Integrating Building Information Modeling and Life Cycle Assessment to Enhance the Decisions Related to Selecting Construction Methods at the Conceptual Design Stage of Buildings

Abstract

The construction industry, which is responsible for nearly 40% of global carbon emissions, is facing increasing pressure to adopt sustainable practices. Traditional construction methods often escalate resource depletion and waste generation, highlighting the need to prioritize sustainability. Life cycle assessment (LCA) is a significant tool for evaluating the environmental impacts of materials across different life cycle stages, yet its application is hindered by data complexities and uncertainties, particularly during the early design phases. Building Information Modeling (BIM) offers a transformative solution by centralizing and automating multidisciplinary data, thus streamlining LCA processes. This study addresses those existing gaps by proposing a structured methodology that integrates BIM with LCA to enhance their applicability during early design. The model leverages BIM’s capabilities to automate data extraction and enable real-time impact assessments by providing precise environmental evaluations of different construction methods. Focusing on modular prefabrication, 3D concrete printing, and conventional construction, this model comparatively evaluates environmental performance across different life cycle phases, highlighting distinct strengths and improvement areas. The Whole Building LCA reveals clear environmental differences, emphasizing modular construction’s substantial opportunities for enhancement to reduce critical impacts such as climate change and fossil depletion. This model supports decision-making, promotes circular economy principles, and aids the construction industry’s transition toward more sustainable practices.

1. Introduction

The rapid growth of the global population has significantly increased the demand for new buildings, intensifying environmental challenges in the construction industry [1]. As a sector responsible for nearly 40% of global carbon emissions, construction contributes heavily to resource depletion, environmental degradation, and climate change [2,3]. Addressing these challenges requires integrating sustainability into building design and construction to minimize environmental impacts, enhance resource efficiency, and support long-term resilience [4]. Sustainable design practices focus on optimizing energy and material use while minimizing the life cycle impacts on human health and the environment [5]. Studies suggest that sustainability in construction can be advanced by (i) employing emerging technologies in design, construction, and deconstruction; (ii) selecting environmentally responsible materials; (iii) managing life cycle costs effectively; and (iv) fostering greener, more affordable urban development [6]. However, industry fragmentation, market constraints, and resistance to change hinder the adoption of these strategies.

Sustainable design strategies and material selection are key factors in sustainable construction, as they significantly impact a building’s life cycle performance [7,8,9]. Sustainable construction methods of buildings have become essential alternatives due to the significant environmental challenges posed by conventional building construction, such as excessive resource consumption, waste generation, and high emissions [10]. Current advancements emphasize sustainable alternatives, notably modular prefabrication and 3D concrete printing [11]. Modular prefabrication, as a prominent off-site construction technique, significantly enhances sustainability through improved productivity, reduced waste, efficient resource use, and component reuse, addressing traditional industry challenges effectively [12,13,14,15,16,17]. Similarly, 3D concrete printing is emerging as a transformative construction technology, providing substantial sustainability benefits through increased design flexibility, reduced material consumption, and optimized resource efficiency [18,19,20,21,22]. Together, these innovative methods represent crucial steps toward achieving more resilient, sustainable, and efficient building practices within the construction industry.

Life cycle assessment (LCA), as defined by ISO 14040 [23] and ISO 14044 [24], is a globally recognized methodology for evaluating environmental impacts from raw material extraction to disposal [25,26,27,28]. LCA quantifies sustainability indicators such as greenhouse gas emissions, resource depletion, and waste generation, helping stakeholders to select materials with lower environmental footprints [29,30]. LCA is increasingly incorporated into early design stages to enhance decision-making, ensuring that material choices support sustainability and circular economy principles [31,32]. By promoting transparency and accountability, LCA aids in reducing emissions, minimizing waste, and optimizing resource efficiency [11]. Additionally, it provides essential data to advance sustainable building practices and drive construction innovation. Through LCA, stakeholders can identify opportunities for improvement, integrate energy-efficient and low-emission construction methods, and prioritize the use of recycled or low-impact materials [27,33].

Despite its benefits, conventional LCA methods are data-intensive and require extensive manual analysis. Standalone LCA applications are often constrained by assumptions, uncertainties, and data gaps, particularly in complex building systems [34]. The United Nations Environment Programme (UNEP) highlights the risk of biases in LCAs, emphasizing the need for improved accuracy and efficiency. To address these limitations of conventional LCA, Building Information Modeling (BIM) provides a digital framework that automates LCA data processing, improves analytical accuracy, and enhances sustainability assessments [35]. BIM integrates multidisciplinary project data into a unified model, facilitating stakeholder collaboration and embedding sustainability indicators within the design process [36,37,38]. It serves as a centralized platform for storing and analyzing material specifications; BIM simplifies the traditionally complex LCA process [39]. Its integration with LCA tools allows for real-time environmental impact evaluations, enabling informed decision-making and improving assessment reliability [37,38,39,40].

This study proposes an integrated BIM-LCA methodology designed to improve the efficiency of environmental performance decisions related to selecting construction methods at the conceptual design stage of buildings. Leveraging BIM’s digital capabilities, the approach optimizes sustainability evaluations, supports circular economy principles, and accelerates the transition toward more sustainable construction practices. The integration of BIM and LCA facilitates more precise and accessible environmental assessments, thereby promoting data-driven decision-making and advancing sustainability in the built environment.

