Sustainability Ontology
A governed, machine-readable ontology for environmental and ESG data: 128 formally defined O-DEF terms across 3 axes, exposed through a semantic layer API for cross-system alignment and backed by a versioned registry with drift detection.
Three Semantic Axes
Every concept in the ontology is classified along three axes, so each term carries an unambiguous, machine-readable meaning.
Object Classes
What the data element represents (e.g., Resource, Process, Indicator, Ledger)
Roles
The relationship or function of the data element (e.g., Emitter, Trader, Auditor)
Properties
The measurable attribute (e.g., Measure, Amount, Factor, Rating, Identifier)
Governed O-DEF Registry
The ontology is maintained as a versioned O-DEF registry. Changes are proposed, validated, and approved through a governed workflow so the definitions in git stay aligned with the models actually running in production.
Versioned approvals
Every release is a numbered version. Proposed changes become a draft, then a pull request that moves the approved pointer — the audit record lives in git.
Drift detection
The registry is continuously compared against the fields applied in the Open Footprint models. Renames and mismatches are flagged before they silently break consumers.
Validation gates
Registry submissions run the same server-side validation as CI. Breaking changes, numbering gaps, and source corrections are surfaced before approval.
Semantic Codes
Each ontology term carries a 3-axis semantic code. Codes are assigned using O-DEF™ (Open Data Element Framework), The Open Group standard we used to define the semantics.
Example:
ofp-sustainability:3.1~1.1_5.1Resource.Emission-Source ~ Trader.Emitter _ Measure.Greenhouse-Gas-Emission
Registry Coverage
Ontology Browser
Search and filter across 128 approved O-DEF registry terms.
Person
Object Classesobject classA human being, whether man, woman, or child.
1Enterprise
Object Classesobject classA collection of people organized to achieve a common set of goals.
2Enterprise.Reporting-Organization
Object Classesobject classAn enterprise that prepares and submits sustainability / GHG reports under a defined reporting boundary (organizational or operational).
2.1Enterprise.Supply-Chain-Partner
Object Classesobject classAn enterprise within the supply chain that contributes emission data for Scope 3 upstream or downstream categories.
2.2Enterprise.Organization-Association
Object Classesobject classAn association, membership, or relationship between organizations or between an organization and a person.
2.3Resource
Object Classesobject classA source or supply from which benefit is produced. Typically, resources are materials, energy, services, knowledge, or other assets.
3Resource.Emission-Source
Object Classesobject classA resource (fuel, feedstock, refrigerant, etc.) that directly or indirectly produces greenhouse gas emissions when consumed or processed.
3.1Resource.Emission-Sink
Object Classesobject classA resource that removes greenhouse gases from the atmosphere (forests, soil, CCUS storage).
3.2Resource.Natural-Asset
Object Classesobject classA natural resource subject to ESG reporting: water, minerals, biological assets.
3.3Resource.E-Ledger
Object Classesobject classA ledger resource for tracking accountability balances, entries, debits, credits, and transfers.
3.4Resource.Equipment
Object Classesobject classA physical asset - machinery, vehicle, meter, or installed unit - that consumes resources or produces emissions when operated.
3.5Location
Object Classesobject classA place or position. Typically, locations provide geographic or geometric context that characterizes the data element.
4Location.Facility
Object Classesobject classA physical installation, plant, or site where emission-producing activities occur.
4.1Location.Jurisdictional-Area
Object Classesobject classA geographic area defined by regulatory or political boundaries relevant to compliance obligations.
4.2Location.Spatial-Reference
Object Classesobject classA coordinate reference system, spatial transformation, or abstract spatial location used for geospatial data.
4.3Location.Address
Object Classesobject classA postal or civic address identifying where an organization, person, or facility can be reached or is registered.
4.4Event
Object Classesobject classAn occurrence happening at some point or points in time, with or without the participation of human agents.
5Event.Emission
Object Classesobject classA recording event capturing one or more emission measurements or calculations for a defined period.
5.1Event.Measurement-Environmental-Data
Object Classesobject classA discrete sensor reading, sampling, or monitoring event producing raw environmental data (CEMS, meters).
5.2Event.Verification-Emission
Object Classesobject classAn audit, assurance, or verification activity applied to emission data.
5.3Event.Allocation-Emission-Quantities
Object Classesobject classAn event where emission quantities are allocated to facilities, activities, organizations, or products.
5.4Condition
Object Classesobject classA particular mode of being of a person or thing; existing state; situation with respect to circumstances.
6Condition.Compliance-State
Object Classesobject classThe regulatory compliance status of an entity against a specific framework (CSRD, SEC, ISSB).
