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Comparative whole building life cycle assessment of renovation and new construction
Abstract
Renovation of existing buildings has been identified as a major strategy for reducing the environmental impacts associated with building construction. From the perspective of embodied impacts, repurposing existing structures can reduce the amount of new materials that have to be extracted, manufactured, and installed. While the literature on energy efficiency retrofitting is relatively abundant, a smaller number of studies investigate the differences in whole-building embodied impacts of major renovations. This study presents an approach for conducting a whole-building life cycle assessment (LCA) on building renovation projects, suggests an approach for conducting comparative assessments between renovation and new construction, and demonstrates the approach on an adaptive reuse case study. The approach consists of comparing the full life cycle impacts of the existing building to the sum of the life cycle impacts of the components added in the renovation and the maintenance and replacement needs of the existing/reused components. The case study showed 53–75% reductions across 6 different environmental impact categories when the renovation was compared to a new construction scenario. The reuse of the structural and envelope components provided the majority of the reductions, as most of the renovation was of the interior components and finishes. The presented work can be used as a model for consistent LCAs on other renovation projects and to show designers, policy makers, and building owners the environmental benefits of adaptive reuse over new construction as a result of reduced need for new building materials.
... Besides the statistical evaluation of the available sources by Schwartz et al., there are a number of case studies that have dealt with the question of the environmental impacts of demolition and new construction or the continued use of a building on the basis of an exemplary building [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. ...
... When examining the case studies, the methodological approaches for the comparison of demolition and new construction or continued use of buildings differ greatly, which influences the results and hinders comparability. While some studies only consider embodied environmental impacts [21][22][23][24][25], others also include the operation of the building in their considerations [26][27][28][29][30][31][32][33][34][35]. ...
... A closer examination of the existing case studies comparing refurbishment measures with demolition and new construction supports the findings of Vilches et al. Hasik et al. have developed a methodology for comparing both scenarios based on a literature review [24]. Their method considers the entire life cycle of the newly installed materials as well as the use phase of the reused materials. ...
One of the main objectives facing climate protection targets is how to deal with the existing building stock. Refurbishment measures are essential to ensure sustainable urban transformation. Life cycle assessments (LCAs) enable refurbishment measures to be evaluated holistically at the environmental level. However, there is still no sufficient methodological basis for the uniform evaluation. This present paper proposes a new perspective for comparing the continuing use with refurbishment as well as the demolition and new construction of a building. Thus, two new indicators are presented and elaborated regarding refurbishment measures: sustained emissions and the avoidance potential. To verify and validate the newly developed methodology, we implement it as part of this case study. We compare the environmental impact of a building’s continuing use with refurbishment measures as well as demolition and a replacement building with functional equivalence. The results indicate the environmental benefits of refurbishment measures compared to other approaches towards existing buildings. Although new buildings typically possess a superior energy standard, nevertheless, irrespective of the major impact of operational energy, refurbishment measures appear to be the most viable option for dealing with existing buildings over their life cycle.
... At the building scale, the primary means for achieving demand reduction is reusing the existing building stock through flexible space management, retrofits, and adaptive reuse (Elefante 2012;Frey et al. 2011;Hasik et al. 2019). Salvaging and recycling building materials through deconstruction is another essential component of demand reduction. ...
... Instead of developing a whole suite of dedicated institutions and mechanisms, local government staff have opportunities to build on existing priorities that already galvanize resources and attention. 4 In particular, waste, equity, and preservation are common local government priorities for which there is also strong evidence of embodied carbon reductions (Bergman et al. 2010;Doran 2021;Frey et al. 2011;Hasik et al. 2019;Nunes et al. 2019;Stephan and Crawford 2016). Building on these foundations to bring embodied carbon from the margins to the mainstream offers multiple benefits. ...
... One study of a whole range of building conversions across the US found that in almost every case, 8 reusing buildings reduced climate impacts compared to energy efficient new construction. Depending on the building type and grid mix, it can take from 10 to 80 years for new construction to compensate for climate impacts as compared to an upgraded existing building (Frey et al. 2011;Hasik et al. 2019). These studies bear out the notion that "the greenest building is one that is already built (Elefante 2012)." ...
With anticipation building around embodied carbon as a “new frontier” of climate policy, it may appear that cities need to develop a whole suite of dedicated institutions and mechanisms to support its implementation. However, to do so risks placing an undue burden on already overstretched local and regional governments. Instead, embodied carbon policy can build on existing priorities that already galvanize resources and attention and have benefited from decades of policy development. Making strong links to a larger urban agenda offers a way to forge buy-in from a wide range of stakeholders. Current visions for embodied carbon policy broadly fall into two categories: (1) material substitution strategies, or technical solutions that incrementally reduce emissions, and (2) demand reduction strategies, more transformative solutions that avoid emissions. Both of these areas have strong ties to existing urban strategies for waste, equity, and preservation. Foundations in waste policy include increasing waste diversion, expanding green demolition, and increasing material efficiencies. Foundations in equity-oriented policy include retrofitting affordable housing, workforce development for deconstruction, and building lower carbon, lower cost housing. Foundations in preservation policy include incentivizing building reuse, supporting the use of low carbon materials for retrofits, and encouraging vertical infill. Amplifying existing policy efforts can bring substantive embodied carbon reductions to the forefront, leapfrogging a long technical start-up phase for implementing stand-alone embodied carbon policy.
... To meet targets of reducing emissions by 2050, there is a need to maximise carbon reduction in the design and construction of buildings. Moreover, implementing zero carbon strategies for refurbishing existing buildings should be prioritised as refurbishment is a better carbon mitigation measure than constructing a new build (Hasik et al., 2019). For instance, a life cycle assessment of an office building in Wellington, New Zealand, showed that the refurbishment building saved approximately 3100 tonnes of carbon emissions compared to a new building (BRANZ, 2018). ...
... The exploratory study employed a qualitative research method, using semi-structured interviews with the building experts to examine opportunities for and challenges in reducing carbon emissions in building refurbishment in New Zealand. The qualitative research method was chosen because it is particularly useful for exploring and seeking new insight into the research topic and providing reliable and comparable qualitative data when working with a complex issue such as carbon reduction for building refurbishment (Saunders et al., 2016;Gray, 2018). ...
... More importantly, the participants mentioned that they were not fully aware of how life cycle carbon assessment was reported in the current building refurbishment projects. These aspects have led to many debates concerning methods and scope of work for calculating carbon emissions; as one participant described: These results reflect those of (Vilches et al., 2017, Hasik et al., 2019. They also found various carbon calculation assumptions and scope of work for refurbished buildings in the literature and current industry practices within the global construction sector. ...
... Retrofit de toda construção [19] Edificação comercial Estados Unidos ...
... Dentre as metodologias de [19] e [21], há uma diferença na fronteira do sistema, sendo que em [21] os impactos ligados ao uso e operação (B) não são computados em ambos cenários (retrofit e construção nova). A exclusão deste estágio pode gerar certa imprecisão nos estudos conforme alguns autores defendem, esta fase é responsável por grande parte dos impactos ao longo da vida útil da edificação (Figura 13) -sendo uma das lacunas quanto à uma metodologia para este tipo de estudo. ...
... Figura 10: Número de casos versus Idade das edificações em estudoConforme observado, para análise comparativa muitos autores delimitam as fronteiras do sistema criando cenários de análise diferentes. Como no estudo[19], em que os autores definem dois cenários: um cenário de renovação (retrofit) e outro para a nova construção, onde são determinados os critérios de corte, incluindo ou excluindo fatores -expresso pela Figura 11. Nota-se que em[19] os estudos avaliam as fases de produção e construção novas (A) e fases de uso e ocupação (B), assim como a fase de demolição / fim da vida (C/D) da etapa de renovação no Cenário (A) e demolição da antiga edificação no Cenário (B). ...
O processo de retrofit de edificações pode ser uma opção sustentável para o reaproveitamento de edificações e a mitigação de impactos ambientais. O objetivo do estudo é realizar uma revisão sistemática de literatura sobre o tema de ACV aplicada em retrofit, buscando analisar as contribuições e os métodos considerados. O estudo parte de 27 artigos publicados em periódicos internacionais, estruturados como estudos de caso e revisões sistemáticas. Nota-se que o retrofit de edificações oportuniza o aproveitamento de edificações existentes, a implementação de estratégias sustentáveis e, também, o desenvolvimento de mais estudos no âmbito científico nacional.
... Initially, research was mainly focused on new buildings (Cuéllar-Franca and Azapagic 2012;Dahlstrøm et al. 2012), whereas the environmental assessment of renovation projects-i.e., the application of energy conservation measures-has become more prevalent over the last decade (Gustafsson et al. 2017;Vilches et al. 2017). The environmental trade-off between renovation and reconstruction-i.e., the demolition of an existing building and replacement by a new building-on the other hand, is a recently emerging topic under study (Alba-Rodríguez et al. 2017;Assefa and Ambler 2017;Gaspar and Santos 2015;Hasik et al. 2019;Meijer and Kara 2012;Verbeeck and Cornelis 2011). ...
... In the latter context, several studies have shown that the environmental impact related to the renovation of a building is lower than that of reconstruction (Alba-Rodríguez et al. 2017;Assefa and Ambler 2017;Gaspar and Santos 2015;Hasik et al. 2019). However, the reported differences vary significantly. ...
... However, the reported differences vary significantly. Hasik et al. (2019) compared the environmental impact across six impact indicators of an office building located in Philadelphia that was either renovated or reconstructed. They found that the environmental impact of renovation was 53-75% lower than reconstruction. ...
PurposeThere has been a growing interest in the environmental trade-off between renovation and reconstruction. Life cycle assessment (LCA) is a widely recognized method to quantify environmental impacts of buildings. However, the existing standards do not provide guidelines for defining the reference system period (RSP) and system boundaries (SB) to allow for a fair, robust, and consistent comparison of renovation and reconstruction. Hence, this research establishes guidelines for defining the RSP and SB.Methods
From literature, existing approaches are gathered for defining the RSP when comparing buildings with different service lives and for defining the SB when an existing building is the starting point of an assessment. Eight criteria are then elaborated for defining the RSP and SB. For example, the RSP approach should differentiate between buildings from different construction periods, and the SB approach should be robust for time-related uncertainties. Therefore, the building’s and building materials’ service lives and replacement rates are varied; the standard deviation (\(\sigma\)) between the results then determines the robustness. Subsequently, the extent to which the approaches meet the predefined criteria is assessed. Finally, guidelines are established for defining the RSP and SB when comparing renovation with reconstruction.Results and discussionThree RSP approaches are selected: the RSP is equal to (i) the RSP of new building, (ii) the difference between the total service life of the building (TSLB) and the building age, or (iii) a service life extension. Furthermore, three SB approaches are selected: (i) the environmental impact is considered at the moment of production, (ii) the moment of occurrence, or (iii) equally divided over different life cycles. As none of the SB approaches meet all predefined criteria, three partial allocation approaches are conceived based on a linear, concave, and convex model. The concave model gives the most robust results (σ = 0.11), but is less consistent with the reality of emissions. The convex model is, in contrast, most consistent with the reality of emissions, but is less robust (σ = 0.16–0.19).Conclusions
Based on the literature review and results, the authors recommend to define the RSP based on the difference between the TSLB and the building age for comparing renovation with reconstruction. For defining the SB in case of building materials that are retained over multiple life cycles, it is recommended to include the impact through a convex partial allocation model to compare the environmental impact of renovation and reconstruction in a robust and consistent way.