2. Literature Review

Life cycle assessment (LCA) serves as a robust analytical framework for modeling complex systems, identifying environmental impacts, and enhancing manufacturing and construction processes [41,42]. LCA was initially developed in 1970 to evaluate resource trade-offs and pollution impacts, ever since it has evolved significantly, transitioning from a tool for incremental improvements to a comprehensive method for assessing the life cycle impacts of diverse products and services, including consumer electronics, biofuels, textiles, and agriculture [43]. In the construction industry, LCA is employed to evaluate the potential environmental impacts of design decisions, encompassing a comprehensive system boundary. This boundary includes the entire product life cycle, spanning from raw material extraction through to manufacturing, transportation, on-site construction, operation, maintenance, demolition, and end-of-life scenarios such as disposal, reuse, or recycling, which is a process commonly referred to as “cradle-to-grave” analysis, while evaluations that are solely focused on the stages from raw material extraction to manufacturing are termed “cradle-to-gate” assessments [44,45]. This approach assesses both inputs, such as materials and energy and outputs, which include waste and emissions. The Society of Environmental Toxicology and Chemistry (SETAC) defines LCA as an objective process to evaluate environmental burdens associated with a product, process, or activity by identifying energy and material usage and waste released, as well as to assess opportunities for environmental enhancements [9,46,47,48]. According to ISO 14044 standards, LCA methodology consists of four critical steps [48,49]. The first step includes the definition of goal and scope, which establishes the purpose of the study, delineates the system boundaries, and selects appropriate functional units to ensure that the study’s objectives are clearly defined. The second step embraces the life cycle inventory (LCI), which focuses on the systematic collection and analysis of data on all relevant inputs (e.g., raw materials and energy) and outputs (e.g., emissions and waste) across the product’s life cycle. The third step incorporates the life cycle impact assessment (LCIA), which evaluates the potential environmental impacts associated with the product based on the inventory data. Finally, the fourth step comprises the interpretation, which involves identifying significant issues, assessing the results to draw meaningful conclusions, explaining the study’s limitations, and providing actionable recommendations for improvement [47]. The methodology is essential to understand and address the embodied carbon emissions by identifying and analyzing strategies to minimize energy and resource consumption, as well as the environmental impacts of buildings’ materials throughout their life cycle. The initial phase is of particular importance, which is often referred to as the embodied energy stage that involves the extraction and manufacturing of raw materials and significantly contributes to a building’s overall embodied carbon emissions through processes such as material sourcing, production, and transportation [50,51]. LCA methodology is also utilized to quantify the impacts associated with embodied carbon in buildings, commonly referred to as greenhouse gas emissions, which is widely applied in the construction industry to evaluate emissions and their potential effects on climate change. This approach tracks emissions throughout the entire life cycle of a product or process and converts them into measurable metrics that reflect their environmental impact, with global warming potential (GWP) serving as a key metric to translate emissions into kilograms of CO₂ equivalent (kg CO₂e), often referred to as the carbon footprint [24,51,52,53]. Furthermore, LCA and circular economy principles have been fundamentally linked in addressing products or buildings’ carbon emissions throughout their life cycle. While LCA provides a robust analytical framework to quantify and assess the environmental impacts of materials and processes (ISO 14044:2006), circular economy concepts focus on enhancing resource efficiency, minimizing waste, and promoting material reuse [54]. The integration of these strategies was evaluated to measure and optimize the carbon footprint at every stage of a building’s life cycle by facilitating informed decision-making, encouraging design solutions that reduce embodied carbon, and offering a comprehensive approach to decarbonizing the construction sector [55]. This integrated approach allows for a systematic evaluation of the environmental impacts, facilitates the comparison of design alternatives, and offers critical insights for effective decision-making throughout a product’s life cycle. Within the construction sector, this analysis can be applied at four distinct levels: (i) building materials, to assess the environmental impacts associated with raw materials’ extraction and processing; (ii) building components, to evaluate assembled systems, such as walls and roofs; (iii) whole buildings, to analyze the entire life cycle, which includes the construction, operation, and demolition phases; and (iv) the building industry, to examine broader industrial impacts and emerging trends [56,57,58]. However, Simonen [59] highlighted the challenges associated with developing sustainable buildings, which led to a desire to understand the building’s structures and their construction method from a system-based perspective by recognizing the interconnected elements of a building’s life cycle and their environmental impacts. The EeBGuide handbook [60] addressed the inadequacies of adapting the LCA methodology with the same level of detail as other industries by proposing three distinct types of LCA studies tailored to evaluate a building’s environmental impact as follows: (i) screening LCA, which is designed for preliminary assessments to identify key environmental hotspots; (ii) simplified LCA, which provides a more focused analysis, balancing detail and practicality; and (iii) complete LCA, which offers a comprehensive evaluation across the entire life cycle [60]. The distinction between the three levels of LCA studies is guided and determined by several key criteria, such as the goal and scope of the assessment, the practitioner’s experience, the availability of relevant data, and the development stage of a building [61,62,63]. Moreover, ENSLIC guidelines (2010) provided a classification framework for practices used to divide the LCA into three levels, based on the practitioner’s expertise and tool complexity, which consist of (1) the basic level for beginners that uses simple tools like Excel for straightforward input–output calculations; (2) the intermediate level, which is for moderately experienced practitioners that employs specialized tools such as Athena’s Impact Estimator and EcoCalculator for more detailed yet user-friendly analyses; and (3) the advanced level, which is designed for experts, that utilizes sophisticated LCA software like Simapro version 7.3 and GaBi version 8.0 to conduct comprehensive assessments with complex data and advanced modeling [62,64].

Integrating the tools of LCA with those of BIM is an effective road map to apply sustainability within the AEC industry. That integration process allows designers to offer design alternatives within all potential variations and design parameters at the early stages of a project [48]. Moreover, that integration would help to calculate the environmental impact of materials in a BIM model, using tools such as Autodesk Revit©version 2020, permitting real-time LCAs during the design process. Some of the advantages of integrating BIM and LCA tools at the design stage include fast, easy, and accurate calculations, better collaboration, and cost efficiency [65]. Soust-Verdaguer et al. [62] highlighted the benefits of using BIM in the LCA study to include data availability, an effective assessment process, and user-friendly results.

Several studies have explored the theoretical framework for BIM-LCA integration by focusing on the methodological steps, development processes, and analytical results. Antón and Díaz [2] proposed two approaches to simplify the integration of BIM and LCA. The first approach is direct access to the information of the BIM model to calculate the LCA performance. In this approach, BIM models have been created during the early design phase as the primary source of information needed to conduct a complete life cycle assessment of buildings. Moreover, this approach helps to avoid manual tasks such as data re-entry, improving environmental performance, evaluating LCA methodology, and empowering decision-making. The second approach is to have the environmental properties of all the objects included in the BIM model. This approach entails the creation of a solid connection between BIM tools and the environmental life cycle assessment database. It motivates designers, architects, and engineers to incorporate the environmental criteria within the decision-making process. Röck et al. [16] utilized a Microsoft Excel-based LCA database with a BIM model that was developed in Autodesk Revit© to establish an automated connection between LCA and BIM tools by creating a custom script via using the visual scripting of the software Autodesk Dynamo version 2.10. Tsikos and Negendahl [66] proposed a method that consists of an integrated dynamic model. Their method uses Autodesk Revit© with an external material life cycle inventory (LCI) database connected via the visual programming language of Dynamo. Jalaei and Jrade [67] used a BIM-compatible plug-in tool that supports product suppliers’ web pages by cataloging green components and their environmental characteristics. Also, Ajayi et al. [68] introduced a BIM-enhanced LCA for a two-floor building that utilizes a 30-year life cycle period to conduct a variability analysis for the design and associated materials, whereas [69] developed a prototype tool that enables interactive analysis of a building’s model alongside its associated environmental impacts. Kreiner et al. [70] developed a methodology for building an environmental assessment based on LCA and acknowledged the integration of LCA with BIM to improve the sustainability performance of buildings.

