LCA Technology key terms

The quantified description of the function a product system delivers, used as the reference to which all inputs and outputs are scaled so that compared systems are genuinely equivalent.

The measurable amount of product or service output needed to fulfil the functional unit in a given system; it links the abstract function to concrete inventory quantities.

The set of unit processes, life cycle stages and flows declared to be inside the studied system, determining which activities are modelled and which are excluded.

Stated thresholds for mass, energy or environmental significance that justify excluding flows or processes from a study, together with the rationale for choosing them.

The procedure for partitioning shared inputs, outputs or environmental burdens among co-products or functions of a multi-functional process, ideally avoided by subdivision or system expansion.

A way of handling multi-functionality in which the studied system is credited or debited with the marginal consequences of the co-products it provides or displaces, instead of splitting burdens arithmetically.

An inventory approach that assigns a share of existing average supply-chain burdens to the product, answering what portion of current environmental flows belongs to it.

An inventory approach that models how background systems change in response to a decision, using marginal suppliers and market effects rather than average shares.

Inventory data collected or modelled specifically for the studied product system, typically covering processes the practitioner controls directly, such as own-site manufacturing or use-phase measurements.

Secondary inventory data drawn from databases or literature for processes outside the practitioner's direct control, such as upstream energy carriers or commodity materials.

A semi-quantitative scoring scheme rating datasets on reliability, completeness, temporal, geographical and technological representativeness, whose scores are converted into uncertainty factors.

Documented descriptors of a dataset's fitness for purpose, covering source reliability, completeness, temporal, geographic and technological match to the study's goal and scope.

A probability distribution assigned to an inventory parameter, such as lognormal or uniform, defined by a mean and dispersion and used to propagate variability through a model.

An impact category located early in the cause-effect chain, such as climate change, acidification or eutrophication, expressed in a category-specific equivalent unit without aggregation across categories.

An impact category placed at the end of the cause-effect chain, typically damage to human health, ecosystem quality or resources, aggregating midpoints through modelling choices and value judgements.

A multiplier that converts an elementary flow's quantity into a common equivalent of an impact category, quantifying that substance's relative contribution per unit emitted or consumed.

A characterisation factor expressing the cumulative radiative forcing of a greenhouse gas over a stated time horizon relative to carbon dioxide, which is fixed at one.

Dividing characterised results by a reference quantity, such as regional emissions per capita or per year, to express results relative to a common baseline and aid interpretation.

Converting normalised or characterised results into a single score using explicit value-based factors that reflect relative importance of impact categories; optional and value-laden.

The smallest modelled element of a product system for which inventory data are quantified, transforming input flows into output flows and connected to others by product flows.

The collection of unit processes connected by flows of intermediate products, performing one or more defined functions and forming the object of an LCA model.

A named variable in a model whose value can be set, calculated or varied, allowing systematic reuse of formulas, scaling of processes and definition of scenario variations.

A coherent alternative set of parameter values or modelling choices representing a possible future or design option, evaluated and compared within one study.

Ranking processes, flows or impact categories by their share of total results to reveal which parts of the system drive impacts and where improvement efforts should focus.

Systematically varying input data, methods or assumptions to determine how much chosen results change, thereby testing the robustness of conclusions.

Quantifying the range and probability of results caused by uncertain input parameters, often by propagating assigned distributions through the model to obtain an output distribution.

A numerical method that repeatedly samples input parameters from their assigned probability distributions, recalculates the model and builds a distribution of results for comparison.

An XML-based data exchange format originating in the ecoinvent database, structured in dataset and master-data sections, widely used to import and export inventory datasets between tools.

A European Commission specification for exchanging life cycle data, including processes, flows, flow properties and LCIA methods, with structured administrative and methodological metadata.

A JSON-based linked-data serialisation used by openLCA to store and exchange complete models, including processes, flows, parameters and impact methods, in a human-readable structure.

An independent examination of an LCA study confirming that methods, data and conclusions are consistent with the goal and scope and meet the requirements of the applicable standards.

The ability of an independent practitioner, given the same documented data, methods and model files, to recreate the reported results within acceptable deviation.

Documenting assumptions, data sources, modelling choices and limitations sufficiently that readers can understand and scrutinise how reported results were produced.

A verified, standardised report of a product's life cycle environmental performance across declared impact categories, based on product category rules and published for comparability.

Rules specifying the functional unit, system boundary, data requirements and reporting format for environmental declarations within a defined product group, ensuring declarations are comparable.

The total greenhouse gas emissions attributable to a product across a defined life cycle, expressed as carbon dioxide equivalent and typically following a dedicated standard.

A structured digital record of a product's composition, origin and sustainability attributes, accessible via a unique identifier and intended to support circularity and regulatory information exchange.

A metric describing how well materials are kept in use, such as recycled content, recovery rate or material circularity, used alongside LCA results to assess circular strategies.