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The building industry is responsible for a large proportion of anthropogenic environmental impacts. Circular economy (CE) is a restorative and regenerative industrial economic approach that promotes resource efficiency to reduce waste and environmental burdens. Transitioning from a linear approach to a CE within the building industry will be a significant challenge. However, an insufficient number of quantitative studies exist to confirm the potential (positive) environmental effects of CE within the built environment as well as a consistent method for characterizing these effects. This paper considers key methodological issues for quantifying the environmental implications of CE principles and proposes a life cycle assessment (LCA) allocation method to address these issues. The proposed method is applied to a case study of a Danish office building where the concrete structure is designed for disassembly (DfD) for subsequent reuse. The potential environmental impact savings vary between the different impact categories. The savings are significantly influenced by the building’s material composition, particularly the number of component-use cycles as well as the service life of the building and its components. The substitution of other material choices (e.g. glass and wood) for the concrete structure exhibited a potential increase in impact savings.
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Building Research & Information
ISSN: 0961-3218 (Print) 1466-4321 (Online) Journal homepage:
Life cycle assessment of a Danish office building
designed for disassembly
Leonora Charlotte Malabi Eberhardt, Harpa Birgisdóttir & Morten Birkved
To cite this article: Leonora Charlotte Malabi Eberhardt, Harpa Birgisdóttir & Morten Birkved
(2018): Life cycle assessment of a Danish office building designed for disassembly, Building
Research & Information, DOI: 10.1080/09613218.2018.1517458
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Published online: 20 Sep 2018.
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Life cycle assessment of a Danish oce building designed for disassembly
Leonora Charlotte Malabi Eberhardt
, Harpa Birgisdóttir
and Morten Birkved
Department of Energy Eciency, Indoor Climate and Sustainability, Danish Building Research Institute, Aalborg University, Copenhagen,
Division for Quantitative Sustainability Assessment (QSA), Department of Management Engineering, Technical University of
Denmark (DTU), Kgs. Lyngby, Denmark;
SDU Life Cycle Engineering, Department of Chemical Engineering, Biotechnology and Environmental
Technology University of Southern Denmark, Odense, Denmark
The building industry is responsible for a large proportion of anthropogenic environmental impacts.
Circular economy (CE) is a restorative and regenerative industrial economic approach that promotes
resource eciency to reduce waste and environmental burdens. Transitioning from a linear
approach to a CE within the building industry will be a signicant challenge. However, an
insucient number of quantitative studies exist to conrm the potential (positive) environmental
eects of CE within the built environment as well as a consistent method for characterizing
these eects. This paper considers key methodological issues for quantifying the environmental
implications of CE principles and proposes a life cycle assessment (LCA) allocation method to
address these issues. The proposed method is applied to a case study of a Danish oce building
where the concrete structure is designed for disassembly (DfD) for subsequent reuse.
The potential environmental impact savings vary between the dierent impact categories. The
savings are signicantly inuenced by the buildings material composition, particularly the
number of component-use cycles as well as the service life of the building and its components.
The substitution of other material choices (e.g. glass and wood) for the concrete structure
exhibited a potential increase in impact savings.
building design; building
materials; buildings; circular
economy; design for
disassembly (DfD); end of life;
life cycle assessment; waste
The demands from a growing world population will have
exceeded most limits on global resource reservoirs by
2050 if the present levels of human consumption con-
tinue (United Nations, 2012). Therefore, it is vital to
improve the management of resource consumption
and the associated environmental impacts.
Buildings are responsible for up to 40% of the
materials produced and consumed globally (by volume),
approximately 40% of the worlds waste generation (by
volume) (Becqué et al., 2016) and they account for 20
35% of the contribution to most environmental-impact
categories such as global warming and smog formation
(European Commission, 2006). By 2030, it is expected
that the global middle class will have doubled from 2 bil-
lion to over 4 billion people (Kharas, 2017). It is esti-
mated that over the next 40 years, the world needs to
build more urban capacity than has been constructed
in the past four millennia (Biello, 2012). Thus, the con-
struction sector represents a major set of opportunities
for achieving local and global environmental objectives,
such as the UN Sustainable Development Goals (United
Nations, 2015).
Some new low-energy buildings have radically
reduced operational energy consumption. Energy gener-
ation for these new buildings is no longer considered to
be the most important contributor to building-related
environmental impacts (Anand & Amor, 2016;
Anderson, Wulfhorst, & Lang, 2015; Birgisdottir et al.,
2017; Blengini & Di Carlo, 2010; Dixit, Fernández-
Solís, Lavy, & Culp, 2012). A recent Danish study
found that the building materials of an oce building
assessed over an 80-year reference study period were
responsible for 72% of the total greenhouse gas emissions
and 50% of the total primary energy consumption (Bir-
gisdóttir & Madsen, 2017). Recent building life cycle
assessment (LCA) method development emphasizes
that a narrow focus on just impacts associated with the
energy consumption of building will not identify all
© 2018 Informa UK Limited, trading as Taylor & Francis Group
CONTACT Leonora Charlotte Malabi Eberhardt
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demands on global resources, and other initiatives are
needed to reach absolute sustainability in the building
sector (Brejnrod, Kalbar, Petersen, & Birkved, 2017).
Hence, there is an obvious need to regulate and optimize
the environmental performance of new buildings by
focusing on buildingsembodied energy and environ-
mental impacts over their life cycle (Birgisdottir et al.,
2017; Dixit et al., 2012; Rasmussen, Malmqvist, Moncas-
ter, Wiberg, & Birgisdottir, 2017). A growing political
and industrial interest exists to change from linear
(take, make, use and dispose) to circular (reduce, reuse
and recycle) business models. This will help to reduce
environmental impacts and secure future needs, while
at the same time exploiting remaining material value
and ensuring the sought economic growth (Advisory
Board for Cirkulær Økonomi, 2017; Ellen MacArthur
Foundation, 2015b; European Commission, 2016,
2017a; United Nations, 2015). In recent years, various
circular economy (CE) initiatives and policy agendas
have emerged in the construction sector, e.g. the adop-
tion of a CE action plan in the industrial sector by the
European Commission in 2015, establishing a tangible
and ambitious programme of actions along with a series
of legislative proposals on waste (European Commission,
2017b) and the ongoing development of 14 new CE stan-
dards that may aect future legislation from the Euro-
pean Commission (Dansk Standard, 2017). Legislative
proposals for waste in other industries (e.g. packaging,
transportation and electronics) have been successfully
adopted, but progress for the construction sector has
been slow due to a lack of specic environmental indi-
cators and targets/goals for the construction sector
(European Commission, 2017b).
A case study of Denmark identies CE opportunities
for policy-makers, and it points to the construction
industry as the sector with the highest potential for the
implementation of CE models (Ellen MacArthur Foun-
dation, 2015a). The CE models put a focus on design
for disassembly (DfD) to extend the service life of build-
ing materials and elements through reuse and recycling,
potentially reducing future resource consumption, waste
generation and environmental impacts of future con-
structions (Bocken, de Pauw, Bakker, & van der Grinten,
2016; European Commission, 2016). DfD is not a new
idea in construction, but it has not yet gained a foothold
in the construction industry due to several obstacles
(Rios, Chong, & Grau, 2015). According to Aye, Ngo,
Crawford, Gammampila, and Mendis (2012), life cycle
aggregated environmental impacts can be signicantly
reduced if the structural elements of a building are
designed to be durable and reusable, and if these attri-
butes are exploited. Although the majority of buildings
are constructed using durable concrete structures, and
although technical know-how exists on how to build
durable buildings with long service lives, the service life
of buildings in general has severely declined. There are
numerous cases of 3040-year-old buildings being
demolished (for various reasons), indicating poor exploi-
tation of the concretes durability potential (Pomponi &
Moncaster, 2017). As the primary ingredient in concrete,
cement alone is responsible for 78% of anthropogenic
global CO
emissions, and therefore there is a need to
rethink the design of concrete structures from a life
cycle perspective, e.g. through DfD (United Nations
Environment Programme (UNEP), 2010).