... Wijnants et al. [7] Hasik et al. [8] Rasmussen and Birgisdottir [9] Zimmermann et al. [10] + If end-of-life (EoL) of existing materials is included, it shows all impacts that happen from today and onwards + Correlates with CEN-standards, thus easier to implement in e.g. regulation + Less workload when EoL of existing materials is not included -Additional workload when EoL of existing materials is included -Challenges in biogenic accounting for global warming potential Residual value or Depreciation Wijnants et al. [7] Rasmussen and Birgisdottir [9] Obrecht et al. [11] + Shows the value of existing materials -Requires service life evaluation -Additional workload in mapping data from existing building Adjusting for past production of existing materials Bin and Parker [12] Potrč Obrecht et al [13] -Requires advanced knowledge about previous production -Additional workload in mapping data from existing building and gathering historical data 3.1. ...
... As mentioned, allocation of reuse and recycling between life cycles can be done for production and end-of-life (EoL), but not for the use-stage, as this belongs to the life cycles where they occur [14]. Thus the use stage in the second life cycle (stage B) has to be accounted for even in a burden-free scenario [8]. However, this is not always done as it entails additional work by the LCA-practitioner, e.g., due to replacements of the reused materials which requires the estimation of quantities and impacts associated with the products. ...
... The use stage for existing materials is for instance not included in the case study by Rasmussen and Birgisdottir [9]. Hasik et al. [8] included the use stage in their case study as the only impacts from existing materials. Here the preserved elements were mainly structural, thus the impacts from the use stage (though not shown explicitly) are likely minimal. ...
With a growing building stock and initiatives such as the European “renovation wave” which aims to double the annual energy renovation rates in the next ten years, environmental assessment of building refurbishment becomes still more important. Using standardized environmental assessment methods such as life cycle assessment (LCA) on renovation projects is important to keep impacts low, and avoid burden shifting. However, a specific methodological challenge in refurbishment projects is how to include the existing building materials in the assessment. The aim of this study is therefore to present and characterise different existing allocation approaches for LCA in refurbishments. Furthermore, the study highlights advantages and disadvantages of the analysed approaches from an LCA practitioner’s view. A literature review was conducted to find studies that illustrate the different allocation approaches and modelling of the existing materials in refurbishment projects. The approaches characterised in the study include allocation using 50:50, avoided burden, product environmental footprint (PEF), burden-free (and semi-burden-free), residual value or depreciation, and adjusting for past production of existing materials. The implications for LCA-practitioners were evaluated based on the work burden required for application. Here, the main cons relate to the large workload connected to modelling the existing building.
... The assessment of the environmental impacts associated with the application of the SID methodology can be performed through the Life Cycle Assessment (LCA) methodology, which is ruled by the general standards ISO 14040:2006 and 14044:2006, and is a powerful tool frequently applied to the construction sector for the assessment of environmental impacts. More specifically, LCA of buildings is developed by analyzing the different stages of the buildings' life cycle, which, according to EN 15978: 2011 [7], are the "production", "construction", "use", "end-of-life", and "benefits and loads" stages [5,25,26], being the production and use the first and second most studied stages, respectively [27]. ...
... LCA has been widely used to compare refurbishment with demolition and reconstruction of buildings [20,25,28,29]. Most of the authors agree on the fact that even an in-depth refurbishment has lower embodied emissions than new construction during the production stage as it implies fewer materials' production and embodied energy consumption, as well as less waste generation [11,20,25,28]. ...
... LCA has been widely used to compare refurbishment with demolition and reconstruction of buildings [20,25,28,29]. Most of the authors agree on the fact that even an in-depth refurbishment has lower embodied emissions than new construction during the production stage as it implies fewer materials' production and embodied energy consumption, as well as less waste generation [11,20,25,28]. Considering the use stage, new buildings can provide higher energy efficiency than refurbished ones along the building's life cycle [30]. ...
This work demonstrated, through Life Cycle Assessment (LCA), the environmental advantages brought by the application of the Structural Inspection and Diagnosis (SID) methodology to the structural refurbishment of 7 traditional buildings located in the city of Porto (Portugal), when compared to the common total demolition and reconstruction approach.
The early diagnosis of the conservation state of the existing structural elements, and their characterization provides fundamental information for optimizing the design of the refurbishment towards environmental sustainability. SID approach can reduce by 75.3%, on average, the demolished material and provide the lowest environmental burdens in the environmental categories of Global Warming, Acidification, Eutrophication, Ozone, and Abiotic Depletion, Photochemical Ozone Creation potential, Human Toxicity as well as Energy Demand when compared with the total demolition and reconstruction scenarios. In terms of relative environmental impact for the reconstruction scenarios, it was concluded that reinforced concrete, in the form of lightweight and solid slabs, presents the worst performance due to the concrete production process. Furthermore, timber structures show better environmental performance when compared to the use of glued laminated timber. The establishment of the SID tool as a consolidated methodology can be a unique opportunity to systematically include, in the refurbishment of traditional buildings, the principles of the environmental sustainability required by EU policies in the construction sector, providing a significant reduction of demolition wastes and the maximization of the preservation of existing structural materials.
... However, the vast majority supported renovation over demolition and new construction. The results of the present study's investigation are similar to those of [21][22][23][24] who found that buildings' renovation or rehabilitation reduce environmental impacts associated with building components' lifecycle. Contrary to popular belief, new construction is heavily reliant on the production of carbon-intensive structural materials such as concrete, steel, and envelope materials [22] , making it the most environmentally damaging option. ...
... The results of the present study's investigation are similar to those of [21][22][23][24] who found that buildings' renovation or rehabilitation reduce environmental impacts associated with building components' lifecycle. Contrary to popular belief, new construction is heavily reliant on the production of carbon-intensive structural materials such as concrete, steel, and envelope materials [22] , making it the most environmentally damaging option. This is from an environmental perspective. ...
... Typically, the studies assess renovation cases in their own right (Galimshina et al. 2022;Ghose et al. 2017;Shirazi & Ashuri 2020) or compared with reference numbers from new-build (Marique & Rossi 2018;Schwartz et al. 2018). Key methodological issues have also been highlighted in the existing literature, such as those concerning the allocation of impacts between systems (Hasik et al. 2019;Obrecht et al. 2021;Zimmermann et al. 2022), or the environmental payback times of material investments (Asdrubali et al. 2019;Brown et al. 2014;Passer et al. 2016;Valančius et al. 2018). However, it has not been investigated in detail to what degree the current national LCA-based approaches developed for new-build are fit for use in GHGe assessments of renovations. ...
... On a practical perspective, it should be considered if these incentives make up for the extra work that is also associated with mapping all the existing materials for the assessment. It is also relevant to consider whether the renovation project is responsible for the burden from the EoL of the existing materials that they have had no influence on choosing, as suggested by Hasik et al. (2019). ...
A variety of life cycle assessment (LCA) calculation methods and rules exist in European countries for building performance evaluation based on new-build. However, the increased focus on the retention and renovation of the existing building stock raises questions about the appropriateness of these the methods and rules when applied to renovation cases. Using a real renovation case, Danish, Finnish and Swedish LCA-based greenhouse gas emissions (GHGe) assessments are assessed for how they position building renovation in relation to demolition and new-build reference values. The influence of these three different methods is examined for future development policies. Results show that upfront emissions for renovation are significantly lower for all approaches. The Swedish approach had the lowest GHG emissions compared with a scenario with demolition and new-build due to the method, which only includes upfront emissions of new materials. The Danish and Finnish renovation cases each performed worse in comparison with the new-build future emissions, specifically from operational energy use. Therefore, method development should consider incentives for upfront and future emissions. Furthermore, methods could account for the existing materials in the building, which are included in the Danish and Finnish approaches. This would provide incentive for renovation and reuse. Policy relevance Future policymaking needs to consider the influence of LCA methods on climate impact assessment of building renovations. The temporal differences occur when renovation is compared with demolition and new-build. Policy needs to take account of these temporal differences for apportioning GHG emissions between upfront and future emissions. A key question is whether existing materials should be included in the assessment as this would incentivise the reuse of these materials. Differences in accounting for the impacts of biogenic carbon in materials yields different results. This is a key issue in carbon accounting and will influence future practice.
... Among the subsystems of a building, masonry walls are used for internal partitioning of rooms and as part of the envelope that separates the building inside from the outside environment, whose main functions are protection, insulation (thermal, acoustic, and humidity), aesthetics, and structural in some cases [6,7]. Compared with other building subsystems, the masonry wall has shown to have significant raw material demand, waste generation, and carbon and energy footprints [8][9][10]. ...
... The masonry wall technologies assessed were soil-cement brick, ceramic block, and concrete block ( Figure 2). subsystems, the masonry wall has shown to have significant raw material demand, waste generation, and carbon and energy footprints [8][9][10]. ...
Masonry wall is a key construction subsystem, but it embodies significant environmental and energy burdens within the life cycle of buildings. Soil-cement bricks and blocks stand as an alternative low-cost masonry material, but despite the widespread claim to be environmentally friendly, more systematic investigation is lacking. This study aimed to assess the life cycle environmental and energy performance of 1.0 m2 of a soil-cement brick masonry wall from cradle-to-construction in terms of carbon, energy, and water footprints, and fossil and mineral resource use, as well as compare it with conventional technologies such as ceramic and concrete block masonries in Brazil. Results showed that raw materials are a major contribution to soil cement masonry walls, followed by the joints and links with columns, in which cement stands out among other inputs. Hydraulic pressing in brick production had a negligible burden increase compared with manual pressing. The PVA mortar joint outperformed the PVA glue one, whereas resin coating performed better than cement mortar. In comparison with ceramic and concrete masonry walls, the soil cement masonry presented overall better environmental and energy performance and was the least affected by the inclusion of finishing coating layers and transport of materials in the sensitivity analysis scenarios, although improved scenarios of conventional options could be competitive, e.g., ceramic masonry with blocks produced by firing reforested wood for the carbon footprint. Scale-up analysis revealed that widespread deployment of soil cement masonry in the built environment would substantially avoid environmental and energy burdens compared with conventional technologies.
