Life cycle assessment of steel building with hollow roof and sensitivity analysis (case study: Isfahan)

This paper provides a comparative analysis using the concept of life cycle assessment (LCA), between high-sulfur (3000 ppm) and low-sulfur diesel (500 ppm) diesel. The comparative LCA considers the stages of production, transport and oil refining , as well as the transport of refined products and their respective end use. This last stage of the life cycle is important for the analysis of potential environmental impacts, due to sulfur oxide (SOx) emissions, which contribute to the formation of acid rain, damage air quality and the ecosystem (land and water acidification), causing gradual damage to human health and the environment. Therefore, comparative LCA identifies critical points from the environmental perspective, weighing the contributions of pollutants (NO2, CH4 and CO2) known as greenhouse gases (GHG) and criteria pollutants (CO, SOX, NOX, VOC's and PM). Simapro 7.2® was used to simulate and evaluate potential environmental impacts generated during the production and use by end consumers of the two fossil fuels. In order to evaluate the impact categories, two methods available in said calculation tool were selected: the first is the IPCC-2007 (GWP-100years), which estimates the carbon footprint and the contributions of each stage of the production chain to the "Global Warming" effect. The second method of evaluation is the Impact 2002+, which assesses the various contributions to the categories of toxicity to "Human Health", "Ecosystem Quality", "Climate Change" and "Depletion of Natural Resources". Thus, the preliminary results of comparative LCA show a slight increase in the carbon footprint (total emissions of CO2 equivalent in the productive chain) of low-sulfur diesel, approximately 3.8% compared to high-sulfur diesel, as a result of the increased emissions generated by the operation of the hydrogenation plant. However, low-sulfur diesel achieves a significant reduction of about 80% in comparison with high-sulfur diesel, in terms of damage to "Human Health" and "Ecosystem Quality". On the contrary, there was an increase of 2% and 6% in the categories of "Climate Change" and "Depletion of Natural Resources", respectively. Finally, despite the minor increase in the carbon footprint, although with remarkable reductions in "Ecosystem Quality" and "Human Health", the production and use of low-sulfur diesel has a single score of environmental impact equivalent to 0.23 milli points (mPt) compared to the single score obtained by high-sulfur diesel of 1.23 (mPt).

Several efforts have attempted to incorporate the sources of uncertainty and variability into the life cycle assessment (LCA) of pavements. However, no method has been proposed that can simultaneously consider data quality, methodological choices, and variability in inputs and outputs without the need for complementary software. This study aims to develop and implement a flexible method that can be used in the LCA software to assess the effects of these sources on the conclusions. A Monte Carlo analysis was conducted and applied in a comparative LCA of pavements to assess the preferred scenario. The uncertainty of the results was first estimated by considering the data quality using the ecoinvent database. Moreover, the variabilities of the materials, construction methods, and repair stages of the pavement life cycle were included in the analysis by assigning continuous uniform probability distributions to each variable. Ultimately, the probability of methodological choices was modeled using uniform distributions and assigning a portion of the area of the distribution to each scenario. The individual and combined effects of these uncertainty and variability sources were assessed in a comparative LCA of asphalt and concrete pavements in a cold region such as Quebec (Canada). The results of the Monte Carlo analysis show that the allocation choices can change the environmentally preferred scenario in four midpoint categories. These categories are significantly dominated by the crude oil supply chain. The variability in construction materials and methods can change the preferred scenario in the damage categories, namely, human health and global warming. Additionally, parameter uncertainty has a significant effect on the conclusion of the preferred scenario in ecosystem quality. The worst qualitative scores are given to the geographical uncertainty of the elementary flow that primarily contributes to this category (i.e., zinc). The simultaneous effect of the uncertainty and variability sources prevents the decision-maker from reaching a less uncertain conclusion about ecosystem quality, human health, and global warming effects. This study demonstrates that it is feasible to assess the cumulative effects of common uncertainty and variability sources using commercial LCA software, including Monte Carlo simulation. Based on the variability and uncertainty of the results, the identification of a certain conclusion is case specific at both the midpoint and endpoint levels. Increasing the quality of the inventory is one solution to decreasing the uncertainties related to human health, ecosystem quality, and global warming regarding pavement LCA. This improvement can be achieved by avoiding the adaptation of a similar process to match the considered process and using practical construction efficiencies and realistic construction materials. The effectiveness of these tasks must be assessed in future studies. It should be noted that these conclusions were determined regardless of the uncertainty in the characterization factors of the impact assessment method.

