6 Things EPCs Really Evaluate When They RFQ an FPSO Process Skid (2026)

In March 2026, SBM Offshore was awarded the FEED contract for ExxonMobil's Longtail FPSO offshore Guyana — a unit built around a standardized hull and a set of standardized topsides modules. Weeks later, the P-81 and P-87 awards for Petrobras moved toward signature offshore Brazil. After a quiet stretch, the FPSO order book is filling again, and almost every one of these floaters is being built the same way: as a stack of pre-engineered, skid-mounted process modules.

That shift changes what an FPSO process skid RFQ is actually about. When a topsides package gets split into skids and sent out for quotation, the EPC or integrator is not really buying a fabricated steel frame with equipment bolted to it. They are buying a module that will arrive at the right weight, with the right interfaces, certified to the right class rules, on the date the integration schedule depends on. Price is the easy part to compare. The things that decide whether a project runs smoothly — or burns 48 hours per problem at the deck — rarely appear on the RFQ form.

We've built marine and offshore skids for the better part of a decade: reliquefaction units, BOG compressor skids, fuel-gas and bunkering modules, water-glycol skids, and process/refrigeration packages for offshore production platforms, delivered under DNV, ABS, BV, CCS, LR and NK. Across those projects, the same six dimensions separate a skid supplier that an EPC can forget about from one that becomes a daily problem. Here is what experienced buyers are really scoring.

The Short Version

For procurement teams who want the conclusion first, an FPSO process skid supplier is evaluated on:

1. Module boundary & interface definition — does the skid's battery limits, tie-ins and documentation match the integrator's interface register?
2. Weight & center-of-gravity control — is the as-built weight and CoG inside the lifting and sea-fastening envelope?
3. Ex-zone & material certification — are hazardous-area equipment and material traceability certified to the project's class and zone?
4. Class approval-drawing timeline — can the fabricator clear class drawing approval fast enough to not delay the vessel?
5. Series repeatability — for multi-unit programs, can the supplier reproduce the same module N times without drift?
6. Commissioning support — will someone competent be there for FAT, integration and start-up?

Price and lead time matter, but they are necessary, not sufficient. The six below are what move a bid from "cheapest" to "awarded."

1. Module Boundary and Interface Definition

The single most expensive misunderstanding in modular FPSO work is the battery limit. Where does the skid scope stop and the integrator's scope begin — mechanically, electrically, in instrumentation, and on paper?

A skid that is fabricated beautifully but whose nozzle orientations, cable-tray entries, or junction-box positions don't match the interface register will still cost the project days at hook-up. Experienced integrators read an RFQ response for evidence that the fabricator thinks in interfaces, not in equipment:

• A clear battery-limit drawing: every mechanical tie-in (process, utility, drains, vents), every electrical/instrument termination, every structural connection to the deck.
• Tagged terminations that map directly to the integrator's interface register and tag philosophy.
• A documented position on who supplies first-fit vs. loose-shipped items (spool pieces, gaskets, fasteners) so nothing is assumed.

When we deliver fuel-gas and bunkering skids into a vessel program, the interface list is locked with the integrator before fabrication drawings are released — because a flange that points the wrong way is cheap to fix on a drawing and very expensive to fix on a module already sitting on the deck.

What good looks like: the supplier returns the RFQ with interface questions, not just a number. That is a feature, not a delay.

2. Weight and Center-of-Gravity Control

On a fixed plot of FPSO deck, every module has a weight budget and a CoG envelope, and both are tied to lifting and sea-fastening engineering. A skid that comes in overweight, or whose center of gravity has drifted from the model, forces the integrator to redo lifting calculations, re-rate slings and lugs, and sometimes re-plan the lift entirely.

Serious fabricators control weight as a managed quantity, not an afterthought:

• A maintained MTO-based weight and CoG report that tracks the as-designed vs. as-built figure through the project.
• Lifting lugs designed and certified for the actual load case, with sling angles and hook positions worked out — not generic.
• Sea-fastening provisions (for the voyage from workshop to integration yard) designed into the frame, with defined seafastening points to the deck.

Weight/lifting item	Why the EPC cares	What to ask for in the RFQ
As-built weight vs. design	Deck load budget, lift crane selection	Weight control report at FAT
Center of gravity (CoG)	Lift stability, sling design	Calculated CoG with tolerance
Lifting lug design	Safe lift, no field rework	Lug calcs + sling angle diagram
Sea-fastening	Survives voyage to integration yard	Sea-fastening design in scope

The difference between a supplier who hands you a verified weight-control report at FAT and one who shrugs at the question is the difference between a predictable lift and a schedule surprise.

3. Ex-Zone and Material Certification

FPSO topsides are hazardous-area environments. Equipment installed in classified zones must carry the right Ex protection and certification, and the pressure-containing materials must be fully traceable. This is where a skid either has a clean documentation spine or a set of holes that surface during the class survey.

Buyers look for:

• Hazardous-area equipment (motors, instruments, junction boxes, lighting) certified to the project's required Ex protection level and zone.
• Material traceability for pressure parts — mill certs (EN 10204 3.1 / 3.2 as specified), heat-number traceability from plate to weld.
• Welding qualifications appropriate to the materials in scope. We maintain 600+ PQR welding procedure qualifications precisely because offshore work mixes carbon steel, stainless, duplex and other alloys on the same job, and each needs a qualified procedure behind it.

A skid is only as certifiable as its weakest undocumented component. The fabricators that win repeat FPSO work treat the material and Ex certification package as part of the deliverable, not as paperwork to chase after the steel is done.