The environmental and economic viability of CE sol-
utions will need careful assessment to provide a success-
ful and sustainable transition towards a circular built
environment (Pomponi & Moncaster, 2017). Recently,
a report by the Danish governments Advisory Board
on CE recommended the development of new, consistent
life-cycle and total-cost calculation tools and method-
ologies to assess the environmental sustainability of CE
business models and products capable of handling
repeating life cycles due to reuse and recycling (Advisory
Board for Cirkulær Økonomi, 2017). This is also sup-
ported by researchers (Bocken et al., 2016; European
Commission, 2017b; Ghisellini, Cialani, & Ulgiati,
2016). Furthermore, the European Commission is com-
mitted to working towards a common European
approach to assess the environmental performance of
buildings, based in part on existing work, e.g. technical
standard EN 15978, as well as relevant research, and
focusing on priority materials, e.g. concrete (European
Commission, 2017b).
LCA is a scientically based and International Organ-
ization for Standardization (ISO)-standardized method
for assessing resource consumption and environmental
impacts of a given product, system or service over its
entire life cycle (EN, 15978, 2012; ISO, 14040, 2008;
ISO, 14044, 2006; ISO, 21931-1,2010) and can facilitate
CE decision-making by identifying the largest environ-
mental impact-reduction potentials within building life
cycles (Pomponi & Moncaster, 2017). Use of LCA is
increasing within the construction industry, and LCA
has been used in some recently published CE studies
(Genovese, Acquaye, Figueroa, & Koh, 2016; Ghisellini
et al., 2016). Despite the political attention CE is gaining,
current political initiatives do not seem to build on exist-
ing LCA research covering construction and demolition
processes (Pomponi & Moncaster, 2017). Although there
are studies showing clear evidence of the environmental
benets of CE principles at building material and com-
ponent level (Nasir, Genovese, Acquaye, Koh, &
Yamoah, 2017), few studies consider the overall building
level and the LCA methodological issues related to CE
design methods such as DfD (Aye et al., 2012). Hence,
LCA faces considerable challenges in becoming a main-
stream environmental assessment approach for decision-
making/support in the building industry (Anand &
Amor, 2016).
The present paper oers a contribution to the devel-
opment of a future environmental performance evalu-
ation method for CE within the built environment. It is
structured as follows. First, the existing literature is
reviewed to present the state of the art of CE in the Euro-
pean built environment, particularly issues pertaining to
development of environmental performance assessment
methods. Next, an LCA allocation method is proposed
to address the identied key methodological issues of
quantifying environmental performance of CE within
the built environment. The proposed method is then
applied in a case study to assess the potential embedded
environmental impact savings of a Danish oce building
when it is designed for disassembly (DfD). A sensitivity
analysis evaluates the inuence of possible sensitive par-
ameters. The paper concludes with a discussion of the
methodological issues and how to further improve and
advance environmental performance assessment of CE
to promote the implementation of CE in the built
Haupt and Zschokke (2017) stress the importance of
applying LCA to quantify the environmental impacts
of implementing CE principles. Such quantication will
clarify if the environmental performance of the new sys-
tem based on CE principles contradicts the fundamental
objective of the CE to improve environmental perform-
ance. However, multifunctional processes, such as the
CE principles, reuse and recycling, constitute a methodo-
logical challenge in LCA, as the LCA method is based on
the idea of analyzing environmental impacts of the pri-
mary function of individual product systems (Hauschild,
Rosenbaum, & Olsen, 2018). Hence, in order for LCA to
support CE, it needs to move from a one-life-cycle
approach towards a multiple life-cycle approach to sup-
port continuous loops of products and materials (Ghisel-
lini et al., 2016; Niero, Negrelli, Homeyer, Olsen, &
Birkved, 2016). Furthermore, multifunctional processes
are shared between more than one product system, and
it is not always obvious to which product system the
environmental impacts and benets should be attributed.
Nor is it always clear how substituted materials and pro-
ducts should be accounted for, which product system can
claim the benet and how resource quality is to be taken
into consideration (Haupt & Zschokke, 2017; van der
Harst, Potting, & Kroeze, 2016). In addition, the long
lifespan of buildings increases assessment uncertainty.
There may well be unknown aspects that need to be
addressed in order to describe the future scenarios in
which the environmental impacts and future reuse or
recycling will occur in terms of LCA for long-term
decisions, e.g. CE in the built environment (Niero,
Ingvordsen, Jørgensen, & Hauschild, 2015). Moreover,
dierences in the LCA approaches applied make it
dicult to compare the environmental performance of
buildings (Genovese et al., 2016).
Although some general LCA recommendations on
how to handle multifunctional issues have been provided
by dierent recognized standards such as ISO 14049, ISO
14044 and EN 15978, several competing approaches
exist, leaving room for interpretation (van der Harst
et al., 2016). The ISO 14044 standard distinguishes
between closed-loop product systems, where materials
are reused/recycled in the same product to replace virgin
materials, and open-loop product systems, where the
materials are reused/recycled from one product system
into a dierent product system. Consequently, there
is a potential need to allocate the environmental
benets and burdens of reuse or recycling between mul-
tiple product systems (ISO, 14044, 2006). Furthermore,
the ISO 14044 standard states that changes in the
inherent properties of materials resulting from reuse
or recycling should be taken into account, but the stan-
dard does not state which changes and how to account
for them. ISO 14044 presents a hierarchical procedure
to deal with multifunctional reuse and recycling from
secondary material production and end-of-life (EoL)
.Allocation between multiple product systems should
be avoided by:
(a) dividing the processes into sub-processes
(b) system expansion, i.e. the secondary function
should be integrated into the system boundary.
.If allocation cannot be avoided, allocation should be
performed in the following order using:
(a) underlying physical relationship (e.g. mass)
(b) other relationships (e.g. economic value)
(c) number of subsequent uses of the recycled
In contrast, the International Reference Life Cycle
Data System (ILCD) handbook recommends that the
ISO hierarchy should be applied when determining the
goals and scope of the LCA study (European Commis-
sion, 2010). However, there are limitations and weak-
nesses in each of the above approaches, e.g. subdivision
is not always possible, suitable substitutes to perform sys-
tem expansion cannot always be found and allocation
can be based on an array of dierent parameters as there
is currently no single, widely accepted modelling
approach (Allacker et al., 2014; van der Harst et al.,
2016). Allacker et al. (2014), however, state that when
subsequent product systems are involved, allocation is
necessary to model EoL processes and secondary
material production (recycling, reuse, energy recovery
and disposal). Allacker et al. studied 11 dierent second-
ary material production and EoL allocation approaches
from recent modelling approaches and standards and
found that the methods can be broadly grouped into
three common approaches: 0:100, 100:0 and 50:50. The
0:100 approach attributes all impacts of the recycled
material to the product producing the recycled material
(Baumann & Tillman, 2004). The 100:0 approach attri-
butes impacts of the virgin material production to the
rst product and impacts of the recycling process and
nal waste treatment to the second product using the
recycled material (Baumann & Tillman, 2004). The
50:50 approach assumes that recycled material replaces
virgin material and attributes impacts of virgin material
production, waste treatment and recycling to the rst
and the second product (Baumann & Tillman, 2004).
After comparing these three methods, Aye et al.
(2012) conclude that, since the potential future reuse of
a material can never be guaranteed, it makes no sense
to allocate any environmental credit to its initial use.
Aye et al. consider that if the material is, after all, reused
after its initial use, the building in which the material is
reused should be rewarded with the environmental sav-
ings resulting from the avoided processing and manufac-
turing of virgin materials. As it is not always clear from
previous case studies how environmental crediting of
reuse/recycling is actually conducted (Allacker et al.,
2014; Aye et al., 2012), EN 15978 (2012) states that
benets from reuse, recovery and recycling (module D
in Table 1) should always be reported separately for
reliable decision support. According to Allacker et al.
(2014), an improvement in the product system model-
ling could potentially be to accommodate the average
number of times a material or element is recycled or
reused, e.g. using the principles in the ILCD handbook.