6.1Condition.Data-Quality-State
Object Classesobject classThe data quality condition of an emission record, assessed against PACT DQI dimensions.
6.2Condition.Quality-Rule-State
Object Classesobject classA data quality rule, rule set, or assessment state used to evaluate and enforce data integrity.
6.3Condition.Non-Conformance
Object Classesobject classA deviation from expected data quality, regulatory compliance, or internal standards requiring corrective action.
6.4Environment
Object Classesobject classThe natural or man-made surroundings of someone or something.
7Environment.Climate-Zone
Object Classesobject classA climatic region that influences emission patterns and baseline assumptions.
7.1Environment.Ecosystem
Object Classesobject classAn ecological system relevant to biodiversity impact assessment.
7.2Law-Rule
Object Classesobject classA law (natural or man-made) or policy that governs a process.
8Law-Rule.Regulation-Framework
Object Classesobject classA regulatory or voluntary reporting framework governing sustainability disclosure (CSRD, SEC Climate, ISSB S2, EU ETS).
8.1Law-Rule.Emission-Standard
Object Classesobject classA technical standard defining how emissions are measured, calculated, and reported (GHG Protocol, ISO 14064, ISO 14067).
8.2Law-Rule.Product-Category-Rule
Object Classesobject classA product category rule (PCR) or environmental product declaration (EPD) standard governing product footprint calculation.
8.3Process
Object Classesobject classA series of actions, changes, or functions bringing about a result.
9Process.Emission-Activity
Object Classesobject classAn activity that produces greenhouse gas emissions: combustion, fugitive release, industrial process, purchased energy.
9.1Process.Emission-Calculation
Object Classesobject classThe application of emission factors, allocation methods, or models to convert activity data into CO2e.
9.2Process.Emissions-Remediation
Object Classesobject classAn activity that reduces, offsets, or removes emissions: renewable energy, carbon capture, efficiency improvement.
9.3Process.Approval-Workflow
Object Classesobject classA workflow process for reviewing and approving emission data, ledger entries, or reports.
9.4Process.E-Liabilities-Transfer
Object Classesobject classA process for transferring e-liabilities between ledgers, organizations, or products along the value chain.
9.5Product
Object Classesobject classThe result of a process.
10Product.Carbon-Intensive-Production
Object Classesobject classA product whose production generates significant embodied carbon (steel, cement, chemicals, aluminium).
10.1Product.Carbon-Footprint
Object Classesobject classA product bearing a Product Carbon Footprint (PCF) as defined by ISO 14067 / PACT.
10.2Product.Lifecycle-Stage
Object Classesobject classA stage within a product life cycle (raw material, manufacturing, distribution, use, end-of-life) relevant to PCF calculation.
10.3Substance
Object Classesobject classA material of a particular kind that bears physical and chemical properties. Substances can be solid, liquid or gaseous.
11Substance.Greenhouse-Gas
Object Classesobject classA gaseous substance contributing to radiative forcing: CO2, CH4, N2O, HFCs, PFCs, SF6, NF3.
11.1Substance.Pollutant
Object Classesobject classA non-GHG substance causing environmental pollution: SOx, NOx, PM, VOCs.
11.2Substance.Water-Stewardship
Object Classesobject classWater in any state relevant to water stewardship reporting: freshwater, wastewater, recycled water.
11.3Information-Set
Object Classesobject classA collection of information, whether in physical form (such as a book), machine-readable form (such as a file on disc), or human memory.
12Information-Set.Emission-Report
Object Classesobject classA structured report of emission data for a reporting period, conformant to a reporting framework.
12.1Information-Set.Audit-Trail-Record
Object Classesobject classAn immutable record documenting data lineage, transformation history, and custody chain.
12.2Information-Set.Conservation-Check
Object Classesobject classA reconciliation record verifying mass-balance or ledger conservation (e.g., e-liability totals match).
12.3Information-Set.Reporting-Period
Object Classesobject classA defined time interval for which emission data is collected and reported.
12.4Information-Set.Emission-Factor
Object Classesobject classReference information carrying emission conversion factors and their sources, used to derive emission quantities from activity data.
12.5Information-Set.Unit-Reference
Object Classesobject classReference information defining units of measure, unit systems, physical quantity kinds, and currencies used to express measured or monetary values.
12.6Information-Set.Emission-Inventory
Object Classesobject classA structured inventory of emission sources and quantities for an organization or facility, organized by category for reporting.
12.7Service
Object Classesobject classA valuable potential or actual action, deed, or effort to satisfy a need or to fulfill a demand.
13Service.Independent-Verification
Object Classesobject classA third-party or internal service providing independent assurance of emission data.
13.1Service.OFP-Data-Ingestion
Object Classesobject classA service that ingests, transforms, and maps raw data to the OFP Recording Domain.