Global warming is the greatest environmental challenge that humanity is phasing. Water availability and biodiversity are also important issues of concern. Efforts towards achieving a sustainable path are required in all major sectors. The construction and infrastructure sector is an important contributor to global resource depletion and environmental impact. Life cycle assessment (LCA) is a frequently used tool to assess the potential environmental impact of a product or service throughout its life cycle. The life cycle of a product involves the extraction of raw materials, processing, production, use, and end-of-life. The environmental performance is quantified according to several impact categories such as: global warming, abiotic depletion, acidification, eutrophication, ozone layer depletion, photochemical oxidation, among others. LCA has been applied with success in the construction and infrastructure sector, in particular for buildings of all types. Literature in LCA of buildings use a variety of methodological approaches. The objective of this literature review is to identify and compare the different methodological approaches used in LCA of residential buildings, with a particular focus on functional unit, system boundaries, environmental impact categories, and data quality. The review indicates that there are different approaches used depending on the objective of each particular study.

Addressing the social life cycle inventory analysis data gap: Insights from a case study of cobalt mining in the Democratic Republic of the Congo

A statistical analysis of life cycle assessment for buildings and buildings’ refurbishment research

The considerable environmental burden of textiles is currently globally recognized. This burden can be mitigated by applying circular economy (CE) strategies to the commonly linear, short garment life cycles that end with incineration or landfill disposal. Even though all CE strategies strive to promote environmental sustainability, they might not be equally beneficial. Environmental data on different textile products is insufficiently available, which leads to complications when assessing and deciding on different CE strategies to be implemented. This paper studies the environmental impacts of a polyester T-shirt's linear life cycle through life cycle assessment (LCA) and evaluates the benefits attainable by adopting different CE strategies, and their order of priority, while noting uncertainty arising from poor data quality or unavailability. The LCA is complemented by assessing health and environmental risks related to the different options. Most of the linear life cycle's LCA-based impacts arise from use-phase washing. Hence, it is possible to reduce the environmental impact notably (37 %) by reducing the washing frequency. Adopting a CE strategy in which the shirt is reused by a second consumer, to double the number of uses, enables an 18 % impact reduction. Repurposing recycled materials to produce the T-shirt and recycling the T-shirt material itself emerged as the least impactful CE strategies. From the risk perspective, reusing the garment is the most efficient way to reduce environmental and health risks while washing frequency has a very limited effect. Combining different CE strategies offers the greatest potential for reducing both environmental impacts as well as risks. Data gaps and assumptions related to the use phase cause the highest uncertainty in the LCA results. To gain the maximum environmental benefits of utilizing CE strategies on polyester garments, consumer actions, design solutions, and transparent data sharing are needed.

Environmental issues have received ascending attention in recent years due to the increase of their negative effects.Greenhouse gas emission levels have experienced an exponential increase in the last decades mainly on account of the development of the building sector.Life cycle assessment (LCA) of buildings is a proper tool to analyse the full environmental impact during their designed lifespan.Inventory databases have a shortage of local parameters in some countries and need to be developed constantly.Life cycle cost (LCC) analysis evaluates the global costs of an investment.Besides the initial cost of implementing a project, usage, maintenance, repair, replacement and demolition costs are also taken into account.The goal of the research presented in this paper is to evaluate the environmental impact of a highly energy efficient residential house, built in western Romania.Life cycle assessments of buildings show that in most cases the impact of operating phase is much higher than construction phase, but in case of highly energy efficient buildings, the results are slightly different.However, energy related processes play a major role in determining the impact of buildings.A cradle-to-grave life cycle analysis, using SimaPro software, offers a complete image of the studied building's environmental impact.The main objective is to determine the fraction of each component of the building with relevant contribution to the human health and ecosystems categories.

