Purpose
The built environment consists of a huge amount of infrastructure, such as roads and utilities. The objective of this paper is to assess the life cycle financial and environmental impact of road infrastructure in residential neighbourhoods and to analyse the relative contribution of road infrastructure in the total impact of neighbourhoods.Methods
Various road sections are analysed based on an integrated life cycle approach, combining life cycle costing and life cycle assessment. To deal with complexity, a hierarchic assessment structure, using the principles of the “element method for cost control”, is implemented. Four neighbourhood models with diverse built densities are compared to gain insight in the relative impact of road infrastructure in neighbourhoods.Results and discussion
The results reveal important financial and environmental impact differences between the road sections analysed. Main contributors to the life cycle financial and environmental impact are the surface layer and electrical and piped services. The contribution of road infrastructure to the total neighbourhood impact, ranging from 2 to 9 % of the total cost, is relatively limited, compared to buildings, but not negligible in low built density neighbourhoods.Conclusions
Good spatial planning of the neighbourhood is recommended to reduce the amount of road infrastructure and the related financial and environmental impact. The priority should be to design denser neighbourhood layouts, before decreasing the financial and environmental impact of the road sections.Purpose
The main aim of the study is to assess the environmental and economic impacts of the lodging sector located in the Himalayan region of Nepal, from a life cycle perspective. The assessment should support decision making in technology and material selection for minimal environmental and economic burden in future construction projects.Methods
The study consists of the life cycle assessment and life cycle costing of lodging in three building types: traditional, semi-modern and modern. The life cycle stages under analysis include raw material acquisition, manufacturing, construction, use, maintenance and material replacement. The study includes a sensitivity analysis focusing on the lifespan of buildings, occupancy rate and discount and inflation rates. The functional unit was formulated as the ‘Lodging of one additional guest per night’, and the time horizon is 50 years of building lifespan. Both primary and secondary data were used in the life cycle inventory.Results and discussion
The modern building has the highest global warming potential (kg CO2-eq) as well as higher costs over 50 years of building lifespan. The results show that the use stage is responsible for the largest share of environmental impacts and costs, which are related to energy use for different household activities. The use of commercial materials in the modern building, which have to be transported mostly from the capital in the buildings, makes the higher GWP in the construction and replacement stages. Furthermore, a breakdown of the building components shows that the roof and wall of the building are the largest contributors to the production-related environmental impact.Conclusions
The findings suggest that the main improvement opportunities in the lodging sector lie in the reduction of impacts on the use stage and in the choice of materials for wall and roof.Purpose
Life cycle sustainability assessment is meaningful for the decision-makers/stakeholders to select the most sustainable option among multiple alternatives; however, there are usually various severe uncertainty problems in sustainability-oriented decision-making, i.e., the vagueness and ambiguity that existed in human judgments and the lack of information. This study aims at developing a novel life cycle multi-criteria sustainability assessment method for helping the decision-makers/stakeholders to determine the sustainability level of the industrial and energy systems. In part 1, an improved interval analytic hierarchy process (AHP) which allows multiple decision-makers/stakeholders to participate in the decision-making was developed to determine the weights of the criteria which were used in life cycle sustainability assessment.Methods
It is usually difficult for the decision-makers/stakeholders to use the numbers from 1 to 9 and their reciprocals for determining the comparison matrix when using the traditional AHP method for weight calculation, because human judgments usually involve various uncertainties. In order to the overcome this weak point of the traditional AHP, an improved AHP, so-called interval AHP, in which, multiple decision-makers/stakeholders are allowed to participate in the decision-making and allowed to use interval numbers instead of crisp numbers to establish the comparison matrix for determining the weights of the criteria for life cycle sustainability assessment, has been developed.Results and discussion
The proposed method was used to determine the weights of the four aspects for life cycle sustainability assessment including economic, safety, social, and environmental aspects. Five representative stakeholders were invited to participate in the decision-making. After Monte Carlo simulation, the final weights of the four aspects have been determined with the proposed interval AHP.Conclusions and perspectives
An interval AHP method was developed for determining the weights of the criteria for life cycle sustainability assessment; the decision-makers are allowed to use interval numbers to establish the comparison matrix for weight calculation. The weighting coefficients determined by Monte Carlo method can accurately reflect the preferences and willingness of multi-actor comparing with the traditional AHP method. This paper merely presents a novel method to calculate the weights of the criteria for life cycle sustainability assessment, but the method for determining the sustainability performance has been presented in part 2.Purpose
The concept of sustainability and sustainable development has been widely incorporated in energy and industrial systems. This paper is the second part of a two-paper series dealing with multi-actor multi-criteria sustainability assessment of alternative energy and industrial systems in life cycle perspective under uncertainties.Methods
The criteria system including four macroscopic aspects (environmental, safety, social and economic aspects) has been developed for sustainability assessment of energy and industrial systems. An improved extension theory which can address interval decision-making matrix has been developed for determining the sustainability degree of the energy and industrial systems.Results and discussion
The weights of the criteria for sustainability assessment are the first part of the two-paper series. An illustrative case has been studied by the proposed multi-criteria decision-making method, and the sustainability of six alternative options for the production of a 1-t product was investigated. The sustainability degree of these six alternative options can be determined by the proposed method.Conclusions and perspectives
