Building Life Cycle Assessment Research Articles

Methodological Challenges in Aligning EPDs with Whole Life Carbon Limits for Buildings: A B2B Approach

Abstract The environmental performance from the materials used in buildings is pivotal in reducing greenhouse gas (GHG) emissions from the building sector; buildings are in the top three of the world’s most significant contributors of GHG emissions and are responsible for one-fifth of the overall resource consumption. Alongside multiple countries enforcing legal GHG limits and requiring Life Cycle Assessment (LCA) for new buildings, the availability of product-level environmental data, known as Type III Environmental Product Declarations (EPDs) has increased exponentially. EPDs were originally used for Business-to-Business purposes but are now the main data source for building-level LCAs. However, this often comes with a large set of uncertainties, as EPDs are still evolving as a documentation approach, and not always readily applicable in the whole life cycle approach. There are a multitude of complex areas to engage into, this study focuses on how use-stage modules are documented in EPDs, and how varied approaches create further complexity and perils in relation to their use in LCA and regulations, in the sense of, potential leading to high uncertainties and wrongful interpretations. The study aims to address the methodological gaps associated with the use of EPDs as data inputs in legally binding LCA requirements particularly concerning modules B1-5, which constitute the embodied part of the use-stage. The findings reveal a significant margin of error if EPDs are not correctly implemented, underscoring the importance of the Business-to-Business documentation approach.

Exploring the relationship of building area and GHGe: a mitigation strategy?

Abstract Greenhouse gas emissions (GHGe) from new constructions must be reduced to address the climate change crisis. Life cycle assessment (LCA) is widely applied to document the environmental impacts of buildings, often reporting results by dividing the total emissions over the measured building area, such as the gross floor area. The appropriateness of this approach has been debated in the building LCA research community and the construction industry, with concerns about the potential consequence of designing larger buildings to reduce emissions over the buildings’ life cycle and if this entails easier compliance with limit values in regulations. With a large collection of 291 case studies divided into four weight categories, potential correlations between constructing larger areas and GHGe are explored by fitting linear models. The results show that theoretically, GHGe reported per area can be decreased due to increased building area. However, this requires significant increases in area, which realistically results in increased costs, resource use, and related environmental impacts, which is not feasible. Therefore, the findings do not support the notion that interpreting LCA results per square meter encourages the enlargement of buildings to reduce emissions over their life cycle. It should be noted that the study’s conclusions are drawn from the end results of individual LCAs. The potential decrease in GHGe by enlarging the building area during the design process is not possible to derive without involving stakeholders. Thus, this study underlines the need for future research to achieve a nuanced relationship between building size, design choices, and environmental impacts.

A multi-life cycle assessment of external wall insulation strategies in an Irish domestic retrofit

European Union (EU) policy and initiatives are driving both building renovation and the uptake of low-embodied carbon and circular design in the construction sector. The European Performance of Buildings Directive (EPBD) recast (2021) introduces global warming potential (GWP) methodology, and the future state will likely be embodied carbon targets for which life cycle assessment (LCA) of buildings will be required. External wall insulation (EWI) will have an important role to play in meeting targets. In this context, this paper compares the carbon emission payoff of three alternative EWI strategies that address conventional, low-carbon and circular solutions to EWI respectively, in the retrofit of an existing dwelling. The circular strategy is based on design for disassembly (DfD). Whereas standard LCA is based on a single building life cycle, the literature reviewed shows that the environmental impact assessment of DfD requires a multi-life cycle approach. In the absence of standardised methods for assessment, four multi-cycle LCA methods are selected and applied holistically in a case study investigation. Three allocation methods, 100:0, linear degressive (LD) and enhanced linear degressive (CELD), provide a range of emissions from ‘conservative’ to ‘best case’ over three building life cycles and the fourth method, the Van Gulck method, assesses the benefits of circularity through the concept of ‘multi-cycling’ based on one building life cycle. As each method of assessment will deliver different results, carbon emission payoff is not a fixed value. Findings show that with multiple use, the circular strategy pays off due to avoided production emissions and benefits from end-of-life (EoL) processes that DfD facilitates, that the upfront carbon cost of the circular strategy is minor relative to the carbon emission savings that reuse brings, and that the margin of improvement relative to the alternative strategies increases with each subsequent reuse.

