Life cycle assessment: A case study of a dwelling home in Scotland

The article provides a life cycle assessment (LCA) of a 3-bed room semi detached house in Scotland. Detailed LCA of five main construction materials i.e. wood, aluminium, glass, concrete and ceramic tiles have been provided to determine their respective embodied energy and associated environmental impacts. Embodied energy of various construction materials involved has been estimated to be equal to 227.4 GJ. It is found that concrete, timber and ceramic tiles are the three major energy expensive materials involved. It as been calculated that concrete alone consumes 65% of the total embodied energy of the home while its share of environmental impacts is even more crucial.     

Life cycle assessment of a single-family residential building in Canada: A case study

The present study quantified the significant environmental impacts of a two-story residential building located in Vancouver, Canada, with a projected 60-year life span: (i) an inventory of all the construction materials was analyzed, covering the building structure and exterior and interior envelopes as well as the energy consumption; (ii) four types of functional units were defined; (iii) the five top building materials were examined, and a sensitivity analysis was conducted to investigate the impact associated with the choice of building materials. Two life cycle phases, manufacturing and operation, were more significant in all of the impact categories, and two building assemblies, the walls and the roof, bore most of the environmental loads. In terms of the sensitivity analysis, the roofing asphalt had the largest impact, dominating three of the seven selected impact categories. Despite different definitions of functional units, the function of the dwelling buildings is always the same, to provide protection and housing for their habitants. Additionally, to improve the performance of an existing building, several strategies were proposed for the building renovation and maintenance, including alternative replacement materials regarding the building components with high environmental burdens, good patterns of the occupants’ consumption behaviors as well as considerations of the financial and environmental cost. Finally, limitations and challenges are discussed to explore better design decisions in future studies.     

Life cycle assessment study of a Chinese desktop personal computer

Associated with the tremendous prosperity in world electronic information and telecommunication industry, there continues to be an increasing awareness of the environmental impacts related to the accelerating mass production, electricity use, and waste management of electronic and electric products (e-products). China's importance as both a consumer and supplier of e-products has grown at an unprecedented pace in recent decade. Hence, this paper aims to describe the application of life cycle assessment (LCA) to investigate the environmental performance of Chinese e-products from a global level. A desktop personal computer system has been selected to carry out a detailed and modular LCA which follows the ISO 14040 series. The LCA is constructed by SimaPro software version 7.0 and expressed with the Eco-indicator'99 life cycle impact assessment method. For a sensitivity analysis of the overall LCA results, the so-called CML method is used in order to estimate the influence of the choice of the assessment method on the result. Life cycle inventory information is complied by ecoinvent 1.3 databases, combined with literature and field investigations on the present Chinese situation. The established LCA study shows that that the manufacturing and the use of such devices are of the highest environmental importance. In the manufacturing of such devices, the integrated circuits (ICs) and the Liquid Crystal Display (LCD) are those parts contributing most to the impact. As no other aspects are taken into account during the use phase, the impact is due to the way how the electricity is produced. The final process steps - i.e. the end of life phase - lead to a clear environmental benefit if a formal and modern, up-to-date technical system is assumed, like here in this study.     

无铅焊料的环境协调性评价

本文通过分析建筑材料行业目前对焊接方法的广泛应用,指出对焊料进行环境协调性评价的重要性,提出采用生命周期评价的方法对目前使用较为广泛的无铅焊料和传统锡铅焊料进行生命周期评价,并确定了研究的系统框架.     

Life cycle of buildings,demolition and recycling potential: A case study in Turin,Italy

One of the most challenging issues presently facing policymakers and public administrators in Italy concerns what to do with waste materials from building dismantling activities and to understand whether, and to what extent, the ever-increasing quantity of demolition waste can replace virgin materials. The paper presents the results from a research programme that was focused on the life cycle assessment (LCA) of a residential building, located in Turin, which was demolished in 2004 by controlled blasting. A detailed LCA model was set-up, based on field measured data from an urban area under demolition and re-design, paying attention to the end-of-life phase and supplying actual data on demolition and rubble recycling. The results have demonstrated that, while building waste recycling is economically feasible and profitable, it is also sustainable from the energetic and environmental point of view. Compared to the environmental burdens associated with the materials embodied in the building shell, the recycling potential is 29% and 18% in terms of life cycle energy and greenhouse emissions, respectively. The recycling potential of the main building materials was made available in order to address future demolition projects and supply basic knowledge in the design for dismantling field.     

