The "ISO 15926 is a standard about interoperability in the process industry. An important part of it is the Reference Data library, which holds technical class descriptions of all the main equipment items, pipe, instruments, buildings, activities and anything else used in engineering, constructing, procuring, operating and maintaining process facilities. This Reference Data Library is made on-line and extendable by the public. This on-line database is called the WIP.
The acronym WIP stands for Work In Progress database. It is the "ISO 15926 Reference Data Library which contains the approved core library set and the Object Information Models (e.g. product models), but is expanded with proposed classes and proposed model extensions.
So, in other words: The set of terms used to classify equipment, activities etc., and their properties are expandable by the users themselves so that extensions can be used immediately.
It has taken the process industry 15 years to build the content. This is now available free to the public.
To expand the set a user must be certified. This is to keep the Reference Data Library in a certain structure, and directly usable for all the various connected projects.
When a new item is submitted by a certified user, it can be used immediately, and it will also enter an approval cycle performed by modeling and domain matter experts. In this cycle the new item can reach a higher status of approval; up until ISO certification.
In order to create the WIP, the builders needed to have the content, the infrastructure and the tools.