The phrase “coded welding” gets used loosely, and that vagueness causes real problems when a project is inspected or an insurer asks questions. A coded welder is not simply an experienced welder. It is a welder who has been formally tested and certified to produce welds to a specific procedure, under a recognised standard, within a defined scope.
What the certification actually covers
Coded welding rests on three connected documents, and understanding them makes it much easier to specify work correctly.
- The WPS (Welding Procedure Specification) is the recipe: the process, material, joint design, filler, gas, current range, pre-heat and technique required to produce a sound weld for that application.
- The PQR (Procedure Qualification Record) is the evidence that the recipe was followed and the resulting weld passed destructive and non-destructive testing.
- The welder qualification certifies that a named individual can execute that procedure, verified by testing their own test piece.
So a properly coded weld means a qualified person working to a proven procedure — not just a skilled hand with good technique.
Certification is scoped, not universal
This is the part most often misunderstood. A welder coding is not a blanket licence to weld anything. Each certificate covers a defined range, typically including:
- The welding process (for example MMA, MIG/MAG or TIG)
- The material group — carbon steel certification does not automatically cover stainless or aluminium
- A thickness range, derived from the thickness of the test piece
- The position welded, since overhead and vertical work is qualified separately from flat
- The joint type, such as plate versus pipe, and butt versus fillet
Certificates also carry validity periods and require confirmation of continuity — evidence that the welder has been working within that scope. An expired or lapsed certificate is not a technicality when an inspector reviews the file.
When your project genuinely needs coded welding
Coded welding is not required for every job, and insisting on it for general fabrication adds cost without adding value. It becomes necessary where weld failure carries safety, statutory or financial consequences:
- Pressure equipment. Pressure vessels, boilers and pressure piping are governed by regulation, and the welding must be traceable to qualified procedures.
- Pipelines and process piping carrying hazardous, flammable or high-pressure media.
- Structural steel where the weld carries load — building structures, gantries, support frames and platforms.
- Lifting and load-bearing equipment, where failure endangers people directly.
- Anything an insurer or client specifies. Many contracts and insurance policies require certified welding regardless of the engineering argument.
The cost of getting this wrong
Uncertified welding on work that required certification tends to surface at the worst possible moment: at inspection, at commissioning, or after a failure. The consequences are predictable — rejected work that must be cut out and redone, delayed sign-off, disputed insurance claims, and in the case of pressure or lifting equipment, potential regulatory exposure.
Cutting out and re-welding a rejected joint is always more expensive than welding it correctly the first time, and that is before counting the schedule damage.
How to verify a contractor’s claim
If a supplier describes their welding as coded, it is entirely reasonable to ask for the documentation. Specifically:
- Ask for the welder qualification certificates of the individuals who will do your work — not a general company statement.
- Check that the scope matches your job: right process, right material, right thickness, right position.
- Check the dates and continuity.
- Ask for the WPS that will be used.
A contractor genuinely working to code will produce these without hesitation, because they keep them on file as a matter of routine.
Specify it properly up front
The cleanest approach is to state the requirement in the enquiry rather than assuming it. Naming the standard, the material and the service conditions at tender stage means every quote is priced on the same basis — and avoids the situation where the cheapest quote is cheapest precisely because it excluded the certification you needed.
RP Strategies provides coded welding services in South Africa for structural steel, pipelines and pressure work, alongside steel fabrication services in Gauteng and nationally.