The technological assessment of green buildings using artificial neural networks

This study aims to construct a comprehensive evaluation model for efficiently assessing appropriate technologies within green buildings. Initially, an Internet of Things (IoT)-based environmental monitoring system is devised and implemented to collect real-time environmental parameters both inside and outside the building. To evaluate the technical suitability of green buildings, this study employs a multifaceted approach encompassing various criteria, including energy efficiency, environmental impact, economic benefits, user comfort, and sustainability. Specifically, it involves real-time monitoring of environmental parameters, analysis of energy consumption data, and indoor environmental quality indicators derived from user satisfaction surveys. Subsequently, a Multi-Layer Perceptron (MLP) is selected as a conventional artificial neural network (ANN) model, while a Long Short-Term Memory (LSTM) model is chosen as an advanced recurrent neural network model in the realm of deep learning. These models are utilized to process and explore the collected data and assess the technical suitability of green buildings. The dataset comprises physical quantities such as temperature, humidity, and light intensity, as well as economic indicators including energy efficiency and building operating costs. Furthermore, the assessment process considers the building's life cycle assessment and indoor environmental quality factors such as health, comfort, and safety. By incorporating these comprehensive criteria, a holistic evaluation of green building technologies is achieved, ensuring the selected technologies' suitability and effectiveness. The model prediction results demonstrate that the proposed hybrid evaluation model exhibits high accuracy and robust stability in predicting building environmental parameters. For instance, the Root Mean Square Error (RMSE) for temperature prediction is 1.2 °C, the Mean Absolute Error (MAE) is 0.9 °C, and the determination coefficient (R2) reaches 0.95. Similarly, for humidity prediction, the RMSE, MAE, and R2 are 3.5 %, 2.8 %, and 0.88. Compared to the traditional MLP and LSTM models alone, the proposed hybrid model shows significant improvements in predicting building energy consumption, with approximately 15 % and 12 % reductions in RMSE and MAE, respectively, and an increase in R2 values of approximately 7 percentage points. These findings indicate that by amalgamation of the IoT and ANNs, this study successfully establishes a comprehensive model for accurately assessing technologies suitable for green buildings. This approach offers a novel perspective and methodology for the design and evaluation of green buildings.

Life Cycle Assessment and Cost Analysis of Mid-Rise Mass Timber vs. Concrete Buildings in Australia

Life Cycle Assessment and Cost Analysis of Mid-Rise Mass Timber vs. Concrete Buildings in Australia

Developing a dynamic life cycle assessment framework for buildings through integrating building information modeling and building energy modeling program

The construction and building sector is one of the largest contributors to the global carbon emissions. Therefore, it is imperative to accurately assess the carbon emissions of buildings throughout the life cycle. Many studies conducted life cycle assessment (LCA) of buildings to evaluate carbon emissions. However, due to the lack of dynamic data, most studies adopted the static LCA methodology, which neglected the dynamic variations during life cycle stages of a building. Unlike previous studies that collected static data from questionnaires and documents, the present study aims to establish a novel dynamic life cycle assessment (D-LCA) framework for buildings by incorporating the building information modeling (BIM) and the building energy modeling program (BEMP) into the static LCA. First, a static LCA is established as the baseline scenario that covers the “cradle-to-grave” life cycle stages. A BIM model is established using Revit to obtain the inventory of building materials. The Designer Simulation Toolkit (DeST) is used as a BEMP to simulate the operating energy consumption of the studied building, taking into account changes in energy mix, climate change, and occupant behavior. At the same time, the DeST results are further used as a data input for dynamic scenarios. The D-LCA framework is applied to a high-rise commercial building in China. This study found that the difference between static and dynamic scenarios was up to 66.7 %, mainly reflected in the dynamic energy consumption during the operation phase, indicating the inaccuracy of traditional static LCA. Therefore, a D-LCA by integrating BIM and BEMP can facilitate dynamic modeling and improve the accuracy and reliability of LCA for buildings.

