Before any structural or pressure-retaining weld is made, three questions should already have answers. Is there an approved method for making this joint? Has that method been proven to produce a sound weld? And is the person holding the torch qualified to carry it out? The documents that answer them are the WPS, the PQR and the welder qualification record, and an inspector reads them before the first arc.
Many disputes about weld quality trace back to one of these documents being missing, mismatched or borrowed from somewhere it was never meant to apply. This guide explains what each one proves, what an inspector checks, and where fabrication projects in Indonesia most often go wrong, particularly when procedures cross company boundaries.
- Three documents, three questions
- What a WPS contains, and essential variables
- The PQR is evidence, not a formality
- Whose qualification is it? The borrowed procedure problem
- Welder qualification: range and continuity
- A pre-welding review checklist
- Red flags inspectors learn to spot
- Frequently asked questions
Three Documents, Three Questions
The welding procedure specification, or WPS, is the instruction. It lists the variables a welder must follow to make a particular joint: process, material, thickness range, consumables, preheat, parameters and more. It is written for the shop floor.
The procedure qualification record, called a PQR under the ASME system and referred to by other names such as WPQR or WPAR under ISO practice, is the proof. It documents the test weld made to show that the procedure produces a joint with the required properties, together with the test results. It is written for the reviewer.
Welder qualification is the third element. It shows that a specific person has demonstrated the skill to make sound welds within a defined range. For mechanized or automatic welding, a similar approval applies to the welding operator. A complete chain therefore runs from the instruction through the proof to the person.
What a WPS Contains, and Essential Variables
A WPS is more than a page of numbers. According to the TWI guidance on welding procedures, it lists the variables needed to achieve the required weld quality and mechanical properties, and it is supported by records of how the test weld was made and tested. Typical content includes joint design, position, filler and shielding, preheat and interpass limits and post-weld heat treatment.
Essential variables are the settings whose change may affect weld quality or properties. When one changes beyond the allowed range, the procedure is no longer covered by its qualification and a new approval test is needed. Typical examples include the material type, the welding process, the thickness range and sometimes the position. The exact list depends on the code.
An inspector reads the WPS with this in mind. The question is not whether the page looks complete, but whether the joint about to be welded falls inside the ranges that the procedure was qualified for. A WPS issued for a thickness the qualification never covered is a document without evidence behind it.
The PQR Is Evidence, Not a Formality
A WPS is normally created by preparing a preliminary procedure, welding a test piece, testing it and recording the results. If the examiner or the responsible party accepts the record, it becomes the basis for one or more production WPSs. The record is the reason the WPS can be trusted.
When reviewing it, the inspector checks several things. Does the record show the tests the code and the contract require, such as tensile, bend, hardness or impact tests where relevant? Were the results within the acceptance limits? Does the record cover the material group, thickness range and heat treatment condition of the production WPS?
Contract requirements often go beyond the basic code. Service conditions, low temperatures or sour environments can add mandatory tests. Establish at the start which requirements apply, because a procedure that satisfies the code may still fail the project specification if it omits a test the contract adds.
Whose Qualification Is It? The Borrowed Procedure Problem
A common trap on projects with foreign owners is the borrowed procedure. A head office supplies a WPS and PQR from another project, or a fabricator proposes one qualified by a sister company or a previous employer. It looks convenient, and sometimes it is permitted, but the rules are stricter than many buyers expect.
TWI explains that under ASME IX the company that controls production welding must use a WPS it has qualified itself, or one of the standard welding procedure specifications formally adopted under the code. Under AWS D1.1, production WPSs must be qualified under the code or be prequalified within its limits, and the using company stays responsible for them. ISO routes allow some use of another organisation’s test data in defined ways.
This is not a statement about what your own contract allows, which may differ. It is a prompt to ask early whose qualification the procedure represents, and who holds responsibility for the production welding. If the answer is unclear, resolve it before fabrication starts.
Welder Qualification: Range and Continuity
A welder’s certificate is valid for a defined range, not for welding in general. The range typically covers the process, the material group, the filler type, the thickness or diameter and the welding position. A welder who tested on plate in one position is not automatically qualified for pipe in another.
Inspectors therefore compare each welder’s certificate with the joints that welder will make. The check is practical: process, material, thickness, position and the identification of the person. Certificates should be dated, signed by the examiner and issued under the code the project uses, or accepted by agreement under an equivalent one.
Continuity is the second point. Codes include rules on how long a qualification remains valid and what keeps it alive. ASME IX contains a continuity rule tied to welding with the process within a period, while ISO 9606 uses a validity and confirmation approach that is not the same. Check the rule of the code in force for your project rather than assuming one applies to the other.
A Pre-Welding Review Checklist
A short checklist makes the review repeatable. Before welding begins, an inspector will typically confirm that:
- the code and edition in the procedure match those in the contract;
- every WPS is supported by a PQR that covers its ranges;
- the production joints fall within the thickness, material and position ranges;
- each welder’s certificate covers the joints that welder will make;
- the consumables named in the WPS are the ones on site, with their batch records;
- required approvals from the buyer or its engineer are on file;
- the weld map links joints, WPSs and welders.
The seventh item matters more than it looks. A weld map that matches joints to procedures and people turns the review from an abstract paper check into a plan for the job, and it exposes gaps, such as a position nobody on the crew is qualified for, before anyone starts cutting.
Red Flags Inspectors Learn to Spot
Experience teaches inspectors to look at certain patterns. A PQR that carries another company’s name and no explanation of how it applies is one. A WPS that was revised after approval with no new qualification, despite a change in an essential variable, is another. A qualification record issued under a different standard without any agreed equivalence is a third.
Welder certificates deserve particular care. Missing dates, unsigned records, certificates issued to another employer without an accepted transfer, or positions that do not match the work are all reasons to pause. A certificate in good order for a different joint offers no comfort.
On Indonesian projects, crews often include sub-contract welders who move between yards. The right response is not suspicion but verification, done calmly and early. G.I Quality Services lists welding inspection and documentation review among its QA/QC services, and these are exactly the reviews that prevent expensive repairs later.
Frequently Asked Questions
What is the difference between WPS and PQR?
A WPS is the instruction that tells welders how to make a joint. A PQR is the record of the test weld and test results that proves the procedure produces a joint with the required properties.
What is an essential variable in welding?
It is a variable whose change can affect weld quality or mechanical properties, such as the process, material type or thickness range. If one changes beyond the allowed range, the procedure needs requalification.
Can a fabricator use another company’s WPS?
It depends on the code and the contract. Under ASME IX, the company controlling production welding must use a procedure it has qualified itself, or a formally adopted standard procedure. Check the applicable code and agree the position before welding starts.
How long is a welder qualification valid?
It depends on the code. Different codes handle validity and continuity differently, so check the rules of the code that applies to your project and ask for evidence that the welder has maintained the qualification.
What should I check on a welder’s certificate?
Check the welder’s identity, the process, material group, filler type, thickness or diameter, position, the code used, the date and the examiner’s signature. Then compare them with the joints the welder will actually make.
Who approves the WPS and PQR on a project?
Usually the fabricator prepares them and the buyer or its engineer reviews and approves them according to the contract. An independent inspector may review them as well and report any mismatch before fabrication starts.