Piping systems for chemical process plants – the seam is crucial
For pipelines carrying acids, alkalis, or process gases, the weld quality is not merely a formality. It determines operational safety, cleanability, and regulatory compliance. STW designs, manufactures, and installs stainless steel process pipelines according to AD 2000 and PED 2014/68/EU – using automated orbital welding technology, with over 25 years of experience in industrial pipeline construction, and up to 100% documentation for regulatory approvals.
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What authorities and auditors want to see during the acceptance inspection
Plant operators in the pharmaceutical, cosmetics, and fine chemical industries are subject to operator obligations under the German Industrial Safety Ordinance (BetrSichV) and the German Pressure Equipment Ordinance (DruckbehV). Operators who commission the wrong company are personally liable in the event of damage – even if the plant was built by a third party.
AD 2000 and PED 2014/68/EU: The approval without which no pressure equipment can be accepted
Certification according to AD 2000-Merkblatt HP 0 / HP 100 R authorizes STW to manufacture pressure-bearing components in accordance with the Pressure Equipment Directive 2014/68/EU. The audit covers in-house production control and the qualifications of all welding personnel. The result is a certificate that is valid for inspection by authorities and operator auditors.
Complete traceability – for auditors and in case of emergency
DIN EN ISO 3834-2 stipulates that welding work must be monitored and fully documented. Every weld is traceable via material batch, welder ID, and inspection report. This level of documentation is not merely a bureaucratic formality – it is a safeguard against liability claims when it matters.
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Corrosive media do not forgive seam defects.
Stainless steel 1.4301 and 1.4404 – and when the medium demands more
For the majority of chemical applications in fine chemicals, water treatment, and food production, the austenitic stainless steels 1.4301 and 1.4404 are used. For applications involving concentrated acids, chlorine compounds, or extreme temperature ranges—such as those encountered in fine chemicals or pharmaceutical production—specific alloys are used.
Orbital welding: Reproducible quality, regardless of the time of day.
Manual welding of pressure lines depends on many influencing factors, including the human factor in terms of experience, physical condition on the day, and access conditions. Mechanized TIG orbital welding eliminates this variable. Weld defects according to DIN EN ISO 5817 – root recession, crowning, and porosity – are systematically reduced. The result is smooth pipe interiors without deposits: easy to clean, verifiable, and verifiable.
Every hour of downtime has a price. Prefabrication reduces it.
Companies that handle all pipeline work on-site pay more: for the fitters' hours and for the downtime. Shifting production steps to the workshop is the most direct way to combat unnecessary downtime – whether for overhauls, modifications during ongoing operations, or new installations in chemical plant construction.
Detect collisions on screen – not during installation
Pipeline routes are designed three-dimensionally before production begins and materials are ordered. Isometrics and parts lists are generated directly from the model. Conflicts with existing plant technology are identified during the planning phase – and not only by the installer on the construction site.
Delivered ready for installation: simply install instead of reworking.
Pipes, elbows, and valve assemblies leave our workshop manufactured to installation dimensions. This eliminates the need for on-site adjustments – measurably reducing installation time and correspondingly minimizing potential errors.
What STW works with – at a glance
| Parameter | STW standard |
|---|---|
| Materials | Stainless steel 1.4301, 1.4404, special alloys as required |
| Nominal diameters | DN 6 to DN 700 (other nominal diameters available on request) |
| wall thicknesses | 1 mm to 3 mm (larger wall thicknesses available on request) |
| welding processes | TIG orbital (mechanized), MIG, manual welding |
| Construction | 3D planning and isometric drawing creation |
| test procedure | Pressure testing, leakage testing, non-destructive weld testing |
| Documentation | Project-specific up to 100% – incl. EN 10204-3.1, welding protocols, test reports |
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From inquiry to print test: four phases, one contact person
1.Technical Inspection
Process data or preliminary planning are checked for feasibility in manufacturing. Interface problems that could later lead to rework are identified here – before they cause costs.
2.3D construction
On-site measurements, coordination of the route alignment, creation of the digital model. This creates the binding basis for manufacturing, assembly and documentation – without room for interpretation.
3.Workshop production
Cutting, bending, welding, and in-house quality control. All seams documented, all batches traceable – ready for acceptance before the first segment leaves the workshop.
4.Assembly and acceptance
Installation of the prefabricated segments, final welding by certified specialists, pressure testing, handover of complete documentation. Commissioning and overhaul scheduled as planned.
Your next piping project
Send us your project information – STW will check the feasibility and prepare a reliable offer.
What planners and operations managers ask us most frequently
Material test certificates according to EN 10204-3.1, weld seam reports, isometric drawings, and reports on pressure and leak tests – project-specific, with up to 100% documentation depth. Certifications according to AD 2000-Merkblatt HP 0 and HP 100 R as well as DIN EN ISO 3834-2 form the formal basis in accordance with PED 2014/68/EU.
Seams are evaluated according to DIN EN ISO 5817. Non-destructive testing methods such as endoscopy, pressure testing, and, if necessary, X-ray testing are used. The orbital welding technology ensures, as part of the process itself, that deviations relevant to defects are systematically reduced.
By maximizing pre-production in the workshop: 3D planning ensures dimensional accuracy, CNC manufacturing and laser cutting produce ready-to-assemble segments. Installation and welding take place on-site – no adjustments, no waiting for remanufacturing.
STW processes individual manufactured products as assemblies as well as complete process piping systems for new plants, overhauls and conversions.
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