Integration of Life Cycle Inventories Incorporating Manufacturing Unit Processes

Sustainable manufacturing (SM) concerns the manufacture of products with regard to environmental, social, and economic impacts over the entire life cycle. With a primary focus on environmental concerns, life cycle assessment (LCA) can support SM practices. The life cycle inventory (LCI) is a key phase of LCA, and this paper considers the integration of manufacturing unit processes (MUPs) into system-level LCIs, which requires consideration of process flow diagrams at different levels of abstraction. Furthermore, uncertainty quantification is an important component of LCA interpretation, and this paper proposes a method to synthesize LCIs from the process-level to the system-level that consistently quantifies uncertainty in the inventories. The method can incorporate MUP data derived from measurements and/or modeling and simulation. Further development towards a complete methodology is discussed. INTRODUCTION A simple definition of a sustainability is “the capability to use a resource without permanently depleting it, thus preserving the resource for future use” [1]. Several facets of sustainability have been identified, the most important of which include environment, society, and economy. Despite the straightforward definition given above, the identification and validation of sustainable practices can be difficult given the complex interactions ∗Address all correspondence to this author. between environment, society, and economy, and the myriad uncertainties involved. Nevertheless, given the reality of limited resources, sustainable living is necessary to ensuring a reasonably sufficient and enduring quality of life. Sustainable manufacturing (SM) refers to the provision of manufactured products in a sustainable manner, i.e., in a manner that does not permanently deplete environmental, social, and economic resources during the complete life cycle of the manufactured product. In SM practice, it is insufficient to design a product merely for function, manufacturability, and profit. Rather, a sustainable design also considers, for example, how the product can be manufactured in an energy efficient way, used in an environmentally and socially responsible manner, and recycled into the raw materials for the next generation of products. These additional considerations require a corresponding evolution of the supporting methodologies, techniques, and computational and information tools for life cycle engineering [2–5].1 SM subsumes traditional manufacturing (TM). Here, TM refers to widely adopted manufacturing principles and practices such as Lean Manufacturing and Total Quality Management, which are not concerned with environmental and social impacts. SM inherits numerous requirements and issues from TM, including customer satisfaction, geometric/functional tolerancing, material/component selection, supply chain management, manufac1Methodologies are concerned with what to accomplish, while techniques are concerned with how to accomplish. Tools (such as computer software and datacollection sensors) implement the techniques that realize a given methodology. 1 Copyright c © 2011 by ASME Proceedings of the ASME 2011 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference