IMO Type C Tank Fabrication

IMO Type C tanks are self-supporting pressure vessels — the format of choice for small-scale LNG carriers, bunkering vessels, LPG carriers and LNG-fuelled ships, because they tolerate partial filling without the sloshing limits that constrain membrane systems.

Meritus coordinates Type C tank fabrication across vetted Chinese pressure-vessel shops, covering vessels from 2,000 m³ through 175,000 m³ in cylindrical and bilobe configurations. We handle shop selection, welding-procedure review, third-party inspection and the documentation pack — so you deal with one counterparty instead of a yard, a class surveyor and a forging mill in three provinces.

Capabilities

Cylindrical and bilobe Type C tanks, 2,000–175,000 m³
5% and 9% nickel steel, stainless and aluminium alloy
ASME Section VIII and IMO IGC Code
Class survey coordination — DNV, ABS, LR, BV, CCS
Heat-number verification against mill certificates
WPS/PQR review before production welding
Impact testing witnessed at design temperature
Full documentation pack released pre-shipment

Scope we cover

Cylindrical and bilobe Type C tanks; saddle and support structures; internal pipework, pump towers and domes; insulation and vacuum jacketing; associated valves, safety relief and instrumentation. Cargoes include LNG, LPG, LEG, ethane, ethylene, ammonia and liquid CO₂ — each with its own material and design-temperature implications we confirm before shop selection.

Materials and welding

Type C service is a materials problem before it is a fabrication problem. Depending on design temperature that means 5% or 9% nickel steel, austenitic stainless or aluminium alloy. We verify heat numbers against mill certificates, review WPS/PQR before production welding starts, and witness impact testing at design temperature rather than accepting a certificate at face value.

Standards and documentation

Fabrication is executed to ASME Section VIII and the IMO IGC Code, with class involvement from DNV, ABS, LR, BV or CCS as your project requires. Every order runs through the same quality chain: shop pre-qualification, material traceability against mill certificates, in-process and final inspection, and a documentation pack released before shipment. Shops hold the Chinese Special Equipment Manufacturing License required for pressure vessels.

Failure modes we inspect for

Four recur. Material substitution — a lower nickel grade or a different heat than certified, which only PMI on the delivered item will catch. Impact-test certificates from a different heat or a warmer temperature than the design case. Post-weld heat treatment charts that do not match the actual furnace run. And repair welds in the shell that were made, ground flush and never recorded — invisible on arrival, decisive for fatigue life.

How an order runs

Enquiry and specification review; shop shortlisting against the actual scope rather than a general vendor list; quotation with the inspection plan priced in, not added later; kick-off with agreed hold and witness points; in-process inspection at those points; final inspection, document pack release and shipment; arrival support if anything is queried. For Type C tanks we set hold points at material release, after root pass on the main seams, before and after PWHT, at hydrostatic test, and before insulation closes over the shell.

Standards and certifications referenced

ASME Section VIII Div. 1 and Div. 2
IMO IGC Code
IMO IGF Code
ISO 9001:2015
CE Marking / PED
China Special Equipment Manufacturing License
Class rules: DNV, ABS, LR, BV, CCS

Frequently asked questions

What sizes of Type C tank can be sourced from China?

Chinese pressure-vessel shops build Type C tanks across the range Meritus covers, from small bunkering and fuel tanks of around 2,000 m³ up to 175,000 m³ for large gas carriers, in cylindrical and bilobe configurations.

Which code applies to Type C tank fabrication?

Type C tanks are pressure vessels, so they are designed and fabricated to ASME Section VIII (or an equivalent national code), with the IMO IGC Code governing their application on gas carriers and the IGF Code where they serve as fuel tanks.

What material is used for LNG Type C tanks?

Design temperature decides it. LNG service at around −163 °C typically calls for 9% nickel steel, austenitic stainless or aluminium alloy; warmer LPG and ammonia service can use 5% nickel or low-temperature carbon steels. Meritus verifies the delivered material by PMI rather than by certificate alone.

Do Chinese shops hold the licences needed for pressure vessels?

Yes — pressure-vessel manufacture in China requires the Special Equipment Manufacturing License, and Meritus works only with shops that hold it, alongside the class approvals your project requires.

Request a Quote

Contact Meritus Technology's ISO 9001:2015 certified procurement desk in Shanghai for imo type c tank fabrication — supplier verification, QA/QC, and global shipping. Request a quote or contact us.