... From these considerations, the analysis boundaries are the element that most significantly influences the final results, particularly regarding placing existing building burden in energy renovation scenarios [13]. Indeed, including the existing buildings' end-of-life stage in evaluations of energy refurbishment interventions significantly penalises the assessment results, preventing a proper measurement [14]. These issues are also present for evaluation regarding the demolition and reconstruction process, especially when assessing design choices related to the circular economy affecting the subsequent life cycle [15]. ...
The Italian residential building stock consists of 12.2 million buildings, with 7.2 constructed post-World War II during the economic boom. These structures were designed without specific regulations for seismic safety, fire resistance, and energy efficiency, and today lies the current state of strong obsolescence. Therefore, energy refurbishment may not always be the best cost/benefit solution due to these intrinsic issues. Consequently, the transition to construction systems based on circular economy principles brings new opportunities and becomes key to proposing replacement interventions for this heritage. This paper presents a comparative GIS-based bottom-up approach to evaluate the lifecycle impact of residential building blocks, encompassing energy, environmental, and economic aspects. Two tools are introduced: one for measuring energy consumption and the other for quantifying the quantities of materials stored in buildings. This methodology permits comparing the new circular buildings and different refurbishment scenarios to identify the most suitable solution from an environmental impact and financial point of view. The application of a case study, a residential urban block in Bologna, built in 1945–1965, highlights how the demolition and reconstruction scenario based on circular economy principles presents the lowest environmental impacts and is economically competitive compared to standard deep renovation techniques.
... An analysis by Sanchez et al. (2019) found a 35%-38% decrease in primary energy demand, GWP, and water consumption, and 70% savings in construction costs for the adaptive reuse (referring to renovation) of a courthouse building compared to a new courthouse construction in Ontario, Canada. Hasik et al. (2019) applied LCA to compare adaptive reuse of a historical beer bottling/warehouse facility into an equivalent-size office building in Philadelphia, U.S., and determined that reusing the existing facility helped to avoid 75% of GHG emissions compared to new construction. Finally, Feng et al. (2020) evaluated the life-cycle GHG emissions of six different renovation and reconstruction (building a new building) scenarios using a building information modeling (BIM)-LCA combined approach for single-family housing in Vancouver, Canada. ...
This study examines the potential strategies for reducing embodied energy and greenhouse gas emissions through adaptive reuse of non-residential buildings for residential purposes, as compared to new construction of apartment buildings. Such an approach can address housing crises in urban areas with an abundance of underutilized non-residential buildings, promoting sustainable housing growth. A comprehensive assessment of repurposing in California reveals approximately 510 million m² of floor space across 230,000 non-residential buildings in the current building stock. The potential reduction in embodied energy and CO2eq emissions ranges from 0.14 to 1.4 billion GJ and 5.0–70 million metric tons for the state, respectively, contingent upon the percentage of repurposed floor space (10–100%) and adaptive reuse scenario (retaining structural components and façade or solely the structure). A repurposed building avoids about 56% of embodied energy, 34-48% of CO2 eq emissions, and 72% of materials by mass compared to building a new apartment building. However, various technical, financial, and regulatory challenges may hinder emissions reductions, necessitating proactive policy measures. Cities can potentially expedite the process by streamlining approvals for mixed-use adaptive reuse projects involving both commercial and residential spaces.
... The World Economic and Social Survey conducted by the United Nations, recognizes 'investment in retrofitting of buildings' and 'upgrading of public infrastructures' as key opportunities for sustainability in developed countries (UN 2013). Research has shown that renovation of existing buildings is associated with 53%-75% reduction in environmental impact in the life cycle of building components (Hasik et al. 2019). Apart from considerations of sustainability, assessment of existing masonry structures for structural and non-structural repair constitutes a significant market share of consulting services provided by structural engineering and architectural firms. ...
"Posted/Reprinted with permission of The Masonry Society (TMS). For additional information, visit masonrysociety.org."
Assessing existing masonry structures for structural and non-structural repair and rehabilitation constitutes a significant market share of consulting services provided by structural engineering and architectural firms. However, there is currently no consensus standard in the United States for existing masonry. The Masonry Society (TMS) 402/602 applies only to new construction. While there are many reference books, seminars, and papers on the subject of existing masonry repair, rehabilitation, and related topics, none of these can be adopted by a governing building code or Authority Having Jurisdiction (AHJ) as an enforceable means of ensuring public safety. This leaves the engineers who perform condition and damage assessments of, and design repairs to, existing masonry structures to operate on an engineering judgment basis, seasoned by experience. A consensus standard for existing masonry could define the minimum standard of care for evaluating masonry and provide an enforceable means of ensuring public safety. A task group to TMS Existing Masonry Committee (EMC) is working to develop a set of guidelines written in code language with the goal of producing such a consensus standard for existing masonry. While a companion paper proposes a flowchart towards this goal, this paper documents the task group's findings to date including industry demand for a standard, a summary of previous attempts to develop a standard, an overview of the parent effort within the American Concrete Institute (ACI) to develop ACI 562-Code Requirements for Assessment, Repair, and Rehabilitation of Existing Concrete Structures, and an overview of strategy moving forward. Preliminary content descriptions of the proposed chapters are also included. Masonry is unique in its many typologies, its broad use as a structural and non-structural material, its role in the building envelope, and as a composite material-it is complex. Developing a standard that honors all facets of masonry construction will not be easy, but it is essential to ensuring public safety.
... Berg and Fuglseth (2018), for instance, studied Dutch residential buildings and found that retrofitting could accomplish up to 60% reduction in the overall environmental impacts emitted over the operational life cycle phase relative to the base case. Furthermore, studies by Hasik et al. (2019) compared retrofitting with an equivalent new construction and found that up to 75% less environmental impact could be achieved, with finishes and glazing responsible for a large amount of the emissions. ...
Purpose
Crucial transition of the Indian residential building sector into a low-emission economy require an in-depth understanding of the potentials for retrofitting the existing building stock. There are, however, limited studies that have recognised the interdependencies and trade-offs in the embodied energy and life cycle impact assessment of retrofit interventions. This research appraises the life cycle assessment and embodied energy output of a residential building in India to assess the environmental implications of selected retrofit scenarios.
Design/methodology/approach
This study utilises a single case study building project in South India to assess the effectiveness and impact of three retrofit scenarios based on life cycle assessment (LCA) and embodied energy (EE) estimates. The LCA was conducted using SimaPro version 9.3 and with background data from Ecoinvent database version 3.81. The EE estimates were calculated using material coefficients from relevant databases in the published literature. Monte Carlo Simulation is then used to allow for uncertainties in the estimates for the scenarios.
Findings
The three key findings that materialized from the study are as follows: (1) the retrofitting of Indian residential buildings could achieve up to 20% reduction in the life cycle energy emissions, (2) the modification of the building envelope and upgrading of the building service systems could suffice in providing optimum operational energy savings, if the electricity from the grid is sourced from renewable plants, and (3) the production of LEDs and other building services systems has the highest environmental impacts across a suite of LCA indicators.
Originality/value
The retrofitting of residential buildings in India will lead to better and improved opportunities to meet the commitments in the Paris Climate Change Agreement and will lead to enhanced savings for building owners.
... Thus, renovation is sometimes used interchangeably with refurbishment, but renovation applies especially to buildings, whereas refurbishment does not [11]. However, retrofit typically means the addition of features for the improvement in performance in particular areas such as energy efficiency [12]. Thus, retrofit is adopted in this paper, and the means of building retrofitting is the process of adopting various measures to renovate the envelope, equipment systems and operation methods of buildings. ...
Buildings consume large amounts of energy resources and emit considerable amounts of greenhouse gases, especially existing buildings that do not meet energy standards. Building retrofitting is considered one of the most promising and significant solutions to reduce energy consumption and greenhouse gas emissions. However, finding suitable energy efficiency measures for existing buildings is extremely difficult due to the existence of thousands of retrofit measures and the need to meet various objectives. In this paper, a multi-stage decision framework, including a multi-objective optimization model, and a ranking method are proposed to help decision-makers select the optimal energy efficiency measures. The multi-objective optimization model considers the economic and environmental objectives, expressed as the retrofit cost and energy consumption, respectively. The entropy weight ideal point ranking method, an evaluation and ranking method that combines the entropy weight method and ideal point method, is adopted to sort the Pareto front and make a final decision. Then, the proposed decision framework was implemented for the retrofit planning of an educational building in Chongqing, China. The results show that decision-makers can quickly identify near-optimal energy efficiency measures through multi-objective optimization and can select suitable energy efficiency measures using the ranking method. Moreover, energy consumption can be reduced by building retrofitting. The energy consumption of the case building was 64.20 kWh/m2 before retrofitting, and the value can be reduced by 6.79% through retrofitting. Furthermore, the reduction in building energy consumption was significantly improved by applying the decision framework. The highest value of energy consumption was 59.84 kWh/m2, while the lowest value was 27.11 kWh/m2 when implementing the multi-stage decision framework. Thus, this paper provides a useful decision framework for decision-makers to formulate suitable energy efficiency measures.
... In terms of environmental aspects, renovation of a building or its adaptive reuse has proven to outperform constructing a new building [1]. The environmental effectiveness of renovations may be further improved by transforming the maintenance paradigm from reactive (emergency renovation after a component breaks down) to proactive (planned renovation before a component breaks down). ...
The renovation planning process is filled with uncertainties and subjective decisions. These make the decisions upon what and when to renovate a complex and ambiguous problem. Selection of renovation measures related to building envelope are often far from optimal as decisions are usually made based on visual inspections. These are manned and thus prone to subjective assessment and the knowhow of individual inspectors. Furthermore, objective criteria which could indicate non-structural failures are often missing. The objective based planning process allowing the estimation of the current damage status of the building envelope by only using non-destructive measurements is still in its infancy. The first step requires establishing reliable and objective based data collection. These could be efficiently collected by Unmanned Aerial Vehicles (UAV) with subsequent image recognition algorithms allowing the identification of imperfections and store the position and extent of such deviations into the building’s digital assessment database. Such tools do not exist. The aim of this study is to investigate the current objectivization possibilities in the domain of building inspections. The first part provides a literature review describing how an autonomous UAV survey of a building envelope may be planned and what computer vision techniques may be used for automatic damage recognition and classification. Subsequently, an objective detection model based on the YOLO-tiny (You Only Look Once) computer vision framework is employed in a case study investigating a building envelope of historical Tjolöholm castle in Sweden. This study contributes to developing a methodology for an objective based visual inspection process.
... For each step, the percentages of salvaged waste are summed and compared to the total waste quantities to obtain two indicators of assessments following Equations (1) and (2). Assessment indicator 1 for 4: satisfactory (60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79), and level 5: significant . This is intended to assess the efficiency of the CWM hierarchy, project lifecycle, and waste material lifecycle, all in parallel. ...
... Since, as a result of statistical analysis, the expert survey data given in Table 1 is recognized as representative, we shall use it as a mathematical basis for determining the previously unknown dependence of relative time losses on the redeployment coefficient. The average expert survey data from Summary Table 1 is given in Table 4 ( Hasik et al., 2019). A graph of the desired dependence was plotted according to Figure 5. ...
