Life Cycle Inventory analysis (LCI) is a phase of Life cycle assessment involving the compilation and quantification of inputs and outputs for a product throughout its life cycle. As defined in ISO 14040 clause 3.3, this essential phase forms the foundation for understanding the environmental profile of a product system by systematically cataloguing all Exchanges that cross the system boundary.
The LCI phase represents the data collection and calculation stage of Life Cycle Assessment. It involves identifying and quantifying all exchanges between the product system and its surrounding environment, as well as exchanges between activities within the system. These exchanges include material inputs, energy inputs, product outputs, emissions to air, water and soil, and other environmental releases throughout the entire life cycle of the product, from raw material extraction through production, use, and final disposal.
According to ISO 14040, the outcome of Life Cycle Inventory analysis is the LCI result, which catalogues the flows crossing the system boundary. This result provides the starting point for Life Cycle Impact Assessment, where the environmental significance of these flows is evaluated. The systematic and comprehensive nature of LCI analysis ensures that all relevant environmental interventions are captured, enabling a holistic understanding of the product system's environmental performance across its complete life cycle.
The compilation process requires careful system boundary definition, data collection from various sources, and allocation procedures when dealing with multi-functional processes. The quantification involves calculating the total amounts of each exchange relative to the functional unit, ensuring that results are comparable and meaningful for decision-making purposes.