Among other things, the handbook proposes a formula
that takes into account the primary amount of material,
the recycling rate and the number of recycling loops
(European Commission, 2010). Some of the allocation
methods analyzed by Allacker et al. (2014)incorporate
a great number of other parameters, making them more
comprehensive, but also more complex. The main-
stream application of LCA for decision-making
requires simplication and standardization to enable
consistent and easy use in practice (Hellweg & Mila
i Canals, 2014).
Case study method
Based on the knowledge gained from the literature
review, LCA was applied to assess and, hence, quantify
the potential environmental impact savings of a Danish
oce building DfD compared with traditional building
methods. The LCA complies with the requirements sta-
ted in EN 15978 (2012), ISO 14040 (2008), ISO 14044
(2006) and the Danish building sectors implementation
of the Deutsche Gesellschaft für Nachhaltiges Bauen
(DGNB) certication system for assessing and bench-
marking sustainable buildings (Birgisdottir, Mortensen,
Hansen, & Aggerholm, 2013). The present study does
not use consequential LCA, i.e. LCA that applies broader
system modelling to quantify potential environmental
consequences of system changes. Instead, it applies attri-
butional LCA, i.e. LCA that quanties the environmental
impacts that can be attributed to the product system
(Hauschild et al., 2018) in accordance with the DGNB
certication system (Green Building Council Denmark,
2014). Table 1 shows the life cycle stages as dened in
EN 15978. It also shows which modules are included
in the DGNB certication system.
The system boundary of the present study includes raw
material extraction, transportation and production of
building materials and components, replacement of build-
ing materials and components during the use stage, waste
recovery and disposal at EoL, and credits for potential
reuse, energy recovery and recycling of materials and
components in subsequent product systems. The focus
of this paper is on the material-related impacts, thus
energy consumption for operation is not included.
Table 1. Life cycle stages.
Life cycle stages Process Module DGNB
Production Extraction of raw materials A1
Transport A2
Production A3
Construction Transport A4
Construction/assembly A5
Use Commissioning B1
Maintenance B2
Renovation/repair B3
Replacement B4
Refurbishment B5
Energy consumption for operation B6 ×
Water consumption for operation B7
End of life Deconstruction/demolition C1
Transport C2
Waste recovery C3
Disposal C4
Next product
Potential for reuse, recovery and
Notes: Life cycle stages are according to EN, 15978 (2012) and modules
included in the Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) cer-
tication scheme.
Modules included in the study.
The building lifespan can have signicant eects on
the overall environmental performance of a building
(Marsh, 2017; Østergaard et al., 2018; Rasmussen & Bir-
gisdóttir, 2016; Silvestre, Silva, & de Brito, 2015). Thus, it
was set to 50 and 80 years respectively, according to the
DGNB certication system for oce buildings, in order
to compare the eects of a longer and shorter building
lifespan (Green Building Council Denmark, 2014). The
functional unit was set to 1 m
of the buildings gross
oor area per year to provide comparability with other
studies. As most current published sustainability
research within the built environment tends to focus
on a limited number of impact categories, thereby
risking burden-shifting (Pomponi & Moncaster, 2017;
The European Commission, 2017b), the LCA was
performed using baseline characterization factors from
the Centre for Environmental Studies baseline 2001
method according to the DGNB certication system.
This is a commonly used and agreed-upon approach in
the construction sector, using open LCA v1.4 software,
but focusing on more impact indicator categories than
commonly used in practice, i.e. a set of environmental,
resource-use and toxicology midpoint impact cat-
egories (global warming potential [GWP], ozone
depletion potential [ODP], photochemical ozone cre-
ation potential [POCP], acidication potential [AP],
eutrophication potential [EP], abiotic depletion poten-
for fossil resources [ADPf], freshwater aquatic ecotroxi-
city potential [FAETP], marine aquatic ecotoxicity
potential [MAETP], human toxicity potential [HTP]
and terrestrial ecotoxicity potential [TETP]). The life
cycle inventory (LCI) of the background system was
based on the Ecoinvent 3.2 database using system pro-
cesses to obtain aggregated results. The LCI of the fore-
ground system was compiled using project-specic
building information models provided by the construc-
tion company to extract building material and com-
ponent volumes. Where data were lacking, estimation
procedures and assumptions based on technical data-
sheets, environmental product declarations (EPDs) for
dierent components and materials, as well as
Table 2. Construction materials by building element (including technical building services).
Building component Elements Element share (%) Component share (%) Mass (kg)
Columns Reinforced concrete 1 1 1.E+05
Beams Construction steel and reinforced concrete 3 3 4.E+05
Roof Reinforced concrete 7 8 8.E+05
Asphalt and plastic 1 8.E+04
Rockwool insulation 0.3 3.E+04
Foundation Reinforced concrete 6 6 7.E+05
Ground slab Reinforced concrete 9 10 1.E+06
Polystyrene insulation 0.03 4.E+03
Screed, epoxy and leca stones 2 2.E+05
Concrete sandwich facade Reinforced concrete 14 15 2.E+06
Rockwool insulation 1 6.E+04
Polystyrene insulation 0.03 4.E+03
Brick shells, mortar and bitumen membrane 1 6.E+04
Floor Varnish and oak tree ooring 0.1 38 1.E+04
Glass wool insulation 0.2 2.E+04
Gypsum 0.2 3.E+04
Galvanized steel 0.4 5.E+04
Reinforced concrete 37 4.E+06
Tiles, mortar and adhesive 0.01 7.E+02
Internal walls Gypsum 0.4 15 5.E+04
Rockwool insulation 0.3 3.E+04
Steel, stainless steel, aluminium 0.1 8.E+03
Glass 0.4 4.E+04
Acrylic paint 0.04 4.E+03
Reinforced concrete 14 2.E+06
Bitumen membrane 0.002 2.E+02
Staircase Reinforced concrete 2 2 2.E+05
Technical building services Stainless steel, galvanized steel and cast iron 1 1 7.E+04
PVC 0.001 7.E+01
Sanitary ceramics 0.03 4.E+03
Others Aluminium windows, doors and solar shading 1 1 8.E+04
Wooden doors 0.04 5.E+03
Total 100 100 1.E+07
Notes: All building related constructions and technical building services have been considered in the study.
information from manufacturers/suppliers and other
professionals from the industry were used.
Oce building
The case study oce building assessed has a gross oor
area of 37,839 m
with eight wings of dierent heights
and a total of nine storeys. Owing to the large size of
the building, the basis of the study was a representative
section of the building. Table 2 lists the construction
materials by building elements and respective quantities.
The buildings structure was predominantly made up
of prefabricated concrete elements consisting of oor
slabs, facades, core walls, columns and beams.
DfD assumptions
The present study focuses on the internal building struc-
ture in terms of DfD and relies on the following
.assembly/disassembly are based on existing joint sol-
utions (Sommer & Guldager, 2016)
.the building is to be built today and decommissioned
in 50 or 80 years after the start of the assessment
(Green Building Council Denmark, 2014)
.the building materials are free of hazardous sub-
stances due to decontamination before disassembly,
i.e. contaminants have been designed out in the design
phase (Sommer & Guldager, 2016)
.owing to the long lifespan of concrete, no mainten-
ance of the prefabricated concrete elements will be
required during their service life to maintain their
quality and the elements are suitable for at least
three reuse cycles in three dierent buildings (Som-
mer & Guldager, 2016)
The percentage of elements suitable for reuse at the
buildings EoL was estimated by a demolition company
to be:
.90% of the concrete columns
.90% of the composite steel/concrete beams
.80% of the concrete beams
.60% of the concrete roof hollow core slabs
.90% of the concrete oor hollow core slabs
.80% of the concrete core walls
Modelled scenarios
A traditional case study building was used as reference
scenario T (all materials are disposed of after use either
by recycling, incineration or landll) for comparison
with all other modelled scenarios. Two types of scenarios
were modelled:
.DfD: two scenarios where the structural elements are
assumed to be DfD for reuse at EoL in one or two
future subsequent product systems.