Integrating BIM and LCA tools helps to quantify the environmental impact of the materials associated with the production, construction, operation, and end-of-life stages of various 3D models (namely modular, 3D concrete printing, and conventional buildings) at the conceptual design stage, including their impact categories such as global warming potential (GWP), energy consumption, water usage, resource depletion, and emissions across various life cycle stages, enabling more sustainable and informed decision-making in construction projects [63]. Modular prefabrication and 3D concrete printing construction continue to have the potential to improve the challenges associated with the traditional building construction method. Modular off-site prefabrication and BIM integration are identified areas that have prospects to drive efficiency and improvement for the construction industry [71]. Similarly, BIM has proven to be an effective method to facilitate the implementation of 3D printing in the construction industry, which can be employed for small- and large-scale buildings [72]. BIM can also facilitate data management in identifying building components that can be reused and/or recycled in advance, including the associated risk and cost of disposing of waste at the deconstruction phase of a building [73,74]. While advancements were made in the development of sustainability models, many of the existing models are predominantly based on the conventional design and on-site construction methods, and there are no existing integrated sustainability models that provide ways to select a sustainable design for various construction methods at the conceptual design stage.

Therefore, additional research is needed to address these gaps and to explore the impact of these methods used in the construction of buildings, with the integration of LCA and BIM to offer a robust framework for informed decision-making so as to achieve the sustainability goals throughout the life cycle of facilities, spanning from design to deconstruction. Therefore, this paper proposes the development of a model that integrates the framework of BIM-LCA as a pivotal tool for advancing sustainable practices, driving innovation and aiding decisions related to the selection of construction methods (i.e., conventional, modular, and 3D concrete printing) at the conceptual design stage of buildings. This integration ensures that critical factors such as embodied carbon, material reuse at the end-of-life, and overall environmental impacts are systematically considered. The benefits of such integration would (1) enable a comprehensive analysis of the entire life cycle of a building, identifying areas for improvement in resource efficiency and environmental performance; (2) provide stakeholders with the ability to explore innovative design alternatives, promoting the adoption of sustainable construction solutions; (3) offer real-time insights into environmental impacts, including immediate feedback on the implications of material and design choices; and (4) act as a shared platform for transparent environmental data, fostering collaboration and collective decision-making among project stakeholders.

3. Development Methodology

The main objective of developing the model is to automate the evaluation of the sustainability of all the building’s activities by assessing their life cycle environmental impact within a BIM environment starting from the materials’ production to the end-of-life, and to generate continuous feedback on LCA results for the three construction methods by using a computer model that integrates BIM and LCA. The goal is to provide a tool that will guide the design team in improving the environmental performance of buildings at the early design stage by using BIM tools (i.e., Autodesk Revit), the LCA tool, and a functional database. Therefore, the adopted methodological process focuses on the conceptual design stage of buildings, considering approximate quantities, size, shape, location, orientation, quantity estimation, and energy analysis. The systematic structure of the integrated model that couples BIM and LCA is built within the framework of ISO 14040 and utilizes goal and scope definition, inventory analysis, impact assessment, and interpretation phases. The model’s development methodology adheres to the standards’ framework and encompasses all the phases, as shown in Figure 1.

3.1. Phase 1—Define the Study’s Goal and Scope

The goal of this study is to establish a methodology to integrate LCA with BIM tools to evaluate the environmental performance of buildings based on the material flows and energy inputs and outputs, as well as to calculate the indicators. The scope of this study involves the assessment of energy efficiency, embodied carbon, water use, etc., for the whole building based on the afore-listed three construction methods, while the functional unit is 1 m² of gross floor area (GFA) per year over a 50-year study period. The starting step in the adopted methodology starts by creating conceptual design models. First, the conceptual design model is developed by using the design families stored in the BIM tool (Autodesk Revit©) for the three construction methods to create BIM models with information related to their sustainability. LCA-related information is also integrated into the characteristics of the buildings’ elements, encompassing their physical, thermal resistance, and functional attributes. The physical properties involve categorizing the elements by their type (e.g., wall, floor, roof), specifying their geometric dimensions and volumes, and identifying the construction materials employed (e.g., wood, steel, or concrete). The thermal transmittance (U-value) of a building’s element measures the rate of heat transfer through the material per unit area for the variation in every temperature between its sides. Lower U-values signify superior thermal performance, as they indicate reduced heat loss. This study determined the U-value by identifying all the material’s layers that comprise the element. The thermal conductivity (k), typically measured in W/m·K, was obtained from the material’s technical specification for each layer. The thermal resistance (R-value) for each layer was then calculated. Finally, the U-value was derived as the reciprocal of the total thermal resistance, including both internal and external resistances. The customized BIM model and the other related data used for the design and construction are extracted and linked with the life cycle inventory (LCI) for each building’s design. The integration of the LCA model follows a semi-automated approach, while the system boundaries covered in this study are materials’ production, buildings’ construction, operation, and end-of-life phases.

The materials’ production phase encompasses all the initial processes involved in acquiring the materials used to construct the building. It begins with extracting the raw materials from earth and continues until the products are manufactured and transported from the manufacturer to the building site. The core materials examined in this study include wood, concrete, and steel, which are commonly used in the construction of buildings. The quantity of each component is determined by calculating and analyzing the quantity takeoff extracted out of the BIM model. However, since this process takes place during the early design stage of the building, the impact of this phase is modeled by using a life cycle inventory database. This database contains unit environmental profiles for each relevant material and provides data on the emissions associated with thousands of substances, which are then aggregated into impact categories. The database of Ecoinvent was used as the life cycle inventory (LCI) reference to analyze the energy consumption in the production processes of these materials and their transportation.

The environmental impacts associated with the construction phase encompass various factors such as energy consumption, emissions resulting from fuel used by construction machinery, and the transportation of materials and workers based on the selected construction method. Since the availability of detailed information is limited during the conceptual design stage of buildings, the energy demands for these activities are estimated by assuming a uniform probability. However, this study adopted the results of Rezaei et al.’s study in 2019, who suggested using information collected from contractors, which proposed that the average electricity and diesel consumption per building area during construction is approximately 60 MJ and 15 MJ, respectively. For an additional assessment of the diesel and electricity consumption during the construction phase, the Ecoinvent inventory data are employed.

The operation and maintenance phase comprises various activities and processes that occur throughout the lifespan of a building. It is considered the most crucial stage in the building’s LCA. The maintenance requirements in this phase are influenced by factors such as construction type, materials used, machinery utilized, and the frequency of the maintenance activities. Therefore, it is vital to accurately consider the sources of the environmental impacts associated with this stage. Three major sources contribute to the environmental impacts during this phase, which are (1) energy consumed by household electrical appliances and lighting; (2) heating, ventilation, air-conditioning, and cooling (HVAC) systems; water usage; and (3) the replacement of materials throughout the building’s service life. The energy requirements for the operational stage are determined by using the DesignBuilder simulation integrated with the BIM tool (Autodesk Revit©).

