API standard · reference card
Does API 1104 govern your girth weld? Scope decision flow for the pipeline welding standard, the workmanship-or-ECA choice, and the codes it sits next to.
API 1104 is a pipeline-specific code, not a general steel-welding standard borrowed for pipelines. It sets welding procedure and welder qualification, inspection and acceptance criteria for girth and fillet welds on pipelines and related facilities carrying petroleum, fuel gases, carbon dioxide and similar fluids, and it offers two acceptance routes: a workmanship-based route sized to weld geometry, and an engineering-critical-assessment route for a project that wants limits derived from a fitness-for-service calculation instead.
The choice between the two routes is a project decision, made once, in writing — not a weld-by-weld option. A specification silent on which basis applies leaves an inspector and a contractor free to disagree about the same finding, and the qualification work behind each route is not interchangeable: a procedure and welder qualified for one basis do not automatically satisfy the other. Tie-in and repair welds near a pipeline already in service carry additional precautions on top of the same qualification and acceptance framework.
Therness equipment does not perform the examination API 1104 acceptance relies on. It gives a mechanized spread the process evidence a fast build otherwise loses: interpass temperature actually measured at the joint along a right-of-way where ambient conditions vary joint to joint, and weld-pool geometry captured on the root pass, before fill and cap cover a problem visible only there. See ASME IX for the equivalent qualification route outside pipeline scope, and ISO 9712 for the certification basis behind the examination result acceptance is judged against.
| Question | If yes | If no |
|---|---|---|
| Is the weld a girth or fillet weld on a pipeline transporting petroleum, fuel gases, carbon dioxide or a similar fluid? | API 1104 is the applicable welding and acceptance standard. | Plant piping and pressure equipment typically fall under a different code — confirm which one the contract names. |
| Does the specification call for a workmanship or an engineering-critical-assessment acceptance basis? | Follow the basis named; the two are not mixed on the same weld without the contract saying so. | Workmanship-based acceptance is the default route absent a stated engineering-critical-assessment basis. |
| Is the open question qualification, rather than production-weld acceptance? | A qualified procedure and welder have to exist before an acceptance criterion means anything. | The acceptance basis the project chose governs the finished weld. |
| Is the weld a tie-in or repair near an existing, in-service pipeline? | Additional precautions for welding near an in-service line apply on top of the same framework. | The standard's general new-construction requirements apply. |
Conformity is decided by inspection and testing against the criteria the standard and the contract set. The records below are evidence that the process was held where it was qualified; they support an inspection result, they never replace one.
| Requirement | Record produced | Source |
|---|---|---|
| Holding preheat and interpass conditions consistent across a cross-country right-of-way where ambient conditions vary joint to joint | Non-contact interpass temperature measurement taken at the joint on every weld | HeatCam IR-C |
| Catching a root-pass problem on a girth weld before fill and cap passes cover it | Continuous weld pool geometry captured through the root pass | PoolDrop |
No, not without the contract saying so. The two bases are not interchangeable weld by weld; the project specification sets which one governs before welding starts.
Therness records what the machine actually delivered on every weld — parameters, thermal signature and a per-weld trail — so a conformity argument rests on measurements instead of recollection.
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Priorità I, Obiettivo Specifico a), Azione 4 – "Sostegno alla nascita delle start up"