.O: four scenarios where the structural elements are
tested in terms of material choices, e.g. steel, wood
and glass, enabling easier disassembly, not necessarily
benetting reuse solely but also for recycling to poten-
tially further decrease the buildings overall environ-
mental impacts. The four scenarios focus on the
structural concrete elements that make up the largest
percentage of the buildings total mass, i.e. potentially
the largest environmental impacts.
Table 3 provides an overview of the material compo-
sitions of the dierent scenarios modelled.
As the concrete facade was not considered for reuse in
the DfD scenario, despite making up 15% of the build-
ings total mass (Table 2), in all O scenarios the concrete
facade of the traditional building design was substituted
with a lighter glass double-skin facade with load-bearing
columns for reuse and recycling. Besides the glass
double-skin facade, the eect of using dierent materials
for the load-bearing columns at the facade was tested. As
the concrete hollow core slabs comprise 37% of the
buildings total mass (Table 2), the eect of substituting
them with bubble-deck slabs containing less concrete
due to plastic bubbles mixed with aggregate but with
Table 3. Percentage of material shares by weight (kg).
Material shares (%)
T DfD O1 O2 O3 O4
Concrete 81.8 81.4 80.6 76.6 78.0 73.8
Mortar 0.2 0.2 0.01 0.01 0.01 0.01
Glass 1.3 1.3 3.0
Gypsum 1.2 1.2 1.3 1.3 1.4 1.6
Insulation 1.7 1.7 1.2 1.2 1.3 1.5
Metals 6.6 7.6
7.2 10.4
7.2 10.5
Paints and varnishes 0.5 0.5 0.5 0.6 0.6 0.7
Plastic 0.2 0.2 0.2 0.2 0.2 0.6
Ceramics and clay 1.5 1.5 0.8 0.8 0.8 1.0
Stone and gravel 0.8 0.8 0.8 0.9 0.9 1.0
Wood 0.4 0.4 0.6 0.6 2.2
Asphalt 3.8 3.8 4.1 4.2 4.3 4.9
Notes: Material shares (kg) over a building lifespan of 80 years taking material
replacements into account.
Obvious material share shifting between the scenarios as a result of substi-
tuting concrete for other materials.
DfD = design for disassembly; O1 = optimization scenario 1 (concrete col-
umns); O2 = optimization scenario 2 (steel columns); O3 = optimization
scenario 3 (wooden columns); O4 =optimization scenario 4 (bubble
decks); T = traditional building design.
increased reinforcement steel was also tested. Hence, the
O scenarios consisted of:
.O1: load-bearing concrete columns at the facade
assumed for reuse
.O2: load-bearing steel columns at the facade assumed
for reuse
.O3: load-bearing timber columns at the facade
assumed for recycling
.O4: load-bearing concrete columns at the facade
assumed for reuse and concrete bubble deck slabs
assumed for recycling
The reuse percentages assumed for the DfD scenarios
were applied to all additional concrete elements in the O
Allocation method
Reuse, recycling and energy recovery of materials were
modelled as avoided impacts according to the rec-
ommendations described in EN 15978 (2012). Thus,
the impacts of the primary material production that is
substituted by the reused, recycled or energy-recovered
material substitutes were subtracted from the net
impacts in module D. The amount of material recycled
and the amount disposed of at the EoL of the
buildings were estimated according to Danish waste
statistics and existing markets (Clean Innovation Green
Solutions, 2014).
For all scenarios, the LCA only focused on the rst
product system from which the reusable building
elements originate. In this case, the study takes into
account a simple combination of the allocation
approaches 0:100 and 50:50 depending on the reusability
and recyclability of the dierent building materials and
elements using their physical relationship, i.e. mass.
Hence, the impacts of the building materials and
elements in reference scenario T, with no reuse but
material rates for disposal through recycling, incinera-
tion or landll at EoL, can be represented mathematically
by equation (1) by applying the 0:100 approach and allo-
cating all the environmental impacts and benets of
these materials and elements to the rst product system:
IT=Iproduction +Iuse +IEoL +INext product system, (1)
where Irepresents the total life cycle-aggregated
environmental impacts; and I
represents the environ-
mental impacts of the jth life cycle stage. For the DfD
and O scenarios, equation (1) applies for all building
materials and elements that cannot be reused. However,
reusable elements were modelled using the allocation
approach 50:50, where all burdens and credits from the
reusable elements are split between the buildings that
will potentially share them. Thus, one system will not
benet over another based on the assumed number of
future reuse cycles. This also enables the LCA to take
into account and credit multiple future reuse loops,
thereby promoting CE. The impacts from the reusable
elements can thus be represented mathematically by:
IDfD,O=(Iproduction +Iuse +IEoL
+INextproductsystem)/U, (2)
where Urepresents the assumed number of use cycles;
and I
refers to the terminal EoL.
Figure 1 shows how the individual life cycle stages con-
tribute to the environmental impacts over an 80-year
building lifespan in scenario T and DfD, with two and
three reuse cycles respectively. Note that for T and
DfD the life cycle stagesrelative impact contributions
are very similar. The slight dierence in the life cycle
stages between T and DfD is a result of the life cycle
impacts of the reusable components being allocated
equally between the use cycles relying on equation (2),
thereby crediting reuse in the Next product system.
The largest impact contribution is found for the pro-
duction and replacements stage in all impact categories
due to high impacts from production of the building
materials. Owing to recycling and energy recovery, the
life cycle stage and the Next product system exhibit
impact savings across all impact categories. The large
savings obtained in the Next product system within
FAETP, HTP and TETP are a result of the high recycling
rate applied for steel (99%) and for concrete and glass
(both 90%).
Figure 2 presents the environmental impact contri-
butions from the individual building components over
an 80-year building lifespan for scenario T and DfD
with two and three reuse cycles respectively. The
majority of the buildings embodied environmental
impacts originate from many of the structurally impor-
tant concrete components with long lifespans, e.g. oor
slabs and inner walls are responsible for large contri-
butions to the majority of the impact categories. The
technical building services also provide noticeable con-
tributions to most categories due to high replacement
of metals occurring during the lifespan of the building.
Windows, doors, roof, foundation, solar shading, stair-
cases, columns and beams account for a minor share of
the impacts, since these components account for a
minor share of the buildings total mass (Table 2). For
DfD, the impact shares decrease for those building com-
ponents groups containing reusable elements, e.g. oors,
beams and columns, and increase for those building
component groups containing no reusable components
as a result of allocating the life cycle environmental
impact of the reusable components between the respect-
ive use cycles using equation (2).
The environmental impact contributions over an 80-
year building lifespan from building materials are pre-
sented in Figure 3 for scenario T and DfD, with two
and three reuse cycles respectively. As seen in Table 3,
although metal only makes up 6.6% of the reference
buildings total mass, it accounts for a large share of
most impact categories; however, it is most pronounced
among the toxicological impact categories FAETP, HTP,
MAETP and TETP with 54%, 50%, 36% and 75%
respectively, and 75% of ADPe caused by the technical
building services. The steel ventilation system is solely
responsible for a large share of these impacts due to a
high replacement rate of every 25 years. Compared
with the metals, concrete accounts for 81.8% of the
buildings total mass, with dominating contribution to
GWP ODP, POCP, AP, EP and ADPf amounting to
48%, 32%, 22%, 24% and 26% respectively of the total
impact within each category. Despite their minor share
the buildings total mass, the insulation, paint and
varnishes also account for a noticeable contribution to
many impacts due to the energy demands associated
with manufacturing glass and stone wool and a frequent
replacement rate of the paint and varnishes of every 10
and 5 years respectively. Wood-based materials yield a
negative GWP because CO
from the atmosphere is
bound to/stored in the wood (i.e. wood serves as a carbon
sink), hence there is a negative GWP value. For those
Figure 1. Contribution of life cycle stagesof environmental impacts over an 80-year building lifespan.
Figure 2. Contribution of building componentsenvironmental impacts, T, over an 80-year building lifespan.
material groups related to the reusable components, e.g.
concrete, it is seen that the impact share is reduced for
DfD due to allocation of the life cycle environmental
impacts of the reusable components between the respect-
ive use cycles using equation (2).
