Pipeline fabrication 101

Pressure pipe fabrication is a specialised field that not only involves fabricating to critical tolerances, but also includes providing the client with a complete package of safety and quality documentation to provide compliance to particular standards or specifications.

The process commences with an authority to proceed by the client, which is established by the subsequent submission and evaluation of the tender documentation. Planning for the type of fabrication involved needs to be considered during the tender stage so the most cost effective fabrication methods are utilised. Procurement and then fabrication will immediately commence following the award of the contract.

Fittings, valves, steel and pipe are supplied to the workshop from a source of suppliers who competitively bid for the contract. The next step is the receipting and processing of the incoming goods which is followed by assembly, welding and testing of the completed piping assemblies.

In some cases, items of equipment have their own unique complexity, meaning that each piece of equipment requires a different type of fabrication, which WDS Ltd Works Manager Andy Douglas says can prove difficult.

There are various grades of materials used, depending on the design requirements. Stipulation of the materials could be based on the corrosive properties, temperature and pressure of the product, and also the surrounding environmental conditions where the final product will be in service.

Mr Douglas says “Common materials are carbon steels, stainless steels and chromyl steels.

“With the industry developing higher grade materials to meet specific end user requirements, the management of quality and welding process control is critical to ensure the compliance to the relevant fabrication code.”

Welding it together

Welding is an extremely important part of the fabricating process. Each individual weld may require extensive testing (radiography/ultrasonic) to ensure that it conforms to service requirements, and with the additional requirement that each individual welder must be qualified to weld on a particular project by passing specific welding criteria.

“Speciality comes into it with the welding on different grades of material, with each grade having its own idiosyncrasies. As such, specific welding procedures are developed to ensure that the welds are suitable for their intended service,” Mr Douglas says.

On top of the fabrication and welding of pipe spools, there is the extensive recording of individual material batch and consumable numbers, weld and welder recordings, and approval and sign off processes. WDS Ltd uses an integrated process database which is crucial to maintaining accurate process data.

Fabricating future

When asked about developments for the future in the fabrication, Mr Douglas says that the industry is continuing to see development in welding processes with the aim of improving production and quality.

One of the main challenges for the local fabrication industry is competing with the outsourcing of equipment and fabricated components from overseas suppliers. Other challenges include the shortage of skilled labour resources which will come into effect when the various projects commence.

Mr Douglas says that the WDS Fabrication and Installation team understands this, and actively trains supervision and management personnel in certified welding technology qualifications for assessing advanced welding processes and equipment, as well as supporting trade apprenticeships and trainee courses.

WDS has also opened up a purpose-built facility at Yatala, which includes a segregated stainless steel fabrication bay and a large lay-down yard, making the facility capable of the fabrication and assembly of modular unit construction, such as pipe racks, gas compression units and process plants.

With a number of coal seam gas infrastructure projects poised for approval in the near future, Mr Douglas believes there will still be a high demand for Australian fabricated content.

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