability rating tools and research studies. The objective of this paper is to critically analyse 23 existing benchmarking systems focusing on the benchmark methodology but also on the benchmark applications and communication. Methods The critical literature review consists of two parts. In a first part, the choices related to the assessment method, functional equivalent, definition of benchmark values, benchmark scope, benchmark applications and benchmark communication are compared. In the second part, benchmark values are compiled from literature and statistically analysed. Results and discussion The comparative analysis allows to identify the main approaches and methods used in benchmarking systems. For each evaluation aspect, the strengths and weaknesses of the various approaches are highlighted. The statistical analysis provides insight in the spread of benchmark values. Important variations are found between the literature sources which can be explained by differences in benchmark approach, scope, system boundaries and applications. Conclusions Based on the comparative analysis, recommendations are formulated for the development of LCA benchmarks for the building sector. The results of the statistical analysis furthermore provide reference values which can be used for the validation of future benchmarks. For global warming, the statistical values for the full life cycle impacts (i.e. embodied and operational impacts) range from about 15 up to 35 kg CO2 eq./m².a.
ABSTRACT Assisted by designers and contractors, dwelling owners have historically based their dec... more ABSTRACT Assisted by designers and contractors, dwelling owners have historically based their decisions (including the choice of building services) on investment costs. Given the increasing interest in the environmental dimension of the built environment, it is also important to include environmental impact in the decisionmaking process. This paper focuses on the life cycle environmental impact and financial costs of heating and ventilation alternatives for new dwellings in Belgium. Insight into the environmental impact and financial costs of correctly dimensioned configurations over the entire life cycle could enable better choices. Commonly used alternatives are considered, as well as more advanced ones. These are compared and the optima are determined, identifying the best choice within a limited budget. The analysis indicates that, in addition to energy-efficiency measures regarding the building skin, a well-designed heating and ventilation system plays an important role in reducing financial costs and environmental impact over the lifespan of a dwelling. Different heating and ventilation solutions are likely to be selected when initial and life cycle costs are juxtaposed with environmental, financial and total costs. Nevertheless, preferences based on total costs generally coincide with those based on financial costs.
Because of its scale and the role it plays in our lives, a healthy built environment is of vital ... more Because of its scale and the role it plays in our lives, a healthy built environment is of vital importance. As a part of material culture, buildings have to support human needs. But because of their static nature, obtained through design, most contemporary buildings and their components have a negative impact on their surroundings. The huge quantities of waste produced during demolition and the still rising emission of greenhouse gases created during use of the building, manufacture and waste treatment of its components are environmental indicators of an ineffi cient and unhealthy design. Moreover, a socioeconomic paradox has been created. Due to inadequate design many buildings are unable to adapt to (fast-changing) contemporary requirements. As a result many constructions are left to their fate and decay. This ineffi cient use of matter and space is in sharp contrast with a global need for affordable housing. In high density countries, such as Belgium, building plots are scarce and expensive. In addition to this, the UN Human Settlements Programme (UN-HABITAT) estimates that 600 million urban residents and 1 billion rural dwellers in developing countries live in inadequate housing. In this paper, three main methods that integrate the fourth dimension, i.e. time, into design are described: design for adaptability (construction reuse), design for deconstruction (component reuse) and design for dismantling (material reuse). These four-dimensional design strategies strive for a healthy built environment, by taking into account, as from the fi rst sketches, the wear and tear of artefacts and the changing and evolving circumstances that will affect them. The design of several construction kits, developed at the Vrije Universiteit Brussel, shows that the designer must pay attention to detailing. The key detailing principles and two design cases are further examined in this paper.
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Papers by Wim Debacker