The accumulated embodied CO
emissions of T, DfD
and O with two and three reuse cycles over an 80-year
building lifespan are presented in Figure 4. For all scen-
arios, a drop in the graphs occurs after 80 years due to
the potential embodied CO
emissions savings obtained
in module D from crediting reuse, recycling and energy
recovery. T and DfD mimic each other well, since the
only dierence between them is that the impacts of the
reusable components are allocated using equation (2),
i.e. these impacts are split between the assumed number
of reuse cycles. The embodied CO
emissions of T is
large due to material replacements accounting for 21%
of the buildings total embodied CO
emissions over
the 80 years. Reuse of the concrete structure two and
three times results in potential CO
emissions savings
of 15% and 21% respectively compared with
T. Substitution of concrete with dierent material
choices such as steel, wood and glass in O reveals higher
emissions saving potentials compared with DfD.
Table 4 presents the potential embodied environmental
impact emissions savings of the reusable components
compared with no reuse.
Considerable savings are observed for all components
across all impact categories, as is also evident from the
weighted impact savings calculated as the average saving
of each component group using equal weighting factors
for each impact category assessed. The oor slabs rep-
resent the largest savings in all impact categories com-
pared with the other components, as they account for
37% of the buildings total mass (Table 2). The lowest
savings are found for the core walls compared with the
Figure 3. Contribution of building materialsenvironmental impacts, T, over an 80-year building lifespan.
Figure 4. Accumulated embodied CO
emissions over an 80-year building lifespan.
beams and columns, which make up a smaller percen-
tage share of the building total mass (Table 2). This is
due to the much more environmentally burdensome
construction steel within the beams and the high reuse
percentage of the columns compared with the core
walls. Table 5 shows the potential embodied environ-
mental impact savings for the dierent building scen-
arios for 50 and 80 years compared with no reuse.
Although potential savings are obtained across most
impact categories covered, compared with the large rela-
tive savings exhibited for the reusable components in
Table 4, it is evident from Table 5 that these considerable
savings cannot be matched at building level. This is
because the material composition has a big inuence
on the savings and magnitude of the savings obtained
for the individual building scenarios within the dierent
impact categories. Impact categories such as ADPe,
FAETP and TETP that are mainly inuenced by the
buildings metals will benet less from reusing the con-
crete components. Consequently, the largest weighted
impact savings are 14.5% and 22.9% for O1, as well as
15.3% and 22.6% for O3 for 50 and 80 years of building
lifespan respectively. The only savings obtained that
match those of Table 4 are found for the O3 GWP for
two component-use cycles: 54% and 49%, and for three
component-use cycles: 59% and 55%, for a building life-
span of 50 and 80 years respectively using wooden col-
umns compared with concrete or steel columns.
However, similar savings are not found for O3 across
the remaining impact categories. This is also reected
by the much lower weighted impact saving for two com-
ponent-use cycles: 12.1% and 18.7%, and for three com-
ponent-use cycles: 15.3% and 22.6% for the 50 and 80
years building lifespans respectively. Although the
bubble decks in O4 use 41% less concrete compared
with hollow core slabs, the average impact savings
obtainable from the bubble decks are very low compared
with the other cases using hollow core slabs. This is
because of the increased amounts of reinforcement
steel needed for the bubble decks. O2 performs worse
Table 4. Potential embodied impact savings of the reusable component compared with no reuse.
Note: Weighted impact savings are calculated as the average impact savings of each reusable component compared with no reuse using equal weighting factors
for each environmental impact category assessed. This includes GWP, ODP, POCP, AP, EP, ADPe, ADPf, FAETP, MAETP, HTP and TETP. For abbreviations, see the
Table 5. Potential embodied impact savings of the building scenarios compared with T.
Notes: Energy consumption during operation is not included. Weighted impact savings are calculated as the average impact savings of each building scenario
compared with no reuse of the reusable components using equal weighting factors for each environmental impact category assessed. This includes: GWP, ODP,
POCP, AP, EP, ADPe, ADPf, FAETP, MAETP, HTP and TETP. For abbreviations, see the text.
DfD = design for disassembly; O1 = optimization scenario (concrete columns); O2 = optimization scenario 2 (steel columns); O3 = optimization scenario 3 (woo-
den columns); O4 = optimization scenario 4 (bubble decks).
compared with O1 due to the use of burdensome steel
columns, resulting in higher impacts across many of
the covered impact categories compared with concrete
columns. Both O2 and O4 show worse performance
within the impact categories ADPe, FAETP and TETP
compared with T due to increased amounts of steel for
columns and bubble decks respectively (Table 3).
Table 5 shows that the highest weighted impact sav-
ings are obtained for a building lifespan of 50 years as
a result of the reduced number of material replacements
over the shorter building lifespan. Thus, the reusable
concrete structures thereby represent an increased
share of the total environmental impacts resulting in lar-
ger saving potentials. Furthermore, the impacts are
spread out over a shorter time period, making the
impacts as well as the savings appear larger. However,
the DGNB in Denmark is about to phase out the use
of a building lifespan of 50 years in favour of 80 years
for oce buildings instead, thereby deviating from the
other DGNB countries in Europe.
Both Tables 4 and 5show that, with the proposed allo-
cation method, the more reuse cycles, the higher the
potential impact savings.
This section discusses the results of the case study
obtained by applying the life cycle impact assessment
method as well as the proposed allocation method
described in the methodology . Recommendations are
provided on how to apply LCA within CE based on
the experiences gathered from the present study.
Focusing on more impact indicator categories than
usual revealed that the magnitude of the savings varies
from impact category to impact category as well as
from scenario to scenario, as the material composition
has a signicant inuence on the buildings embodied
environmental impacts and greatly depends on the num-
ber of component reuse cycles, the materials life span
and the buildings lifespan. Thus, optimization of a single
component group leading to potentially high environ-
mental impact savings (Table 4) may not necessarily
benet the overall building level to the same extent
(Table 5). Hence, it is not obvious which scenario per-
forms best and which material choices to aim at. Since
studies identifying material interdependencies and inu-
ences on the environmental performance of dierent
building types are lacking, the material choices applied
in this study are based on intuition. Other material
choices than those used here might improve the build-
ings overall environmental burden even further.
It is considered realistic to expect that the potential
impact savings of DfD with three reuse cycles should
be even larger compared with two reuse cycles (Table 5).
However, a fraction of the prefabricated concrete
elements will not be suitable for reuse. Thus, the impacts
from these elements are allocated to the initial building,
making the potential impact savings of three reuse cycles
smaller than expected. Furthermore, for the DfD scen-
arios, only a moderate share of the buildings concrete
and metals (approximately 50% and 20% respectively)
can be reused, because only the internal concrete struc-
tures are considered for reuse. Since concrete and metals
are responsible for the largest shares of most impacts
(Figure 3), this also results in smaller savings within
the dierent building scenarios (Table 5). This is also
reected in the small dierence in impacts between T
and DfD seen on Figure 1. Hence, it is likely that consid-
ering additional building components for reuse will
potentially further increase future impact savings.
Virgin material states were assumed for all materials
used for the initial building, as it is still unclear how to
account for multiple material uses with changing material
qualities in LCA (Haupt & Zschokke, 2017). As a result,
high recycling and energy recovery rates were assumed
at the EoL, providing high avoided impacts in the Next
product system (Figure 1). Diverting material from recy-
cling to reuse at the buildings EoL will most likely increase
the potential future environmental impact savings.
