Pipe classes can have different sources of origin. For example the process licensor has defined the basic 'lay-out' of the pipe class, defining the material, component types and size ranges.

In this particular case the licensor provided the basic requirements for the pipe class. The pipe class included the material of construction the pressure/temperature range and the size range. The pipe classes have been further detailed regarding the welding grouping, material certificates, schedules of the pipe and fittings, commodity codes per customer requirements and the full approval cycle with the Notified Body for authority approval. (Borealis)