Life cycle cost assessment of masonry structures

The objective of this study is to propose a life cycle cost (LCC) model able to assess the structural performance of masonry structures. For this purpose the proposed LCC model is used for assessing the structural behaviour of one unreinforced and three retrofitted masonry structures derived following three retrofit scenarios that are suitable for strengthening this type of structures. According to the proposed LCC model the exceedance probabilities required, are calculated by means of fragility analysis (FA). In particular, FA is applied to the unreinforced and retrofitted masonry structures and the limit-states' exceedance frequencies are obtained by convolving fragilities with hazard curve. Life-cycle cost analysis models are recognised as suitable for assessing the structural performance, especially when the structure is expected to be functional for a long period of time. For the needs of the study, linear time history analyses are performed over a large database of natural records.     

空调热源的寿命周期评价

基于寿命周期评价方法建立了空调热源的寿命周期清单模型,用寿命周期影响评价法对热泵、电锅炉、燃油锅炉、天然气锅炉和燃煤锅炉作为空调热源的环境影响进行了评价。评价结果表明天然气锅炉的环境影响最小,寿命周期评价方法可用于可持续节能的研究。     

沥青混凝土生命周期环境影响评价研究

沥青混凝土在生产、铺筑和废弃过程中会消耗大量的自然资源和能源,因此有必要对其开展生命周期环境影响评价.采用生命周期评价方法,对沥青混凝土生命周期过程中的资源、能源消耗及污染物排放进行了评价.结果表明,沥青混凝土生命周期中能耗最大的是拌和过程,环境负荷影响类型重要性的大小依次为:不可再生资源＞温室效应＞酸化效应＞光化学烟雾＞人体健康损害;不同生产阶段的环境影响大小依次为:原材料生产过程＞运输过程＞拌和过程＞废弃过程＞摊铺压实过程.     

Life cycle energy assessment of Australian secondary schools

The Australian Department of Commerce builds many secondary schools in New South Wales every year, and the impact of energy consumption for such a type of construction has rarely been done before in Australia. Although there is a particular responsibility to ensure that public-owned projects contribute to the future well-being of the natural environment, environmental performance and energy efficiency of public projects are not well studied. In order that more informed design and planning decisions can be made about the future construction of school projects, this research paper uses life cycle energy analysis to study the total energy consumption of 20 public secondary school projects in New South Wales. The results will serve as a model for a more comprehensive analysis of energy consumption in establishing environmental performance criteria for the design and construction of future school projects in New South Wales.

Le ministère australien du Commerce construit chaque année de nombreuses écoles secondaires dans la province de Nouvelle Galles du Sud; l'étude de l'impact de la consommation d'énergie de ce type de bâtiment a rarement été faite auparavant en Australie. Bien qu'il existe une responsabilité particulière à s'assurer que les projets contribuent au développement harmonieux de l'environnement naturel, les performances environnementales et l'efficacité énergétique des projets publics ne font pas l'objet d'études sérieuses. Pour que l'on puisse prendre des décisions mieux étayées en matière de conception et de planning de futurs projets de construction d'écoles, cette communication s'appuie sur l'analyse énergétique du cycle de vie pour étudier la consommation énergétique totale de 20 projets d'écoles secondaires publiques en Nouvelle Galles du Sud. Les résultats obtenus serviront de modèles à une analyse plus complète de la consommation d'énergie en établissant des critères de performances environnementales applicables à la conception et à la construction de futures écoles en Nouvelle Galles du Sud.