One of the most important aspects of the development of the urban environment is the comprehensive reconstruction of the municipal development territories, with the aim of creating favorable living conditions and the effective use of the production, engineering, scientific, and other potentials of the complex of edification. The structural condition of many industrial buildings means that they can be operated for more than a decade. This coefficient sparks great interest in industrial buildings precisely for the purpose of their redistribution, rather than reconstruction or demolition combined with new construction. The objective of this study is to define an algorithm for organizational and technological construction, in order to determine the redistribution of industrial facilities. The methodology used refers to the dependency graphs of the relative time loss, versus the redistribution coefficient and also the economic efficiency of the project, versus the actual duration of the construction and installation. From this methodology an adequate mathematical model is introduced.
... At present, China is facing a transition stage from new construction to renovation of existing buildings, thus choosing a sustainable building development model is crucial for energy conservation and carbon reduction [80]. Considering that large-scale demolition and rebuilding will lead to a lot of waste of building materials [81], deep renovation to prolong the building life and recycle building materials is treated as an important means of sustainable development for China's construction. Zhang et al. [80] have pointed out that by controlling the per capita building stock to tend to saturation after 2030, increasing the retrofit rate to 50% by 2060, and prolonging building lifespan to 50/40 (urban/rural) years (due to the large-scale demolition and reconstruction, the average lifespan of buildings in China today is only about 30 years [82], which are much lower than the design life [83]), more than 70% of reduction in constructive material and carbon emissions can be achieved by 2060. ...
Realizing the conservation and circulation of steel is of great significance to the global low-carbon and sustainable development, which requires the joint efforts from both the supply and demand sides. The first step for these efforts begins with the in-depth understanding of the steel use panorama, including steel flows in the production system and steel footprints in the consumption system. This study provides a unified methodological basis for tracing and analysing the steel use from production to consumption, taking China as a case study. By combing material flow analysis with the extended input-output approach, this study traced China's steel use from iron ore, intermediate products, end-use products to direct consumption, embodied consumption and final use in 2018. Based on this, policy implications for China's steel sustainable development were put forward from both supply and demand sides. The results indicate that investment drove 75.1% of China's steel production; construction accounted for 58.6% of China's direct steel consumption; the service industry's embodied steel consumption accounted for 6.8% of China's total steel consumption, although without direct steel consumption; and scrap accounted for 21.5% of China's steel sources, of which 56.7% entered basic oxygen furnaces rather than electric arc furnaces. Therefore, transforming economic growth model is crucial to reducing steel demand. Currently, construction should be the focus of efforts to improve material efficiency, while in the future, policies should guide the dematerialization of the service. From the perspective of production, the pathway lock-in should be broken for promoting China's steel recycling and low-carbon development.
... Adaptive reuse of a building (either heritage or not), differs from the construction of a new building, and in the case of histor-ical buildings, from the other conservation methods such as maintenance and repair, reconstruction, etc., due to the existing properties of the building which usually needs to be upgraded to new function's spatial, structural, and physical requirements [11][12][13] . In addition, in the case of heritage buildings, their heritage/sociocultural value [ 11 , 14 ], in the case of industrial heritage facilities their technological/scientific value additionally (e.g., machinery, equipment, mines and sites, infrastructure, etc.), and the intangible dimensions of both of them (e.g., human memories, records, etc.) gain importance [ 3 , 15 ]. ...
Conservation of the industrial facilities, which reflect their period's production and construction technology, social, cultural, and economic life, is a subject of concern since 1960–70 s. In this respect, adaptive reuse is seen as one of the appropriate methods to conserve and supply their continuous use. In adaptive reuse process, there are some risks and uncertainties because of different parameters like the requirements about conservation of the building and about the new function, time, budget, etc. It is possible to alleviate them by examining existing reused examples adapted to a similar function and reviewing possible different reuse strategies and interventions suitable for the characteristics of the building to be reused together with their outcomes. Hereof, it is aimed to develop a database to be used as a guiding tool while scrutinizing a building to be reused, a new function and interventions, and thus help minimizing the possible risks and uncertainties. To provide information to this database, a systematic approach was developed to assess the relationship between new function and the interventions made for reuse. The approach and possible uses of the database in this process are explained through seven reused industrial facilities in Turkey adapted from food and textile production to assembly and education facilities.
... Several studies suggest that building refurbishment (i.e. avoiding demolition) is preferable from a climate and resource perspective [7]. However, when refurbishment is not an option then reuse should be considered as it has a great potential to reduce new buildings' CO2 emissions [8][9][10]. ...
Immense amounts of natural resources are consumed and processed by the construction sector every year resulting in a significant climate impact. In return, the resource and environmental value of these resources is lost due to the vast amounts of construction and demolition waste (C&DW) that is down-cycled. Thus, the potential of transitioning the construction sector from a linear to a circular economy (CE) are expected to be significant. In Denmark, C&DW make up 40% of all waste. Although 88% of the C&DW is recycled only 36% is upcycled (i.e. recycled with an equal or higher quality than the original resource) while 52% is down-cycled (e.g. crushed for road filling). More recently interest in direct reuse has increased as better way of exploiting the remaining technical service life of the materials and retaining the inherent value of the materials and avoid environmentally heavy material processing. In coming years, a large number of homes on Denmark’s ‘ghetto list’ (i.e. socio-economically disadvantaged residential areas) corresponding to 1,360,300 m ² are to be demolished. At the same time, a large number of new buildings is to be built in the same affected areas. The Resource Block project seeks scalable reuse solutions that can link the large amount of resources in the existing buildings to be demolished with the need for resources to build the new buildings in these areas. On the basis of a life cycle assessment (LCA), the paper at hand assesses the environmental benefit of the reuse solutions found from the Resource Block project. The results show that reuse of these elements may on average potentially save 49% of the new buildings’ greenhouse gas emissions compared to building solely with virgin materials depending on the availability and degree of reuse and which types of virgin materials the reuse is combined with.
... The term retrofitting is quite different from repair and refurbishment or renovation which are commonly used terms when dealing with the preservation of existing buildings. Repairing building structures is about fixing damaged structures to good working conditions, this involves processes such as patching up defects, cracks, re-building non-structural elements within the building and redecorations [4]. Refurbishment, on the other hand, involves restoring the structural integrity of damaged structures to their original state, often used interchangeably with renovation [5,6]. ...
Structural retrofit of existing buildings for reuse remained one of the key steps toward decarbonisation of the existing housing stocks in the UK. This implies that any structural retrofitting procedure should aim at sustainability by ensuring net reduction in energy use with minimum cost, environmental and social impact. However, several factors impede the attainment of sustainable structural retrofit programs. In this study, quantitative data collection and exploratory factor analysis were used to investigate the factors that impede achieving sustainability in structural retrofitting of existing buildings. The study conducted a review of pertinent literature to draw up a list of potential impediments to sustainable structural retrofit. The lists were used to form Likert scale questionnaire that was administered to 126 professionals within the built environment sector in the UK. The data collected were subjected to reliability analysis and exploratory factor analysis using the SPSS IBM Statistics v24. The analysis revealed that there are four groups of barriers that impede sustainability in structural retrofitting of existing buildings. These are (i) cultural barriers involving factors that are characterised by human behaviour and interest; (ii) economic barriers involving cost functions; (iii) technical knowledge barriers involving education & skills factors and (iv) regulatory barriers involving legislation and policies around retrofitting old buildings. The findings of this study contribute to the broader discussion of sustainability within the built environment by increasing awareness of the key barriers to overcome to promote sustainable structural retrofit of existing buildings.
... Compared to the remaining terms, the 2nd term is dominant since it claims a considerable proportion from LCC. The 3rd term evaluates demolition and disposing costs [69], and the last term of the equation represents the recoverable amount after the design life of the building [71,72]. Several indices are available to interpret LCC. ...
Heat transfer through roof slabs significantly increases the operational energy consumption of buildings. Therefore, passive implementations are necessary to improve the thermal performance of roof slabs in tropical climates. This paper presents a novel roof slab insulation using expanded polystyrene (EPS) based lightweight concrete panels. The workflow consists of field experiments and numerical simulations performed in Design Builder. Moreover, we offered a holistic life-cycle approach to investigate the economic and environmental feasibility of alternate forms. Accordingly, the roof slab with 75 mm EPS insulation and a white exposed surface performed satisfactorily. Corresponding decrease in life cycle cost, carbon emission (kgCO 2 e), and operational energy consumption were 8.3%, 20%, and 41%, respectively. The overall eco-efficiency index (EEI) implies that the recommended insulation system is environmentally and economically feasible under tropical climatic conditions. Further, manufacturing EPS concrete is eco-friendly since it reduces EPS waste content which does not decay through natural means.
... In addition, some other issues should be considered in such a choice: economic issues, given that in some cases demolition may be more convenient, especially when deep renovation works are required; technical issues, considering that the structural capacity of existing buildings may be compromised by heavy structural decay [47]; and social issues, given that demolition of a building always requires relocation of its occupants, which is acknowledged as the first barrier to the renovation of buildings [48]. Advantages of renovation against reconstruction are also discussed in Hasik et al. [49] and in Dunant et al. [36], among others. ...
The decarbonization of the construction sector, which is one of the most impactful sectors worldwide, requires a significant paradigm shift from a linear economy to a circular, future-proofed and sustainable economy. In this transition, the role of designers and structural engineers becomes pivotal, and new design objectives and principles inspired by Life Cycle Thinking (LCT) should be defined and included from the early stages of the design process to allow for a truly sustainable renovation of the built environment. In this paper, an overview of LCT-based objectives and principles is provided, critically analyzing the current state of the art of sustainability and circularity in the construction sector. The effectiveness of applying such design principles from the early stages of the design of retrofit interventions is then demonstrated with reference to a case study building. Four seismic retrofit alternatives made of timber, steel and concrete, conceived according to either LCT principles or traditional, were designed and compared to a demolition and reconstruction scenario on the basis of five common environmental impact indicators. The indicators were calculated adopting simplified LCA analyses based on Environmental Product Declarations (EPDs), considering the product and End of Life stages of the building. The results of the comparative analyses confirm that LCT-based retrofit solutions are less impactful than both the traditional seismic retrofit interventions and the demolition and reconstruction scenario.
... Performing LCA on historical buildings can indeed be used to identify the most environmentally friendly options for transforming the existing building stock. Moreover, re-use of the existing building stock usually allows for avoiding production of impact-intensive virgin materials, such as concrete, mineral wool and steel, that would otherwise be needed for construction of new buildings [11]. Here, LCA can also be used to quantify the potential savings from transforming historical buildings due to the avoided production of virgin materials. ...
Construction and operation of buildings are a major contributor to environmental impacts. Assessments of environmental impacts of buildings often focus on new buildings, while studies on the existing building stock often focus on energy efficiency renovation. However, historical and traditional buildings are of historical and visual importance, which should be kept. Hence, a key question is if maintaining original aesthetic via restoration is at the expense of the environment or if it is possible maintain the original appearance of the building while keeping environmental impacts comparable to that of energy renovation. To investigate this, we conducted a Life-Cycle Assessment (LCA) of two options: a restoration and a renovation of an old building from 1887 located on Bornholm, Denmark. The restoration scenario focuses on the use of traditional materials and maintaining the original appearance of the house. The renovation scenario focuses on the use of modern materials and complying with energy requirements for renovated buildings. The results showed that, while the impacts of the two scenarios are of similar magnitude, the restoration scenario performs slightly better in the majority of the impact categories in the default LCA-model. A Monte Carlo simulation showed that the restoration scenario performs better in, at least, 90% of the simulations for 8 of 15 impact categories. This study indicates that restoration is a potentially viable alternative to renovation as a mean for maintaining the original appearance of historical buildings to keep cultural heritage while also keeping environmental impacts at levels similar to renovation.
... Numerous studies on building retrofitting have been conducted in European countries, such as in the UK (Ginks and Painter, 2017;Murtagh et al., 2021), the United States (Hasik et al., 2019), and Greece (Dan and Gehbauer, 2004). Based on these researches, extensive destruction and reconstruction will cause a significant waste of building materials and ultimately lead to elevated energy use and emissions. ...
Embodied carbon emissions of the building sector constitute the majority of carbon emissions. The selection of a building stock development pathway, construction mode, and synergy between the building construction and industry sectors will greatly influence the future embodied carbon emissions in China's building sector. The main purpose of this study is to analyze the carbon emission related to China's building construction under different path choices, to provide quantitative support for policy makers, helping to realize low-carbon development in China's construction sector. So, we developed the China Building Construction Model to illustrate the relationship between building stock, material stock, and embodied carbon emissions. The results show that controlling the total building stock at a reasonable level, extending the building lifetime by avoiding the buildings' early demolition, and encouraging building retrofitting can significantly reduce the material demand of construction as well as the carbon intensity of the production of building materials. Over 70% of the reduction in carbon emissions can be realized through these measures by 2060. Moreover, low carbon development depends on recycling and increased efficiency in producing building materials; this way, embodied carbon emissions can be reduced by nearly 50% by 2060.
... Previously performed studies and analyses based on life cycle assessment and life cycle costs of building facilities include construction costs-both material and labor costsand maintenance costs including material replacement, painting, etc., as well as final disposal [29]. It is typical that plumbing, electrical and air conditioning are often not included in the analysis [29][30][31]. ...
Repairs of water supply, sewage and central heating installations in residential buildings should be carried out systematically. However, very often, renovation dates are postponed, which results in installation failures. The failures of water supply, sewage and central heating installations, due to the currently used methods of masking them and running them as under-plaster and under-floor installations, are always connected with the damage and necessity of reconstruction of the building elements. As a result, renovation work has to be carried out to a greater extent and the amount of construction waste is much greater. The analysis of different renovation strategies of water supply, sewage and central heating systems in residential buildings made in traditional technology has been carried out. The article presents the results of the research on the effects of the postponement of the renovation works on the changes in the technical condition of the building and on the scope of renovation works. The aim of the research is to develop a method for planning repairs of the installation taking into account optimization of the amount of construction waste. The aim of the research is also to answer the question: To what extent does the postponed repair of water and sewage installations influence the amount of construction waste? In the proposed method, the Prediction of Reliability according to Rayleigh Distribution (PRRD) model is used. The results of the research indicate the necessity of conducting the renovation works of the installation in a timely manner due to the increasing amount of construction waste and the introduced reduction of its amount with the increase of the recycling rate
... Third, an analysis by Sanchez et al. (2019) found a 35-38% decrease in primary energy demand, global warming potential, and water consumption, and a 70% decrease in construction costs for the adaptive reuse of a courthouse building in Ontario, Canada. Finally, Hasik et al. (2019) applied LCA to compare adaptive reuse of a historical beer bottling/warehouse facility to an equivalent new construction of an o ce building in Philadelphia, U.S., and determined that reusing the existing facility helped avoid 75% of GHG emissions compared to new construction. ...
Quantitative studies of environmental benefits of repurposing, or adaptively reusing, buildings are very rare. It is generally believed that the structure can be saved in repurposing, but much of the façade and interior materials are often replaced. A life-cycle assessment of the materials needed to repurpose a mid-size 5-storey office building (of which there are about 155,000 in the United States alone, some in excess of market needs) into apartments reveals that 51% of energy, 57% of greenhouse gas emissions, and 75% of generated waste can be avoided when compared to constructing a new apartment building. The key materials driving the embodied energy and emissions are concrete, steel, and façade and interior materials. Replacements of materials and service assemblies in the maintenance phase more than double the embodied energy of initial construction and increase embodied greenhouse gas emissions by 60–77%, while adding just 6–7% to the mass of the buildings.
... A review of 250 case studies [28] emphasizes that the most pressing issue in application of LCA data is the lack of transparency regarding assessment choices, namely, clearly outlined functional unit, service life, gross floor area, and data sources. Moreover, previous scarce whole-building LCAs mainly focused on residential superstructures and studied variations in envelope and climate [29,30], material [31], construction techniques [32], insulation [33,34], or renovation [35], whereas comparison between different building subsystems received less attention. However, for most real-life projects, the building's topology (in terms of building height and area) is already decided by other project constraints, and subsystems' selection (e.g. ...
Minimizing environmental impacts over a building's life cycle is critical to achieving sustainable communities. Early design is the most critical step to improve construction's sustainability, as the majority of important decisions have not yet been made. However, the implementation of sustainability assessment in early design is data- and effort-intensive, resulting in limited whole building life cycle assessments. Previous studies have mainly focused either on single residential structures, included only a subset of building components, or investigated early design parameters mostly associated with energy efficiency. Whereas, comparison of alternative building subsystems at early design received less attention. This study aims to provide and utilize benchmark data for the life-cycle impacts of mid-rise office buildings, focusing on the impact of building subsystem selection at early design exploration. Environmental impacts were compared across six professionally-designed archetypes comprising compatible combinations of foundation, floor, and structural assemblies for a site in Charleston, South Carolina. Detailed operational energy modeling was performed using the EnergyPlus framework, where a range of code-compliant envelope systems are studied and paired with other assemblies. Lastly, sensitivity assessment and statistical analysis are performed to quantify uncertainty associated with the use of such data for early design guidance. The results suggest that decisions associated with the use phase (such as envelope selection) dominates life cycle impacts and should be prioritized. Additionally, no single subsystem governs all embodied impacts across different buildings. Lastly, it is critical to consider a large number of alternatives at the early design stage, as excluding a combination of subsystems might close pathways to reaching a more environmentally suitable alternative during design iterations/optimization.
EU aims to reach carbon neutrality by 2050. Besides energy consumption reduction, also greenhouse gas emissions have to be cut starting from the production of materials and construction work through the use phase to the end of the use of the building. Existing buildings are estimated to provide a high potential for reducing global warming. This paper focuses on research question, how reasonable are energy efficiency improvements of existing buildings, as the materials used in the process produce CO2 emissions and increase costs compared with conventional maintenance. This issue is a part of the Sustainable Development Goal 13 Climate Action, which integrates climate change measures into national policies, strategies, and planning and a part of Goal 11 Sustainable cities and communities, which tries to increase the number of cities and human settlements adopting and implementing integrated policies and plans towards inclusion resource efficiency mitigation and adaption to climate change. The carbon footprint of an existing renovated building constitutes mainly from energy consumption emissions. In life cycle costs, the deciding factor is investment. If the building was heated by zero-emission ground source heat, structural renovations would not be worth doing. On the other hand, structural improvement of energy efficiency is recommendable if a building is connected to district heating (DH). Strong reasons, either endogenous or exogenous, must exist for replacing an existing building with a new one. They cannot be justified with the carbon footprint or life cycle costs. These results apply to countries, where the energy efficiency of existing buildings is reasonably good.KeywordsDeep renovation Rebuilding Carbon footprint Life cycle cost
Energy efficiency
The pace of building retrofit is expected to increase significantly in the coming decade if the European Union is to meet its ambitious climate targets. This study explores successes and challenges with current retrofit efforts, with focus on indoor environmental quality and occupants’ satisfaction with the technical installations. A survey, indoor environmental monitoring and semi-structured interviews were carried out in a Danish social housing area undergoing a deep energy retrofit. The retrofit considerably improved winter thermal comfort and indoor air quality, which was a great source of satisfaction for the occupants. Overheating was however identified as an important concern in summer. The mechanical ventilation units suffered from faults which caused discomfort, in particular dry air, noise and draft. Occupants lacked knowledge on ventilation and manual control over it, which led a share of them to mitigate discomfort in alternative ways, by obstructing diffusers or disconnecting the units. To avoid the risks linked to such behaviors, new retrofit efforts should pay particular attention to user-friendliness of technical installations, clear communication of technical information to the residents and a close monitoring of the installations’ performance and occupants’ satisfaction after move-in.
Energy consumption in buildings has become one of the most critical problems in all countries and principles of sustainability suggest that a satisfactory solution must be found to reduce energy consumption. This study aims to identify and prioritize energy consumption optimization strategies in buildings. Data collection consists of gathering primary data from the existing literature and secondary data from interviews, questionnaires, and simulations through building information modeling (BIM) tools. Twenty-nine strategies were identified and categorized into five groups according to their nature and ranked using one of the multiple criteria decision-making (MCDM) methods called the step-wise weight assessment ratio analysis (SWARA). A case study building in Shiraz, Iran, was simulated using BIM software, and the energy saving potential of the highest ranked strategies were obtained. According to the results, significant contributors to the energy consumption optimization were “Using renewable energy resources,” “Using efficient insulation,” and “Using suitable materials,” providing 100%, 35%, and 23% efficacy, respectively. The results obtained from this study can inform the building industry’s key stakeholders regarding the best strategies to apply in order to reduce energy consumption and improve sustainability in the construction industry.
Abstract
Buildings and constructions are responsible for a great amount of global energy and energy-related carbon dioxide emissions. Because of these negative impacts, there is an increase in Life cycle assessment research in the construction sector to measure these effects and evaluate the sustainability performances. Life cycle assessment is a tool that can facilitate the decision-making process in the construction sector for material selection, or for the selection of the best environmentally friendly option in the building component level or building level. In this study, a comparative life cycle assessment analysis is conducted among 12 roof coverings of 1 square meter in the 60-year lifetime of a building. Impact categories that are available in environmental product declarations and included in this study are the global warming potential, ozone depletion potential, acidification potential, eutrophication potential, photochemical ozone creation potential, abiotic depletion potential of non-fossils and abiotic depletion potential of fossils resources. To facilitate the decision-making process, panel and monetary weightings are applied to convert environmental product declaration data of seven impact categories into one single-score. Monetary weightings applied in the study are in Euro 2019, differentiating itself from other comparative life cycle assessment studies. The single-score results are ranked and compared. R04 has the best performance for all panel weightings, while for monetary weightings, R03, R07 and R08 have the best performance for EPS, MMG and EVR, respectively. As a result, for 12 roof coverings, the weighted results could not address one single roof-covering material for numerous reasons. Among the weighting methods, panel weighting sets show more similarity in ranking results, while monetary-weighting sets results are more diverse.
