Life cycle assessment of an underground car park's retaining walls

A life-cycle impact assessment of hardwood resources across the eastern United States was conducted based on the life-cycle inventory data for hardwood forest resource management and was integrated with the Forest Vegetation Simulator (FVS). This integration allowed for the analysis of forest carbon dynamics in the four subregions: northeast (NE), mid-Atlantic (MA), southeast (SE), and northcentral (NC). The system boundary was selected to be consistent with the A1 module (extraction and upstream production) required by an Environmental Product Declaration (EPD) for wood products. The results indicated that uneven-aged management (UA) yielded higher carbon stocks than even-aged management (EA) across all subregions. In contrast, clearcutting under EA resulted in higher carbon removal. Fuel consumption-related greenhouse gas (GHG) emissions for manual and mechanized harvesting systems for both management practices ranged between 9.13 and 12.15 kilograms of CO2 equivalent per cubic meter (kg CO2e/m3), with an average of 11 kg CO2e/m3 of hardwood timber harvested across all subregions. It was estimated that 63-187 megajoules (MJ) of energy were needed to produce 1 m3 of hardwood sawlogs. The extraction and loading processes contributed more to the total GHG emissions than the felling and processing within the system boundary. The study concluded that UA led to higher forest carbon and net carbon balance (excluding carbon stock) compared to EA in the eastern U.S. hardwood forests. Forest management practices should be determined based on the ecological goal of increasing forest carbon stock and the economic goal of maximizing timber production. The findings of this study have implications for policymakers and forest managers in mitigating climate change and enhancing carbon sequestration through sustainable forest management practices for timber production. The Life Cycle Assessment (LCA) was used to assess the environmental impact of hardwood cross-laminated timber (CLT) production in the eastern United States. CLT is an emerging sustainable construction material with the potential to replace concrete. LCA has been widely applied to quantify the environmental impact of CLT materials and buildings. However, current research on CLT LCA mainly focuses on softwoods, lacking reports on hardwood CLT. Despite the less frequent utilization of hardwoods by CLT manufacturers, hardwood CLT is technically feasible and provides value-added uses for low-quality timber. This study developed a cradle-to-gate life cycle modeling framework for the production of hardwood CLT in the eastern United States to address this research gap. The framework integrates process-based modeling of log production, lumber production, and CLT production and explores

The current decarbonisation scenario demands a decrease in embodied and operational environmental impacts of buildings, wherein the Life Cycle Assessment (LCA) method and the Environmental Product Declaration (EPD) play a crucial role. The main objective of EPDs is to provide validated and geographically representative data to conduct LCA, since they play a major practical role in the application of LCA. However, development of EPDs in the European context remains irregular. Several countries, such as Germany and France, have a great number of EPDs of construction products, while other countries, such as Spain, present a much lower number. This study aims to analyse the existing EPDs of construction products developed in Spain, and to identify the EPD programs, the type of products (building system or element-associated), which LCA information modules are included, and the accuracy of the declared impact values. The results obtained show that ceramic cladding, gypsum plasterboard, cement, and clay products are those with the greatest number of EPDs. On the other hand, building service products have relatively few EPDs. Finally, several recommendations are proposed towards improving EPD development and challenges are detected.

The building sector has seen recent growth in the number of published environmental product declarations (EPDs). EPDs share environmental data of construction materials, which can help building practitioners prioritize products with lower environmental impacts. However, EPDs rely on varying assumptions within their life cycle assessment (LCA). This study aimed to evaluate the use of EPDs as a data source instead of a generic data source and its effect on the life cycle impacts of a multi-residential building. This study focused on 19 North American EPDs of structural wood products. The impact assessment results found in the EPDs were compared to the Ecoinvent V3.8 database. The findings of the present study suggest that EPDs can generally be used without distinction compared to the data in the Ecoinvent V3.8 database. However, a few data were found to be outliers. In addition, EPDs of structural wood products only disclosed its manufacturing stage. Other life cycle stages, such as transport of the construction product, can have a significant impact on the building’s LCA. Therefore, using EPDs to assess building impacts is recommended over their direct comparison for practitioners to make more comprehensive decisions towards embodied impacts of buildings.

