A quantified description of the performance requirements a product system fulfills. It provides a reference to which all inputs and outputs are related in a Life Cycle Assessment (LCA). It defines what is being studied and establishes a basis for comparison. For instance, instead of simply comparing “two light bulbs,” one might compare “providing 6000 lumen-hours of light over a period of one year.” This detailed specification allows for a meaningful comparison of different lighting solutions that achieve the same function.
Its criticality stems from ensuring comparability and relevance within the LCA study. It ensures the results are pertinent to the question being asked and enables meaningful benchmarking against alternative products or services. Establishing this element early in the LCA process prevents system boundary ambiguity and ensures consistent allocation of environmental burdens. Historically, inconsistencies in defining it led to flawed comparisons and inaccurate conclusions, highlighting the need for a standardized and rigorous approach to its selection.