As the material composition of the building scenarios
signicantly aected the results, the sensitivity coecient
resulting from a 10% input value increase was calculated
for input parameters that control the material amounts,
i.e. the materials mass, materials service life and the build-
ingsservice life in scenario T, since all scenarios derive
from T (see the sensitivity analysis in the supplemental
data online) (Hauschild et al., 2018). The input parameters
that exhibited highest sensitivity coecients were found to
be the service life of the ventilation ducts (25 years) in AP,
EP, ADPe, HTP and TETP with 30%, 20%, 516%,
26% and 11% respectively. Furthermore, the material
mass of the ventilation ducts has a high contribution of
66% in ADPe. The high negative sensitivity coecient
in ADPe is caused by the technical building services
high contribution to ADPe (Figure 2). However, the build-
ings service life was found to have the highest sensitivity
coecient in all impact categories assessed (between
21% and 93%). All other input parameters tested only
had minor sensitivity coecients in comparison.
As existing studies in the eld are limited, validation
of the results found from this study is challenging. How-
ever, comparing the result with an LCA study of an oce
building (Rasmussen & Birgisdottir, 2015), the material
composition is similar to that of the oce building
assessed in this study except for metals which are more
pronounced in the present study. Comparing the life
cycle stages impact share shows that trends in GWP,
ODP, POCP and AP assessed in the LCA study are simi-
lar to those found in the present study, except for the
impacts at EoL and the Next product system, which
yield much higher negative impacts in the present
study, indicating dierences in EoL modelling and cred-
iting. Comparing the building components impact share
show for both studies that the oors have large contri-
butions; however, the trends for the other building com-
ponents dier. Comparing the material impacts shares
shows that the cement-based materials have by far the
highest contribution in both studies, followed by the
metals. Comparing the elements share of the CO
sions in the present study with that of a related study of
prefabricated reusable building modules (Aye et al.,
2012) shows similar trends, i.e. the external walls and
oors have the highest contribution. However, due to
dierences in assessment method and building elements
included in the study, it is dicult to make a direct
Module D (Next product system) in Table 1 acknowl-
edges the design for reuse and recycling concept, and
quanties the net environmental benet or loads result-
ing from reuse, recycling and energy recovery beyond the
conventional system boundaries (EN, 15978, 2012).
However, using equation (2) means that credits for reus-
ing the building elements are not directly reported separ-
ately in the Next product system as stated by EN 15978,
since the life cycle impacts as well as credits of each reu-
sable element are split between the respective use cycles
that will share them. Hence, some form of crediting
occurs within each life cycle stage of the elements.
The results obtained from applying the proposed allo-
cation method shows benets of prolonging the service
life of the structural components, i.e. the more reuse
cycles the better, thereby both avoiding the generation
of new products consuming virgin raw materials and
waste production as well as reducing environmental
impacts in accordance with the CE idea. However, as
made evident in previous studies (Allacker et al., 2014;
Aye et al., 2012), several dierent allocation approaches
exist. Hence, using another allocation methodology is
likely to inuence the results signicantly, e.g. if the
impacts and benets of reuse are allocated entirely to
the rst or second use and the result does not display
the benets of product service life extension. Further-
more, allocating the impacts and benets to the rst
use will ascribe no environmental benets for a sub-
sequent system, and allocating to a subsequent
system potentially means that no product takes respon-
sibility for these parts if no reuse occurs in the future.
There is also a risk of double-counting impacts and
benets between the systems when allocating to one
system over another. Although the proposed allocation
method is based on an uncertain number of assumed
future reuse cycles, a fairer share of the environmental
impacts and benets of the reusable components is cred-
ited to the rst use and potential subsequent uses, thus
promoting CE.
As noted above in the literature review, the long life-
span of buildings and change in use during their building
lifespan lead to increased uncertainty about future scen-
arios and future environmental impacts (Haupt &
Zschokke, 2017; Niero et al., 2015). The present study
relies on the traditional LCA methodology, i.e. a
restricted system boundary limited to the initial building
from where the reusable elements originate (EN, 15978,
2012;ISO, 14040, 2008; ISO, 14044, 2006). In this study,
subsequent uses of the reusable elements are taken into
account indirectly through allocation of the potential
environmental impacts based on the assumption of two
or three future reuse cycles. Hence, any potential
additional future reuse cycles beyond the assumed two
or three cycles before the terminal EoL are not taken
into account. Furthermore, the lifespan of the reusable
elements will be 2 × 80 years and 3 × 80 years with two
and three reuse cycles respectively, with a building life-
span of 80 years. However, the potential future reuse of
a material can never be guaranteed (Aye et al., 2012),
neither can the actual lifespan of the building. Addition-
ally, a static LCA approach was used, i.e. dynamic
changes during the buildings long life span were not
included in the study. Such dynamic changes include
future resource scarcity, future waste systems, nearing
tipping points (global warming), and future economy
and energy systems. Thus, the potential of reuse in the
future found in this study is not guaranteed, as these
future circumstances are not known nor easily predict-
able. A solution could be to perform LCA scenario analy-
sis allowing for inclusion of estimated future projections
and of the uncertainty relating to prospective assess-
ments (Niero et al., 2015). Consequently, instead of a
single output analysis, a range of possible scenarios will
give an output in the form of a span within which the
future impacts can be expected to be present.
The temporal representativeness of the data used in
the study is challenging, as the building is assumed to
be built today and decommissioned in 50 or 80 years.
Hence, calculation of the potential environmental impact
savings in future is based on environmental impacts
from production today; however, the potential future
reuse will not occur until 240 years (after three use
cycles), when module D is expected to occur.
Although potentially qualied joint solutions exist in
the market allowing assembly and disassembly of con-
crete structures with the purpose of subsequent reuse
(Sommer & Guldager, 2016), a concept such as DfD also
requires changing traditional building methods and con-
struction waste management to store and relocate reusa-
ble components (Sommer & Guldager, 2016).
In order to reduce the negative impacts on the natural
environment, successful implementation of CE prin-
ciples, such as DfD, is both necessary and attractive.
The potential for the reuse of materials and components
by the construction sector can be aided and accelerated
by identifying the most eective long-term improvement
opportunities and eorts. This will require clear decision
support for environmental performance assessment, e.g.
LCA. The literature review identied the lack of a unied
method for how to credit reuse and the many uncertain
future circumstances in which the environmental
impacts and benets will potentially occur.
To address these concerns, a simplied allocation
method was presented. This method divides a fairer
share of the impacts between the potential use cycles
and was applied to an LCA of a case study of a Danish
oce building with a concrete structure DfD. The case
study found that the materials composition has a signi-
cant inuence on the buildings embodied environmental
impacts and greatly depends on the number of com-
ponent reuse cycles, the materials service life and build-
ings service life. However, the longer the lifespan and
the more reuse cycles the better, as the service life of
materials is prolonged. This, in turn, postpones the pro-
duction of new products consuming virgin raw materials.
Before a consistent prospective LCA concept promot-
ing CE in the building industry can be formulated,
further research is needed:
.to identify improvement opportunities by under-
standing the interdependencies and inuence that
material compositions have on the environmental
performance of dierent building types
.to account for substituted materials and products as a
result of reuse and recycling
.to generate consensus on how to handle future cir-
cumstances in which the potential environmental
impacts and benets of CE concepts will occur
.to determine how to best implement these factors into
environmental performance assessments
This will provide key stakeholders (designers, clients,
users, authorities etc.) with a valid and consistent basis
for life cycle-based decision-making and policy initiat-
ives to better link CE concepts to the environmental
performance of buildings. It will help to establish clear
objectives and targets regarding CE concepts.
The authors thank MT Højgaard A/S for providing infor-
mation and data on the case study building used in the study.
Disclosure statement
No potential conict of interest was reported by the authors.
Leonora Charlotte Malabi Eberhardt
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... The EE refers to the energy required for the product stage (A1-A3), maintenance, repair/replacement/refurbishment processed during the use stage (B2-B5) and the end of life management of structures including demolition, waste processing and final disposal (C1-C4), see Figure 2. A life cycle assessment of the EE and the associated greenhouse gas emissions, termed ECO 2 e (CO 2 -equivalent quantities) throughout this paper, may also account for the potentially large benefits related to recycling of materials or reuse of structural components or entire systems (stage D in Figure 2), see e.g. Andersen et al. (2020), De Wolf et al. (2020, Eberhardt, Birgisdottir, and Birkved (2019), and Eberhardt, Birkved, and Birgisdottir (2020). ...
