Building Life Cycle Assessment Research Articles

A framework for evaluation of improvement opportunities for environmental impacts on construction works using life cycle assessment and value stream mapping concepts: offsite and onsite building construction

There have been various concerns about the environmental impact of construction works. This generates a need to take a more proactive approach in evaluating the environmental impacts of construction operations and further explore ways to reduce the environmental impacts. Enormous opportunities exist within the building industry to achieve a reduction in greenhouse gas emissions. The aim of the study is to develop a framework for the evaluation of improvement opportunities for environmental impact for onsite and offsite building construction works using life cycle assessment (LCA) and value-stream-mapping concepts. Various tools for LCA exist; however, there is a need for the development of an LCA framework and improvement opportunities that can be localized to various communities to evaluate improvement opportunities for building construction. This study conducts a review of methods to evaluate the LCA of buildings on local construction sites. A procedure for establishing improvement opportunities is also developed. Based on the author’s knowledge and experience, including site visits, using value stream mapping (VSM) techniques, a conceptual framework of the present state map and future state map of residential construction works was developed. The study presents a procedure for the evaluation of improvement opportunities for the environmental impacts of construction operations.

Carbon Footprint Analysis of Buildings Based on LCA Theory Under Carbon Neutrality Goals: Taking the 3rd China International Solar Decathlon Competition as an Example

This paper focuses on the design of residential buildings oriented to the efficient use of solar energy, and selects the entries HUI HOUSE of Hefei University of Technology and Lille I University of France in the 3rd China International Solar Decathlon China Competition, based on the theory of the life cycle assessment (LCA) of buildings, and analyzes the carbon footprint from four aspects: building materials production and transportation stage, building construction stage, building operation stage, and building demolition stage. Through the calculation of the carbon footprint of buildings, the socio-economic benefits of HUI HOUSE in carbon reduction were analyzed; the result of the calculation was that HUI HOUSE achieved carbon neutrality in the ninth year, and continued carbon reduction after that, contributing a cumulative total of 947.54 tons of carbon negative in the life cycle of buildings.

The Use of Environmental Product Declarations of Construction Products as a Data Source to Conduct a Building Life-Cycle Assessment in Spain

The Life-cycle Assessment (LCA) method and the Environmental Product Declaration (EPD) each play a crucial role in reducing buildings’ embodied environmental impacts. EPDs provide the validated and geographically representative data necessary to conduct an LCA. However, the development of EPDs in the European context is still irregular. Countries such as Germany and France have many EPDs for construction products, while other countries, such as Spain, have a limited number of EPDs and more than one operator programme, which is pointed out in the literature as a possible limiting factor for comparing results. This study aimed to examine the use of construction product EPDs manufactured in Spain, to then use as a data source to conduct a building LCA. We analysed the comparability of the results among the different EPD programmes and investigated to what extent the use of Spainߣs geographically representative construction product EPDs can contribute to conducting a building LCA, including all the materials and products that compose a building, and covering all the building life-cycle stages (product, construction, use, and end-of-life). The results showed that plasterboard and thermal insulation products have the highest numbers of EPDs in different EPD programmes. The case study analysis showed that 20% of the construction products that compose a building can potentially use these EPDs as a data source to conduct a building LCA, and 89% of those product categories include at least the product, use, or end-of-life stage modules. Finally, recommendations and challenges to improve LCA development in the architecture, engineering, construction, and operation industries were included.

Energy simulation and life cycle assessment of a 3D printable building

The construction industry plays a key role in the economic development of countries. The industry faces challenges such as high energy consumption, long construction time, high manufacturing costs. 3D printing technology can solve many problems in this industry. The goal of this research is to find suitable materials for the 3D printing of an energy-efficient building with the least environmental impact. Magnesium potassium phosphate cement (MKPC) was selected for this study. In the next step, energy consumption in the building is simulated and different scenarios are considered to optimize energy consumption and reduce environmental impacts. Then, the life cycle assessment is done for the best scenario. Finally, this scenario is compared to the case where portland cement enters the composition. The simulation results show that PCM (phase change materials) has very little effect on reducing the energy consumption of the building. In contrast, insulation has almost halved energy consumption. Magnesium oxide and monopotassium phosphate have a significant share in the environmental effects of concrete walls. By adding 30% by volume of M20 concrete, the environmental impacts are reduced almost 28%.