4. Classification Approval-Drawing Timeline

Here is the dimension that EPCs underweight in the RFQ and regret later. On a classed FPSO, the skid's drawings have to clear the classification society before fabrication can proceed in earnest, and the vessel's certification cannot close until every module's documentation is in order. A skid supplier who is slow or clumsy with class drawing approval becomes a critical-path problem for the entire floater.

What protects the schedule:

• A fabricator who has worked directly with the relevant class society (DNV, ABS, BV, CCS, LR, NK, KR) and knows that society's drawing-review expectations.
• A realistic, committed drawing-approval timeline — the approval "clock" starts at order, and a supplier who has done it before can tell you how long their drawings take to clear.
• An in-house design team that can turn class comments around in days, not weeks.

Our marine skid programs have been certified across the major societies because each project lives or dies on getting approval drawings cleared on the society's terms. When a supplier already speaks the surveyor's language, the EPC inherits that fluency as schedule certainty.

5. Series Repeatability

Modern FPSO programs are increasingly built in series — standardized hulls, standardized topsides, sister units. When the same module is needed 2, 3, 8 or 12 times, the question is no longer "can you build one?" It's "can you build the Nth one exactly like the first, on a repeatable cadence?"

This is where a fabricator's track record matters more than its brochure. We have delivered marine skids in true multi-unit series — for example, reliquefaction units delivered in batches of six and twelve against a single vessel program, and BOG compressor skids supplied in sets of eight across sister hulls. Series work exposes whether a supplier has:

• Frozen, version-controlled fabrication drawings so unit #8 matches unit #1.
• A QC process that catches drift between units before it ships.
• Production capacity (we run an 8,000 m² assembly workshop) to hold cadence without subcontracting quality away.

For an EPC running a multi-FPSO or multi-module program, a supplier who has demonstrably repeated a skid is worth more than a cheaper one who has only ever built a prototype.

6. Commissioning and FAT Support

A skid is not "delivered" when it leaves the workshop. It's delivered when it has passed Factory Acceptance Test, been integrated, and started up. The last dimension EPCs evaluate — and the one that separates a vendor from a partner — is whether the supplier shows up, competently, for the part that happens after the steel is painted.

• A structured FAT with the client and class present, against an agreed ITP (inspection and test plan).
• A complete Manufacturing Record Book (MRB) that closes the documentation loop — certs, NDT reports, test records, as-built drawings — so the integrator isn't chasing paper during hook-up.
• Engineers available for integration questions and start-up support, not a supplier that goes quiet after the final invoice.

The cost of a missing commissioning answer offshore is measured in vessel-days. The EPCs who have been burned once score this dimension heavily ever after.

How the Six Fit Together

None of these six is exotic. What's hard is doing all six, every time, on a schedule that a billion-dollar floater depends on. A price-only comparison flattens them into a single number and hides exactly the risks that cost the most.

Dimension	The hidden risk if ignored	The question to put in your RFQ
1. Interfaces	Field rework at hook-up	"Show me your battery-limit drawing and interface list."
2. Weight & CoG	Lift re-engineering	"Give me a weight-control report at FAT."
3. Ex & material certs	Failed class survey	"Provide your Ex certs and material traceability plan."
4. Class drawings	Vessel certification delay	"What's your class drawing-approval timeline?"
5. Repeatability	Drift across sister units	"Show me a multi-unit series you've delivered."
6. Commissioning	Vessel-days lost at start-up	"Who supports FAT, integration and start-up?"

A fabricator who can answer all six with evidence is not the cheapest line on your bid tab. They are the one you can stop worrying about — which, on an FPSO program, is what you are actually buying.

FAQ

What's the difference between an FPSO process skid and a regular industrial skid?
The engineering is similar; the certification and integration bar is much higher. An FPSO skid must satisfy marine classification rules, hazardous-area (Ex) requirements, marine-grade material traceability, and a controlled weight/CoG and sea-fastening regime — because it ships to and is lifted onto a floating production unit, not bolted to a concrete pad onshore.

Why does the classification approval-drawing timeline matter so much?
Because the vessel cannot be certified until every module's drawings and documentation clear the class society. A skid supplier slow on drawing approval can put the entire FPSO on the critical path. Asking for a committed, evidence-backed approval timeline in the RFQ is one of the cheapest risk reductions a procurement team can make.

How do I verify a skid supplier can handle a multi-unit series?
Ask for a delivered series, not a single prototype: how many identical units, over what period, under which class society, with what drawing version-control. A supplier who has shipped, say, six or twelve identical reliquefaction or BOG skids against one program has demonstrably solved the repeatability problem.

Should price be the deciding factor in an FPSO skid RFQ?
Price should be necessary but not sufficient. The largest costs on a modular FPSO are not in the skid price — they're in integration rework, lift re-engineering, certification delay and commissioning problems. The six dimensions above are where those costs are decided.

Further Reading

• Reliquefaction Skids: A Decade of Series Delivery
• BOG Compressor Skids for LNG-Fuelled Vessels
• Fuel Gas Supply System (FGSS) Skids
• Modular Skid Packages: Workshop to Sea Trial
• Lmart Marine & Offshore Project References

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Lmart (Suzhou Lmart Energy Equipment Co., Ltd.) designs, fabricates, integrates, tests and documents modular process skids for marine and offshore programs in-house, certified across DNV, ABS, BV, CCS, LR and NK. If you're evaluating skid suppliers for an FPSO or offshore module package, we're happy to walk through any of the six dimensions above for your scope.