A core component of successful implementation of a circular economy (CE) strategy is the quantification of improvements or changes with respect to environmental impacts, resource usage, waste and/or economic costs. Life cycle assessment (LCA) is a vital tool for the quantification and assessment of effectiveness and impacts associated with CE strategies. Incorporating LCA allows a comprehensive and transparent assessment of products, services or organizations, and can help to identify any potential unintended consequences associated with a change in process or practice. The implementation of LCA can appear complicated for non-practitioners, but there exist clear guidelines on how to conduct life cycle assessments, as described in this chapter. There are several frameworks for the incorporation of LCA into CE strategies, as described here, and LCA may play a key role in the development of meaningful indicators for CE with regards to the product level assessment. This chapter includes an assessment of the challenges associated with implementing LCA in CE, which include the difficulty in managing numerous indicators in parallel, and the lack of available data. Additionally, this chapter highlights the benefits associated with transparency, consistency, comparability and the system approach and its complementarities with the CE strategy.

Concrete, the most widely utilized material in construction worldwide, contributes significantly to the consumption of natural resources and energy. The construction sector is a major source of waste and greenhouse gas (GHG) emissions, making it essential to improve the environmental impact of concrete to address climate change and pollution concerns. Evaluating the environmental footprint of concrete is crucial for advancing sustainable building practices. Cement, a key binder in concrete, is particularly responsible for GHG emissions due to its energy-intensive production process. This study applies the Life Cycle Assessment (LCA) methodology, using SimaPro software and the Ecoinvent database, to assess the environmental impact of concrete. A modified concrete mix was developed by replacing Portland Composite Cement with Eggshell Powder (ESP) (60% by weight) and Sawdust Ash (SDA) (40% by weight) at varying replacement rates of 10%, 20%, 30%, and 40%. The results showed up to 20% for replacement cement with ESP and SDA improved compressive strength in a 28-56 day period, with the highest strength growth rate of 29.58% observed for the mixes with replacement. However, higher replacement levels of 30% and 40% showed limited strength improvement during the same period. The enhanced compressive Strength and higher strength growth (compared to tra- ditional concrete) are observed withare0-20 % replacement of cement s. This suggests that this blend of materials could be used in projects with significant budget constraints, directly decreasing carbon emissions associated with concrete production. This aligns with global sustainability goals and can be used in projects aiming for green certifications like LEED (Leadership in Energy and Environmental Design). The study indicates that substituting cement with ESP and SDA reduces costs. This can sig- nificantly benefit low-budget housing projects or areas with high cement prices, providing a direct economic advantage. The environmental performance of the modified concrete was analyzed through LCA following the ISO 14040:2006 framework, focusing on the cradle-to-grave impacts, including raw material extraction, energy consumption, and water usage. One cubic meter of concrete was chosen as the functional unit. The analysis revealed significant reductions in the endpoint impact categories, including a 59% reduction in ecosystem impacts, 60% in human health, 61% in resource depletion, 59.79% in ozone depletion, and 54.32% in fossil fuel depletion. These results highlight the potential of ESP and SDA as sustainable alternatives for improving concrete's mechanical properties and environ- mental performance, supporting the development of more sustainable construction practices.

Clothes play a main role in societies. They protect people from weather conditions and are important means of communication and expression. However, the clothing industry is at the center of increasing criticism because of its contribution to climate change, resource depletion, water pollution, and waste generation, among others. These impacts are closely linked to the fast-paced, massive consumption-oriented, and linear model in which clothes are produced, marketed, distributed, used, and disposed of. The Circular Economy (CE) concept emerged as an alternative to the mainstream linear scheme, which seeks to recycle wastes into resources, keep products, components, and materials at their highest level of utility and value for as long as possible, while designing out waste and pollution and regenerating natural systems. Despite some identified challenges, Life Cycle Assessment (LCA) is very well suited to analyze CE strategies and contribute to a better environmental performance of products and systems. In this context, this research aims to contribute to a better understanding of the role of LCA in supporting CE strategies for the clothing industry by conducting a systematic literature review. After analyzing 256 papers, the results show that LCA has been applied to assess the environmental impacts of clothing since 1997, while CE and clothing publications start to appear almost 20 years later. Despite the CE framework being newer than the LCA, the speed in which CE publications increase is significantly faster. There is a wide range of LCA studies applied to different clothing life cycle stages that could be used to inform CE strategies. A number of these studies were specifically developed to inform CE. Our review shows that CE researchers today are mostly evaluating stakeholder perceptions and consumer attitudes, influenced by a business model mindset. However, CE strategies require a conscious analysis to be proved efficient and claiming that currently promoted generic circular fashion strategies have better environmental performance than traditional strategies in any scenario would still be inexact. Therefore, further work in landing CE strategies through a closer relationship with science-based tools like LCA is needed.KeywordsLife cycle assessmentCircular economyClothingSustainabilityCircularityLiterature reviewEnvironmental assessment