The end-of-life stage includes all the activities related to the deconstruction and dismantling of the building once it reaches the end of its useful service life. During this phase, the environmental impacts are attributed to several factors. These include the use of machinery for building deconstruction and demolition, loading, hauling, and treatment of wasted materials. The management strategies employed in this stage typically involve options such as reuse, recycle, or dispose in a landfill. In addition, the transportation of materials to the landfill site is considered by assuming a travel distance of 30 km. On the other hand, recycled materials are transported to the recycling yard, assuming a travel distance of 25 km. Similarly, reusable materials are transported to a dedicated reusable material center, with an estimated travel distance of approximately 40 km.

3.2. Phase 2—Data Extraction and Integration

The second phase in the development methodology focuses on the data transmission between BIM and LCA tools. OpenLCA is the assessment tool used to establish a link between life cycle inventory (LCI) analysis data and BIM data, as per [75]. The necessary design’s data are automatically extracted from the BIM model and integrated into the developed functional database as an input for LCA data. LCI contains details about the resources flowing into a construction process and the emissions flowing from a process to air, soil, and water. In this process, the BIM tool (Autodesk Revit©) is applied to extract the materials’ quantities from the created BIM model(s) comprising various characteristics, which are transformed into a detailed bill of quantities (BOQs) and converted into an acceptable unit of measurement supported by the inventory database that is required to conduct the LCA for the different building elements for the three construction methods. Next, all the materials extracted from the BIM model are linked to a corresponding process, which is obtained from the Ecoinvent database in the functional database. Jointly with the results received from the energy simulation process, energy consumption and associated emissions during the operation stage and the other life cycle stages of buildings are considered as input for the operation energy demand. However, integrating the data between the BIM tool and the Ecoinvent database appears to be difficult due to the disparity between the specificity and level of detail in the BIM tool’s list of materials if compared to the Ecoinvent database. That list of materials lacks the same level of specificity, making direct integration a big challenge. These associated difficulties will be handled by using the RSMeans database to define the materials’ specifications. Following the recommendations derived from a study conducted by [76], for LCA at the conceptual design stage, this study considers the following building elements: floor, ceilings, doors, windows, exterior walls, interior walls, and roof. An average consumption of 60 MJ of electricity and 15 MJ of diesel per building area will be considered during the construction phase, while the energy consumed during the operation phase will be calculated by using the DesignBuilder version 7.02 software (using EnergyPlus version 9.4 dynamic simulation engine). The end-of-life phases are simplified by obtaining data from the literature.

3.3. Phase 3—Impact Assessment and Calculation

In the third phase, the life cycle impact assessment (LCIA) is conducted in OpenLCA version 1.10.2 schema to translate the findings of the life cycle inventory into the impact categories to enhance the comprehension and interpretation of results upon introducing all the required data for all the building’s stages, from raw materials’ extraction to end-of-life, from the functional database that connects the BIM tool’s data with LCA data. This study uses the ReCiPe(H) endpoint indicator method with the following categories: damage to human health, damage to ecosystems, and damage to resources, as shown in

Table 1. ReCiPe(H) endpoint impact categories method [75].

Impact Category Group	Name of the Impact	Hierarchist (H) *
Acidification	Terrestrial acidification	TAP100 EQ-H
Climate change	Climate change	GWP100 HH-H GWP100 EQ-H
Depletion of abiotic resources	Metal depletion Fossil depletion	MDP100 RD-H FDP100 RD-H
Ecotoxicity	Freshwater ecotoxicity Marine ecotoxicity Terrestrial ecotoxicity	FETP100 EQ-H METP100 EQ-H TETP100 EQ-H
Eutrophication	Freshwater	FEP100 EQ-H
Human toxicity	Human toxicity	HTP100 HH-H
Ionizing radiation	Ionizing radiation	IRP100 HH-H
Land use	Agricultural land occupation Urban land occupation Natural land transformation	ALOP100 EQ-H ULOP100 EQ-H LTP100 EQ-H
Ozone layer depletion	Ozone depletion	ODP100 HH-H
Particulate matter	Particulate matter formation	PMFP100 HH-H
Photochemical oxidation	Photochemical oxidant formation	POFP100 HH-H

* where H = Hierarchist (H); EQ = ecosystem; RD = resources; HH = human health.

, to assess the potential impacts of the three design/construction method types: conventional, modular, and 3D concrete printing, for the following impact categories: climate change; fossil depletion; freshwater ecotoxicity; human toxicity; ionizing radiation; marine eutrophication; metal depletion; particulate matter formation; photochemical oxidant formation; terrestrial acidification; and urban land occupation. The ReCiPe(H) framework provides a comprehensive and scientifically sound approach to evaluating the sustainability of various activities and focuses on impact assessment methods that are hierarchically organized by considering multiple levels of environmental impact categories. This approach allows for a detailed understanding of the potential consequences of human activities on the environment, ranging from local to global. Thus, scholars, policymakers, and business owners can gain valuable insights into the environmental implications of their choices and make informed decisions to promote more sustainable practices and reduce the ecological footprint.

3.4. Phase 4—Interpretation

The fourth phase is the final stage of the life cycle assessment (LCA) process. In this phase, the results of the life cycle impact analysis for the examined activity are visualized within the design environment of the BIM tool, facilitating a more comprehensive assessment of environmental performance for decision-making. Subsequently, these results undergo a comprehensive evaluation and comparison with other activities or existing studies to contextualize their significance. However, the interpretation process is inherently linked to this study’s specific objectives, which may vary based on the context of the application. This study concentrates on determining the contribution of each life cycle phase to the overall impact, assessing the impact of different comparing emissions and resource consumptions among various alternatives. Thus, this study focuses on comparing different construction methods, with specific attention given to the impact of the materials’ production stage to enhance the decision-making process at the conceptual design phase.

4. Model’s Development

The development of the model that integrates BIM and LCA is implemented through the creation of a new plug-in, an extension that adds new functionality to BIM tools, to help users assess the environmental impact associated with their design options and processes for building projects to enhance their sustainability and environmental impacts through life cycle assessments at the conceptual design stage. The development is centered on integrating BIM and LCA tools. OpenLCA v.1.10.2 from GreenDelta is used as the LCA tool and Autodesk Revit© is selected as the BIM tool. Autodesk Revit is the preferred BIM tool for this development because it empowers users to collaborate and encompasses every aspect of the building’s project with the ability to be integrated with analysis and assessment tools of diverse building elements. However, there is a lack of compatibility between the BIM tool and openLCA data; therefore, to support the interoperability with OpenLCA, a new plug-in is developed and implemented by customizing and extending its capabilities by using C# programming language. The APIs of Autodesk Revit© are customized to automate the associated tasks, such as integration and user interface modification, to aid users in analyzing the overall life cycle of a building during the conceptual design phase by providing a cradle-to-grave approach for assessing its environmental performance according to EN 15978 [77]. The model’s development process consists of two steps. The first step focuses on data processing and synchronization, where the construction material quantities are automatically extracted and systematically stored in a functional database for different building elements across the three building designs. This step ensures that the design data align with the requirements of the LCA application. Subsequently, the extracted data are linked with the life cycle inventory (LCI) data source from a functional database corresponding to each building design. Examples of LCI of material production for the three construction methods from openLCA used for the model data integration and development are shown in Figure 2.

