Buyer's guide

How to evaluate an offshore fabrication supplier

Choosing an offshore fabrication supplier comes down to evidence you can verify: welding certified to EN ISO 3834-2 and EN 1090-2 with a stated execution class, coating qualified to NORSOK M-501, a named classification society scope, and documented lead times. This guide sets out the questions to ask, the documents to request, and the answers that should end a conversation.

By Madis Kollo, Head of Sales & Business Development, First In Service OÜ
Published ·Updated
Why this matters

The cheapest quote is rarely the cheapest supplier.

Offshore components live in an environment that punishes every shortcut taken onshore. A procurement decision made on price-per-kilo can cost its savings many times over in coating failures, documentation gaps that stall commissioning, or a schedule slip that idles a vessel. This guide lists what experienced offshore buyers verify before awarding fabrication work: checkable facts rather than brochure claims.

Checklist 1

Certifications: ask for the specific ones.

ISO 9001 says a company has a quality management system. It says nothing about welding. For welded offshore structures, the relevant evidence is EN ISO 3834-2 (comprehensive quality requirements for fusion welding) and EN 1090-2 for structural steel execution. For anything pressure-containing, PED 2014/68/EU. For coating, ask specifically for NORSOK M-501 or C5-M capability with logged film-thickness records, because offshore corrosion protection is a process discipline, not a paint choice.

Verify rather than accept: certificates carry issuing bodies and validity dates, and can be checked against certification registries. A supplier who publishes them openly is telling you something; a supplier who sends a low-resolution scan on request is telling you something too.

Checklist 2

NDT: ask who inspects, and who they answer to.

Every fabricator will say welds are tested. The question that separates suppliers is: by whom? Non-destructive testing (VT, PT, MT, UT) performed by an independent certified party removes the conflict of interest inherent in a workshop grading its own homework. Ask whether NDT reports are traceable to individual welds and welders, and whether they arrive as part of the documentation package or have to be chased afterwards.

Checklist 3

Documentation: the MDR is part of the product.

A Manufacturing Data Record covers material certificates to EN 10204 3.1 (3.2 where the project demands third-party witnessing), weld maps, NDT reports, dimensional logs and test protocols. For regulated scope, it is the difference between equipment that can enter service and steel that cannot. Ask a candidate supplier to show you a redacted MDR from a previous delivery. The speed and completeness of the answer is the audit.

Checklist 4

Envelope and logistics: measure twice, award once.

Confirm the supplier's real envelope against your largest component: maximum dimensions, weight and lifting capacity. Then confirm the route from their door to your port. A workshop that can build your 120-tonne structure but sits three permit-bound road days from a harbour has quietly added cost and schedule risk to every delivery. Distance from quay, heavy-haul road access and ro-ro capability are checkable facts; ask for them in numbers.

Checklist 5

Accountability model: one roof or many?

Some suppliers fabricate, machine, coat and assemble in one facility; others coordinate networks of workshops. Networks offer capacity elasticity. Single-site integration offers something different: one audit covers the entire production chain, one contract carries the accountability, and there are no handovers between suppliers, which is where schedules and traceability quietly fail. Neither model is universally right; know which risk you are buying.

First In Service operates the single-site model: fabrication to 35 × 7 × 7 metres and 160 tonnes, machining to ±0.02 mm, NORSOK M-501 coating, and FAT-tested assembly in one 18,000 m² Tallinn facility, 20 km from Muuga Harbour. If that model fits your risk profile, send one to three drawings and judge us on the quote.

Primary sources: NORSOK M-501 · PED 2014/68/EU · EN 10204 · EN 1090-2 · EN ISO 3834-2

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FAQ

Questions buyers ask

What certifications should an offshore fabrication supplier have?

At minimum EN ISO 3834-2 for welding quality and EN 1090-2 for structural steel execution. For pressure-containing scope, PED 2014/68/EU. For coating in offshore service, capability to NORSOK M-501 and C5-M. ISO 9001 alone is not sufficient evidence of welding competence.

Why does independent NDT matter when choosing a fabricator?

Non-destructive testing performed by an independent certified party removes the conflict of interest of a workshop inspecting its own welds. Ask who performs NDT and whether reports are traceable to individual welds.

What is a Manufacturing Data Record (MDR)?

The complete documentation package that ships with a fabricated component: material certificates (EN 10204 3.1 or 3.2), weld documentation, NDT reports, dimensional inspection logs, and test protocols. Without a complete MDR, a component may not legally enter service.

