Module 5.4

• Scope definition


  The scope of the study determines what product systems are to be assessed and how the assessment should take place
• Components of the goal and scope definition phase


  • Goal of the study
  • Scope of the study
• Elements of scope definition

  • Function, functional unit and reference flows
  • System boundary
  • Data quality requirements
• Function


  What the product provides to a user
• Functional unit


  The quantitative measure of a product's function
• Reference flow


  The product flow to which all input and output flows for the processes in the product system must be quantitatively related
• When comparing two product systems, functional unit should be the same while reference flow may vary
• Unit process


  The smallest element considered in a life cycle inventory model for which input and output data are quantified
• Elementary flow


  A material or energy entering (or leaving) the system being studied that has been drawn from (or released into) the environment without previous human transformation
• Product flow


  Products entering from or leaving to another product system
• Intermediate flow


  A product, material or energy flow occurring between unit processes of the product system being studied

  
• Product system


  A system of consecutive and interlinked unit processes which models a product life cycle
• A product system is a collection of unit processes
• Grass


  Input for cattle slaughter
• Cattle slaughter


  1. Beef processing

  2. Hotdog production
• System boundary


  Set of criteria specifying which unit processes are part of a product system
• Environment


  Surrounding system of the product system being studied

  
• Methane from cows


  Air emission
• Other product systems


  Systems that interact with the product system being studied
• Veterinary medicine


  Input for cattle slaughter
• Electricity


  Input for other product systems
• Plastic packaging

  Input for other product systems
• Cattle hide

  Output for other product systems
• Cow manure

  Output for other product systems
• Wastewater

  Output for other product systems
• Process flow diagram


  Describes the product system

  
• Intermediate flow


  Product, material or energy flow occurring between unit processes of the product system being studied

  
• Mature cattle

  Input for beef processing
• Beef carcass

  Output of beef processing
• Product system


  System of consecutive and interlinked unit processes which models a product life cycle
• The scope of an LCA clearly defines the system boundary of the product system being studied
• System boundary criterion

  • Based on mass (hotdog production)
  • Based on environmental significance (transportation of hotdogs)
• Data quality requirements

  Specify the characteristics of the data needed for the study
• Completeness


  Percentage of flow that is measured or estimated
• Completeness expressed

  • Quantitatively
  • Qualitatively
• Geographical coverage

  Specifies the geographical coverage of the processes or combination of processes taking place in the product system
• Geographical coverage


  • Based on southern Brazil
  • Based on Thailand
• Time-related coverage

  Specifies the timeframe of the processes in the different stages of the product life cycle
• Time-related coverage


  • 1997-2004 for conventional cattle farming, 2006-2013 for organic cattle farming
  • 2008-2011 reference period
• Technology coverage

  Specifies the list of technologies involved in the processes considering the geographical and time-related coverage