Les certificats d’économie d’énergie (CEE) encouragent la rénovation des bâtiments et le remplacement de vieux équipements en obligeant les fournisseurs de gaz naturel, d’électricité et de fioul à réduire leurs livraisons. L’analyse microéconomique permet de relier le marché des certificats au marché des travaux d’économies d’énergie et à celui de l’énergie. Le handicap informationnel des ménages pour évaluer le lien entre travaux et consommation d’énergie et l’appartenance des travaux à la catégorie des « biens de confiance » expliquent la faible efficacité quantitative et financière du dispositif. Nous expliquons aussi pourquoi les CEE gardent les faveurs des pouvoirs publics malgré leurs mauvaises performances en mettant en avant leur appartenance à la panoplie des micropolitiques non punitives, non fiscales, décentralisées et créatrices d’emplois locaux. Classification JEL : D13, D82, L97, Q48, Q51.
The need to mitigate climate change calls for the construction industry to achieve net-zero greenhouse gas (GHG) emissions for new and existing buildings by 2050. Zero carbon refurbishment (ZCR) for existing buildings is a significant area of interest, as many existing buildings will still be there in 2050. This paper investigates the global development, knowledge structure and gaps in the research field by conducting a systematic literature review. The final selection of 147 up-to-date journal articles was analysed using mixed-method data analysis, including quantitative (science mapping) and qualitative (thematic) analysis. Quantitative results reveal evolving research topics including energy performance and efficiency, life cycle environmental impacts, energy resources and policy, and decision-making with multi-objective optimisation. Research in ZCR is well-established in European countries and there is much interest and activity around the world. ZCR research on residential and office buildings provokes much consideration compared to other building types. The qualitative findings discuss the mainstream research areas (e.g. decision-making with multi-objective optimisation), determines research gaps (e.g. carbon impact), and recommends the future research agenda. The study offers academics a comprehensive understanding of ZCR research to link current research areas into future trends. It also provides construction professionals with current practices and an interdisciplinary guide to better deliver ZCR projects.
In the context of worldwide efforts towards energy efficiency and circular economy, embodied energy has been increasing its weight in the total lifecycle energy use of buildings. By investigating the context and the extent to which it is crucial to calculate embodied energy quantities for existing buildings, this paper investigates the concept itself of embodied energy in existing buildings as a still untapped potential for driving sustainable renovation and reuse of urban environments.
A new research gap emerges from a critical literature review. A new comprehensive approach for definition and calculation of embodied energy that integrates both retroactive and prospective perspectives is proposed within two boundary systems expressed in terms of life-cycle energy analysis, revealing the potential role of embodied energy in supporting decision at city-level regarding adaptive reuse or demolish-rebuild scenarios on buildings as part of urban heritage. Results investigates the extent to which embodied energy stored in our urban heritage should be considered as a decision parameter to prioritize preservation and reuse interventions among the large number of existing buildings composing the present and the future built environment, delineating new open issues for further research.
The built environment continues to grow rapidly and is currently estimated to account for 30–40% of all Greenhouse Gas (GHG) emissions globally. Continuing on a ‘business as usual’ trajectory will see global annual increases in GHG emissions as a result of considerable urban growth. Some past studies have quantified national GHG emissions associated with the built environment but, to-date, no national framework for GHG emissions accounting of the built environment exists. This study presents a robust methodology for estimating GHG emissions associated with the built environment using Ireland as a case study. Taking a Whole Life Carbon (WLC) perspective it quantifies both operational and embodied emissions. One single method is used for operational emission quantification, for which well-documented data exists. For embodied emissions two methods are applied: 1) Material-based emissions are calculated using the Commodity Accounting Method (CAM) and 2) Sectoral-based emissions are quantified using constructed floor area and other construction-related data (the Sectoral Summation Method – SSM). Reasonable agreement between the methods is observed which enables robust conclusions to be drawn. ∼37% of all Irish GHG emissions are attributed to the built environment while ∼1/3 of these emissions are embodied in the production of the raw materials, the transport of materials and the construction and demolition of buildings and infrastructure.
Although the energy and cost benefits for retrofitting existing buildings are promising, several challenges remain for accurate measurement and verification (M&V) analysis to estimate these benefits. Due to the rapid development in advanced metering infrastructure (AMI), data-driven approaches are becoming more effective than deterministic methods in developing baseline energy models for existing buildings using historical energy consumption data. The literature review presented in this paper provides an extensive summary of data-driven approaches suitable for building energy consumption prediction needed for M&V applications. The presented literature review describes commonly used data-driven modeling approaches including linear regressions, decision trees, ensemble methods, support vector machine, deep learning, and kernel regressions. The advantages and limitations of each data-driven modeling approach and its variants are discussed, including their cited applications. Additionally, feature engineering methods used in building energy data-driven modeling are outlined and described based on reported case studies to outline commonly used building features as well as selection and processing techniques of the most relevant features. This review highlights the gap between the listed existing frameworks and recently reported case studies using data-driven models. As a conclusion, this review demonstrates the need for a flexible M&V analysis framework to identify the best data-driven methods and their associated features depending on the building type and retrofit measures.
El presente estudio muestra un análisis multiparamétrico de tres sistemas constructivos elaborados de tabiques y block de cemento. El análisis se realizó considerando como unidad funcional un metro cuadrado de muro de construcción para cada tabique y block, e incluyendo indicadores de sustentabilidad: (a) ambientales, a través del Análisis de Ciclo de Vida (ACV), evaluando categorías de impacto como calentamiento global, acidificación y eutrofización (b) económicos, estimando el costo de materias primas y costo de construcción para la unidad funcional y (c) energético-funcionales, mediante la resistencia mecánica, la resistividad térmica y resistencia acústica de los materiales de construcción analizados. También se realizó una simulación térmica con los ladrillos estudiados. El análisis resultante es herramienta comparativa que muestra las diferencias entre los materiales estudiados y representa una metodología para la toma de decisiones con base en la importancia de cada uno de los indicadores propuestos.
This study uses material flow analysis to estimate the material stocks and flows and associated upfront embodied carbon emissions for gravity building structural systems in the United States. Seven scenarios that align with the shared-socioeconomic pathways are conceptualized and used to estimate floor space and structural material demands through 2100. These scenarios consider aggressive, moderate, and low adoption rates of timber-based structural materials. Under all scenarios, total floor space is projected to increase to a maximum upper-bound of 202% (162,187 m²) between 2020 and 2100. The results indicate that the associated increase demand for structural materials cannot be met solely by urban mining of decommissioned buildings. Assuming present-day carbon emissions intensities of structural materials, the average upfront embodied carbon intensity for gravity superstructures in the building stock decreases from 49 kg CO2e/m² in 2020 to 29 kg CO2e/m² in 2100 under the scenario with aggressive adoption of timber-based systems.
The repair of existing reinforced concrete (RC) elements is mainly realized by overlaying them with a higher strength concrete layer strengthened with reinforcement, known as jacketing. The efficiency of the method is based on the stress transfer and strain compatibility at the interface. The common methods used on-site to enhance the concrete-to-concrete bond is roughening the surface and/or applying a bonding agent layer on the old concrete surface. The purpose of this research is to evaluate the contribution of roughness and bonding agent on the bonding strength and, additionally, to develop a general predictive model. Thus, three different levels of roughness were materialized: (i) left-as-cast, (ii) wire-brushed and, (iii) splitting-fractured while two modes of adhesion were tested: (i) substrate with repair cement paste and, (ii) use of a bonding agent. Bi-surface symmetrical shear tests were carried out to assess the ultimate bonding strength of specimens with properties usually found in situ. The experimental results showed that an increase of roughness leads to a better bond performance. The bonding agent effect, however, was notable only for the left-as-cast specimens. A physically-based model is proposed to predict the shear bonding strength concerning the surface roughness, as well as the old and repair concrete’s properties. The model aims to offer to designers and researchers an accurate tool to evaluate the effectiveness of the interfacial bond in renovation jacketing procedures.
Purpose
Building refurbishment (BR) is promoted as a green alternative to demolition and new build for urban renewal. The construction and demolition (C&D) waste of BR is increasing and recognized as more complex to manage. To address the limitations of the current static and linear life cycle assessment (LCA) method for evaluating the environmental impact of C&D waste, this study decodes the complex process and provides a causal loop model for evaluating the carbon emissions (Greenhouse Gases emissions) of BR C&D waste.
Methods
The study integrates system dynamics (SD) and a LCA approach to produce an integrated and holistic model for evaluating the carbon emissions of BR C&D waste. The environmental assessment system boundary and main factors of evaluating the carbon emissions of BR C&D waste are identified based on a LCA approach. Stakeholders in the life cycle of BR C&D waste are involved in development of the causal loop model. Semi-structured interviews are conducted with key stakeholders to validate the factors and identify the key processes of BR C&D waste management through a case study of Suzhou, China.
Results
Five causal loops are developed in this study: a general model for evaluating the carbon emissions of the life cycle of BR C&D waste, a sub-model for evaluating carbon emissions of BR C&D waste at the dismantlement stage, a sub-model for evaluating carbon emissions of BR C&D waste at the refurbishment material stage, a sub-model for evaluating carbon emissions of BR C&D waste at the refurbishment construction stage, and a sub-model for evaluating carbon emissions of BR C&D waste at the refurbishment material end of life stage.
Conclusion
The integrated SD-LCA causal loop model developed in this study will help decision makers to more clearly visualize and understand the current problems associated with BR C&D waste management and thereby strategically intervene to reduce the carbon emissions in the life cycle of BR C&D waste.
Graphical Abstract
Purpose-Whole building life cycle assessment (WBLCA) is a key methodology to reduce the environmental impacts in the building sector. Research studies usually face challenges in presenting comprehensive LCA results due to the complexity of assessments at the building level. There is a dearth of methods for the systematic evaluation and optimization of the WBLCA performance at the design stage. The study aims to develop a design optimization framework based on the proposed WBLCA method to evaluate and improve the environmental performance at the building level.
Design/methodology/approach-The WBLCA development method is proposed with detailed processes based on the EN 15978 standard. The environmental product declaration (EPD) methods were adopted to ensure the WBLCA is comprehensive and reliable. Building information modeling (BIM) was used to ensure the building materials and assembly contributions are accurate and provide dynamic material updates for the design optimization framework. Furthermore, the interactive BIM-LCA calculation processes were demonstrated for measuring the environmental impacts of design upgrades. The TOPSIS-based LCA results normalization was selected to conduct the comparisons of various building design upgrades.