Mind the gap: Facilitating early design stage building life cycle assessment through a co-production approach

Despite the transition towards a circular economy (CE) being a significant element in achieving the decarbonisation of the built environment, a clear and common pathway to applying CE principles to building design is still lacking in both industry practice and academia. The integration of Building Information Modelling (BIM) and Life Cycle Assessment (LCA) has the potential to enable the identification of feasible pathways to increase circularity. This study aims to investigate its practical use to facilitate the application of circular economy principles at the early stage of building design via using LCA-based BIM plugins. Within this aim, the paper centres on a co-production approach and presents a gap analysis by identifying gaps in knowledge and implementation as well as addressing the pressing needs of the current practice in the UK. A series of semi-structured interviews with expert practitioners in the field were conducted for data collection, contributing to the following phases of the co-production by allowing for an in-depth investigation and reflection of the practice. The findings have revealed that: (a) there is still an insufficient level of contextual awareness and readiness in the implementation of CE principles in the built environment and LCA understanding and (b) the adoption of BIM at the early stages of building design is still limited in the current practice; BIM models with sufficient level of data details and quality to enable circularity assessment are rarely produced. Thus, the paper highlights the need for enabling mechanisms, including the introduction of legislative instruments, the involvement and commitment of the industry and key stakeholders, the support for training and skills improvement, and the establishment of effective communication and implementation process management frameworks. Future research agenda points to the need of formulation of a BIM protocol to enable integration of BIM and LCA to promote CE principles in the building design process.

Building-SAT: a whole building life cycle assessment tool framework to quantify the global warming potential of buildings in South Asian Region

Building-SAT: a whole building life cycle assessment tool framework to quantify the global warming potential of buildings in South Asian Region

Soil carbon sequestration in building life cycle assessment: Offsetting measure or site impact

Abstract The environmental impacts of the built environment typically focus on the materials and operations within the building envelope. Little, if any, consideration is given to impacts that occur outside the building. This can be an appropriate simplification for urban settings where the building dominants the site. However, it would ignore impacts and benefits associated with site activities in more rural settings. The present study investigates soil carbon sequestration (SCS) principles to determine whether SCS can be considered an offsetting measure for buildings or should be considered within the site impacts for a project. Soil organic carbon (SOC) levels change overtime in response to external factors and interventions, however this response time is within the reference study period commonly used for building-scale life cycle assessments (LCAs). Therefore, it would be plausible to monitor changes in SOC throughout the lifespan for a project. Currently, there are some emerging methods but no consensus standards on accounting for SCS in building LCAs and current methodologies for quantifying SCS need further development to align with carbon offset principles. However, since soil is an intrinsic part of the landscape, it would be appropriate to incorporate SCS within the use phase impacts for a site. Expanding the system boundary to account for SCS should include accounting for the environmental impacts associated with landscaping, maintenance, and land management practices. Guidelines for calculating SCS and landscaping environmental impacts need to be developed to better reflect the complete environmental impact of the built environment.

A review of building life cycle assessment software tools: Challenges and future directions

A review of building life cycle assessment software tools: Challenges and future directions

A review of evolving climate and energy economy trends to enhance the dynamic life cycle assessment of buildings

The changing global climate is impacting life cycle effects of all sectors, including the building sector. To effectively decrease the construction sector's 40 % share of global annual energy use and carbon emissions, it's crucial to integrate these changes into life cycle assessments (LCA) to inform current and future energy policies, since buildings have lifespans exceeding 100 years. Current research lacks methods and data to embed future weather and energy shifts into LCA. This paper quantifies these future changes and discusses their integration into building LCA. Using industry reports and scholarly articles, we calculated global energy trends and weather patterns for 2030, 2050, and 2080. The projected energy use changes across United States economic sectors were also analyzed. Projections indicate a 41–59 % decline in fossil fuel use by 2050, with renewable energy increasing from 11 % to 41 %. Concurrently, global temperatures may rise by 2–5 °C, signaling major weather shifts. These shifts will translate into an economy-wide energy intensity decrease, showing an expected drop of 8 %. A Dynamic LCA (DLCA) framework is also discussed to include these shifts into LCA, to help not only researchers and practitioners involved in the LCA of buildings but also energy policy makers in effectively mitigating climate change.