Computationally efficient sensitivity analysis for building ecodesign with many-level categorical input factors

Dynamic building energy simulation and life cycle assessment (LCA) are useful ecodesign tools to mitigate the energy and environmental impacts of buildings. Various uncertain factors can affect the building energy and environmental modelling, including continuous and categorical factors (i.e., discrete factors without logical ranking). Sensitivity analysis (SA) is applied to identify the most influential factors on which additional research efforts are needed to increase the robustness of results. The Sobol method (Sobol) is the reference SA method, but it requires a significant amount of computation. Less time-consuming methods, such as an adaptation of the Morris screening (Morris), have shown a good ability to quantify the influence of factors, but their performance has not been investigated for categorical factors having many (more than two) levels. Two strategies (2LA-Morris and MA-Morris) based on the adaptation of Morris are proposed to handle many-level factors. Their performance is compared to that of Sobol based on four criteria: computation time, factor's relative influence, factor's ranking, and ability to detect interactions. For the LCA of a house including 24 uncertain factors, MA-Morris was able to quantify the influence of factors in the same way as Sobol, while reducing the computation time by a factor of 12.

Life cycle assessment of green buildings: A comprehensive analysis of environmental impacts

Life cycle assessment of green buildings: A comprehensive analysis of environmental impacts

Integrating building information modeling and life cycle assessment to analyze the role of climate and passive design parameters in energy consumption

With the Architecture, Engineering, and Construction industry representing a significant share of global energy consumption and greenhouse gas emissions, developing sustainable design and reducing buildings’ environmental impacts has become a priority over the past decades. Adopting building information modeling tools and implementing them into life cycle analysis techniques at the early stages of design has been an effective method for buildings sustainability evaluation. With our environment constantly changing, it is reasonable that the construction industry should also aim to adapt to these changes and use them. However, the role of local climate features and their effects on a building's energy output is often neglected. By using building information modeling–life cycle analysis integration techniques, this research aims to consider the role of climatic attributes along with some passive design strategies in the life cycle assessment of the building and see how it affects that building's energy performance. By only applying passive design strategies (not including heating, ventilation, and air conditioning system type), the models’ energy demand was reduced up to 30% of the original value. It is also witnessed that by using the proper equipment and construction materials that match the respective climate, up to 28% of the building's energy consumption during the operational phase, can be saved. Although insulation of the walls does reduce energy consumption values, it also contributes to more greenhouse gas emissions. The increase in greenhouse gas emissions was estimated to be around 3%, but since the insulation boards make up only 2% of the building's area, it is a considerable amount.

Prediction and scenario simulation of the carbon emissions of public buildings in the operation stage based on an energy audit in Xi'an, China

The carbon emissions (CEs) of public buildings (PBs) in the operation stage significantly impact building life cycle assessments (LCA). Energy conservation and carbon reduction during this stage is necessary for China to achieve peak CEs and neutralization. Energy consumption and CEs are analyzed using energy audit data for PBs in Xi'an. CEs of PBs in the operation stage are calculated by our prediction method with an average deviation of only 4.41%. Using the logarithmic mean Divisia index (LMDI) method to analyze factors influencing CEs, we find that economic development levels impact CEs the most in the operation stage; the impact coefficient reaches 3.81. This study discusses the contribution of various driving factors of CEs via the stochastic impacts by regression on population, affluence, and technology (STIRPAT) method and simulates seven scenarios to predict change trends of the CEs of PBs in the operation stage. The rough development scenario fails to achieve the peak, the comprehensive optimization development scenario achieves the peak in 2040, and the remaining scenarios achieve the peak in 2050. The results provide practical and theoretical support for CE research and a scientific basis for predicting the CEs of PBs in the operation stage throughout China and worldwide.

