The procedure test. A coupon is welded and tested destructively, and what it proves becomes a qualified range. The range is what counts.

Procedure qualification is not paperwork

A preliminary welding procedure specification is written, a test piece is welded under supervision, and the result is examined and tested: visual, radiographic or ultrasonic, surface crack detection, transverse tensile, bend or fracture, impact where required, hardness where required, macroscopic examination.

What comes out is a welding procedure qualification record, and from it the range over which the procedure may be used in production.

Levels

The standard provides two levels. Level 2 requires more testing and gives narrower qualified ranges; it applies by default and automatically covers Level 1. Level 1 (aligned with ASME) is available only where the contract or the application standard permits it.

Ranges

Parent material group, thickness, diameter, process, filler metal, position, heat input, preheat and interpass temperature, post-weld heat treatment: each has a rule for how far the qualification extends. Some are generous, some are narrow, and the narrow ones are where production quietly steps outside the range.

The failure mode is not dramatic. Nobody welds outside a procedure on purpose. It happens because the thickness on this job is 22 mm and the qualification was made at 12 mm, and the person making the assignment did not have the range in front of them.

The relationship to the code you are working under

EN 1090, PED and EN 15085 all reach for this standard rather than restating it. That is why it sits underneath several regimes at once — and why a shop working across regimes qualifies once and reuses, provided the record is precise enough to be reused safely.