Should I choose a single-site fabricator or a network of workshops?

Both models can work. A single-site fabricator offers single-point accountability and one audit covering the whole chain; a network offers capacity flexibility but adds handovers where schedule and traceability risk concentrate. Match the model to your project's documentation and schedule risk tolerance.

In brief

160 tonnes. 35 metres. 20 km to the ship. Heavy fabrication, precision machining and mechanical assembly under a single contract. One supplier is responsible for the finished geometry and for the documentation that proves it.

At a glance

Sectors served

Marine, offshore & subsea
We machine and fabricate parts for high pressures and corrosive marine conditions, from podded propulsion components to structural elements for offshore platforms. Fabrication, machining and corrosion protection are all done in-house, so the coating is never handed to a third party. Weight: 100 kg – 50,000 kg. Envelope: Up to 25 × 5 × 5 m (L×W×H). Materials: Marine-grade steels, carbon steel, stainless steel, duplex / super duplex. Surface treatment: NORSOK M-501 and C5-M, applied in-house. Class approvals: DNV, Lloyd's Register, Bureau Veritas, RINA — scope per project. Inspection: VT, PT, MT, RT.
Oil & gas / process equipment
We manufacture certified pressure vessels, tanks, piping modules and skids in strict compliance with PED and international safety standards. Design: EN 13445 / PED 2014/68/EU. Weight: 200 kg – 25,000 kg. Envelope: Up to 25 × 5 × 5 m (L×W×H). Materials: Carbon steel, stainless steel, duplex, super duplex. Inspection: VT, PT, MT, RT.
Rotating parts & shafts
Made to drawing for pumps, compressors, fans, turbines and power generation: impellers up to Ø 4,000 mm, rotors, shafts up to 3,250 mm, casings, and fan and blower components. Welded parts are stress-relieved, and rotating parts are dynamically balanced in the same order. Weight: 10 kg – 5,000 kg. Envelope: Ø 500 – Ø 4,000 mm. Balancing: Up to Ø 4,000 mm and 4,000 kg. Materials: Carbon steel, stainless steel, duplex / super duplex, titanium. Inspection: VT, PT, MT, RT.
Pulp & paper machinery
Precision spare parts and critical process components for mills in continuous production. Our priority is fast, reliable manufacturing that keeps your downtime short. Design: EN 13445 / PED 2014/68/EU. Weight: 200 kg – 25,000 kg. Envelope: Up to 25 × 5 × 5 m (L×W×H). Materials: Carbon steel, stainless steel, duplex. Inspection: VT, PT, MT, RT.
Mining & machine building
Heavy machine-building assemblies for the mining sector, precision-machined from wear-resistant materials for high-impact, abrasive service. Components: Machine assemblies, structural frames, conveyor elements. Materials: Hardened and wear-resistant steels. Conditions: High-impact, abrasive environments. Inspection: VT, PT, MT.
Defence
Precision manufacturing of regulated, mission-critical defence components, with full traceability, strict quality control and compliance with defence industry specifications. Focus: Mission-critical precision components. Requirements: Full traceability, strict QC, defence specifications. Capabilities: Welding, machining, assembly to military standards.

Why buyers choose us

Proven in demanding sectors
We are a specialised contract manufacturer and heavy engineering subcontractor delivering precision-welded, machined, and assembled products for demanding industrial applications.
Early DFM review
Before we build to print, our production engineers carry out a Design for Manufacturability (DFM) review to find potential failure points, optimise welding sequences and reduce your overall manufacturing cost.
Certified quality systems
Our operations are certified to ISO 9001, ISO 14001, EN ISO 3834-2 and EN 1090-2, and our documentation complies with PED.
Full material traceability
We guarantee full material traceability from prototype to series production. Weld integrity is verified by NDT (VT, PT, MT, UT) carried out by certified partners.
Scale and lifting capacity
With 18,000 m² of floor space and lifting capacity up to 160 tonnes, we can scale resources to your project timeline and handle very large components.
Heavy-haul port access
Our Tallinn site is 20 km from Muuga Harbour and 60 km from Paldiski Port, with direct heavy-haul road access that avoids city traffic. Oversized components up to 160 tonnes ship roll-on/roll-off to Europe and the Nordics.
Environmental responsibility
Waste, chemical safety and emissions are actively managed as part of our ISO 14001-certified operations.