Feasibility of Planting Trees around Buildings as a Nature-Based Solution of Carbon Sequestration—An LCA Approach Using Two Case Studies

In response to Canada’s commitment to reducing greenhouse gas emissions and to making pathways to achieve carbon neutral buildings, this paper presents two real case studies. The paper first outlines the potential of trees to absorb CO2 emissions through photosynthesis, and the methods used for the estimation of their annual carbon sequestration rates. The net annual carbon sequestration rate of 0.575 kgCO2eq/m2 of tree cover area is considered in our study. Then, this paper presents the carbon life cycle assessment of an all-electric laboratory at Concordia University and of a single-detached house, both located in Montreal. The life cycle assessment (LCA) calculations were performed using two software tools, One Click LCA and Athena Impact Estimator for Buildings. The results in terms of Global Warming Potential (GWP) over 60 years for the laboratory were found to be 83,521 kgCO2eq using One Click LCA, and 82,666 kgCO2eq using Athena. For the single-detached house that uses natural gas for space heating and domestic hot water, the GWP was found to be 544,907 kgCO2eq using One Click LCA, and 566,856 kgCO2eq using Athena. For the all-electric laboratory, a garden fully covered with representative urban trees could offset around 17% of the total life cycle carbon emissions. For the natural gas-powered single-detached house, the sequestration by trees is around 3% of the total life cycle carbon emission. This paper presents limits for achieving carbon neutral buildings when only the emissions sequestration by trees is applied, and discusses the main findings regarding LCA calculations under different scenarios.

Lifespan prediction of existing building typologies

Life-cycle assessment (LCA) is currently one of the construction industry's most widely used methods of environmental assessment. Because LCA calculations is based on life-cycle thinking are the lifespan of the building a sensitive parameter in relation to the calculated overall environmental impact of the building. More accurate assessments of the lifespans of buildings are therefore a prerequisite for reducing errors and uncertainties in LCA and Life Cycle Costing (LCC) calculations. This study evaluates a generalized logistic lifespan prediction model for existing building typologies. The model is tested as part of a Danish case study based on building data collected from 124,096 cases of demolition. The objective is to investigate whether the typical lifespan used in LCA or LCC calculations accurately describes the remaining service life of existing buildings based on different building typologies and construction periods. The study show that office buildings generally have much shorter expected lifespans than previously assumed and that multi-family housing has nearly twice the lifespan of single-family housing. The results show a tendency for a declining lifespan based on the construction period, in which newer buildings, i.e. those that are no more than thirty years old, have a lifespan that is much shorter than the average lifespan for all construction periods. These results are highly relevant for both LCA and LCC calculations of buildings since they indicate that newer buildings in northern Europe have a lower lifespan than previous studies have shown.

Using systematic building decomposition for implementing LCA: The results of a comparative analysis as part of IEA EBC Annex 72

The building Life Cycle Assessment (LCA) applied to buildings requires collecting and organizing large quantities of data over all building life cycles. To overcome specific difficulties related to the system boundaries definition and life cycle inventory stages, the literature recognizes that systematic building decomposition methods (SBDM) can be used to classify building components, elements and materials, as well as to increase the reliability and transparency of LCA results, particularly for embodied carbon and other environmental impacts. In this paper developed in the context of the research project IEA EBC Annex 72, the authors aim to provide a basis for understanding how different SBDMs decompose a building and classify its parts. This study analyses the implications of using different SBDM along the steps of an LCA study. Such as to support transparent and comprehensible (de)composition of the life cycle inventory (LCI), definition of service lives for different building parts or clear and comparable communication of assessment results and environmental hotspots particularly when using digital tools to conduct LCA. The study analyses 12 national SBDMs used in participating countries of IEA EBC Annex 72. To showcase the implications of SBDMs in building LCA practice, an office building was used as a common case study for applying the different SBDM approaches. Differences were identified among the decomposition levels and the consequences of these differences on the LCI organization. Thus, some of the main contributions to this study are the investigation of different SBDM approaches for improving the design workflows, by discussing BIM model definitions and the recommendation to use hierarchically based methods to allow the building elements and materials decomposition.

Improving the life cycle greenhouse gas emissions of transport infrastructure assets – a case study in Brussels, Belgium

Infrastructure transportation assets represent a significant share of environmental effects associated with built stocks. Although there is a growing body of knowledge on the life cycle assessment of buildings and material flow analysis of building stocks, infrastructure assets have received less attention. Existing life cycle assessment studies tend to rely on process analysis which is known to underestimate embodied environmental flows. The aim of this paper is to introduce a bottom-up parametric model for infrastructure transport assets, which can support a detailed characterization of the stock in a consistent and transparent manner. It relies on comprehensive hybrid exchange data for the quantification. This paper establishes the approach and equations used in the proposed model. The model consists of four main steps, namely: developing parametric representations of transport infrastructure assets, quantifying their material stock and replacement-related flows, quantifying life cycle embodied environmental flows and visualizing the results. One pilot case study of a road (including pedestrian sidewalks and bike lanes) and light railway, is used to demonstrate the model. Results assessing this pilot case study over 60 years are presented, including the material stock and replacement flows, as well as life cycle embodied greenhouse gas emissions (LCEGHG). Together these results provide important insights into material/infrastructure asset hotspots assets (e.g. steel lighting posts). Emissions-intensive material products and assets have a notable impact on results of LCEGHG, and they dominate both Initial greenhouse gas emissions (IEGHG) and recurrent greenhouse gas emissions (REGHG). However, they contribute marginally to the total mass. Another important observation is the significance of REGHG representing ~30% of LCEGHG. Interestingly, steel, asphalt and concrete are the main contributors to both REGHG and IEGHG. Future research consists of automating the proposed model and packaging it as a python-based Rhinoceros Grasshopper plugin before conducting testing and verification.

Process-specific digital recording of construction site LCA-inventory to identify decarbonisation pathways

In building life cycle assessment, construction site processes are currently hardly accounted for in detail. If considered, the emission values are determined by globally capturing effort values and by allocating them to individual work steps, equipment, or materials. To identify improvement potential to decarbonize construction activities, detailed process data must be captured for specific processes to determine the carbon dioxide emissions of single processes. The results can then be aggregated to larger process units e.g. to components or trades. To fully implement this approach, a recording of process-specific data at construction site is necessary. Therefore, the basic framework to record specific processes at construction site is developed in this article and LCA methodology to systematically link them to emissions is explained. Further, the method of computer vision for automated recording of construction site activities is being presented.

Template for Evaluating Cradle-to-Site Environmental Life Cycle Impacts of Buildings in India.

A massive amount of building construction is expected in economically developing nations such as India over the next few years. The first step in ensuring that the new construction takes place in a sustainable manner is the knowledge about the building's impact on multiple environmental domains. Life cycle assessment (LCA) is a promising tool for this, but its application in the Indian construction sector is hampered by a lack of access to detailed inventory data on amounts of all building materials used and the per unit environmental footprints of individual materials (characterization factors). Here, we overcome these limitations by proposing a novel approach that connects the building bill of quantity data with publicly available analysis of rate documents to obtain the detailed material inventory. The approach then combines the material inventory data with the newly available India-specific environmental footprint database of construction materials to calculate the impacts of a building during its different life cycle stages (cradle to site). We demonstrate the new approach through a case study of a residential building within a hospital in North-East India and quantify its environmental footprint on six domains of the environment: energy use, global warming, ozone depletion, acidification, eutrophication, and photochemical oxidant formation potential. Results show that out of 78 materials used, bricks, aluminum sections, steel bars, and cement are the major contributors to the building's total environmental impact. The material manufacturing stage is the hotspot in the building's life cycle. Our approach can act as a template for conducting "cradle-to-site" LCA of buildings for which BOQ data becomes available in India and other countries in the future.

