Life-Cycle Inventory & Life-Cycle Assessment
One well-known environmental impact measurement method utilized in the marketplace is the combination of life-cycle inventory (LCI) and life-cycle assessment (LCA). LCI and LCA work in tandem to quantify the material flows, energy flows, and environmental impacts of a given product.
- A life-cycle inventory (LCI) is the data collection portion of LCA. LCI is the straight-forward accounting of everything involved in the system of interest. It consists of detailed tracking of all the flows in and out of the product system, including raw resources or materials, energy by type, water, and emissions to air, water and land by specific substance. This kind of analysis can be extremely complex and may involve dozens of individual unit processes in a supply chain (e.g., the extraction of raw resources, various primary and secondary production processes, transportation, etc.) as well as hundreds of tracked substances.
Life-cycle assessment (LCA) is a multi-step procedure for calculating the lifetime environmental impact of a product or service. The complete process of LCA includes:
- goal and scope framework/objective of the study
- life-cycle inventory input/output analysis of mass and energy flows
- life-cycle impact assessment evaluation of environmental relevance of each flow
- interpretation locating where there is potential to optimize
A traditional LCA measures impacts from cradle-to-grave, or raw material acquisition to end-of-life. However, it is possible to only evaluate certain parts of the full LCA, such as a gate-to-gate or cradle-to-gate study. The standard for EPDs to meet LEED® v4 requirements are cradle-to-gate studies, so they only evaluate the environmental impact of producing a building material/product.