with each process identified by a reference number.
It covers the main processes (one digit), groups (two digits) and sub-groups (three digits). The reference number for any process has a maximum of three digits. This system is intended as an aid in computerization and the drafting of, for example, drawings, working papers and welding procedure specifications, and enables the uniform international designation of the processes.
This document does not cover all process variants. The process numbers can be supplemented with additional information for variants not listed.