Mots clés: Performances des bâtiments, énergie intégrée, analyse énergétique du cycle de vie, énergie opérationnelle, bâtiments publics, écoles     

从基本元素开始

本文通过解析一个以“基本元素”为主题展开的建筑设计教案,探讨如何以研究的方式进行教学与设计, 其目的在于将教学作为学术手段,对建筑学专业的本质及内涵进行探索。整个教案按照“知识的认识与分析”、“设计理念的推导与实现”二个阶段依次展开,借助多种研究方法,在关注建筑本体逻辑、实际建造与抽象思辨相互结合、严格限定设计目标的基础上,寻找对“基本元素”的新见解。     

预拌混凝土生命周期环境影响评价

预拌混凝土是目前重点推广和用量巨大的建筑材料。为客观评价预拌混凝土的环境影响,基于BEPAS(Building Environmental Performance Analysis System)评价系统,从六种等级预拌混凝土(C30～C100)的生产、施工、拆除三个阶段的资源和能源消耗基础数据收集入手,建立了各等级预拌混凝土的投入产出清单。依据更新的货币化环境影响评价权重,得到了单位体积预拌混凝土的生命周期社会意愿支付值。此外,给出了基于6个模拟算例的混凝土框架结构的环境影响评价结果。结果表明:单一预拌混凝土材料的环境影响随等级提高而上升;对于框架结构,C50和C60高强预拌混凝土兼具环境表现和经济效果良好的特点。     

发泡聚苯乙烯保温板全寿命周期评价

既有建筑绿色化改造中使用较多的保温材料是EPS板,对外墙保温改造使用EPS板产生的环境效益给出量化结果具有重要意义。采用生命周期评价(LCA)方法,结合实际调研,从EPS生产、销售运输、既有建筑使用EPS、回收运输、回收生产、回收得到PS颗粒等6个方面,用Ebalance软件对EPS板全寿命周期能源消耗及环境排放进行计算。结果表明,在全寿命周期中,1 kg EPS板可减少酸化潜值0.331 kg SO2当量、减少不可再生资源消耗55.0 kg Coal-R当量、减少能源消耗27.7 kgce当量、减少富营养化潜值0.0218 kg PO43-当量、减少全球变暖潜值61.6 kg CO2当量,既有建筑应进行外墙保温改造。     

苏州多层住宅建筑生命周期评价

依据美国开发的BEES软件,选择张家港当地某一栋具体的多层住宅建筑(6层,每层大约750 m2)进行了生命周期评价.把建筑的全生命周期范围确定为建材准备阶段(包括原材科开采、运输、原材料加工等)、建造阶段、运行阶段(运行70年)、拆毁阶段和建筑垃圾处理阶段.依据确定的范围进行了清单分析.根据建筑的结构形式,计算得到各种建材的需求量和建造、运行、拆毁、建筑垃圾处理时的各种输入输出,以统一的功能单位(一栋建筑)合并各种输入输出数据,得到总的数据清单.采用BEES分类表征方法进行影响评价.根据我国的具体情况确定环境影响因子和类别(酸雨、全球变暖、资源枯竭等),将不同的环境影响因子分配到一个或多个环境影响类别中,再根据具体情况确定各指标的权重系数进行加权,得到综合的评价结果.找出了建筑物全生命周期阶段中产生环境影响最大的阶段,即运行阶段.     

Life cycle assessment applied to wastewater treatment: State of the art

Life cycle assessment (LCA) is a technique to quantify the impacts associated with a product, service or process from cradle-to-grave perspective. Within the field of wastewater treatment (WWT) LCA was first applied in the 1990s. In the pursuit of more environmentally sustainable WWT, it is clear that LCA is a valuable tool to elucidate the broader environmental impacts of design and operation decisions. With growing interest from utilities, practitioners, and researchers in the use of LCA in WWT systems, it is important to make a review of what has been achieved and describe the challenges for the forthcoming years. This work presents a comprehensive review of 45 papers dealing with WWT and LCA. The analysis of the papers showed that within the constraints of the ISO standards, there is variability in the definition of the functional unit and the system boundaries, the selection of the impact assessment methodology and the procedure followed for interpreting the results. The need for stricter adherence to ISO methodological standards to ensure quality and transparency is made clear and emerging challenges for LCA applications in WWT are discussed, including: a paradigm shift from pollutant removal to resource recovery, the adaptation of LCA methodologies to new target compounds, the development of regional factors, the improvement of the data quality and the reduction of uncertainty. Finally, the need for better integration and communication with decision-makers is highlighted.     

