CEN/TC 121 is responsible for standardization of welding by all processes, as well as allied processes; these standards include terminology, definitions and the symbolic representation of welds on drawings, apparatus and equipment for welding, raw materials (gas, parent and filler metals) welding processes and rules, methods of test and control, design of welded joints, qualification and/or education of welding personnel, as well as safety and health. Excluded: Electrical safety matters related to welding which is the responsibility of CENELEC/TC 26.

CEN/TC 121/SC 5 is responsible for the standardization providing uniform uniform procedures for non-destructive testing of welded joints and acceptance criteria for the individual methods.