The second step involves designing and developing the user interface. C# programming language alongside the Windows Presentation Foundation (WPF) are used to develop the interface. WPF, an integral part of the NET framework, which is supported by Visual Studio, offers a robust graphical framework for the user interface (UI). The utilization of WPF aims to provide a robust platform for creating interactive and dynamic user interfaces. It facilitates the segregation of the visual presentation and behavior of an application’s UI from its underlying logic, thereby streamlining the creation of sophisticated and visually appealing applications. Furthermore, C# is employed to script the backend application code, encompassing the logic, functionality, and integration rules governing the application’s behavior. This included the development of a new tab within Autodesk Revit© named COMMTH_LCA and the associated interface, as shown in Figure 3.

The interface’s design aims to achieve a smart and visually appealing interface that considers sustainability themes and ease of use. The development process begins with a thorough analysis of the user requirements of the model within the COMOTH process and with an understanding of the plug-in’s goals, functionalities, and needs. Thus, included in the COMOTH_LCA tab are run LCA button, building type selection, design option(s), LCA stages, data visualization (tables and charts), saving functionality, and intuitive user interfaces. Figure 4 shows the boundaries of the LCA system and the associated reports in graphical and tabulated formats so that the user can access them from within the developed model. The developed BIM-LCA model incorporates full functionality and operational buttons, such as building design options, 1–3 floors building, and a building above 3 floors. However, the 3D concrete printing design option is not compatible for a selection above the 3 floors. Hence, users must select (i) the 1–3 floor option for 3DCPrint design; (ii) three construction methods, namely conventional, modular, and 3D concrete printing; (iii) the generate button, which opens a window presenting the selection of life cycle stages (tables and charts); the LCA process will not be activated unless the building design option and construction method are both selected; (iv) the back button terminates the ongoing processes in the main window and returns to the intro window; (v) the about button provides users with a general introduction and background information to become familiar with the plug-in and interface sections; (vi) the exit button shuts off the model; and (vii) the control buttons provide the options to maximize, minimize, or close the user interface (UI). For instance, users can assess the life cycle environmental impact of the 3D concrete printing construction method by selecting the 1–3 floor design, 3DCPrinting method, and generate button.

5. Model Testing and Validation

The developed model is tested to verify its functionalities and capabilities for the evaluation of environmental impact and the selection of associated construction methods at the conceptual stage of design. Three-dimensional BIM design models for multiple-floor residential buildings with uniform windows were created at a level of detail (LOD) of 300 by using Autodesk Revit 2020 in an identical appearance and gross area, but they are different in relation to their construction materials and method, as shown in Figure 5. It is important to note that, typically, conceptual design models are created at LOD 100, but in this study, the case project’s model(s) was/were upscaled to LOD 300 to enable the building’s layers and textures for the required calculations, analysis, and simulations to be adequately defined. These case projects aim to test and verify the workability, functions, and performance of the integrated model. The buildings are intended to be constructed in Ottawa, ON, Canada, with a total gross area of 7650 ft² and are currently under design. To accurately present the characteristics of each building, its associated materials are customized with additional parameters that define their identity, appearance, graphics, and physical and thermal properties.

The design of the building’s components involves multiple materials’ layers, each contributing distinctively to the overall performance and visual character of the component. In the context of Revit modeling, these elements are typically represented as a single entity that incorporates multiple material properties. Figure 6 explains the materials’ layers for the modular construction method, highlighting their associated thermal transmittance.

This representation offers a detailed and reliable depiction of the construction process, capturing both the physical and thermal aspects crucial for building an environmental assessment. The details of the material layers and the Quantity Takeoffs (QTOs) for the design of the various construction methods are shown in

Table 2. Details of the material QTOs and layers of the design models.

Family Category	QTOs (m2)	Conventional Construction			Modular Construction			3D Concrete Printing
		Material	Thickness (mm)	U-Value (W/m2 K)	Material	Thickness (mm)	U-Value (W/m2 K)	Material	Thickness (mm)	U-Value (W/m2 K)
FLOOR	576	Wood flooring Floor tiles Sheathing—OSB Batt insulation Wood joist/rafter	15 15 50 50	0.448	Steel joist floor Vinyl composite tile Wood—sheathing Rigid insulation Steel bar joist layer Wood—sheathing	15 15 50 100 15	0.328	Precast concrete floor slabs Floor finish tile Precast slab	15 100	0.338
WALL	540	Brick veneer wall on wood Brick veneer Wall sheathing—OSB Air gap Wall insulation Wood—stud Gypsum board	20 15 10 100 100 12	0.341	Sandwich panel on mtl. stud Metal panel Rigid insulation Stud layers Metal panel Gypsum board	2.5 80 100 2.5 12	0.268	3DC printing exterior wall Printed concrete (inner layer) Insulation—spray form Printed concrete (outer layer)	50 50 50	0.361
	751	Interior wall Gypsum, board Wood—stud layer fiberglass batt Gypsum, board	12 50 20 12	0.250	Modular sandwich panels Gypsum wall board Metal stud layer Semirigid insulation Gypsum board	12 25 25 12	0.227	3DC printing interior wall Printed concrete Insulation—spray form Printed concrete	25 25 25	0.181
ROOF	200	Asphalt shingle on wood rafters Rigid insulation Wood joist/rafter Sheathing—OSB Water/vapor barrier Asphalt shingle	100 50 15 6 3	0.213	Steel truss on metal standing seam Metal—Sheeting Rigid insulation Steel structure Vapor barriers Metal seam	6 100 25 10 25	0.370	Asphalt shingle on wood rafters Rigid insulation Wood joist/rafter Sheathing—OSB Water/vapor barrier Asphalt shingle	100 50 15 6 3	0.213

.