Life cycle assessment of end-of-life vehicle recycling in China: a comparative study of environmental burden and benefit

The continuous increase in car ownership in recent years has led to a sharp increase in the number of end-of-life vehicles (ELVs). In this paper, life cycle assessment (LCA) was used to establish a mathematical computation model and nested iterative inventory data in order to assess the environmental impact of recycling a passenger ELV. The model was used to calculate and analyse the environmental burden caused by dismantling, reverse logistics, and recycling and to assess the environmental benefit of recycled materials, remanufactured engines, and recovered energy. The results showed that human toxicity potential was the only factor that had a higher environmental burden than benefit, with a difference of approximately 36%. The incineration of automotive shredder residues was the main contributing factor, accounting for 79% of the total contribution. Moreover, aluminium recycling and plastic recycling contributed the most to abiotic depletion potential and photochemical ozone creation potentials, respectively.     

Life cycle assessment of a railway bridge: comparison of two superstructure designs

Railway bridges currently encounter the challenges of increasing the load capacity while the environmental sustainability should be achieved. However, it has been realised that the environmental assessment of railway bridges has not been integrated into the decision-making process, the standard guideline and criterion is still missing in this field. Therefore, the implementation of life cycle assessment (LCA) method is introduced into railway bridges. This article provides a systematic bridge LCA model as a guideline to quantify the environmental burdens for the railway bridge structures. A comparison case study between two alternative designs of Banafjäl Bridge is further carried out through the whole life cycle, with the consideration of several key maintenance and end-of-life scenarios. Six impact categories are investigated by using the LCA CML 2001 method and the known life cycle inventory database. Results show that the fixed-slab bridge option has a better environmental performance than the ballasted design due to the ease of maintenances. The initial material manufacture stage is responsible for the largest environmental burden, while the impacts from the construction machinery and material transportations are ignorable. Sensitivity analysis illustrates the maintenance scenario planning and steel recycling have the significant influence on the final results other than the traffic disturbances.     

Comparative environmental assessment of wood transport models: A case study of a Swedish pulp mill

Wood transportation from forest landing to forest-based industries uses large amounts of energy. In the case of Sweden, where forest operations are highly and efficiently mechanized, this stage consumes more fossil fuels than other elements of the wood supply chain (such as silviculture and logging operations). This paper intends to compare the environmental burdens associated to different wood transport models considering a Swedish pulp mill as a case study by using Life Cycle Assessment (LCA) as an analytical tool.Five scenarios (the current one and four alternative reliable scenarios) were proposed and analysed taking into account two variables. On the one hand, the influence of imported pulpwood share from Baltic countries and on the other hand, the use of rail transportation for wood transport. In particular, the following impact categories were assessed: Eutrophication, Global Warming, Photochemical Oxidant Formation, Acidification and Fossil fuel extraction. The environmental results indicate that transport alternatives including electric and diesel trains, as well as the reduction in Baltic wood imports should present better environmental performance than the current scenario in terms of all the impact categories under study. Remarkable differences were identified with regard to energy requirements. This divergence is related to different long-distance transport strategies (lorry, boat and/or train) as well as the relative import of wood selected.The combination of lorry and train in wood transportation from Southern Sweden plus the reduction of wood imports from 25% to 15% seems to be more favourable from an environmental perspective. The results obtained allow forecasting the importance of the wood transport strategy in the wood supply chain in LCA of forest products and the influence of energy requirements in the results.     

Tropical architecture - a case study

In this Paris '89 paper Winston Suite, a senior lecturer in the Department of Civil Engineering at the University of the West Indies, recommends design modifications to minimise the undesirable aspects of thermal comfort and deals with artificial vs natural lighting. Dr Suite has experience as an engineer and contractor and interestingly highlights the need to rediscover decoration as an important cultural expression.     

Life cycle inventory of buildings: A calculation method

Traditionally, life cycle assessment (LCA) is mostly concerned with product design and hardly considers large systems, such as buildings, as a whole. Though, by limiting LCA to building materials or building components, boundary conditions, such as thermal comfort and indoor air quality, cannot be taken into account. The life cycle inventory (LCI) model presented in this paper forms part of a global methodology that combines advanced optimisation techniques, LCI and cost-benefit assessment to optimise low energy buildings simultaneously for energy, environmental impact and costs without neglecting the boundary conditions for thermal comfort, indoor air quality and legal requirements for energy performance. This paper first outlines the goal and scope of the LCI. Then, the partial inventory models as well as the overall building inventory model are presented. Finally, the LCI results are shown and discussed for one reference dwelling for the context of Belgium.