Life cycle assessment of the building industry: An overview of two decades of research (1995–2018)

The aim of the current study was to analyze the impacts of acrylic fiber manufacturing on the environment and to obtain information for assisting decision makers in improving relevant environmental protection measures for green field investments in developing countries especially in Africa and Middle East and North Africa (MENA) regions. The key research questions were as follows: what are the different impacts of acrylic fiber manufacturing on the environment and which base material has the highest impact? The life cycle assessment (LCA) started from obtaining the raw material until the end of the production process (cradle to gate analysis). Focus was given on water consumption, energy utilization in acrylic fiber production, and generated waste from the industry. The input and output data for life cycle inventory was collected from an acrylic fiber manufacturing plant in Egypt. SimaPro software was used to calculate the inventory of twelve impact categories that were taken into consideration, including global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), carcinogen potential (CP), ecotoxicity potential (ETP), respiratory inorganic formation potential (RIFP), respiratory organic formation potential (ROFP), radiation potential (RP), ozone layer depletion (OLD), mineral depletion (MD), land use (LU), and fossil fuel depletion (FFD). LCA results of acrylic fiber manufacturing on the environment show that 82.0 % of the impact is on fossil fuel depletion due to the high-energy requirement for acrylonitrile production, 15.9 % of the impact is on human health, and 2.1 % on ecosystem quality. No impacts were detected on radiation potential, ozone layer depletion, land use, mineral depletion, or human respiratory system due to organic substances. Based on these study results, it is concluded that acrylic fiber manufacturing is a high-energy consumption industry with the highest impact to be found on fossil fuel depletion and human health. This study is based on modeling the environmental effects of the production of 1-kg acrylic fiber and can serve to estimate impacts of similar manufacturing facilities and accordingly use these results as an indicator for better decision-making.