Program for propriety analysis of global warming potential caused by the operational energy consumption of buildings in Korea

Various studies have reported that energy consumption in the operation stage in the life cycle of a building has the largest impact on global warming. However, suggesting appropriate practical directions for reducing global warming potential (GWP) is challenging owing to the absence of appropriate standards for GWP according to building energy consumption. In South Korea, environmental data of various buildings have been accumulated based on building life cycle assessment, conducted by adhering to the G-SEED standard for many years. This study aimed to develop a program that can support sustainable design by evaluating the appropriateness of GWP in the building operation stage in a simple manner and consequently suggest directions for efficiently reducing GWP passively or actively. To develop the program, first, GWP standard models were derived for each building’s energy use and source. Subsequently, a program, E2C, was built to assess the appropriateness of GWP emissions according to the energy effective area ratio from the building to be assessed, for each energy use and source, by employing the derived standard models. Finally, the applicability of the proposed program was examined through a case study and it was confirmed that design directions for securing the appropriateness of GWP could be suggested through E2C. Consequently, E2C has the potential to be used in the design stages of sustainable buildings.

Dynamic modelling of operational energy use in a building LCA: A case study of a Belgian office building

Strict energy performance requirements have reduced the building's operational energy use and related environmental impact in the past decades. Consequently, the embodied impacts of buildings gained importance, and hence focussing on the life cycle impacts has become essential to further reduce the environmental impact of buildings. Life cycle assessment (LCA) is an internationally accepted method used for this purpose. Current LCA studies of buildings typically look at their whole life cycle but ignore potential changes in operational energy use due to climate change. However, the latter is expected to influence the operational energy use of buildings to a significant extent. This paper aims to improve the assessment of the operational phase by including variations in the yearly operational energy use caused by climate change and expected changes in the electricity mix as a strategy for climate change mitigation. This adapted dynamic assessment method is used to assess a Belgian office building. The results indicate that a Representative Concentration Pathway (RCP) 8.5 climate change scenario causes a decrease of 18 % for the end use of gas for heating and an increase of 32.4 % for the electricity use for cooling and ventilation. For the case study, the reduction of the environmental impact due to the decrease in gas use compensates the impact increase due to the higher electricity use. An increase in environmental impact in future would however occur if both heating and cooling are provided by electricity. Furthermore, depending on the changes that will occur in the electricity mix, the global warming potential of the office building will change by −13 % for an electricity mix dominated by renewables and by + 10 % for one with mainly production by gas compared to the situation with the current mix. However, the inclusion of a more extended list of environmental indicators shows that the overall environmental impact will only reduce by 4 % or even increase by 7 % compared to the situation with the current mix.

Challenges in developing a holistic Whole Building Life Cycle Assessment (WBLCA) software tool: developers’ goals

The Intergovernmental Panel on Climate Change (IPCC) recently released a report emphasizing the importance of reducing carbon emissions, indicating that the construction industry is a key player in this process. Whole Building Life Cycle Assessment (WBLCA) is the most efficient method for evaluating buildings’ environmental impacts. It considers the effects of energy consumption during operation and the environmental impacts of extracting, manufacturing, transporting, assembling, and maintaining the building’s components. However, numerous obstacles prevent WBLCA from being fully applied by decision-makers during the building project process (BPP). This paper discusses and suggests improvements to the challenges of integrating WBLCA and BPP. An online survey was performed with nine WBLCA software developers worldwide, examining the critical challenges and how to overcome them. Most participants agreed that increasing WBLCA demand is the most pressing issue. It would encourage the entire construction sector to adopt a life-cycle mindset, pushing WBLCA software developers to improve software tool integration with the BPP. Results from this study will assist software companies and policymakers develop tools and regulations more aligned with the interests of designers.

Comparison of Green Building Rating Systems from LCA Perspective

Buildings account for a considerable proportion of carbon emissions throughout their lifecycle. Therefore, Green Building Rating Systems (GBRSs) have been developed globally to evaluate building environmental performance and mitigate their impacts on climate change. Life Cycle Assessment (LCA) as a science-based method has been recognised in the GBRSs to enhance the building environmental assessment. Regardless of the wide implementation of GBRSs, buildings carbon emissions have continued to rise by nearly 1% per year since 2010. Furthermore, no academic research has been conducted to compare GBRSs assessment criteria from the LCA perspective in respect of the recognition and weighting of (1) whole building LCA, (2) embodied carbon emissions and (3) operational carbon emissions. To this end, this research aims to evaluate the efficiency, validity and reliability of five international GBRSs (i.e., LEED, BREEAM, BEAM Plus, Green Star and Homestar) in terms of assessing and auditing the building total carbon emissions; embodied and operational emissions. Results show that conducting whole building LCA is an optional assessment criterion with negligible weighting. Moreover, the assessment of the operational carbon emissions make up the major portion of the total weighting in the existing GBRSs. By contrast, the assessment of building embodied carbon emissions is overlooked. Based on the results, shifting focus from operational carbon towards a full life cycle perspective is urgently needed to achieve the emissions reduction targets and so decarbonising the built environment.

