Edelen Ashley, Ingwersen Wesley W, Rodríguez Cristina, Alvarenga Rodrigo A F, de Almeida Artur Ribeiro, Wernet Gregor
Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, 37831 TN, USA.
Life Cycle Assessment Center of Excellence, National Risk Management Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH USA.
Int J Life Cycle Assess. 2017 Jul 1;2017:01-13. doi: 10.1007/s11367-017-1354-3.
Elementary flows are essential components of data used for life cycle assessment. A standard list is not used across all sources, as data providers now manage these flows independently. Elementary flows must be consistent across a life cycle inventory for accurate inventory analysis and must correspond with impact methods for impact assessment. With the goal of achieving a global network of LCA databases, a critical review of elementary flow usage and management in LCA data sources was performed.
Flows were collected in a standard template from various life cycle inventory, impact method, and software sources. A typology of elementary flows was created to identify flows by types such as chemicals, minerals, land flows, etc. to facilitate differential analysis. Twelve criteria were defined to evaluate flows against principles of clarity, consistency, extensibility, translatability, and uniqueness.
Over 134,000 elementary flows from five LCI databases, three LCIA methods, and four LCA software tools were collected and evaluated from European, North American, and Asian Pacific LCA sources. The vast majority were typed as "Element or Compound" or "Group of Chemicals" with less than 10% coming from the other seven types Many lack important identifying information including context information (environmental compartments), directionality (LCIA methods generally do not provide this information), additional clarifiers such as CAS numbers and synonyms, unique identifiers (like UUIDs), and supporting metadata. Extensibility of flows is poor because patterns in flow naming are generally complex and inconsistent because user defined nomenclature is used.
The current shortcomings in flow clarity, consistency, and extensibility are likely to make it more challenging for users to properly select and use elementary flows when creating LCA data and make translation/conversion between different reference lists challenging and loss of information will likely occur.
We recommend the application of a typology to flow lists, use of unique identifiers and inclusion of clarifiers based on external references, setting an exclusive or inclusive nomenclature for flow context information that includes directionality and environmental compartment information, separating flowable names from context and unit information, linking inclusive taxonomies to create limited patterns for flowable names, and using an encoding schema that will prevent technical translation errors.
基本流是生命周期评估所用数据的重要组成部分。由于数据提供者现在独立管理这些流，所有来源并未使用标准列表。基本流在整个生命周期清单中必须保持一致，以便进行准确的清单分析，并且必须与影响评估的影响方法相对应。为了实现全球生命周期评估数据库网络的目标，对生命周期评估数据源中基本流的使用和管理进行了批判性审查。
从各种生命周期清单、影响方法和软件来源中，以标准模板收集流。创建了基本流的类型学，以便按化学品、矿物质、土地流等类型识别流，以促进差异分析。定义了十二条标准，以便根据清晰度、一致性、可扩展性、可翻译性和唯一性原则评估流。
从欧洲、北美和亚太地区的生命周期评估来源中，收集并评估了来自五个生命周期清单数据库、三种生命周期影响评估方法和四个生命周期评估软件工具的超过134,000个基本流。绝大多数被归类为“元素或化合物”或“化学品组”，其他七种类型的占比不到10%。许多流缺乏重要的识别信息，包括背景信息（环境介质）、方向性（生命周期影响评估方法通常不提供此信息）、额外的说明符（如CAS编号和同义词）、唯一标识符（如UUID）以及支持的元数据。流的可扩展性较差，因为流命名模式通常复杂且不一致，这是由于使用了用户定义的术语。
当前在流的清晰度、一致性和可扩展性方面的不足，可能会使用户在创建生命周期评估数据时更难正确选择和使用基本流，并且会使不同参考列表之间的翻译/转换具有挑战性，很可能会出现信息丢失。
我们建议对流列表应用类型学，使用唯一标识符并根据外部参考包含说明符，为流上下文信息设置包含方向性和环境介质信息的排他性或包容性术语，将可流动物名称与上下文和单位信息分开，链接包容性分类法以创建可流动物名称的有限模式，并使用一种编码模式来防止技术翻译错误。