Full-text available
Engineering structures consume a significant fraction of resources and contribute to greenhouse gas emissions worldwide. A conducted literature review shows that most existing approaches to improve the environmental performance of structures concern the adoption of decisions during the conceptual design stage (e.g. on the choice of material), often in connection with life cycle assessment. However, approaches for addressing environmental objectives in practice are often hampered by economic interests pursuing short-term profit. Moreover, such approaches are rather descriptive and lack criteria for assessing the acceptability of specific solutions. Sustainable development of our built environment requires hence a shift of paradigm on how engineering structures are designed. In this paper it is claimed that this should be approached at the strategical level of structural design codes, which contain the rules that support everyday engineering decisions in regard to structural safety and functionality. The paper discusses the reasons why these rules as conceived do not foster an optimal use of materials and explores possibilities for savings of resources and greenhouse gas emissions through modifications of these rules. The potential of risk-informed decision approaches in this context is highlighted and illustrated by a case study - the design of steel beams in building structures.
... This variability can be partly explained by the large number of studies exploring reuse, compared to other CE strategies. Specifically, thirteen studies focus on reuse as a single strategy (Fig. 3) and four more focus on reuse in combination with other strategies (Fig. 4) such as optimisation and material substitution [46], recycling [59], design for disassembly [60] and intensive use [61]. The dominance of studies on reuse (along with recycling) is consistent with findings by other researchers [14]. ...
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Environmental benefits of circular economy (CE) measures, such as waste reduction, need to be weighed against the urgent need to reduce CO 2 emissions to zero, in line with the Paris Agreement climate goals of 1.5-2 °C. Several studies have quantified CO 2 emissions associated with CE measures in the construction sector in different EU countries, with the literature's focus ranging from bricks and insulation products, to individual buildings, to the entire construction sector. We find that there is a lack of synthesis and comparison of such studies to each other and to the EU CO 2 emission reduction targets, showing a need for estimating the EU-wide mitigation potential of CE strategies. To evaluate the contribution that CE strategies can make to reducing the EU's emissions, we scale up the CO 2 emission estimates from the existing studies to the EU level and compare them to each other, from both construction-element and sector-wide perspectives. Our analysis shows that average CO 2 savings from sector-wide estimates (mean 39.28 Mt CO 2 eq./year) slightly exceeded construction-element savings (mean 25.06 Mt CO 2 eq./year). We also find that a conservative estimate of 234 Mt CO 2 eq./year in combined emission savings from CE strategies targeting construction elements can significantly contribute towards managing the EU's remaining carbon budget. While this is a significant mitigation potential, our analysis suggests caution as to how the performance and trade-offs of CE strategies are evaluated, in relation to wider sustainability concerns beyond material and waste considerations.
... On the other hand, using an LCA is more likely to result in an optimal building design and circular solutions adapted to the wider context. For example re-use of building materials will according to Arora et al. (2020) and Eberhardt et al. (2019) reduce environmental life cycle impacts from the building perspective, but extensive refurbishment to enhance energy performance may be counterproductive due to the technical lifetime of building materials, especially if renewable energy is used in the building. The optimum balance here is difficult to evaluate on the material level, but may more easily be optimized at the building level. ...
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The construction sector and built environment have the potential to impact on a variety of systemic dimensions, ranging from specific processes in the production of construction materials to pan-national regulations affecting regional areas and cities. This case study uses the CapSEM Model in order to identify the potential enabling and constraining impact of different methods, schemes and regulations for reducing environmental impact in the construction sector. The use of a systemic perspective highlights that all methodologies are working recursively in actor-networks, thereby affecting society and the market differently, depending on the systemic level.
... Impacts from additional processes (e.g., transport and fuels for enabling reuse (Martínez et al., 2013;Pantini and Rigamonti, 2020;Vitale et al., 2017)) or materials (e.g., chemicals in biobased materials (Sotayo et al., 2020)) to realise a circular strategy can outweigh the environmental savings. Carbon savings of circular building strategies are also dependent on specific conditions, such as the number of reuse cycles in design for disassembly (De Wolf et al., 2020;Eberhardt et al., 2019) or the relationship between the environmental impacts from the construction and the impacts saved during operation of the building (Montana et al., 2020). These conditions for realising decarbonisation potential of different circular building strategies have been outside the scope of this paper but are critical for capturing decarbonisation potential of circular strategies in buildings in practice. ...
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The application of the circular economy (CE) in the building industry is critical for achieving the carbon reduction goals defined in the Paris Agreement and is increasingly promoted through European policies. In recent years, CE strategies have been applied and tested in numerous building projects in practice. However, insights into their application and decarbonisation potential are limited. This study analysed and visualised 65 novel real-world cases of new build, renovation, and demolition projects in Europe compiled from academic and grey literature. Cases were analysed regarding the circular solution applied, level of application in buildings, and decarbonisation potential reported, making this study one of the first comprehensive studies on the application and decarbonisation potential of circular strategies in the building industry in practice. The identified challenges of using LCA for CE assessment in buildings are discussed and methodological approaches for future research are suggested.
... While many buildings have been designed for disassembly, a formal and structured analysis of those projects has highlighted the principles of design for disassembly in theory only, with no significant empirical testing [14]. Recent case studies of buildings designed for disassembly demonstrate good practice [15], but the link between theory and practice is still underdeveloped. The research project presented here seeks to explicate the principles through design-led research to test the principles in practice to understand their value and consequences. ...
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The construction industry is responsible for a significant portion of the solid waste that industrialised nations dispose of each year. One reason for this is the low rates of reuse and recycling, largely due to the difficulties in deconstructing buildings and an inability to easily separate materials and components. If buildings were designed to facilitate deconstruction and the easier separation of the parts, then future material and component recovery would be easier. Previous research into historic examples of deconstruction has identified numerous principles for design for disassembly. This paper presents research that expands on this understanding of design for disassembly though the application of these principles in architectural design projects. A methodology of ‘research through designing’ is implemented to explore the principles and assess their suitability for integration into mainstream construction practice. Several domestic scaled architectural projects were used to trial the principles and the overarching philosophy. This experimentation and research through creative practice, has confirmed the value of the principles of design for disassembly as strategies for the potential reduction of future demolition waste. Further to this, it has made explicit some of the otherwise unrealised consequences or constraints of designing for future disassembly.
... For example, in their research on the different types of LCA used to evaluate the effects of buildings on the environment, [19] compared the objectives, methodologies, and findings of three different types of LCA: traditional LCA, Life Cycle Carbon Emissions Assessment (LCCO2A), and Life Cycle Energy Assessment (LCEA). The researchers in [20] concluded that while there are differences in the focus of the LCA, all three are suitable to be used as decisionmaking tools to reduce the environmental impact of buildings. In [57], the authors also explored the use of LCA to aid decisionmaking through software development that can produce building energy audits and examine energy efficiency. ...
... In addition, life cycle assessment (LCA) can properly help to support and to promote the deployment of self-healing concrete, assessing all the impacts from mining, production, and use until the possible end-of-life scenario [354,355]. Compared to LCA studies for traditional concrete, the scientific literature about LCA of self-healing concrete, is limited. As a matter of fact, previous LCA studies focused mostly on sustainable concrete options like concrete containing incinerator ashes, marble sludge, blast furnace slag, recycled aggregates or fly ash [50,[356][357][358][359]. ...
Self-healing is recognized as a promising technique for increasing the durability of concrete structures by healing cracks, thereby reducing the need for maintenance activities over the service life and decreasing the environmental impact. Various self-healing technologies have been applied to a wide range of cementitious materials, and the performance has generally been assessed under ‘ideal’ laboratory conditions. Performance tests under ideal conditions, tailored to the self-healing mechanism, can demonstrate the self-healing potential. However, there is an urgent need to prove the robustness and reliability of self-healing under realistic simulated conditions and in real applications before entering the market. This review focuses on the influence of cracks on degradation phenomena in reinforced concrete structures, the efficiency of different healing agents in various realistic (aggressive) scenarios, test methods for evaluating self-healing efficiency, and provides a pathway for integrating self-healing performance into a life-cycle encompassing durability-based design.