Building Information Modeling (BIM) Driven Carbon Emission Reduction Research: A 14-Year Bibliometric Analysis.

Governments across the world are taking actions to address the high carbon emissions associated with the construction industry, and to achieve the long-term goals of the Paris Agreement towards carbon neutrality. Although the ideal of the carbon-emission reduction in building projects is well acknowledged and generally accepted, it is proving more difficult to implement. The application of building information modeling (BIM) brings about new possibilities for reductions in carbon emissions within the context of sustainable buildings. At present, the studies on BIM associated with carbon emissions have concentrated on the design stage, with the topics focusing on resource efficiency (namely, building energy and carbon-emission calculators). However, the effect of BIM in reducing carbon emissions across the lifecycle phases of buildings is not well researched. Therefore, this paper aims to examine the relationship between BIM, carbon emissions, and sustainable buildings by reviewing and assessing the current state of the research hotspots, trends, and gaps in the field of BIM and carbon emissions, providing a reference for understanding the current body of knowledge, and helping to stimulate future research. This paper adopts the macroquantitative and microqualitative research methods of bibliometric analysis. The results show that, in green-building construction, building lifecycle assessments, sustainable materials, the building energy efficiency and design, and environmental-protection strategies are the five most popular research directions of BIM in the field of carbon emissions in sustainable buildings. Interestingly, China has shown a good practice of using BIM for carbon-emission reduction. Furthermore, the findings suggest that the current research in the field is focused on the design and construction stages, which indicates that the operational and demolition stages have greater potential for future research. The results also indicate the need for policy and technological drivers for the rapid development of BIM-driven carbon-emission reduction.

Comparative Lifecycle Analysis of Sri Lankan Non-Conventional Roofing Materials

Building materials, especially roofing products, play a major role as they are essential for any building construction. Knowledge of the environmental performance of building materials is vital when building life cycle assessment. However, only a few studies have been conducted in Sri Lanka in this regard. The present study focuses on the environmental life cycle assessment of two different non conventional roofing materials used in Sri Lanka. Acrylonitrile Styrene Acrylate roofing sheets and Calicut-type clay roofing tiles have been selected for the study. In order to measure and calculate environmental impacts of both types of roofing materials, field data was collected quantitatively and noted as per ISO14040 and ISO14044. Using the Cradle-to-Gate LCA technique and OpenLCA software, the environmental impacts as midpoint and endpoint categories were evaluated. As the main output of the study, environmental performance of these two roofing materials were compared, the hotspots of the manufacturing process and the causes were also identified. . Accordingly, the global warming potential of Acrylonitrile Styrene Acrylate roofing sheets and Calicut-type clay roofing tiles is 13.5 kgs of CO2 eq. and 8.95 kgs of CO2 eq. respectively. Further, comparison of the endpoint categories showed the resource depletion was most impactful, indicating 0.814012 points and0.65305 points, respectively for the two roofing material types. Further, kiln firing was identified as the environmental hotspot contributing most to the endpoint and midpoint impact categories for clay roofing tiles, while mixing materials by hot mixer was the hotspot for Acrylonitrile Styrene Acrylate roofing sheets. In addition, the overall results demonstrated how the production process of clay tile influences more than the Acrylonitrile Styrene Acrylate roofing sheet on both the midpoint as well as the endpoint impact categories. KEYWORDS: Acrylonitrile Styrene Acrylate, Calicut tiles, Cradle-to-Gate, End-pint impacts, Mid-point impacts