The purpose of ISO 15926 is "Integration, sharing, exchange, and hand-over of distributed Plant Lifecycle Information.".
This paper gives a possible configuration scenario.
A picture says more that a thousand words:
During the life cycle of a facility hundreds of applications contribute data about activities performed for and by that facility. These data are mapped to objects and templates and stored in an Application or Discipline Store. Such a store is a commercial triple store with an API that is (for now: "will be") standardized in ISO 15026-9. All Part 9 stores behave in an identical manner.
Once the discipline or group that uses the application feels that their information is good enough to be shared with others, they can perform a "hand-over" from the applicable Application or Discipline Store to the Project Store.
Most applications require data that have been created by others. By means of SPARQL queries each application can be fed with those data. The query results have to be mapped to the internal format of that application. Applications used by external parties must be served via the "Pub Triple Store" (see below).
At the time of a custody transfer of a particular process unit to the plant owner/operator, the applicable data can be selected from the Project Store and the custody thereof can be handed over as well.
The plant owner/operator could feed operational data and maintenance data into his Facility Store in a similar manner. At the time of a revamp information about the unit to be revamped can be made available to the EPC contractor, thus avoiding mismatches caused by changes due to maintenance taking place during the engineering and procurement activities of that EPC contractor.
All triple stores of the EPC preferrably are on their Intranet, except for the shown "Pub Triple Store", that is for data and/or documents that need to be exchanged with an external party, with due security measures and a log. This is their 'Gateway to the World'. And identical set-up can be made at the side of the Owner/Operator and any organization that has ISO 15926 compliant software.