Buildings are an important part of society's environmental impacts, both in the construction and in the use phase. As the energy performance of buildings improve, construction materials become more important as a cause of environmental impact. Less attention has been given to those materials. We explore, as an alternative for conventional buildings, the use of biobased materials and circular building practices. In addition to building design, we analyze the effect of urbanization. We assess the potential to close material cycles together with the material related impact, between 2018 and 2050 in the Netherlands. Our results show a limited potential to close material cycles until 2050, as a result of slow stock turnover and growth of the building stock. At present, end‐of‐life recycling rates are low, further limiting circularity. Primary material demand can be lowered when shifting toward biobased or circular construction. This shift also reduces material related carbon emissions. Large‐scale implementation of biobased construction, however, drastically increases land area required for wood production. Material demand differs strongly spatially and depends on the degree of urbanization. Urbanization results in higher building replacement rates, but constructed dwellings are generally small compared to scenarios with more rural developments. The approach presented in this work can be used to analyze strategies aimed at closing material cycles in the building sector and lowering buildings' embodied environmental impact, at different spatial scales.
In the construction sector, LCAs typically apply an approach based on fixed or partially fixed building lifespans/service lives/reference study period. The temporal scopes applied in building LCAs are hence typically not reflecting that the timeframes buildings can provide the service they are intended to provide, are (highly) dependent on numerous factors e.g.: building location, materials used to construct the building, energy supply and the use of the building. Inaccurate estimation of the temporal scope of a building LCA will lead to incorrect quantification of the environmental impacts of buildings. Incorrect quantification of the environmental performance of buildings may, in the worst case, derange/decelerate the development within the building sector towards more sustainable buildings. In this paper, a data set consisting of 20999 Danish buildings, demolished between 2009 and 2015, is analyzed. A multiple linear regression model is derived and used to quantify the temporal scope (often referred to as the reference study period) of building LCAs in an attempt to improve the accuracy of sustainability assessment of buildings, taking several influencing factors into account. The results obtained from the derived model are subsequently compared with several fixed/partially fixed building lifespan/service life/reference study period quantification approaches The regression model proved to estimate the lifespan with lower errors (compared to observed values) than the prevailing approach relying on a single fixed value for all building locations, uses and building materials. The application of model based site, use, and/or material specific etc. temporal scope quantification in LCA is new and provides a mean to reduce the uncertainty of LCA results; however, the approach needs to be formalized.
This book is a uniquely pedagogical while still comprehensive state-of-the-art description of LCA-methodology and its broad range of applications. The five parts of the book conveniently provide: I) the history and context of Life Cycle Assessment (LCA) with its central role as quantitative and scientifically-based tool supporting society's transitioning towards a sustainable economy; II) all there is to know about LCA methodology illustrated by a red-thread example which evolves as the reader advances; III) a wealth of information on a broad range of LCA applications with dedicated chapters on policy development, prospective LCA, life cycle management, waste, energy, construction and building, nanotechnology, agrifood, transport, and LCA-related concepts such as footprinting, ecolabelling,design for environment, and cradle to cradle. IV) A cookbook giving the reader recipes for all the concrete actions needed to perform an LCA. V) An appendix with an LCA report template, a full example LCA report serving as inspiration for students who write their first LCA report, and a more detailed overview of existing LCIA methods and their similarities and differences.
The importance of embodied energy and embodied greenhouse gas emissions (EEG) from buildings is gaining increased interest within building sector initiatives and on a regulatory level. In spite of recent harmonisation efforts, reported results of EEG from building case studies display large variations in numerical results due to variations in the chosen indicators, data sources and both temporal and physical boundaries. The aim of this paper is to add value to existing EEG research knowledge by systematically explaining and analysing the methodological implications of the quantitative results obtained, thus providing a framework for reinterpretation and more effective comparison. The collection of over 80 international case studies developed within the International Energy Agency's EBC Annex 57 research programme is used as the quantitative foundation to present a comprehensive analysis of the multiple interacting methodological parameters. The analysis of methodological parameters is structured by the stepwise methodological choices made in the building EEG assessment practice. Each of six assessment process steps involves one or more methodological choices relevant to the EEG results, and the combination potentials between these many parameters signifies a multitude of ways in which the outcome of EEG studies are affected.
The current regulations to reduce energy consumption and greenhouse gas emissions (GHG) from buildings have focused on operational energy consumption. Thus legislation excludes measurement and reduction of the embodied energy and embodied GHG emissions over the building life cycle. Embodied impacts are a significant and growing proportion and it is increasingly recognised that the focus on reducing operational energy consumption needs to be accompanied by a parallel focus on reducing embodied impacts. Over the last six years the Annex 57 has addressed this issue, with researchers from 15 countries working together to develop a detailed understanding of the multiple calculation methods and the interpretation of their results. Based on an analysis of 80 case studies, Annex 57 showed various inconsistencies in current methodological approaches, which inhibit comparisons of results and difficult development of robust reduction strategies. Reinterpreting the studies through an understanding of the methodological differences enabled the cases to be used to demonstrate a number of important strategies for the reduction of embodied impacts. Annex 57 has also produced clear recommendations for uniform definitions and templates which improve the description of system boundaries, completeness of inventory and quality of data, and consequently the transparency of embodied impact assessments.
Our paper presents a novel approach for absolute sustainability assessment of a building's environmental performance. It is demonstrated how the absolute sustainable share of the earth carrying capacity of a specific building type can be estimated using carrying capacity based normalization factors. A building is considered absolute sustainable if its annual environmental burden is less than its share of the earth environmental carrying capacity. Two case buildings – a standard house and an upcycled single-family house located in Denmark – were assessed according to this approach and both were found to exceed the target values of three (almost four) of the eleven impact categories included in the study. The worst-case excess was for the case building, representing prevalent Danish building practices, which utilized 1563% of the Climate Change carrying capacity. Four paths to reach absolute sustainability for the standard house were proposed focusing on three measures: minimizing environmental impacts from building construction, minimizing impacts from energy consumption during use phase, and reducing the living area per person. In an intermediate path, absolute sustainability can be obtained by reducing the impacts from construction by 89%, use phase energy consumption by 80%, and the living area by 60%.
The built environment puts major pressure on the natural environment; its role in transitioning to a circular economy (CE) is therefore fundamental. However, current CE research tends to focus either on the macro-scale, such as eco-parks, or the micro-scale, such as manufactured products, with the risk of ignoring the additional impacts and potentials at the meso-scale of individual buildings. This article sets out to unpack the fundamental defining dimensions of a CE and frame them for CE studies for the built environment. A critical literature review forms the basis for identifying and framing such fundamental dimensions. Our contribution highlights the key roles of interdisciplinary research and of both bottom-up and top-down initiatives in facilitating the transition to ‘circular buildings’. The frame for reference has been used to capture current discourse on the sustainability of the built environment and has proved to be a valuable tool to cluster existing initiatives and highlight missing links for interdisciplinary endeavours. The article represents a contribution to the theoretical foundations of CE research in the built environment and a stepping stone to shape future research initiatives.
The built environment puts major pressure on the natural environment; its role in transitioning to a circular economy (CE) is therefore fundamental. However, current CE research tends to focus either on the macro-scale, such as eco-parks, or the micro-scale, such as manufactured products, with the risk of ignoring the additional impacts and potentials at the meso-scale of individual buildings. This article sets out to unpack the fundamental defining dimensions of a CE and frame them for CE studies for the built environment. A critical literature review forms the basis for identifying and framing such fundamental dimensions. Our contribution highlights the key roles of interdisciplinary research and of both bottom-up and top-down initiatives in facilitating the transition to 'circular buildings'. The frame for reference has been used to capture current discourse on the sustainability of the built environment and has proved to be a valuable tool to cluster existing initiatives and highlight missing links for interdisciplinary endeavours. The article represents a contribution to the theoretical foundations of CE research in the built environment and a stepping stone to shape future research initiatives.