Carbon Footprint of a Nearly Zero Energy Building in Accra (Ghana): an LCA-based Model

This study presents a comprehensive Life Cycle Assessment (LCA) of a Nearly Zero Energy Building (NZEB) in Accra, Ghana, comparing its environmental impact with a conventional Business-As-Usual (BAU) building over a 50-year lifespan. Adhering to ISO 14040 and ISO 14044 standards, the research evaluates the carbon footprint and operational efficiencies essential to sustainable building designs. Utilizing SimaPro 9.5 software and the IPCC 2021 GWP100 method, the total carbon footprint was quantified at 1727 tons of CO2-equivalent for the NZEB, significantly lower than the BAU comparison. The analysis highlights the operational phase, including waste generation as the most substantial contributor to the NZEB's environmental impact, accounting for 725 tons of CO2-equivalent emissions. Conversely, the strategic inclusion of solar panels and enhanced material selection for the NZEB markedly reduced energy demands, contributing to a net positive environmental outcome with an avoided carbon footprint of approximately -859.72 tons CO2-eq. This reduction underpins the NZEB's effectiveness in leveraging eco-friendly materials and renewable technologies, setting a benchmark for future sustainable construction practices. The study ultimately advocates for an integrated approach, harmonizing technological innovation with environmental stewardship, to mitigate the carbon footprint of the built environment, steering the construction industry towards sustainability.

Accounting for product recovery potential in building life cycle assessments: a disassembly network-based approach

PurposeExisting life cycle assessment (LCA) methods for buildings often overlook the benefits of product recovery potential, whether for future reuse or repurposing. This oversight arises from the limited scope of such methods, which often ignore the complex interdependencies between building products. The present paper, backed by its supplementary Python library, introduces a method that addresses this gap, emphasizing the influence of product interdependencies and future recovery potential on environmental impact.MethodsImplementing the proposed method requires adding a phase, the recovery potential assessment, to the four phases that constitute an LCA according to the ISO 14040/14044 guidelines. Given the disassembly sequence for each product, in the first step of the recovery potential assessment, a disassembly network (DN) is created that displays structural and accessibility dependencies. By calculating the average of the disassembly potential (DP) of each structural dependency (second step) associated with that product, we obtain the DP (0.1–1) at the product level in a third step. Because there is no empirical data available to support a specific relationship between product disassembly potential and recovery potential (RP) (0–1), we employ, in a fourth step, a flexible model specification to represent scenarios of how this relationship may look like. Ultimately, for each scenario, the resulting RP is used to enable a probabilistic material flow analysis with a binary outcome, whether to be recovered or not. The resulting product-level median material flows are then used to quantify the building’s environmental impact for a given impact category in the life cycle impact assessment (LCIA). The results are interpreted through an uncertainty, hotspot, and sensitivity analysis.Results and discussionOur results show that not considering the interdependencies between building products in building LCAs results in underestimating the embodied greenhouse gas (GHG) emissions by up to 28.29%. This discrepancy is primarily attributed to a failure to account for additional material flows stemming from secondary replacements owing to the interdependencies during the life cycle. When accounting for end-of-life recovery benefits, a zero-energy building (ZEB) design incorporating some DfD principles demonstrated up to 45.94% lower embodied GHG emissions than the ZEB design with low disassembly potential when assuming that recovered products will be reused.ConclusionsOur approach provides first-of-a-kind evidence that not accounting for recovery potential may significantly distort the results of an LCA for buildings. The method and its supporting code support the semi-automated calculation of the otherwise neglected potential environmental impact, thus helping to drive the transition towards a more sustainable built environment. The supporting code allows researchers to build on the proposed framework if more data on the relationship between DP and RP become available in the future. Finally, while applied to buildings in this paper, the proposed framework is adaptable to any complex product with limited modifications in the supporting code.