District heating (DH) is a proven heat generation and distribution technology that enhances energy efficiency and reduces carbon emissions at scale, making it a key component of sustainable energy strategies. Compared to traditional heat generation methods such as using onsite fossil-fuelled combustion boilers or electrically driven heating systems, DH offers superior environmental advantages, particularly when renewable energy and waste heat are deployed as primary fuel energy mix. To comprehensively evaluate the sustainability of DH, life cycle assessment (LCA) is widely adopted to determine environmental impacts across all life cycle stages, from material extraction to disposal. This systematic review identifies the absence of a unified, adaptable framework for LCA application in DH systems. To address this, the study proposes a structured multi-level framework, interpreting methodological diversity across component, facility, and network levels. Component-level studies offer insights into specific technologies and materials; facility-level assessments focus on operational performance and energy sources; network-level evaluations provide holistic system impacts. Aligning studies within these analytical levels enables fairer comparisons, supports cross-regional learning, and promotes methodological integration. Recurring challenges include inconsistent methodologies, varying system boundaries, and limited local data. Emerging technologies such as hybrid systems, smart grids, and energy storage remain underrepresented in LCA studies. Tools like SimaPro, GaBi, and OpenLCA are widely used, yet the rapid evolution of DH systems calls for more tailored applications. This review supports the development of standardised, yet flexible LCA practices and proposes a refined multi-level framework to guide comprehensive, context-specific evaluations. It emphasises the importance of validating approaches across diverse contexts and strengthening LCA’s contribution to the design of sustainable, low-carbon DH solutions for urban energy systems. Multi-level LCA approach categorises DH systems into component, facility, and network levels. Current LCA research on DH systems focuses on Europe, with gaps in Asia and the US. Tools like SimaPro, GaBi, and OpenLCA support detailed LCA analyses of district heating. LCA for DH systems faces challenges like data gaps, system boundaries, and variability. The proposed workflow enables tailored, actionable LCA assessments for diverse DH systems.

The use of wood and timber products in the construction of buildings is repeatedly pointed towards as a mean for lowering the environmental footprint. With several countries preparing regulation for life cycle assessment of buildings, practitioners from industry will presumably look to the pool of data on wood products found in environmental product declarations (EPDs). However, the EPDs may vary broadly in terms of reporting and results. This study provides a comprehensive review of 81 third-party verified EN 15804 EPDs of cross laminated timber (CLT), glulam, laminated veneer lumber (LVL) and timber. The 81 EPDs represent 86 different products and 152 different product scenarios. The EPDs mainly represent European production, but also North America and Australia/New Zealand productions are represented. Reported global warming potential (GWP) from the EPDs vary within each of the investigated product categories, due to density of the products and the end-of-life scenarios applied. Median results per kg of product, excluding the biogenic CO2, are found at 0.26, 0.24, and 0.17 kg CO2e for CLT, glulam, and timber, respectively. Results further showed that the correlation between GWP and other impact categories is limited. Analysis of the inherent data uncertainty showed to add up to ±41% to reported impacts when assessed with an uncertainty method from the literature. However, in some of the average EPDs, even larger uncertainties of up to 90% for GWP are reported. Life cycle assessment practitioners can use the median values from this study as generic data in their assessments of buildings. To make the EPDs easier to use for practitioners, a more detailed coordination between EPD programs and their product category rules is recommended, as well as digitalization of EPD data.

The built environment is responsible for reaching global climate targets such as the Paris agreement and carbon neutrality in 2050. It is a well-known fact that buildings stand for 37% of global greenhouse gas (GHG) emissions, where 10% is due to emissions from the production of building materials, while the remaining 27% comes from energy consumption [1]. The awareness of the major contribution to global GHG emissions from the built environment has enabled a great interest in developing more sustainable buildings, reducing the contribution to GHG emissions, and conducting life cycle assessments (LCA) of buildings in Denmark. In March 2021 a national strategy towards more sustainable buildings was introduced, which requires an LCA of new buildings, and compliance with the limit value of 12 kg CO2e/m2/year for new buildings with > 1000 m2. The strategy underlines the urgency of educating the Danish construction sector in conducting LCAs of new buildings and gaining knowledge in environmental product declarations (EPD) available for the Danish sector to apply. Eventually, this will enable more specific and transparent LCA results of Danish buildings. We investigate the availability and applicability of EPDs from a Danish perspective in the first part of the study, and in the second part, we investigate the influence on LCA results when applying industry- or product-specific data instead of generic data (Ökobau 2020 II). Three exterior wall types A, B and C are outlined based on the same U-value, and generic data are replaced with EPD data. The results show the various combinations possible with applying the EPD data. Secondly, the LCA results are highly dependent on the chosen materials and their corresponding EPD data.