The conventional conceptual design employed in this case study consists of the assembly of a brick veneer/wood frame from exterior to interior; this structure includes brick veneer cladding, a drainage cavity, moisture barriers, oriented strand board (OSB), insulation within the stud cavities, a vapor barrier, and gypsum panels. The core structural system consists of wood studs, which offer essential support and structural integrity. Utilizing a wood frame system provides considerable flexibility, enabling straightforward design customization or modifications. In contrast, the modular prefabrication approach incorporates a rigid steel frame made of metal studs designed using Cold-Formed Steel (CFS), compliant with the specifications outlined in BS 5950-1:2000 [78] and the technical framework described in [79]. The floor slab is proposed as a composite steel corrugated decking supported by purlins spaced at one-meter intervals. The exterior elements are thermally insulated sandwich panel walls, while interior walls utilize fire-resistant gypsum and insulation. With the modular structural system, we aimed to achieve a weight range of approximately 35 to 50 kg/m², consistent with the guidelines for low-rise steel structures between two and six stories, as indicated by [18]. The 3D concrete printing methodology aligns with the process suggested in [80]. The structure is anticipated to be printed by Nidus3D, an Ontario-based company employing COBOD’s BOD 2 gantry system printer along with Lafarge Canada’s environmentally friendly OneCem concrete paste. The printer equipment will be transported from Kingston, Ontario. The method involves the construction of load-bearing walls without the inclusion of a steel reinforcement. Consequently, only the internal and external walls will be 3D-printed and serve as effective load-bearing walls.

However, the only printed components of the structure will be the interior and exterior walls, since they serve as effective load-bearing walls without requiring additional reinforcement. Additionally, precast hollow-core panels will be used for slabs, as they are subjected to bending, eliminating the need for formwork. Finally, the scope testing and verification focuses on evaluating and justifying environmental sustainability indicators and associated criteria across the three described construction methods, including their impact categories for addressing sustainability in a building.

Users can use the developed model to evaluate the environmental footprints/impacts associated with the materials’ production, construction, building operation, and end-of-life for their design via a newly created plug-in in the BIM tool (i.e., Autodesk Revit©) named COMOTH_LCA to access the user interface. To start, users must select the number of floors for the building under design by selecting from either 1–3 floors or above 3 floors. After that, they must specify the construction method, the life cycle stage, and the result format before clicking on the generate button, as depicted in Figure 7. It is important to note that the same process applies to the three construction methods. For example, users assess the environmental impact of the materials’ production stage for various construction methods by choosing the “material production” from the dropdown menu of the life cycle stages, selecting the format of the desired result, and initiating the analysis is achieved by clicking the run button to generate the final report. The impact report of the materials’ production stage is depicted in Figure 8 as a table report, while Figure 9 illustrates the same data in a graphical format. In addition,

Table 3. Environmental impact (EI) comparison of materials’ production.

Impact Category	Reference Unit	3DCPrinting	Conventional Construction	Modular Construction
climate change—GWP100	kg CO2-Eq	210,160.47	136,965.92	374,750.32
fossil depletion—FDP	kg oil-Eq	54,765.60	38,489.79	106,749.04
freshwater ecotoxicity—FETPinf	kg 1,4-DCB-Eq	2360.37	1641.23	15,545.78
human toxicity—HTPinf	kg 1,4-DCB-Eq	76,208.03	62,810.39	169,141.51
ionizing radiation—IRP_HE	kg U235-Eq	8846.69	6523.82	19,542.24
marine eutrophication—MEP	kg N-Eq	201.51	164.77	383.33
metal depletion—MDP	kg Fe-Eq	25,808.55	5863.36	426,604.03
ozone depletion—ODPinf	kg CFC-11-Eq	0.01	0.01	0.02
particulate matter formation—PMFP	kg PM10-Eq	468.74	358.59	1330.11
photochemical oxidant—POFP	kg NMVOC	675.78	520.23	1297.19
terrestrial acidification—TAP100	kg SO2-Eq	911.08	717.84	1802.38
urban land occupation—ULOP	m2a	3388.30	17,773.20	5284.88

shows a detailed comparison of the environmental impacts of the three construction methods, highlighting that modular construction has the highest impact, followed by 3D printing, whereas conventional construction exhibits the lowest impact at the materials’ production stage.

To evaluate the environmental impact of the construction stage, the averages of electricity and diesel consumptions are approximately estimated to be at 60 MJ and 15 MJ, respectively, per building area. Ecoinvent inventory data are referenced to assess the diesel and electricity consumptions during the construction stage. Users can assess the impact of the construction stage for various construction methods by selecting “Building construction” from the dropdown menu of the life cycle stages, specifying the desired format of the results, and initiating the analysis by clicking on the run button to generate the final report, as shown in Figure 10. Comparing the impacts for the building construction stage, it shows that 3D concrete printing presents the highest impact, followed by conventional construction, whereas modular construction displays the lowest impact during this stage, as illustrated in

Table 4. Environmental impact comparison of building’s construction.

Impact Category	Reference Unit	3DCPrinting	Conventional Construction	Modular Construction
climate change—GWP100	kg CO2-Eq	2124.41	1142.00	870.90
fossil depletion—FDP	kg oil-Eq	719.27	389.64	309.64
freshwater ecotoxicity—FETPinf	kg 1,4-DCB-Eq	13.38	6.52	36.78
human toxicity—HTPinf	kg 1,4-DCB-Eq	631.663	291.84	307.19
ionizing radiation—IRP_HE	kg U235-Eq	10,936.39	5473.10	3702.02
marine eutrophication—MEP	kg N-Eq	4.269	2.92	1.19
metal depletion—MDP	kg Fe-Eq	114.17	59.03	314.66
ozone depletion—ODPinf	kg CFC-11-Eq	0.00	0.00	0.00
particulate matter formation—PMFP	kg PM10-Eq	4.29	2.80	17.08
photochemical oxidant—POFP	kg NMVOC	11.89	8.29	6.11
terrestrial acidification—TAP100	kg SO2-Eq	8.87	5.68	3.61
urban land occupation—ULOP	m2a	14.02	12.25	13.71

.

The environmental impacts during the operation stage of buildings primarily stem from three major sources: energy consumed by households, water usage, and materials’ replacement. The energy requirements for the operational stage are determined from the DesignBuilder simulation tool, while the materials’ replacement is estimated by using R.S. Means online cost data, and both are integrated with the BIM tool (Autodesk Revit©). Consequently, users can evaluate the impact of the operation stage for different construction methods by selecting “Building operation” from the dropdown menu of the life cycle stages, specifying the format of the desired result, and executing the analysis by clicking the run button to generate the final report, as illustrated in Figure 11. The result shows that this stage has the highest impact among all the life cycle stages, with modular buildings having the least impact, followed by conventional construction, and 3DCP showing the highest impact when compared among the three construction methods, as illustrated in

Table 5. Environmental impact comparison of building’s operation.