Inventory regionalization of background data: Influence on building life cycle assessment and carbon reduction strategies

Robust carbon reduction strategies are needed to meet climate targets, especially for emissions from building materials. Although research has shown that the production of materials can be influenced by local conditions, such as the energy mix, the impact of regionalization on embodied emissions from buildings has not yet been fully explored. In this paper, we investigate the impact of inventory regionalization on the life cycle assessment of buildings and its influence on greenhouse gas (GHG) reduction strategies. This is performed by first developing a consistent, automated and reproducible method for regionalizing the production process of building materials for all countries. We then apply life cycle assessment to a building for all European countries using the created regionalized processes. The results show strong deviations for certain countries, reaching a difference of up to 17% to the regional average data. When investigating the influence of regionalization on the choice of typical GHG reduction strategies, results show that the choice of strategy can be influenced by the regional context, supporting the need for greater geographic representativeness of building materials inventories for successful GHG emissions reduction pathways. Regionalization can also support the development of more accurate product-specific environmental product declarations (EPDs), which currently rely on average background data.

Comparison of Embodied Carbon Footprint of a Mass Timber Building Structure with a Steel Equivalent

The main purpose of this study is to quantify and compare the embodied carbon (EC) from the materials used or designed to build the Adohi Hall, a residence building located on the University of Arkansas campus in Fayetteville, AR. It has been constructed as a mass timber structure. It is compared to the same building design with a steel frame for this study. Based on the defined goal and scope of the project, all materials used in the building structure are compared for their global warming potential (GWP) impact by applying a life cycle assessment (LCA) using a cradle-to-construction site system boundary. This comparative building LCA comprises the product stage (including raw material extraction, processing, transporting, and manufacturing) plus transportation to the construction site (nodule A1–A4, according to standard EN 15804 definitions). In this study, GWP is primarily assessed with the exclusion of other environmental factors. Tally®, as one of the most popular LCA tools for buildings, is used in this comparative LCA analysis. In this study, the substitution of mass timber for a steel structure with a corrugated steel deck and concrete topping offers a promising opportunity to understand the GWP impact of each structure. Mass timber structures exhibit superior environmental attributes considering the carbon dioxide equivalent (CO2 eq). Emissions per square meter of gross floor area for mass timber stand at 198 kg, in stark contrast to the 243 kg CO2 eq recorded for steel structures. This means the mass timber building achieved a 19% reduction in carbon emissions compared to the functional equivalent steel structure within the building modules A1 to A4 studied. When considering carbon storage, about 2757 tonnes of CO2 eq are stored in the mass timber building, presenting further benefits of carbon emission delays for the life span of the structure. The substitution benefit from this construction case was studied through the displacement factor (DF) quantification following the standard process. A 0.28 DF was obtained when using mass timber over steel in the structure. This study provides insights into making more environmentally efficient decisions in buildings and helps in the move forward to reduce greenhouse gas (GHG) emissions and address GWP mitigation.

Literature Review on The Whole Life Cycle Assessment of Passive Buildings in The Context of Dual Carbon Emissions

With the increasing global demand for sustainable buildings, passive building design has become an area of concern. The design concept of passive buildings is known for its efficient energy use and excellent indoor environmental quality. However, there is a need to delve deeper in order to fully assess the economics and sustainability of passive buildings. The whole life cycle management of passive buildings is a relatively new management concept, and the evaluation research of the whole life cycle of passive buildings under the dual-carbon target is still limited. This paper reviews the evaluation methods and criteria based on the whole life cycle of passive buildings. The literature review includes research conducted over the past two decades and will focus on evaluation indicators for passive buildings. Many reviews present evaluation indicators for low energy design in the full life cycle evaluation of passive buildings and discuss future design directions. This literature review serves as a preliminary step to guide the evaluation criteria of passive buildings in light of China's two-carbon target, which will help to enrich the evaluation indicators of passive buildings and promote the transition to high-quality development of passive buildings.