Transparent and credible environmental labeling of products is vital for a sustainable future. Ecolabeling shows information on the environmental performance of products, processes, and services. This article focuses on one type of ecolabeling referred to as environmental product declarations (EPDs) that provide environmental impact information based on life cycle assessment (LCA) data. Businesses and consumers who are not familiar with life cycle analysis can use LCA-based EPDs for comparison between competing products, much like using nutritional labels. In addition, this article describes the process of developing EPDs from LCA data in conjunction with product category rules and the status and future needs of EPDs in the U.S. forest products industry.

<abstract> <p>Development of Environmental Product Declarations (EPD)s used for green marketing, specification, procurement, certification and green building rating systems are important for documenting and understanding product environmental performance. Considering such applications any misleading of stakeholders has serious legal ramifications. Various studies have highlighted EPD veracity depends mainly on the data quality of underpinning life cycle assessment (LCA). This paper compares data quality across polyester product case studies, literature surveys and EPDs. Life Cycle Inventory (LCI) and Life Cycle Impact Assessment (LCIA) results are presented and interpreted. Surveys show recycled polyester fibre results are most sensitive to melt spinning energy data which varies over a wide range. The case studies compare results from median, lower and upper energy use in melt spinning. The work highlights that, accurate, clear definitions and vocabulary is as vital for specific foreground process data as it is for generic background supply chain data. This is to avoid misconceptions and mismatched assumptions in respect of EPD data quality and incorrect acceptance of inadequate charting of all essential processes. If product-specific accurate data is inaccessible, EPD options include presenting impact assessment results from LCI of best and worst-case scenarios. This is preferable to legal risks of using junk data that misleads stakeholders in marketing. General recommendations are presented for LCA practitioners to improve EPD data quality and accuracy. These include using multiple data sources to avoid reliance on any single database. Data also needs to be verified by a third-party with industry expertise independent of the specific manufacturer. It recommends using suitable, comprehensive and specific product-related scenarios for data development in any EPD.</p> </abstract>

In building's sustainability assessment, the role of the main construction materials is crucial. Even though the number of components is very high, the heaviest environmental impacts are due to a very short list, which comprises structures and envelope. For this reason, good environmental performances of walls materials are the base for achieving high sustainability levels for the building. The Life Cycle Assessment (LCA) is a consolidated scientific method for the analysis of the environmental profile of products, processes, and services taking into account the energy consumptions and the environmental impacts. Therefore, it is more and more applied in the construction sector to analyze the sustainability of products, certified with the Environmental Product Declaration (EPD). A research was conducted with the aim to compare the environmental performances of different solutions of building enclosures, highlighting the positive behavior of the autoclaved aerated concrete (AAC) blocks. The study was updated after 3 years, underlining the positive effects of some improvements in the production process of AAC on the environmental profile of the construction solutions. The environmental profile of the AAC blocks was measured through the LCA and the results were certified by an EPD that thus could be a useful tool for the sustainability communication from producers to architects and engineers.

This article is a review of advances in sustainability metric (SM), focusing on life cycle assessment (LCA) and material flow analysis (MFA), the most commonly used among all SMs. The presentations at the past 10 Society and Materials (SAM) conferences were used as a database. LCA, the most popular of these methodologies, is thriving among academics, practitioners and clients. Standardized initially by United Nations Environment Program (UNEP) and the European Commission, it passed from the Global North to the Global South and branched into Environmental Product Declarations (EPDs) that provide LCA‐formatted information, initially to the construction sector. Some important issues have progressed but are not completely resolved yet: multifunctional products or processes, circulatory practices, dynamic LCA, regionalization, monetarization, human and eco‐toxicity, biodiversity loss or resource availability, and they need more development work. Although LCA focuses on a microscale vision of the economy, MFA, being macroscale, emphasizes strategic and policy issues, thanks to its dynamic version. MFAs are now available for at least one third of the substances in the periodic table and for countless materials, from metals, to composites and construction aggregates for civil engineering. MFA has shed light on many strategic issues, such as (1) the fate of end‐of‐life goods and of the materials of which they are made, which constitute the so‐called urban mine, (2) the role of stocks in driving material demand and long‐term evolution of production (the so‐called Intensity‐of‐Stock model), (3) the connections with economic and social models that extend the scope and ambition of MFA, and (4) material flow accounting (MFAc), particularly Total Material Requirement (TMR). These two SMs are entirely devoted to objectifying the connection between human activities and the environment, mostly, based on quantitative indicators originating from Sciences, Technology, Engineering and Mathematics (STEM). However, LCA and MFA have left aside the full depth of society’s dynamics, as described by Social Sciences and Humanities (SSH) disciplines. Contributions from SSH disciplines do not match the indicator‐based approach: they explored the concepts of social value of materials and social acceptance, used non‐engineering metaphors to report on hard‐science issues, called on Humanities, from History to Literary Criticism, on Science and Technology Studies (STS), on Design studies, on Ethics or Gender issues to shed light on sustainability issues. How the divide between SSH and SMs can be bridged is not yet fully clear. However, attempts were made to develop approaches that would mimic SMs: Social Cycle of Materials (SCM) mixes Design philosophy with STS, and ANT‐reliant LCA , which posits that materials have agency, takes on board Actor Network Theory (ANT) , a sociological model of society as a whole, to report on objects described by LCA. In between STEM and SSH approaches, lie approaches based on thermodynamics, which claim that physics can tackle social and economic dimensions: thermoeconomics is one of them.