13.2Service.Sustainability-Assurance
Object Classesobject classA service providing formal assurance or attestation of sustainability reports and organizational boundaries.
13.3Trader
RolesroleAny role derived from any kind of trade relation of the implied or referenced object.
1Trader.Emitter
RolesroleAn entity that produces greenhouse gas emissions and holds the resulting e-liability.
1.1Trader.Offsetter
RolesroleAn entity that generates or purchases carbon offsets/credits to compensate for emissions.
1.2Trader.Supplier
RolesroleA supply chain partner providing embedded emission data for Scope 3 upstream categories.
1.3Lineage
RolesroleAny role derived from a relationship of the implied or referenced object with a common heritage.
2Lineage.Emission-Provenance-Chain
RolesroleThe provenance chain tracing emission data from measurement point through processing to final report.
2.1Lineage.Product-Supply-Chain
RolesroleThe supply chain lineage of embodied carbon through product life-cycle stages.
2.2Organized-Structure
RolesroleAny role derived from the configurational/organizational relation of an object.
3Organized-Structure.Reporting-Hierarchy
RolesroleAn organizational hierarchy defining the reporting boundary (equity share, operational control, financial control).
3.1Organized-Structure.Address
RolesroleA postal or physical address structure within an organizational entity.
3.2Organized-Structure.Contact
RolesroleA contact person or point of contact within an organizational entity.
3.3Citizenship
RolesroleAny role derived from nationality of an implied or referenced person object.
4Proxy
RolesroleAny role derived from a kind of intermediation on behalf of an implied or referenced object.
5Proxy.Emission-Factor
RolesroleA proxy value used to convert activity data into estimated GHG emissions when direct measurement is unavailable.
5.1Proxy.Estimated-Value
RolesroleAn estimated quantity derived from proxy data, models, or extrapolation rather than direct measurement.
5.2Proxy.Aggregation
RolesroleAn aggregated or rolled-up value derived from detail-level records.
5.3Target
RolesroleAny role derived from a treatment with the intent to change an implied or referenced object.
6Target.Reduction-Goal
RolesroleA defined emissions reduction goal (SBTi-aligned, net-zero, absolute/intensity target).
6.1Target.Compliance-Threshold
RolesroleA regulatory threshold or cap that must not be exceeded (EU ETS allocation, EPA limits).
6.2Capability
RolesroleAny role derived from an acquired, trained, tuned, configurated or calibrated capability of an implied or referenced object.
7Capability.Emissions-Measure
RolesroleThe ability to directly measure emissions via instruments (CEMS, flow meters, gas analysers).
7.1Collectiveness
RolesroleAny role derived from collective characteristics of implied or referenced objects.
8Collectiveness.Scope-Individual-Emissions-Aggregation
RolesroleThe aggregation of individual emission records into Scope 1, 2, or 3 totals.
8.1Collectiveness.Portfolio-Multiple-Entities-Emissions-Aggregation
RolesroleThe aggregation of emissions across multiple entities, facilities, or products into portfolio-level totals.
8.2Leveragability
RolesroleAny role derived from leveragability of an implied or referenced object.
9Leveragability.Intensity-Ratio
RolesroleA ratio expressing emission intensity relative to a business metric (revenue, production volume, FTE).
9.1Classifier
RolesroleThe member acts as a controlled classification value - a type, category, status, or scheme entry - that categorizes instances of its object class rather than being an instance itself.
10Identifier
PropertiespropertyA value that is intended to identify uniquely the object of the data element.
1Identifier.External
PropertiespropertyAn identifier originating from an external system, registry, or partner.
1.1Identifier.Reference
PropertiespropertyA foreign key reference to another entity within the OFP data model.
1.2Name
PropertiespropertyA word or phrase that refers to the object of the data element but is not intended to identify it uniquely.
2Code
PropertiespropertyA value from an enumerated list of possible values that is not an Indicator and that is not subject to continual change.
3Code.Emissions-Scope
PropertiespropertyA code categorizing emissions into Scope 1 (direct), Scope 2 (energy indirect), or Scope 3 (other indirect).
3.1Code.Emissions-Data-Quality
PropertiespropertyA code representing data quality along PACT DQI dimensions (temporal, geographical, technological, reliability, coverage).
3.2Code.ESG-Governance
PropertiespropertyA code representing ESG governance metrics (board diversity, policy compliance, anti-corruption).
3.3Code.Social-Performance
PropertiespropertyA code representing social performance metrics (workforce safety, diversity, training, living wage).
3.4Code.Entity-Category
PropertiespropertyA code classifying an entity into a type or category from a controlled vocabulary.