Visualisation of building life cycle assessment results using 3D business intelligence dashboards

Visualisation of building life cycle assessment results using 3D business intelligence dashboards

BIM based on energy & cost analysis in response to the day light intensity of a building

Construction of building with proper auditing of energy is one of the challenges faced in the AEC (Architecture Engineering and Construction) industries. The need of opt sources of energy affordability in the building lights can reduce the consumption of electricity and cut down the cost of bills. The trending application in using building information modelling (BIM) for the energy saving concept on daylight factors in various building like government office, commercial complex, school building and office building are significant to achieve the sustainability goals on sustainable cities and communities, responsible consumption and production including life on land. For the present studies, perspective BIM model is developed for the G+1 residential building covering the plot area of 1,815 square feet located in Phagwara, India. The building plan is prepared considering the sunlight orientation to configure the maximum daylight and ventilation are provided for the building as per the prevailing wind direction towards North-East latitude and longitude of 31° 13’ 26.4720’' N and 75° 46’ 14.8728’' E respectively. On the aspect of saving energy, the solar panel idea is added over the roof top, which can be utilized for the electric geysers and garden lighting, excess energy is used for the recharging of inverter batteries of the house. The energy model is audited with conventional building, it is understood the annual energy consumption has decreased to 36.9 k Wh/m2/ year as per the Punjab state electric board. Building Energy Simulation (BES) and Life Cycle Assessment (LCA) data is collected as per the location of the building, further the details are used for the modelling by using the Autodesk Revit and Autodesk Insight. Energy Used Intensity identified as less than 14.6 kWh/m2/year is needed to meet the Passive House criteria as per the studies, which can reduce the daylight effect on energy consumption. Therefore, it is understood, by the application of BIM is adding the virtual importance and elicit awe in the civil engineering domain.

On the estimation of interior walls in the district-scale Life Cycle Assessment of buildings

The large-scale Life Cycle Assessment (LCA) of buildings supports decision-making processes in reaching the climate goals of the building sector. Yet, the considerable amount of data required for detailed assessments hinders the method. This is particularly the case for buildings’ interior, which oftentimes surpasses the normative cutoff criteria’s negligibility threshold, and thus has to be considered in building LCA. In light of interior walls’ contribution to buildings’ overall environmental impacts, and a lack of cohesive determination methods thereof, this article proposes a parametric approach to complement an existing district-scale LCA workflow for residential buildings. The approach is applied to an exemplary residential district, using a Latin Hypercube Sampling (LHS) method, to establish a range of interior wall areas and resulting effects on LCA calculations. Thereafter, the outcome is compared with the results of a preexisting approach and validated project data. The novel method is capable of significantly reducing the tool’s overestimation of interior wall areas from 400% to a value between 7% and 53%. However, it is evident that the area estimation in terms of Life Cycle Inventory (LCI) needs to be complemented with a more accurate material setup, which could be differentiated by building archetypes.

Digital twins a digital transformation for management of the construction industry

In recent years technologies have been transforming working relationships in the construction industry. To dynamize the sector, new ways are sought to obtain better control over its lifecycle. The goals are to achieve cost savings, improvement in the quality of services, greater security and less environmental impact. Important information, to reach such goals, is generated during the project, the construction, the use/upkeep of assets. Nevertheless, this information is not used properly, because it requires participative management for the data to be kept updated and available in real time. A process that allows for this management right from the project-planning phase is Building Information Modeling (BIM). Its association with cloud-based communication platforms allows users to access all the data in real time. Allied to the resources of the Internet of Things (IoT), BIM makes it possible to transfer data to specific software that assist this information to remain alive during the whole lifecycle of the construction. The cloud-based platforms integrated to the BIM and the IoT, make it possible to digitalise and transfer the information related to the construction in real time, to create the Digital Twin (DT). With this DT all this information can be managed on one only digital platform which permits intelligent constructions and operational excellence in the sector. In this article, concepts relating to the creation of a DT are analysed by means of the Life Cycle Assessment (LCA) for buildings. A review of the literature was also carried out on the recent applications of the DT and, especially, in the construction industry. It became clear in the study that in recent years the DT is gradually being implemented in different sectors. Most of the research presents a review of the literature followed by small-scale experiments or case studies. It was found that the concept of DT has attracted the attention of the construction industry, and debate on the theme is developing rapidly in the academic sector, so as to establish the ways of effectively developing it in the construction industry.