A methodology for multi-actor multi-criteria sustainability assessment of energy and industrial options has been developed in this study, the traditional extension theory has been modified to deal with the uncertainty problems and the proposed method can rank the alternative energy and industrial systems with the decision-making matrix in which the data of the alternatives with respect to the evaluation criteria are intervals. In the improved extension theory, sustainability has been dived into five grades: excellent, good, satisfied, barely adequate and fail. According to the method for calculating the weights of the criteria for sustainability assessment proposed in part 1, these weights were used to calculate the integrated dependent degree which is a measure of what degree an alternative belongs to the classical fields. An optimal programming model for maximizing the satisfied degree has been developed to rank the sustainability sequence of the alternative options and determine the sustainability degree of each alternative.Purpose
The aim of this work is to propose an objective method for evaluating subcategories in social life cycle impact assessment (S-LCIA). Methods for assessing subcategories have been available since 2006, but a number of these either fail to include all the subcategories envisaged in the guidelines for S-LCA (UNEP/SETAC 2009) or are subjective in their assessment of each subcategory.Methods
The methodology is characterized by four steps: (i) the use of the organization as unit process, in which it was decided to assess the social profile of the organization responsible for the processes involved in the product life cycle, (ii) definition of the basic requirement to assess each subcategory, (iii) definition of levels based on the environment context or organizational practice and the data availability and (iv) assignment of a quantitative value.Results and discussion
The result of the method applied was the development of the subcategory assessment method (SAM). SAM is a characterization model that evaluates subcategories during the impact assessment phase. This method is based on the behaviour of organizations responsible for the processes along the product life cycle, thereby enabling a social performance evaluation. The method, thus, presents levels for each subcategory assessment. Level A indicates that the organization exhibits proactive behaviour by promoting basic requirement (BR) practices along the value chain. Level B means that the organization fulfils the BR. Levels C and D are assigned to organizations that do not meet the BR and are differentiated by their context. The greatest difficulty when developing SAM was the definition of the BR to be used in the evaluation of the subcategories, though many indications were present in the methodological sheets.Conclusions
SAM makes it possible to go from inventory to subcategory assessment. The method supports evaluation across life cycle products, thereby ensuring a more objective evaluation of the social behaviour of organizations and applicable in different countries.Recommendations
When using SAM, it is advisable to update the data for the context environment. The method might be improved by using data for the social context that would consider not only the country, but also the region, sector and product concerned. A further improvement could be a subdivision of the levels to better encompass differences between organizations. It is advisable to test SAM by applying it to a case study. 相似文献The main objective of this paper is to develop a model that will combine economic and environmental assessment tools to support the composite material selection of aircraft structures in the early phases of design and application of the tool for an aircraft elevator.
MethodsAn integrated life cycle cost (LCC) and life cycle assessment (LCA) methodology was used as part of the sustainable design approach for the laminate stacking sequence design. The model considered is the aircraft structure made of carbon fiber reinforce plastic prepreg and processed via hand layup-autoclave process which is the preferred method for the aircraft industry. The model was applied to a cargo aircraft elevator case study by comparing six different laminate configurations and two different carbon fiber prepreg materials across aircraft’s entire life cycle.
Results and discussionThe results show, in line with other studies using different methodologies (e.g., life cycle engineering, or LCE), that the combination of LCA with LCC is a worthwhile approach for comparing the different laminate configurations in terms of cost and environmental impact to support composite laminate stacking design by providing the best trade-off between cost and environment. Elevator LCC reduces 19% by changing the material type and applying different ply orientations. Elevator LCA score reduces 53% by selecting the optimum instead of best technical solution that minimizes the displacement. Improving the structural performance does not always lead to an increase in the cost.
相似文献The objective of the study is to progress towards a comprehensive component-based Life Cycle Assessment model with clear and reusable Life Cycle Inventories (LCIs) for high-speed rail (HSR) infrastructure components, and to assess the main environmental impacts of HSR infrastructure over its lifespan, to finally determine environmental hotpots and good practices.
MethodsA process-based LCA compliant with ISO 14040 and 14044 is performed. Construction-stage LCIs rely on data collection conducted with the concessionaire of the HSR line combined with EcoInvent 3.1 inventories. Use and End-of-Life stages LCIs rest on expert feedback scenarios and field data. A set of 13 midpoint indicators is proposed to capture the diversity of the environmental damage: climate change, consumptions of primary energy and non-renewable resources, human toxicity and ecotoxicities, eutrophication, acidification, radioactive and bulk wastes, stratospheric ozone depletion, and summer smog. Three characterization methods are used: the “Cumulative Energy Demand” method to quantify energy demand, the EDIP method for waste productions, and the CML method for the rest.
Results and discussionThe study shows major contributions to environmental impact from rails (10–71%), roadbed (3–48%), and civil engineering structures (4–28%). More limited impact is noted from ballast (1–22%), building machines (0–17%), sleepers (4–11%), and power supply system (2–12%). The two last components, chairs and fasteners, have negligible impact (max. 1 and 3% of total contributions, respectively). Direct transportation can contribute up to 18% of total impact. The production and maintenance stages contribute roughly equally to environmental deterioration (respectively average of 62 and 59%). Because the End-of-Life (EoL) mainly includes recycling with environmental credit accounted for in our 100:100 approach, this stage has globally a positive impact (??9 to ??98%) on all the impact categories except terrestrial ecotoxicity (58%), radioactive waste (11%), and ozone depletion (8%). Contribution analyses show that if concrete production is one of the important contributing processes over the construction stage, primary steel production is unquestionably the most important process on all the impact categories over the entire life cycle.
ConclusionsThese results are of interest for public authorities and the rail industry, in order to consider the full life cycle impacts of transportation infrastructure in a decision-making process with better understanding and inclusion of the environmental constraints. Suggestions are provided in this way for life cycle good practices—for instance as regards gravel recycling choices—and additional research to reduce the impact of current major contributors.
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