3.5Code.Lifecycle-Status
PropertiespropertyA code representing the lifecycle or workflow status of an entity.
3.6Code.Verification-Status
PropertiespropertyA code representing the verification or assurance status of a data element or report.
3.7Indicator
PropertiespropertyA value that is one of only two (true or false) possible choices.
4Measure
PropertiespropertyA numeric quantity that has an explicit or implied unit of measure other than a monetary unit.
5Measure.Greenhouse-Gas-Emission
PropertiespropertyA measure of greenhouse gas emissions in a CO2-equivalent unit (kgCO2e, tCO2e).
5.1Measure.Water-Volume
PropertiespropertyA measure of water volume (withdrawal, discharge, consumption) in cubic metres or equivalent.
5.2Measure.Biodiversity-Index
PropertiespropertyA measure of biodiversity status or impact (MSA, BII, species richness index).
5.3Measure.Spatial
PropertiespropertyA spatial coordinate, distance, or geometric measurement.
5.4Quantity
PropertiespropertyAn integral numeric quantity that has no unit of measurement.
6Quantity.Greenhouse-Gas-Emissions
PropertiespropertyThe total quantity of greenhouse gas emissions for a given activity, period, and scope.
6.1Quantity.Emissions-Activity-Drivers
PropertiespropertyThe quantity of an activity driver (kWh consumed, litres fuel burned, km travelled) used in emission calculations.
6.2Amount
PropertiespropertyAn explicit or implied monetary unit of measure.
7Amount.Carbon-Amount
PropertiespropertyA monetary or physical amount specifically associated with carbon (carbon price, carbon tax, carbon credit value).
7.1Amount.Ledger
PropertiespropertyA monetary or quantitative amount in a ledger context (balance, debit, credit).
7.2Rate
PropertiespropertyA real numeric quantity, possibly expressed as a fraction, but not as a percentage.
8Rate.Greenhouse-Gas-Emission
PropertiespropertyThe rate of greenhouse gas emission per unit time (kg/hr, t/year) or per unit activity (kgCO2e/kWh).
8.1Percent
PropertiespropertyA numeric quantity expressed as a percentage. Percent is a specialized Rate.
9Percent.Emissions-Reduction
PropertiespropertyThe percentage reduction of emissions relative to a baseline year or reference scenario.
9.1Date
PropertiespropertyA specific date in the progression of time.
10Date.Period-Start
PropertiespropertyThe start date of a reporting, validity, or observation period.
10.1Date.Period-End
PropertiespropertyThe end date of a reporting, validity, or observation period.
10.2Date.Validity-Start
PropertiespropertyThe start date of a validity or applicability window for factors, rules, or registrations.
10.3Date.Validity-End
PropertiespropertyThe end date of a validity or applicability window for factors, rules, or registrations.
10.4Date-Time
PropertiespropertyA specific date plus time in the progression of time.
11Date-Time.Effective
PropertiespropertyThe date-time when a record, rule, or status becomes effective.
11.1Date-Time.Termination
PropertiespropertyThe date-time when a record, rule, or status ceases to be effective.
11.2Time
PropertiespropertyA specific time within a specific timeframe.
12Text
PropertiespropertyText that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, or time.
13Text.Description
PropertiespropertyDescriptive free text providing context about an entity or record.
13.1Text.Formula
PropertiespropertyA textual formula, rule expression, or calculation specification.
13.2Text.Comment
PropertiespropertyA free-text annotation, reviewer note, or explanatory comment.
13.3Binary
PropertiespropertyA value that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, time, or text.
14Semantic Layer API
The ontology is not just documentation — it is served as a semantic layer for cross-system alignment. Connectors and agents can look up the canonical meaning of a field, discover which fields share a semantic code, and map external data to Open Footprint without guesswork.
Cross-system alignment
A source-system field (e.g., SAP Material Group) can be related to its canonical counterpart (e.g., CPC Code) through a shared O-DEF semantic code, even when the names and formats differ.
GET /api/v1/ofp/semantics/{code}
Model-wide annotations
Every entity response carries field.odef data, and the semantic layer exposes which of the 660+ annotated fields share each code, complete with field-count cautions to avoid mapping onto noise.
Semantic Grounding Chain
The approved O-DEF registry annotates every Open Footprint data element with a 3-axis semantic code. That code is exposed through the semantic layer API so external systems — ERP, LCA tools, satellite pipelines — can map to the canonical model with confidence.
Alignment Ontologies
QUDT, SOSA, PROV-O, GeoSPARQL, and FIBO mappings from the O-DEF grounding chain.
Units of Measure
Energistics UoM as system of record, QUDT as its RDF face in the knowledge graph.
Semantic API
Natural-language and programmatic access to verified emissions data and model validation.