Impact Category	Reference Unit	3DCPrinting	Conventional Construction	Modular Construction
climate change—GWP100	kg CO2-Eq	1,150,032.91	1,130,020.31	1,084,769.99
fossil depletion—FDP	kg oil-Eq	452,756.16	444,596.45	426,979.33
freshwater ecotoxicity—FETPinf	kg 1,4-DCB-Eq	3396.87	3406.97	3197.07
human toxicity—HTPinf	kg 1,4-DCB-Eq	73,670.68	74,522.31	69,767.31
ionizing radiation—IRP_HE	kg U235-Eq	417,249.81	417,892.77	416,641.04
marine eutrophication—MEP	kg N-Eq	228.11	227.91	215.46
metal depletion—MDP	kg Fe-Eq	15,316.13	15,454.30	14,463.57
ozone depletion—ODPinf	kg CFC-11-Eq	0.14	0.14	0.14
particulate matter formation—PMFP	kg PM10-Eq	439.56	436.99	414.89
photochemical oxidant—POFP	kg NMVOC	1203.42	1186.43	1136.41
terrestrial acidification—TAP100	kg SO2-Eq	1048.36	1039.54	990.36
urban land occupation—ULOP	m2a	1249.49	1244.54	1182.19

.

The major consideration for end-of-life impacts is the equipment for loading and hauling the wasted materials during the building’s deconstruction or demolition involving activities such as reuse, recycle, or dispose in a landfill. Transporting and handling all the materials to various facilities at different sites are considered via the circular economy model by using a travel distance of 30 km. On the other hand, recycled materials are transported to the recycling yard with a travel distance of 25 km. Similarly, reusable materials are transported to a dedicated reusable materials center, with an estimated travel distance of approximately 40 km. Users can assess the associated environmental impacts by selecting “Building End-of-life”, as shown in Figure 12. Moreover,

Table 6. Environmental impact comparison of building’s end-of-life stage.

Impact Category	Reference Unit	3DCPrinting	Conventional	Modular
climate change—GWP100	kg CO2-Eq	5790.46	4204.42	4282.19
fossil depletion—FDP	kg oil-Eq	2272.35	805.45	1675.85
freshwater ecotoxicity—FETPinf	kg 1,4-DCB-Eq	21.84	13.17	15.85
human toxicity—HTPinf	kg 1,4-DCB-Eq	1773.83	1307.68	1269.97
ionizing radiation—IRP_HE	kg U235-Eq	460.56	167.93	338.46
marine eutrophication—MEP	kg N-Eq	11.65	4.39	9.06
metal depletion—MDP	kg Fe-Eq	175.80	107.13	130.68
ozone depletion—ODPinf	kg CFC-11-Eq	0.00	0.00	0.00
particulate matter formation—PMFP	kg PM10-Eq	14.41	5.40	10.94
photochemical oxidant—POFP	kg NMVOC	37.33	12.89	28.87
terrestrial acidification—TAP100	kg SO2-Eq	25.19	8.97	19.25
urban land occupation—ULOP	m2a	526.60	−151.41	374.29

provides users with a detailed comparison of the three construction methods. Toward the end, the overall impact of the entire building can be evaluated by choosing the “Whole Building LCA” option, as shown in Figure 13, and then be compared across the three construction methods, as described in

Table 7. Whole building’s environmental impact comparison.

Impact Category	Reference Unit	3DCPrinting	Conventional	Modular
climate change—GWP100	kg CO2-Eq	1,368,108.24	1,272,332.62	1,464,673.40
fossil depletion—FDP	kg oil-Eq	510,513.37	484,281.33	535,713.86
freshwater ecotoxicity—FETPinf	kg 1,4-DCB-Eq	5792.46	5067.89	18,795.48
human toxicity—HTPinf	kg 1,4-DCB-Eq	152,284.20	138,932.19	240,485.98
ionizing radiation—IRP_HE	kg U235-Eq	437,493.44	430,057.63	440,223.76
marine eutrophication—MEP	kg N-Eq	445.54	399.99	609.04
metal depletion—MDP	kg Fe-Eq	41,414.64	21,483.82	441,512.94
ozone depletion—ODPinf	kg CFC-11-Eq	0.15	0.15	0.16
particulate matter formation—PMFP	kg PM10-Eq	927.01	803.77	1773.02
photochemical oxidant—POFP	kg NMVOC	1928.42	1727.84	2468.58
terrestrial acidification—TAP100	kg SO2-Eq	1993.50	1772.03	2815.60
urban land occupation—ULOP	m2a	5178.40	18,868.58	6855.07

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6. Discussion

6.1. Model Evaluation and Comparative Analysis

The model that has been developed in this study empowers designers to make swift and informed decisions while selecting materials with minimal environmental impact during the early design stages of building projects. The model represents a notable advancement in integrating BIM and LCA to evaluate the environmental impacts of construction processes by addressing compatibility challenges between the BIM tool (Autodesk Revit) and LCA tool (OpenLCA); the model incorporates customized functionalities that make the assessment of three distinct construction methods easily accessible through an interactive user interface (UI). The developed model facilitates a seamless workflow for practitioners at the conceptual design stage, offering stakeholders versatile resources to evaluate and compare the environmental impacts across various scenarios.

The said model serves as a decision support framework for assessing the sustainability of construction projects, seamlessly integrating the BIM tool (Autodesk Revit) for 3D design modeling, data analysis, evaluation, collaboration, and output visualization. The BIM tool’s capabilities are enhanced through automation to enable the extraction of materials’ quantities for life cycle assessments from the database management system (DBMS) that stores all the collected 3D design families and retrieves them afterward when needed. OpenLCA functions as the backend system, processing the data extracted from the BIM model and linking it with life cycle inventory (LCI) datasets to perform comprehensive environmental impact analyses. The Ecoinvent database is also incorporated into the model to ensure efficient access to reliable and detailed inventory data. By evaluating the environmental impacts across multiple categories, the model provides a holistic perspective on the sustainability of various construction methods.

Nevertheless, testing and comparing the developed model’s output to an actual project are challenging due to the scarcity of data on real projects that have utilized 3D concrete printing techniques and design for deconstruction (DfD) principles in conjunction with modular prefabrication. In addition, the existing models presented in the literature predominantly emphasize traditional construction practices that involve conventional design approaches and on-site building techniques. Furthermore, their methodology for the integration of BIM with off-site manufacturing techniques, such as modular building systems or 3D printing, tends to mainly focus on contrasting these innovative methods against traditional construction approaches. These comparisons usually aim to validate the sustainable performance of these methods by evaluating specific design parameters or illustrate BIM’s potential advantages when applied to prefabricated methods. Hence, the current study has developed and tested an integrated model specifically to ensure its practical effectiveness and usability regarding data input, operational application, and the generated output. Furthermore, one can better understand the correctness of the model presented in this study by comparing it with existing models found in the literature that integrate BIM with LCA tools during the conceptual design phase, such as [31,38,58,66,67,68,69,81,82]. This comparative approach underscores several key advantages of the model: (1) its ability to evaluate the environmental impacts across the life cycle stages of three distinct construction methods; (2) its capability to integrate various methods, including conventional, modular, and 3D concrete printing; (3) its capacity to efficiently assess the environmental impacts of building designs for both 1–3 floors and those exceeding 3 floors by utilizing the three construction methods; and (4) its potential to provide designers with readily accessible predefined data, facilitating swift and informed decision-making throughout the design process.

