【正文】 ulturedimproved crop and grazing land management to increase soil carbon storage。 improved rice cultivation techniques and livestock and manure management to reduce CH4 emissions。 dedicated energy crops to replace fossil fuel use。 reforestation。 reduced deforestation。 use of forestry products for bioenergy to replace fossil fuel use.7. Wastedlandfill methane recovery。 recycling and waste minimisation. Other resources for generating sustainable design solutions include BRC [7], Constructing Excellence [8], SEEDA [9], The Carbon Trust [10], UK Government Office of Government Commerce [11]. There are an enormous number of literature and sustainable design tools providing numerous sustainable design options for designers to choose。 the design of buildings should practically reduce the life cycle costs and improve the sustainability of the buildings. Life cycle assessment is the best tool to bine both the longterm environmental and the economical evaluations of building designs. Tukker [12] claimed that life cycle assessment is a generic environmental evaluation framework. It should be pointed out that life cycle assessment also includes economic and risk evaluations in analysis. The key economic analysis is life cycle costing, which is a technique to estimate the overall costs of design options during the economic life of the building. In order to pare the longterm economic performance of the design options, life cycle costing should be included in strategic designs because the economic concerns drives the decision makers may be sometimes more than the other concerns. There are many cost models that have been developed to estimate life cycle costs such as NHS hospital buildings [13], running cost for building element [14], and noise barrier wall selection [15].As a powerful environmental assessment tool, life cycle assessment has been widely used in many areas such as solar PV system [16], municipal solid waste management system [17] and chemicals [18].The advantages and disadvantages of those sustainable design tools are listed in Table 1. The life cycle assessment tool can evaluate unlimited sustainable design options and also include theTable 1 The advantages and disadvantages of some main sustainable assessment tools. Assessment tools Advantages Disadvantages BREEAM Covers a wide range of design aspects Serves the UK public nonmercial buildings. Limited sustainable design options Code for sustainable homes Higher standard requirements on energy efficiency.Request zero carbon for new houses on level 6 Limits to residential projects only. Limited sustainable design options LEEDs Covers various types of buildings Exclude waste management. Limited sustainable design options WRAP recycle content tool Building breaking down into ponents in order to select the high recycle content building materials for projects. Suitable for all types of buildings Focuses on only the recycle content aspect of sustainable design. Limited sustainable design options IPCC Includes new considerations such as industry, agriculture and forestry, etc. Just a general guidance for sustainable design. Limited sustainable design options Life cycle assessment tool Combines the longterm environmental and the economical evaluations. It can include as many design criteria and options as required into assessment process Requests a range of expertise and time consuming. 1416 N. Wang et al. / Building and Environment 45 (2010) 1415–1421 economical evaluation into the assessment. Although it appears great advantages but it is rarely used in practice because it is deemed as time consuming and requires a wide range of expertise such as engineers, quantity surveyors. A case study on a live project is necessary in order to test the effectiveness of the lifecycle assessment tool and the impact of the result on the decision makers in practice. The various design criteria are evaluated by different parties and should be integrated to a single measurement to rank the design options, therefore the multicriteria decision making tool should be introduced in the life cycle assessment. There are various multicriteria decision making tools. The directweighting method is good for unsophisticated decision making [19]. It is one of the best known and widely used traditional methods for multicriteria decisionmaking issues [19]. The principal assumption of direct weighting is that the criteria are preferentially independent。 and rank ordering problems [25,30]. The various fuzzy decision making tools are more suitable to be implicated in the situation when the criteria cannot be easily quantified. Among all the available technologies, the life cycle assessment tool appears great advantages in solving the sustainable evaluation issue over the other technologies. As the characteristics of this case study, the direct weighting method is preferred in this multicriteria decision making problem.2. Methodology. The structure of the life cycle assessment toolThe legislation and regulations regarding sustainable buildings and environmental affect of construction industry in China are less strict than some other developed countries [31]. In order to test the development process and implication of the life cycle assessment in sustainable design, a case study of an international retailer’s sustainable strategymaking in their Flagship Store in China has been chosen to be applied in this research. The retailer’s objective is to select the sustainable design options with longterm economic benefit and environmental conscious for their future global stores. The chosen case study is a typical multicriteria decision making problem involving longterm economical and noneconomical analysis, therefore it was chosen to test the life cycle assessment tool in practice. The proposed life cycle assessment tool involves the qualitative evaluation from practitioners and the quantitative data from technical engineers and quantity surveyors. Various pa