Environmental product declarations (EPDs) are standardized tools based on life cycle assessment (LCA) to communicate and compare environmental performance of products according to well-defined product category rules (PCRs). However, despite the comparability enabled by the PCRs, the use of this information for benchmarking is still challenging, since there is still no consensus or standardization regarding techniques and procedures to be adopted. Therefore, here, we suggest and apply a framework to benchmark and develop a ranking system for the products based on data from EPDs. The proposed framework is based on efficiency assessment using data envelopment analysis (DEA). The main advantages of DEA are that it does not require potentially non-scientific factors, e.g., for normalization and that it provides an efficiency score based on all the used indicators, rather than just based on a subset of them. A five-step benchmarking framework is presented which includes data collection from EPDs, statistical analyses, selection of the variables, application of DEA, and cluster analysis to establish the environmental performance ranking on a scale from A (best) to E (worst). In order to illustrate the applicability of the proposal, two case studies of different product categories are presented: bakery products and insulation materials. In the first case, 72 bakery products are evaluated of which 9 were ranked in the category A, while 9 other products are considered the most inefficient and were ranked in category E. For insulation materials, 89 products are evaluated and 9 are categorized as A of which 5 are considered efficient, while the category E comprises 20 products. The results obtained through DEA are compared with those from other approaches (being internal normalization and external normalization, respectively, each with subsequent aggregation) to obtain single scores. There are significant differences in the results obtained from the three approaches, especially when dealing with trade-offs, because DEA does not relate the scores to specific values, but to a so-called “efficiency frontier”. The use of DEA allows an analysis based on the efficiency of the products in terms of environmental performance and can be applied using data from EPDs. The framework proposed allows benchmarking of the results and opens a new perspective to contribute to the issue of limitations in the communication function of EPDs. However, DEA is limited to analyzing the efficiency of a given product in relation to a pre-determined group.

In the framework of the Energy Performance of Buildings Directive (EPBD) [1], Member States develop their roadmaps based on two methodological pillars: life cycle assessment (LCA) and integration of environmental data of construction products. UNE-EN 15978:2012 [2] defines the environmental assessment criteria at building level, while UNE-EN 15804:2012+A2:2020/AC: 2021 [3] establishes the product category rules (PCR) for environmental product declarations (EPD). At the product level, the new version of the standard expands the number of impact categories that the EPD can provide some basic (which must be included in the EPD) and others additional (not mandatory). This research focused on the analysis of the EPD of mass concrete, due to its significant influence on the overall result of the analysis, attributed to its high relative weight in the set of materials used in buildings. EPDs from different sources were analysed according to the two versions of the standard, as well as the stability of the indicators. The study shows a convergence in GWP-total stages A1-A3, which reinforces its reliability as the first mandatory parameter towards decarbonisation in 2050. A comparison of thirteen DAPs shows emissions for stage A1-3 of 270.9 Kg CO 2 eq. /m 3 . In contrast, the remaining impacts show high variability, with increases in many cases exceeding 100%, suggesting that their stability requires further parameterisation.

The importance of life cycle sustainability in the construction sector is increasing in the light of rising awareness on sustainability issues in society. A means to identify more sustainable options is to assess and compare their sustainability performance. The standards ISO 21931-2 and EN 15643-1 to 5 establish the framework and requirements for sustainability assessment of buildings and civil engineering works. The standards require life cycle assessment (LCA) to be the basis for the environmental part of the sustainability assessment. LCA is a powerful evidence-based method but it requires extensive data. Access to free, easily available and preferably machine-readable LCA data is essential to increase the use of LCA in the construction sector and to make competition fair for all tenderers. This paper aims to compile existing online sources for open-access LCA data of interest for the construction sector. The purpose is to provide a reference document that facilitates the use of LCA in construction. An in-depth search of publications and internet resources was performed, focusing on European sources of Environmental Product Declarations (EPD) and process-based LCA datasets. A comprehensive overview of the European data sources available online and relevant to the construction sector is presented. This research work reveals the existence of numerous sources, often difficult and time-consuming to find. The overview in the paper facilitates finding online data needed for LCA, in many cases in a machine-readable format. This can contribute to increasing the use of LCA in the construction sector, which is important when developing buildings or civil engineering works that are more sustainable over their whole life cycle. A greater use and better integration of LCA in the design process contributes to evidence-based life cycle sustainability of our built environment.

Context The European Commission (EC) recognised Life Cycle Assessment (LCA) as "the best framework for assessing the potential environmental impacts of products". It also identified "the need to improve data availability and quality worldwide by internationally cooperating on LCA data and methods". The life cycle approach is also part of the 2011 Communication on "A resource-efficient Europe – Flagship initiative under the Europe 2020 Strategy". To support these life cycle based EU policies, the EC has started the "European Platform on Life Cycle Assessment (EPCLA)"[1]services (e.g. consulting or research services), tools (e.g. LCA tools, ecodesign tools), databases (e.g. LCI databases) and the corresponding developers and providers. in 2005. This Platform is implemented and coordinated by the EC Directorate-General Joint Research Centre (JRC), Institute for Environment and Sustainability, in close collaboration with DG Environment. The Platform works on the basis of coherent and quality-assured life cycle data, methods, and studies. The LCA Resource Directory is one of the deliverables of the Platform. This application has been running since 2006 and it contains lists of Novelty The LCA Resource Directory has recently been further developed so that it can contain and organize LCA case studies and metadata on these studies. The new LCA Resource Directory will be launched during the Fall 2011. Methods The new functionalities of the LCA Resource Directory allow users (LCA expert and non-expert) to browse a database of LCA studies. Thanks to the searching tool, a user can sort the information available as metadata and identify relevant LCA studies according to his/her interests. Many of the fields of the template used to characterize LCA studies are based on the ISO 1404x series. Some fields of the template are mandatory (e.g. functional unit and system boundary) in order to assure that the information showed in the application fulfills most of the requirements of the ISO 14044 for reports to be disclosed to the public. Other fields of the template include: "Intended application(s)", "LCIA impact categories" and "Compliance". The LCA study has to be uploaded on the Directory. Moreover, a final verification step is performed by the web application administrator to ensure quality and consistency. The application is open worldwide (http://lca.jrc.ec.europa.eu/lcainfohub/directory.vm). Any research group, company, university, etc. is now able, after registration, to upload studies and give metadata on them using a template. DG JRC will be in charge of the maintenance of the application and will populate the Directory with the first set of studies during the Fall 2011. An open call to relevant research groups and institutions will be send in order to populate the Directory with registered users and studies. Conclusions With these new capabilities of the Resource Directory, the EPLCA makes progress in its aim of promoting life cycle thinking when making available to all kind of LCA practitioners a good quality database of LCA studies, together with a searching tool. [1] http://lct.jrc.ec.europa.eu/

This paper shows the work made by the Ecodesign Learning Centre of Engineering School at the University of the Basque Country and at Mondragon University. Some engineering students have carried out Life Cycle Assessment, Ecodesign and applied research projects in some Basque Companies. One of those projects consisted in a Life cycle assessment of a hydraulic press. The aim of this project was to point out some improvement measures to be used in future designs of machine tools. That kind of products will soon be affected by the Energy using Products Directive. In another project, an environmental product declaration was made for a radio controlled electronic lock. The last project which is presented in this paper is a research work comparing three life cycle impact assessment methodologies and its application on one case study. In all of the three projects useful results were obtained for the stakeholder companies and for the industrial sector as well, giving help to the development of methodologies and other related projects in the Basque industry. KEYWORDS: ecodesign, life cycle assessment, energy using products, environmental product declaration, life cycle impact assessment methodologies.