6.2. Evaluation of the Life Cycle Impact Results Across the Different Construction Methods

The developed model provides an impact analysis report of the three construction methods, 3D concrete printing (3DCP) and conventional and modular construction, across various life cycle stages and environmental impact categories. The environmental impacts associated with the production of materials vary significantly across the three construction methods. For instance, in the climate change category (GWP100), modular construction has the highest global warming potential (374,750.32 kg CO₂-eq), followed by 3D concrete printing (3DCP) at 210,160.47 kg CO₂-eq and conventional construction at 136,965.92 kg CO₂-eq. A similar trend is observed for fossil depletion (FDP), where modular construction exhibits the most significant impact (106,749.04 kg oil-eq). However, in other impact categories, 3DCP consistently outperforms modular construction but has a greater impact than conventional construction in categories such as human toxicity and terrestrial acidification. During the construction phase, the environmental impacts are relatively lower but still significant. Modular construction demonstrates the least impact, with 870.90 kg CO₂-eq, followed by conventional construction at 1142.00 kg CO₂-eq. In contrast, 3D concrete printing (3DCP) exhibits the highest impact, reaching 2124.41 kg CO₂-eq for global warming potential. A similar trend is observed in the ionizing radiation category, where 3DCP imposes the greatest environmental burden. However, modular construction again outperforms the other methods in the particulate matter formation category.

The operational phase has the highest environmental impact among all life cycle stages. However, modular construction demonstrates the lowest burden, with a global warming potential of 1,084,769.99 kg CO₂-eq, compared to 3DCP at 1,150,032.91 kg CO₂-eq and conventional construction at 1,130,020.31 kg CO₂-eq. Similarly, modular buildings consistently show the lowest environmental impact across other impact categories in all measured aspects. The end-of-life stage reveals significant impacts from material handling, transportation, and recycling. In terms of global warming potential, conventional construction demonstrates the lowest impact at 4204.42 kg CO₂-Eq, while 3D concrete printing (3DCP) shows the highest impact at 5790.46 kg CO₂-Eq. In relation to metal depletion, modular construction has lower impacts than 3DCP but still exceeds conventional construction.

The comparative Whole Building LCA reveals significant environmental differences among the three construction methods analyzed. Modular construction exhibited notable impacts in several critical assessment areas, including climate change (1,464,673 kg CO₂-eq), fossil depletion (535,714 kg oil-eq), freshwater ecotoxicity (18,795 kg 1,4-DCB-eq), human toxicity (240,486 kg 1,4-DCB-eq), metal depletion (441,513 kg Fe-eq), and terrestrial acidification (2816 kg SO₂-eq). Conventional construction demonstrates notably lower environmental impacts in most categories—such as climate change (1,272,333 kg CO₂-eq), fossil depletion (484,281 kg oil-eq), and human toxicity (138,932 kg 1,4-DCB-eq)—but significantly higher urban land occupation (18,869 m²a). The 3D printing approach offers intermediate impacts across the categories, with climate change (1,368,108 kg CO₂-eq), fossil depletion (510,513 kg oil-eq), and urban land occupation (5178 m²a), making it a promising alternative for balanced sustainability outcomes. The comprehensive result of this assessment shows that each construction method has unique environmental strengths and weaknesses. For instance, modular construction offers operational efficiency but requires improvement in materials’ production and end-of-life stages. 3DCP, while innovative, requires optimization in terms of its operational and end-of-life processes. The construction stage analysis also highlights the nuanced trade-offs between methods. Modular construction’s lower operational energy demand during assembly translates to minimal impacts compared to conventional and 3D printing methods. However, the end-of-life stage reveals notable efficiencies in 3D printing due to reduced material wastage and streamlined deconstruction processes.

7. Conclusions

A key accomplishment of developing the integrated model is the creation of a new plug-in, which enhances its seamless interoperability, achieved through customized APIs and C# programming, which enable automatic data extraction and integration across various tools. This innovation eliminates the need for manual data entry and error-prone processes, ensuring that design, construction, operational, and end-of-life material and process information are accurately aligned with LCA requirements. The user interface was designed using Windows Presentation Foundation (WPF), which offers an intuitive and accessible platform, making it user-friendly and suitable for widespread adoption by industry professionals. The integration of BIM and LCA highlights their combined potential as complementary tools, enhancing the decision-making process during the early design stages when the majority of sustainability impacts are considered, determined, and incorporated into the building. Furthermore, the plug-in’s inclusion of end-of-life impact assessments aligns with circular economy principles by encouraging recycling, reusing, and sustainable disposing practices. The findings in adopting this process indicate that modular construction, with its steel-intensive components, achieves lower end-of-life impacts due to the established recycling pathways. In contrast, conventional construction’s reliance on mixed-material components presents challenges for recycling efficiency. The ability to simulate transportation impacts further enhances the tool’s utility in promoting localized and sustainable waste management strategies.

The BIM-LCA integrated model offers significant potential to revolutionize sustainable construction practices by providing stakeholders with reliable, data-driven insights. By comparing conventional, modular, and 3D concrete printing methods, the model facilitates tailored strategies to minimize environmental impacts while ensuring cost efficiency. However, its scope is currently limited to the impact categories associated with the life cycle stages of these construction methods. It does not extend to evaluating the environmental impacts of individual construction materials used in various building designs. Future iterations could integrate emerging technologies, such as machine learning, to enhance the precision of impact predictions and improve compatibility with a broader range of LCA databases. Moreover, incorporating social sustainability metrics, such as occupant well-being and community impacts, could provide a more comprehensive evaluation framework. Expanding the developed model to include additional data and analyses related to BIM and sustainability applications (such as CO₂ emissions accounting, decarbonization strategies, net-zero carbon goals, resilience, and climate adaptation) would address key areas of focus in sustainable construction practices and offer valuable insights for advancing the field of sustainability.

In conclusion, the developed BIM-LCA model provides a scalable and practical solution for addressing the construction industry’s sustainability challenges regarding the environmental impact of various construction methods. Its ability to simulate and compare impacts across life cycle stages empowers decision-makers to make informed choices, paving the way for more environmentally responsible building practices. This integration of advanced technologies represents a critical step toward achieving global sustainability goals in the built environment.