Context
A knowledge graph needs a metamodel, a schema that says what kinds of nodes and relationships exist. You can roll your own, but for asset information there is a mature, well-considered option: ISO 15926-11. It is the most developed semantic standard for industrial asset information.
Most customers don't need to invent a domain ontology. ISO 15926-11 gets them 80% of what they need on day one.
Explanation
Three things to know:
What it is
ISO 15926-11 is the 'integrated information model' part of the broader ISO 15926 standard, under development across the process and energy industries since the 1990s. It defines core classes (Physical Object, Functional Object, Activity, Property) and the relationships between them. Battle-tested in oil & gas, power generation and increasingly in nuclear.
Why we ship it as default
Most customers don't need to invent a domain ontology, and inventing one is one of the most failure-prone parts of any asset-information project. ISO 15926-11 gets them 80% of what they need on day one. Adopting an open standard also avoids the 'every vendor has its own metamodel' problem that has plagued asset management for two decades.
Why it's extensible
The standard expects customisation. You inherit the core classes and add domain-specific subclasses. 'NuclearReactorVessel' is a subclass of 'Physical Object' with its own properties. The extensions are RDF, queryable, and machine-readable, not vendor-proprietary.
Adopting ISO 15926-11 isn't mandatory in Weaver, you can ship your own metamodel if you have one. But starting from a standard saves months of ontology work and ensures cross-organisation interoperability when external auditors, regulators or partners need to read your data.