Findings-The case study conducted for a residential building showed that the material embodied impacts and the operational energy use impacts are the two critical factors that contribute 60-90% of the total environmental impacts and resource uses. Concrete and wood are the main material types accounting for an average of 65% of the material embodied impacts. The air and water heating for the house are the main energy factors, as these account for over 80% of the operational energy use. Based on the original WBLCA results, two scenarios were established to improve building performance through the design optimization framework.
Originality/value-The LCA results show that the two upgraded building designs create an average of 5% reduction compared with the original building design and improving the thermal performance of the house with more insulation materials does not always reduce the WBLCA results. The proposed WBLCA method can be used to compare the building-level environmental performances with the similar building types. The proposed framework can be used to support building designers to effectively improve the WBLCA performance.
This paper proposes an approach of sensitivity analysis for LCA of building retrofit measures aiming to establish the impact of input data uncertainties on the output variance. The approach includes the quantification of data input uncertainties in terms of their Probability Distribution Functions (PDFs), their sampling and the uncertainty propagation through Monte Carlo (MC) methods. A sensitivity analysis through Variance based decomposition (Sobol’ method) techniques are used to point out the key parameters uncertainties that mostly affect the LCA results distributions. The paper presents a building case-study where the MC-based uncertainty and sensitivity analysis method is applied considering different design options (XPS and Cork internal insulation measures) and different scenarios for the assessment of the building energy need (use phase). Results obtained highlight that the differences on the Climate change environmental impact between the two design options is quite limited (about 12%) and this is mainly due to the use phase which is the more relevant input parameter on the overall result. Concerning the Sensitivity Analysis, when the building energy need is considered as a “deterministic” input in the LCA assessment, the unitary impacts of the design options materials uncertainties are the most influential parameters. On the other hands, when the building energy need is represented by a PDF, the quantity of energy carrier consumed and its unitary environmental impact are the most influential parameters on the output variance.
This review organises and summarises the recent contributions related to the environmental evaluation of building refurbishment and renovation using the lifecycle assessment (LCA) methodology. This paper classifies the recent contributions in this field and selects the primary methodology options. The review shows that most LCAs focus on energy refurbishment, comparing the environmental impacts before and after refurbishment. In contrast, almost none of the LCAs study the environmental impact of building system reparations, such as structure or finishing. The more frequently studied life cycle stages are those related to the manufacturing and use phases. Similarly, the most considered impact categories are the global warming potential and embodied energy. The main barriers found for disseminations are discussed: system boundaries interpretation of EN 15978, functional unit, LCI methods, operational stage and the end-of-life stage definition.
The building sector contributes up to 40% of energy consumption and 30% of greenhouse gases emissions (GHG) worldwide [1]. One of the main driver to mitigate these energy and GHG emissions is the renovation of existing buildings. While the energy demand is reduced during an energy related renovation, investment costs and environmental impacts increase due to the materials and building integrated technical systems (BITS) replaced or added to improve its energy performance. To address these trade-offs, there is a need to consider a life cycle approach to avoid impacts’ transfer between the operational and embodied energy and impacts. In this paper, we present a pragmatic Life Cycle Assessment (LCA) methodology for energy related renovation measures of building developed in the framework of the IEA annex 56 “Cost effective energy and carbon emissions optimization in building renovation”. The approach is consistent with the existing building LCA's state-of-the-art but goes into a more applicable methodology by focusing only on the significant life cycle stages for energy related building renovation i.e. the production, transportation, replacement and end of life of new materials for the thermal envelope and building integrated technical systems (BITS) and the operational energy demand. In this paper, the methodology is applied on a Swiss multi-family residential building built in 1965 which was renovated in 2010. The LCA is presented using three indicators: the total and non-renewable cumulative energy demand (CED) and the global warming potential (GWP). Results show that embodied CED and GWP remain negligible in the renovated building compared to the energy savings. Further studies are needed to further apply this LCA methodology.
Purpose
Life cycle assessment (LCA) has not been widely applied in the building design process because it is perceived to be complex and time-consuming. There is a high demand for simplified approaches that architects can use without detailed knowledge of LCA. This paper presents a parametric LCA approach, which allows architects to efficiently reduce the environmental impact of building designs.
Methods
First, the requirements for design-integrated LCA are analyzed. Then, assumptions to simplify the required data input are made and a parametric model is established. The model parametrizes all input, including building geometry, materials, and boundary conditions, and calculates the LCA in real time. The parametric approach possesses the advantage that input parameters can be adjusted easily and quickly. The architect has two options to improve the design: either through manually changing geometry, building materials, and building services, or through the use of an optimization solver. The parametric model was implemented in a parametric design software and applied using two cases: (a) the design of a new multi-residential building, and (b) retrofitting of a single-family house.
Results and discussion
We have successfully demonstrated the capability of the approach to find a solution with minimum environmental impact for both examples. In the first example, the parametric method is used to manually compare geometric design variants. The LCA is calculated based on assumptions for materials and building services. In the second example, evolutionary algorithms are employed to find the optimum combination of insulation material, heating system, and windows for retrofitting. We find that there is not one optimum insulation thickness, but many optima, depending on the individual boundary conditions and the chosen environmental indicator.
Conclusions
By incorporating a simplified LCA into the design process, the additional effort of performing LCA is minimized. The parametric approach allows the architect to focus on his main task of designing the building and finally makes LCA practically useful for design optimization. In the future, further performance analysis capabilities such as life cycle costing can also be integrated.
The building sector significantly impacts on the environment during every stage of the building life cycle. The necessary transition toward a carbon-neutral society is driving a growing attention toward the refurbishment of old buildings, fostering intervention measures with the twofold objective of reducing operational energy consumption, typically upgrading the thermal insulation, and ensuring the quality of the consumed energy by adopting renewable and sustainable energy in the supply chain, such as thermal and photovoltaic solar energy.In seismic prone areas the vulnerability of existing buildings, not designed according to modern building codes, could hamper the efficiency of the solely energy refurbishment, besides representing a safety hazard. The present paper investigates a framework to quantify the influence of seismic events on the environmental impact assessment of buildings.The investigated framework is applied to a selected building, considering the building as alternatively located in regions with different seismicity. As an example, the building environmental impact is evaluated, in terms of carbon footprint, in the case of two different scenarios: upon completion of an energy refurbishment only, and after a coupled intervention targeting energy refurbishment and seismic retrofit. The results show that, in case of energy refurbishment only, the building located in a high-seismicity region presents an expected additional annual embodied equivalent carbon dioxide due to seismic risk, which almost equals the annual operational carbon dioxide after thermal refurbishment.
The first aim of the present work is to assess the environmental impact of specific rendering mortars able to be applied in the vertical opaque envelopes of an existing school building from the 80's built in Portugal, to reduce condensation effects and heat transfer. Ordinary cement and hydraulic lime mortars where compared to cork added and EPS added mortars. Energy performance and energy audit of the building was estimated and compared to the original behaviour of the school building. LCA variant called cradle to gate was used to compare the environmental impacts of building thermal rehabilitation and its effect on the energy consumption for heating and operational energy (OE), for different mortars service life. The simulation made in the school show that ordinary cement or hydraulic lime mortars, leads to much higher global warming potential, where CO2 emissions are more than 3 tonnes per building intervention. The use of mortars with cork addition, leads to a reduction of CO2 emission up to 30% and 20% reduction in embodied energy (EE), when compared to traditional mortars. Cork mortars present smaller EE than EPS mortars. Results shows that it is possible to slightly reduce OE by using materials with lower EE value.
Norwegian Bank "SpareBank 1 SMN" in 2008 decided to reestablish their headquarters in Trondheim. The key question addressed in the process, was whether to rehabilitate the existing building or demolish it and construct a new one. Becoming aware of the environmental issues related to the decision, a project was set up to assess the consequences for green building. The analysis concluded that from a climate point of view the most favourable strategy was to replace the existing construction and build a new one. A hybrid LCA approach was used as the assessing tool, and in the paper we discuss the methodological challenges facing analyses addressing the issue of comprehensive analytical approaches in order to inform decisions in this respect. The paper shows the usefulness of life cycle models as input to a decision making process in a feasibility phase of the project. In addition, data availability and methodological issues are discussed in some detail.
Buildings demand energy in their life cycle right from its construction to demolition. Studies on the total energy use during the life cycle are desirable to identify phases of largest energy use and to develop strategies for its reduction. In the present paper, a critical review of the life cycle energy analyses of buildings resulting from 73 cases across 13 countries is presented. The study includes both residential and office buildings. Results show that operating (80–90%) and embodied (10–20%) phases of energy use are significant contributors to building's life cycle energy demand. Life cycle energy (primary) requirement of conventional residential buildings falls in the range of 150–400 kWh/m2 per year and that of office buildings in the range of 250–550 kWh/m2 per year. Building's life cycle energy demand can be reduced by reducing its operating energy significantly through use of passive and active technologies even if it leads to a slight increase in embodied energy. However, an excessive use of passive and active features in a building may be counterproductive. It is observed that low energy buildings perform better than self-sufficient (zero operating energy) buildings in the life cycle context. Since, most of the case studies available in open literature pertain to developed and/or cold countries; hence, energy indicative figures for developing and/or non-cold countries need to be evaluated and compared with the results presented in this paper.
Interest in sustainability and resilience of buildings has led to a growing body of literature on merging environmental impact assessment methods with seismic loss estimation methods. Researchers have taken different approaches to connecting the two fields with the common goal of estimating the social, environmental, and economic impacts of damage to buildings subject to seismic events and thus enabling the study of tradeoffs
between performance objectives. The differences among these studies include topics such as treatment of uncertainty, types of components and systems considered in the performance assessment, fidelity of structural analysis ranging from region-specific empirical fragility curves to detailed building-specific finite element analysis, scope of life cycle assessment, and so on. One of the aspects of the most diverse treatment has been in obtaining environmental impact data and relating it to pre-use impact estimates. For example, the translation of damage and repairs into life-cycle environmental impacts has been done by one of three approaches: (1) Economic Input-Output Life Cycle Assessment (EIO-LCA) has been applied to economic loss estimates; (2) repair cost-ratios have been applied to environmental impacts from the pre-use stage; and (3) repair descriptions have
been used to model environmental impacts of damage scenarios directly using process life cycle assessment (LCA). All of the approaches are generally accepted but may pose limitations in certain applications and can potentially result in inconsistent conclusions from study to study. A review of existing literature in the area is presented and is followed by a comparative analysis and discussion of the outcomes of taking different environmental life cycle assessment approaches. This paper provides a comprehensive overview of the research efforts in this area and discusses opportunities for further development in order to make the implementation consistent and practical for design decision making.
