When a steam line ruptures during a plant shutdown, the inspector's first question is never "who welded this?" — it is "show me the WPS and the qualification record." Welding documentation is the invisible skeleton that holds your job together, and confusing its three parts —WPS, PQR/WPQR and the welder's certificate— is the fastest route to a rejected joint or a non-conformance that stalls start-up.
What a WPS really is, and why "knowing how to weld" isn't enough
The WPS (Welding Procedure Specification) is the recipe: the document that tells the welder how to make the joint. It is not decorative paperwork. It defines the process (for example 111 stick/MMA, 135 MAG with solid wire, or 141 TIG), the base material and its group, the filler metal, the amperage and voltage range, the position (from 1G to 6G on pipe), preheat, interpass temperature and the shielding gas with its flow rate.
A concrete example: for a TIG root pass in 316L stainless steel, the WPS specifies back-purging (argon) until residual oxygen drops below 0.5% before striking the arc; without that detail the root sugars over and the joint is scrapped no matter how skilled the welder. The WPS turns individual skill into a repeatable, auditable process. When Sparks Service mobilizes teams of certified welders, every work front starts with the approved WPS in hand — not with each operator's personal habits.
PQR and WPQR: proof the recipe works (and what they do NOT qualify)
Here is the industry's most expensive misconception. The PQR / WPQR (Welding Procedure Qualification Record) is the record that documents a real test weld, made under the WPS, and the tests it passed. Under EN ISO 15614-1 (or ASME IX in the American scope), that coupon is subjected to tensile, bend and macro tests and, where required, Charpy impact and hardness testing.
Critical, non-negotiable point: the WPQR qualifies the PROCEDURE, not the person. A valid WPQR proves that that way of welding produces a sound joint in that material and thickness. It says absolutely nothing about whether the welder standing on the scaffold today can reproduce it. Confusing the two is the mistake a quality-control inspector spots within five minutes of opening the dossier.
The correct logical chain is: a preliminary WPS (pWPS) is drafted, the coupon is welded and tested, and if it passes, the WPQR is issued to support the final WPS. A single WPQR can cover a range of thicknesses and diameters under the standard's rules, which optimizes cost on large jobs.
The human link: welder qualification under ISO 9606
If the WPQR validates the recipe, who validates the cook? The welder's certificate under EN ISO 9606-1 (for steels), the result of a Welder Qualification Test (WQT). It is a separate, named document with an expiry: it typically requires a validity confirmation every 6 months by the employer or welding coordinator, plus periodic revalidation.
Its coverage range depends on very specific essential variables: process, product type (plate or pipe), test position, material group and diameter. A welder qualified in the 6G pipe position (the toughest test — fixed pipe inclined at 45°) covers the lower positions by extension; one qualified only in flat 1G cannot legally run a vertical or overhead joint. On a real site, therefore, three distinct and complementary papers coexist: the WPS (how), the WPQR (the recipe is proven) and the ISO 9606 certificate (this person can execute it).
Where this plays out in Spanish industry
This documentary tripod is not theoretical: it is what separates a shutdown that starts on time from a contractual penalty. The target market is Spain. In the petrochemical hub of Tarragona and the ChemMed cluster, unit turnarounds demand full per-joint traceability dossiers, with isometrics linking each weld to its WPS, its WPQR and the welder's stamp. In naval construction at Cartagena (Navantia), naval steels and positional butt joints require highly specific qualifications. In refining —Petronor in Bilbao, the Huelva complex— and in steelmaking such as ArcelorMittal in Gijón, imposing EN ISO 3834 (quality requirements for fusion welding) on the contractor is routine.
Cost reflects that demand. A qualified pipe/plate welder with an in-order dossier runs, depending on specialty and urgency, in the €28–45/h range on a project basis; a certified orbital TIG welder for stainless or duplex commands more. Well-built documentation avoids the real hidden expense: redoing joints that radiography flagged as rejected, which multiplies the cost roughly fivefold across cut-out, re-beveling, re-welding and re-inspection.
How to build a dossier that passes inspection first time
A robust dossier rests on the Responsible Welding Coordinator (RWC), the role EN ISO 14731 requires and that many sites subcontract badly. Its minimum components:
- Index of current WPS, each backed by its referenced, traceable WPQR.
- Welder matrix: valid ISO 9606 certificates, with validity-confirmation dates and coverage range checked against the assigned joints.
- Inspection and Test Plan (ITP) covering the non-destructive tests (VT, PT, RT, UT) and NDT personnel qualified under EN ISO 9712 (levels I, II, III).
- Consumable traceability: filler-metal heat numbers, 3.1 certificates, low-hydrogen electrode control in the holding oven.
When these four elements line up, inspection stops being a lottery. That is the standard Sparks Service works to when deploying teams for this kind of shutdown: not just hands that weld, but the paper that backs them up. If you need to mobilize qualified personnel with documentation in order, you can request a quote and scope the work.
Preguntas frecuentes
Does the WPQR qualify the welder? No. The WPQR qualifies the procedure (the recipe for how to weld) under EN ISO 15614 or ASME IX. The welder is qualified separately, with a personal certificate under EN ISO 9606 after passing their test (WQT). They are two different documents and both are mandatory.
How often does a welder's certificate expire? The EN ISO 9606-1 certificate requires periodic validity confirmation —typically every 6 months by the welding coordinator— and revalidation under the standard's conditions. A welder with a lapsed certificate invalidates the joints they run, even when the physical quality is sound.
Can I reuse a WPS from another job? Yes, if its supporting WPQR covers the essential variables of the new work (process, material, thickness, diameter and position within the qualified range). Outside that range you must draft and qualify a new procedure; accepting it "because it looks similar" is a direct cause of non-conformance.
