Specifying functional units and reference flows for comparable alternatives

Goal, Scope, and Background  

Despite documentation of product lifetime, performance, and system dependency issues, requirements for specifying functional units and reference flows in LCA have not been developed. The ISO standards simply note that selection between functions is dependent on the goals and scope of the study, that the functional unit must be clearly defined and measurable, and that the reference flows are the amount of product necessary per functional unit. The goal of this work is to suggest and demonstrate the use a set of requirements for specifying the functional unit and reference flows for comparative LCAs.