To minimize the environmental impacts of construction and simultaneously move closer to sustainable development in the society, the life cycle assessment of buildings is essential. This article provides an environmental life cycle assessment (LCA) of a typical commercial office building in Thailand. Almost all commercial office buildings in Thailand follow a similar structural, envelope pattern as well as usage patterns. Likewise, almost every office building in Thailand operates on electricity, which is obtained from the national grid which limits variability. Therefore, the results of the single case study building are representative of commercial office buildings in Thailand. Target audiences are architects, building construction managers and environmental policy makers who are interested in the environmental impact of buildings. In this work, a combination of input–output and process analysis was used in assessing the potential environmental impact associated with the system under study according to the ISO14040 methodology. The study covered the whole life cycle including material production, construction, occupation, maintenance, demolition, and disposal. The inventory data was simulated in an LCA model and the environmental impacts for each stage computed. Three environmental impact categories considered relevant to the Thailand context were evaluated, namely, global warming potential, acidification potential, and photo-oxidant formation potential. A 50-year service time was assumed for the building. The results obtained showed that steel and concrete are the most significant materials both in terms of quantities used, and also for their associated environmental impacts at the manufacturing stage. They accounted for 24% and 47% of the global warming potential, respectively. In addition, of the total photo-oxidant formation potential, they accounted for approximately 41% and 30%; and, of the total acidification potential, 37% and 42%, respectively. Analysis also revealed that the life cycle environmental impacts of commercial buildings are dominated by the operation stage, which accounted for approximately 52% of the total global warming potential, about 66% of the total acidification potential, and about 71% of the total photo-oxidant formation potential, respectively. The results indicate that the principal contributor to the impact categories during the operation phase were emissions related to fossil fuel combustion, particularly for electricity production. The life cycle environmental impacts of commercial buildings are dominated by the operation stage, especially electricity consumption. Significant reductions in the environmental impacts of buildings at this stage can be achieved through reducing their operating energy. The results obtained show that increasing the indoor set-point temperature of the building by 2°C, as well as the practice of load shedding, reduces the environmental burdens of buildings at the operation stage. On a national scale, the implementation of these simple no-cost energy conservation measures have the potential to achieve estimated reductions of 10.2% global warming potential, 5.3% acidification potential, and 0.21% photo-oxidant formation potential per year, respectively, in emissions from the power generation sector. Overall, the measures could reduce approximately 4% per year from the projected global warming potential of 211.51 Tg for the economy of Thailand. Operation phase has the highest energy and environmental impacts, followed by the manufacturing phase. At the operation phase, significant reductions in the energy consumption and environmental impacts can be achieved through the implementation of simple no-cost energy conservation as well as energy efficiency strategies. No-cost energy conservation policies, which minimize energy consumption in commercial buildings, should be encouraged in combination with already existing energy efficiency measures of the government. In the long run, the environmental impacts of buildings will need to be addressed. Incorporation of environmental life cycle assessment into the current building code is proposed. It is difficult to conduct a full and rigorous life cycle assessment of an office building. A building consists of many materials and components. This study made an effort to access reliable data on all the life cycle stages considered. Nevertheless, there were a number of assumptions made in the study due to the unavailability of adequate data. In order for life cycle modeling to fulfill its potential, there is a need for detailed data on specific building systems and components in Thailand. This will enable designers to construct and customize LCAs during the design phase to enable the evaluation of performance and material tradeoffs across life cycles without the excessive burden of compiling an inventory. Further studies with more detailed, reliable, and Thailand-specific inventories for building materials are recommended.

Life cycle assessment (LCA) is a method for assessing the environmental impact of a product, activity, or system across all the stages of its life cycle. LCA can identify the activities with a major impact on the environment throughout the life cycle of a product. To analyze the environmental implications of footwear, the LCA was applied to a pair of shoes designed for professional use. In this paper, the impact of a single pair of shoes was studied. Every year, footwear production worldwide is over 22 billion pairs, which has a significant impact on the environment. In this case study, the “cradle-to-grave” approach was used, which refers to all the activities involved in the life cycle of a footwear product, starting from raw material extraction, manufacturing, use, maintenance, and, in the end, disposal. The LCA was conducted using the SimaPro software. The environmental impact assessment of the analyzed shoe needed the acquisition of two crucial datasets. Background inventory data were sourced from the Ecoinvent database (version 3.3). The impact was quantified using the Global Warming Potential (GWP) metric, which calculates the contribution of emissions to global warming over a 100-year time limit according to the established values provided by the Intergovernmental Panel on Climate Change (IPCC). The impact of greenhouse gas (GHG) emissions was measured in relative carbon dioxide equivalents (kg CO2eq) to facilitate a standardized comparison. The results show that the total carbon footprint for a pair of safety boots is 18.65 kg of CO2eq with the “component manufacture” stage as a major contributor accumulating almost 80%.

The relevance of exergy to the life cycle assessment (LCA) of buildings has been studied regarding its potential to solve certain challenges in LCA, such as the characterization and valuation, accuracy of resource use, and interpretation and comparison of results. However, this potential has not been properly investigated using case studies. This study develops an exergy-based LCA method and applies it to three case-study buildings to explore its benefits. The results provide evidence that the theoretical benefits of exergy-based LCA as against a conventional LCA can be achieved. These include characterization and valuation benefits, accuracy, and enabling the comparison of environmental impacts. With the results of the exergy-based LCA method in standard metrics, there is now a mechanism for the competitive benchmarking of building sustainability assessments. It is concluded that the exergy-based life cycle assessment method has the potential to solve the characterization and valuation problems in the conventional life-cycle assessment of buildings, with local and global significance.