Glossary

Terms as this project uses them. Where a term is common in LCA but used here more narrowly, the narrower sense is given.

altLabel

A synonym. From SKOS, where skos:altLabel is the alternative to skos:prefLabel. Stored per language.

Supplier grades, trade names and database accessions are not synonyms and are removed; see A product code is not a name.

CAS number

CAS Registry Number. Widely used but not a unique key for substance identity in this project's sense: one CAS may be listed by several database records, and database records occasionally claim a CAS belonging to a different substance. See How decisions are made.

ChEBI

Chemical Entities of Biological Interest, the EBI's chemical ontology. The primary source of synonyms and cross-references here.

ChemROF

The chemical representation ontology whose IRIs are used as property keys — molecular formula, molecular mass, elemental charge, atomic number, SMILES, InChI, InChIKey, IUPAC name — and as semantic types such as FullySpecifiedAtom and MonoatomicIon.

Concept association

A recorded correspondence between a consensus flow and a flow in a source list, expressed as an xkos:ConceptAssociation carrying a SKOS mapping property. This is what makes the output usable as a translation table.

Which property is a statement about the pair, not about the source list. skos:exactMatch is symmetric and transitive, so it is used only where the pairing is one-to-one on both sides; skos:broadMatch where one consensus flow groups several source flows, skos:narrowMatch where one source flow spans several consensus flows, and skos:relatedMatch where both are true.

That is counted after the merge has seen the whole source list, never while a row is being merged: which property a pairing supports depends on how many other rows of the same list land on the same consensus flow, and the row being merged cannot see them. A skos:closeMatch — written where a row was matched by identifier or label rather than asserted equivalent by a curator — is left as it is either way. It claims nothing that chains, and promoting it to a hierarchy would state more than the match knows.

Consensus matching

The step that decides a flow's preferred name and identifiers by weighing several independent sources against each other, acting only when confidence rules are met. Not to be confused with the project name.

Context

The compartment an elementary flow belongs to, expressed in this project's controlled vocabulary: a dimension, usually a media, and optionally one sub-attribute. There are 59 allowed contexts. See Flow contexts.

Context IRI

The canonical identifier for a context, e.g. https://vocab.brightway.one/flow-contexts/envi-air-grle-ur10pesq. This, not the display strings, is the authoritative form. Contexts should always be resolved from the IRI; reconstructing one by parsing display strings loses information, because Unknown values are omitted from the display form.

Dimension

The top level of the context taxonomy: Environmental, Resource, Land Use, Economic, Social, or Inventory Indicator. Added on top of the Edelen taxonomy so that flows without a direct environmental effect can still be characterised.

Elementary flow

Here specifically: one substance in one context, identified by elementary_flow_id. Carries context, unit, LCIA methods, and source references. See Flow objects and elementary flows.

EF 3.1

The European Commission's Environmental Footprint reference flow list, version 3.1, distributed in ILCD format. The base input for this project.

Flow object

The canonical identity of a substance, identified by flow_object_id (format fo- followed by 16 hex characters). Carries names, synonyms, registry numbers, and chemical properties. Shared across all contexts in which the substance appears.

GLAD

The Global LCA Data Access network. Its ILCD-to-SimaPro substance mapping workbook is used to generate concept associations to SimaPro flows, by a build that merges a list whose flows originate in SimaPro. Each row pairs an EF 3.1 flow with a SimaPro one; the SimaPro concept is identified by substance and compartment, because the workbook's TargetFlowUUID names only the substance.

Harmonised flow

An intermediate record: one input flow after all processing steps have run, but before the split into flow objects and elementary flows. Stored in elementary_flows.flow_json; it was written to harmonised-flows.json until the pipeline stopped producing that file.

ILCD

International Reference Life Cycle Data System, the XML format EF 3.1 ships in.

InChI / InChIKey

IUPAC structure identifiers. The InChIKey is a fixed-length hash of the InChI; its first block (the "skeleton") encodes connectivity, so two records with different skeletons are structurally unrelated substances.

Layering

The step that takes processed flows and resolves them into the two output layers — flow objects and elementary flows. Also available on its own via the build command.

Merge

Folding an additional source list (currently ecoinvent) into an existing consensus list, adding source references to matching flows and creating new flows where nothing matches. Distinct from the transform, which builds the list in the first place.

Origin qualifier

A tag marking a flow that must not share a flow object with the base substance despite sharing its CAS number: biogenic, fossil, land_use_change, biogenic_resource_correction, biogenic_100yr, green_water, blue_water, grey_water, alpha_emitters, delayed_emission_correction, biogenic_delayed_emission_correction, fossil_delayed_emission_correction.

prefLabel

The preferred name, one per language. From SKOS.

Provenance

A structured record of where a data value came from, following PROV-O — not free text. Distinct from the change log, which records which processing step wrote a field.

Resource (dimension)

In this project, Resource is reserved for accounting concepts such as "mass fraction of zinc" or "energy, geothermal, converted". A named mineral such as sphalerite is a tangible substance and gets Environmental with a media instead. This differs from most source lists and is a deliberate choice — see Flow contexts.

SKOS

Simple Knowledge Organization System. Supplies prefLabel, altLabel, definition, and the mapping properties (exactMatch, closeMatch, broadMatch, narrowMatch, relatedMatch) used in concept associations.

Source ref

An entry in an elementary flow's source_refs recording one contributing source flow: its list name and version, original UUID, original name, and original compartment strings. Never discarded, so a merge remains auditable.

Transform

The main pipeline run: load inputs, apply every processing step in order, then layer and export. Invoked as consensus-flow-list build.

Transformer

One processing step in the transform. Twenty run by default, in a fixed order. Each proposes changes rather than editing flows directly, which is what makes the change log complete. See Harmonisation steps.

XKOS

An extension of SKOS for statistical classifications, used here for xkos:ConceptAssociation. Note that XKOS defines no property for the type of a mapping, so the match kind is expressed with the SKOS mapping property itself rather than with any mapType property.