With the world's uncertain energy outlook, buildings should be designed and constructed to use lesser fossil fuel-based energy and have lower environmental impacts. In the past decades, the research and practice have successfully focused on reducing the operational energy use. As a result, the share of embodied energy, the other energy component, has increased in the life cycle energy use of buildings.
The present article provides an overview of literature on embodied energy use in buildings in several directions. It reports on key estimation methodologies and tools for embodied energy and presents the embodied energy values for different types of buildings, as studied by the extant literature. It also examines embodied energy in relation to operational energy and highlights the recent shifts in share and significance of embodied energy in the building life cycle energy use. The article also presents a review of the embodied energy of tall buildings and explores the relation between embodied energy and building height. Finally, major strategies to reduce embodied energy, and research gaps and trends in the field are covered.
Architects and planners have been at the forefront of envisioning a future built environment for millennia. However, fragmental views that emphasize one facet of the built environment, such as energy, environment, or groundbreaking technologies, often do not achieve expected outcomes. Buildings are responsible for approximately one-third of worldwide carbon emissions and account for about 40% of primary energy consumption in the U.S. In addition to achieving the very ambitious goal of reducing building-associated greenhouse gas emissions by 75% by 2050, buildings must improve their functionality and performance to meet current and future human, societal, and environmental needs in a changing world. In this article, we introduce a new framework to guide potential evolution of the building stock in the next century, based on greenhouse gas emissions as the common thread to investigate the potential implications of new design paradigms, innovative operational strategies, and disruptive technologies. This framework emphasizes integration of multidisciplinary knowledge, scalability for mainstream buildings, and proactive approaches considering constraints and unknowns. The framework integrates the interrelated aspects of the built environment through a series of quantitative metrics that aim to improve environmental outcomes while optimizing building performance to achieve healthy, adaptive, and productive buildings.
This literature review addresses the Life Cycle Energy Analysis (LCEA) of residential buildings. As the fluctuation in the choice of functional units, boundaries of the system, life cycle inventory (LCI) methods, metrics and impact indicators complicated the potential comparability, the guidelines of Product Category Rule (PCR) 2014:02 for buildings were applied for the normalization procedure. Even though PCR provided a clear statement of the boundaries and a complete presentation of the results, uncertainty deriving from the LCI methods and the omissions in the system boundaries indicates that further standardization is needed. The sample consisted of 90 LCEA case studies of conventional, passive, low energy and nearly zero energy residential buildings (nZEB). Additional analysis identified an underestimation between case studies that use process instead of hybrid analysis, as the average value of embodied energy in hybrid analysis appears to be 3.92 times higher than in process analysis case studies. The highest value of embodied energy for an nZEB case study quantified with process analysis appears to be lower than all the input-output hybrid case studies. A revised definition, according to current trends and requirements in energy efficiency regulations, was also provided as an update of their consistency in time. Operating energy appeared to dominate in life cycle energy of residential buildings in the past. The results of this review show an increasing share of embodied energy in the transaction from conventional to passive, low energy and nZEB, despite the reduction in the total life cycle energy that could reach up to 50%. The share of embodied energy dominates, mainly in low energy and nearly zero energy buildings, with a share of 26%–57% and 74%–100% respectively. In passive buildings, the share of embodied energy varies within a range between 11% and 33% that reaches the embodied energy limits of both a conventional and a low energy building. The use of renewable energy sources (RES) in a passive house, for the production of electricity, classifies it in the range of embodied energy of an nZEB. A significant gap of 17% in the share of embodied energy, between the nearly zero and the most energy efficient building examined in the current review, is identified. This difference appears to be more important for the conventional and passive buildings, indicating the relative significance of embodied energy through time and towards the nZEB. Furthermore, if uncertainty and the underestimation of embodied energy deriving by process analysis were considered this gap could be different. The increase of embodied energy in buildings, indicates that a whole life cycle energy analysis may be needed in the methodological framework of current energy efficiency regulations.
The article could be downloaded for free until 31 of July 2016 at the following link:
http://authors.elsevier.com/a/1TBel1HudMoGgY
When a building undergoes a retrofit project, the goal of assessing energy and environmental performances of retrofit actions is a complex matter. Building and its environment are complex systems in which all sub-systems are strongly interdependent and influence the overall efficiency performance. In the following paper, starting from a literature review of building life-cycle studies, the authors highlight that there is a strong interplay among all the phases of a building life-cycle, as each one can affect one or more of the others.
The building industry uses great quantities of raw materials that also involve high energy consumption. Choosing materials with high content in embodied energy entails an initial high level of energy consumption in the building production stage but also determines future energy consumption in order to fulfil heating, ventilation and air conditioning demands.This paper presents the results of an LCA study comparing the most commonly used building materials with some eco-materials using three different impact categories. The aim is to deepen the knowledge of energy and environmental specifications of building materials, analysing their possibilities for improvement and providing guidelines for materials selection in the eco-design of new buildings and rehabilitation of existing buildings.The study proves that the impact of construction products can be significantly reduced by promoting the use of the best techniques available and eco-innovation in production plants, substituting the use of finite natural resources for waste generated in other production processes, preferably available locally. This would stimulate competition between manufacturers to launch more eco-efficient products and encourage the use of the Environmental Product Declarations.This paper has been developed within the framework of the “LoRe-LCA Project” co-financed by the European Commission’s Intelligent Energy for Europe Program and the “PSE CICLOPE Project” co-financed by the Spanish Ministry of Science and Technology and the European Regional Development Fund.
The environmental and resource impacts of wooden single-family residences designed to meet the conventional Norwegian Building Code from 2010 (TEK10) and the Norwegian passive house standard NS 3700 are compared using life cycle assessment. Four different heating systems are evaluated for the two building designs: (1) electric (resistance heating), (2) electric and wood, (3) electric and a solar heat collector and (4) electric and an air-water heat pump system. The goal of the research is to evaluate the different ways of lowering the total environmental burden of a building's life cycle, considering the two building standards, and evaluating the impacts due to implementation of renewable heating systems in comparison to standard Norwegian systems largely based on electricity. The life cycle results show that the wood-framed single-family residence built according to the passive house standard provides a consistent and clear reduction of cumulative energy demand of 24-38% in comparison to the conventional building standard TEK10 with electric panel heating. In combination with efficient heating systems, a passive house building envelope with a heat pump system provides the largest savings, an improvement of almost 40% compared to a conventional house with electric heating. The reduction in greenhouse gas emissions of the cleanest design compared to the standard alternative is almost 30%. Solar heated water also provides substantial environmental gains for the passive house. On the other hand, a standard building envelope with a heat-pump system reduces impacts to a level comparable to that of a passive house building with only electric heating.
A literature survey on buildings' life cycle energy use was performed, resulting in a total of 60 cases from nine countries. The cases included both residential and non-residential units. Despite climate and other background differences, the study revealed a linear relation between operating and total energy valid through all the cases. Case studies on buildings built according to different design criteria, and at parity of all other conditions, showed that design of low-energy buildings induces both a net benefit in total life cycle energy demand and an increase in the embodied energy. A solar house proved to be more energy efficient than an equivalent house built with commitment to use "green" materials. Also, the same solar house decreased life cycle energy demand by a factor of two with respect to an equivalent conventional version, when operating energy was expressed as end-use energy and the lifetime assumed to be 50 years. A passive house proved to be more energy efficient than an equivalent self-sufficient solar house. Also, the same passive house decreased life cycle energy demand by a factor of three - expected to rise to four in a new version - with respect to an equivalent conventional version, when operating energy was expressed as primary energy and the lifetime assumed to be 80 years.
The paper presents the results of an energy and environmental assessment of a set of retrofit actions implemented in the framework of the EU Project "BRITA in PuBs" (Bringing Retrofit Innovation to Application in Public Buildings - no: TREN/04/FP6EN/S07.31038/503135). Outcomes arise from a life cycle approach focused on the following issues: (i) construction materials and components used during retrofits; (ii) main components of conventional and renewable energy systems; (iii) impacts related to the building construction, for the different elements and the whole building. The results are presented according to the data format of the Environmental Product Declaration. Synthetic indices, as energy and GWP payback times, and energy return ratio, are defined to better describe the energy and environmental performances of the actions. The project highlights the role of the life cycle approach for selecting the most effective options during the design and implementation of retrofit actions.
A comprehensive case study life cycle assessment (LCA) was conducted of a 7300 m2, six-story building with a projected 75 year life span, located on the University of Michigan campus. The bottom three floors and basement are used as classrooms and open-plan offices; the top three floors are used as hotel rooms. An inventory of all installed materials and material replacements was conducted covering the building structure, envelope, interior structure and finishes, as well as the utility and sanitary systems. Computer modeling was used to determine primary energy consumption for heating, cooling, ventilation, lighting, hot water and sanitary water consumption. Demolition and other end-of-life burdens were also inventoried.The primary energy intensity over the building’s life cycle is estimated to be 2.3×106 GJ, or 316 GJ/m2. Production of building materials, their transportation to the site as well as the construction of the building accounts for 2.2% of life cycle primary energy consumption. HVAC and electricity account for 94.4% of life cycle primary energy consumption. Water services account for 3.3% of life cycle primary energy consumption, with water heating being the major factor, due to the presence of hotel rooms in this building. Building demolition and transportation of waste, accounts for only 0.2% of life cycle primary energy consumption.All impact categories measured (global warming potential, ozone depletion potential, acidification potential, nutrification potential and solid waste generation) correlate closely with primary energy demand.The challenges in developing a life cycle model of a complex dynamic system with a long service life are explored and the implications for future designs are discussed.
There is an increasing complexity and interplay between all the issues associated with property portfolio decisions. This paper explores the relationships between financial, environmental and social parameters associated with building adaptive reuse. An adaptive reuse potential (ARP) model is developed and discussed in the context of its application to the Hong Kong market. The model can assist in the transformation of the traditional decision-making processes of property stakeholders towards more sustainable practices, strategies and outcomes, by providing a means by which the industry can identify and rank existing buildings that have high potential for adaptive reuse. This in turn enhances Hong Kong's ability for sustainable, responsive energy and natural resource management by allowing issues regarding excessive and inappropriate resource use to be identified and assessed, and enabling appropriate management strategies to be implemented. The ARP model proposed in this paper provides, illustrated by a real case study, an important step in making better use of the facilities we already have and the residual life embedded in them.
Total energy use during the life cycle of a building is a growing research field. The embodied energy makes up a considerable part of the total energy use in low energy buildings. Recycling provides the opportunity to reduce the embodied energy by using recycled materials and reusable/recyclable materials/components. This paper presents values on embodied energy, energy needed for operation and the recycling potential of the most energy efficient apartment housing in Sweden (). In a life span of 50 years, embodied energy accounted for 45% of the total energy need. The recycling potential was between 35% and 40% of the embodied energy.
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