What are the ranks of a welder?

In Canada they are called "levels" , and start with level "C" then B and A there are also higher levels of sorts like "boiler maker" , but most other levels are added certifications which involve the different processes, as example "all position FCAW" (flux core arc welding ) these certifications can be achieved at different levels. The aforementioned could be achieved at level C , B or A . All of which require separate testing.