Bureau Veritas Type Approval for double-ferrule compression fittings.

What is Type Approval for marine and offshore components, and why does it matter?

Type Approval is a certification process by which a classification society validates a product’s design for marine or offshore use. It involves reviewing drawings, assessing construction, and performing prototype tests to ensure the component meets applicable technical and safety requirements. In essence, the product design is examined once and, if approved, that certification is considered valid for all future products of the same design.

This approval is essential in the maritime and offshore sector for several reasons:

• International trust and recognition: Type Approval issued by recognized bodies increases market confidence in product quality. In short, it’s a globally recognized seal that facilitates acceptance of the component on ships and platforms worldwide.
• Regulatory compliance: Many pieces of equipment must comply with international rules (SOLAS, MARPOL, etc.) and flag-state or classification-society requirements. In some cases, Type Approval is mandatory (for example, for marine diesel engines, electrical cables, or other critical systems). In other cases it’s not strictly required, but obtaining it voluntarily provides advantages.
• Safety and reliability: It ensures the component has been rigorously tested under representative conditions, reducing the risk of in-service failures. For example, it verifies that the design withstands the pressures, vibrations, and corrosive environments typical of marine applications.
• Shipbuilding efficiency: A product with Type Approval is usually accepted more quickly by inspectors and customers during vessel construction. For manufacturers and suppliers, this avoids repetitive technical reviews for each order or installation and speeds up the supply chain. Buyers and engineers save time by not having to assess each component’s conformity from scratch, relying instead on the granted Type Approval.

But you’ll ask me: what is a Classification Society?

“Classification Societies are the organizations that issue Type Approvals.”

Type Approval certificates are issued by classification societies—organizations specialized in maritime safety and technical standards. These entities set rules and standards for ships and equipment and verify compliance. Among the main classification societies worldwide (members of IACS, the International Association of Classification Societies) are:

• Bureau Veritas (BV): A French classification society founded in 1828, with a broad global presence in maritime certification.
• Lloyd’s Register (LR): Founded in the UK in 1760, the first classification society; highly prestigious in the naval sector.
• DNV: Formed from the merger of Det Norske Veritas (Norway) and Germanischer Lloyd (Germany), one of the largest societies today, known for rigorous technical standards.
• RINA: Registro Italiano Navale (Italy), active since 1861, with experience in both commercial shipping and offshore.
• ABS (American Bureau of Shipping): A U.S. classification society founded in 1862, deeply involved in the maritime and offshore oil industries.
• ClassNK (Nippon Kaiji Kyokai): A Japanese classification society established in 1899, a benchmark in the Asian market and internationally.

All of them offer Type Approval schemes with a very similar approach. The manufacturer applies for certification, and the society performs a technical design review, physical testing, and manufacturing audits before issuing the certificate. While certificates from different societies are not identical, in general a Type Approval issued by any of these organizations indicates that the product meets recognized standards. In some cases, mutual recognition agreements exist: for example, IACS member societies in the European Union share certain approvals under a common scheme, which helps avoid unnecessary duplicate testing. Nevertheless, for specific projects it’s advisable to check whether approval from a particular society is required (for instance, if an owner prefers certificates from a specific entity).

Double-ferrule compression fittings

A practical case of Type Approval is Redfluid’s double-ferrule fittings used in instrumentation and hydraulic tubing. These small adapters, elbows, tees, unions, and crosses ensure leak-tight connections in high-pressure systems. Despite their size, they’re critical: a leak on a ship or platform can have serious consequences. That’s why manufacturers often seek Type Approval for their fitting lines, proving they deliver safe, consistent performance under extreme conditions.

To achieve certification, representative tests are performed on product samples, such as:

• Repeated assembly test: assemble and disassemble the fitting multiple times to verify it maintains sealing after repeated use (confirming the double ferrule still guarantees tightness).
• Burst pressure test: subject the connector to a pressure well above its maximum working pressure until failure, ensuring there is a wide safety margin before rupture occurs.
• Vibration test: test the fitting under continuous vibration to confirm it doesn’t loosen or leak in a vibratory environment similar to marine equipment.

In addition, leak (tightness) tests are usually included and, where applicable, pulsating pressure or thermal shock tests, ensuring robust performance under different conditions. All these tests are witnessed by the inspector from the relevant classification society, guaranteeing the objectivity of the results.

At Redfluid we offer double-ferrule fittings with Type Approval—issued in our case by Bureau Veritas.
In simple terms, our fittings have been examined and approved for installation on different types of vessels and maritime structures, such as:

• Steel Ships: covers most merchant vessels with steel hulls—cargo ships, container ships, oil tankers, product/chemical tankers, ferries, cruise ships, etc. These are BV’s general rules for ocean-going commercial ships.
• Offshore Units: covers oil platforms, FPSOs, drilling rigs, mobile offshore units, and offshore support vessels. It ensures the fittings can be used on offshore structures subjected to severe conditions.
• Naval Ships: refers to military/navy vessels (patrol boats, frigates, logistics ships, etc.) that follow specific military classification rules (BV NR 483). Our fittings also comply with these demanding standards for warships.
• Yachts: covers large yachts and luxury pleasure craft that require class certification. It ensures the fittings are suitable for yachts and superyachts in terms of safety and reliability.

In short, with Redfluid fittings you can cover virtually any relevant type of vessel or floating platform: from steel oil tankers to private yachts, including naval vessels and offshore platforms.

Type-approved double-ferrule (twin-ferrule) fittings and passed tests

The Type Approval covers our range of double-ferrule (twin-ferrule) fittings in sizes from DN3 to DN50 (approximately 1/8” to 2” in diameter). All these fittings are manufactured in AISI 316/316L stainless steel.

Thanks to this approval, these fittings are considered suitable for onboard piping systems of Classes I, II, and III, i.e., all kinds of fluid services—from the most critical (high pressure, fuels, oil, steam, etc.) to general services.

Want to see all the specifications of our Twin-Ferrule fittings?

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Practical benefits:

With the approval granted, a double-ferrule fitting is pre-certified for use on ships and platforms. In practice, this means a class inspector or surveyor will not require individual tests for that fitting when inspecting the installation, nor—in most cases—will they ask you for an EN 10204 3.2 type certificate, as long as it’s within the approved scope.

The result is a faster installation with solid documentation support. For the manufacturer, holding the certificate increases market acceptance of their products in the naval industry worldwide and demonstrates a commitment to quality. Likewise, classification societies typically require the manufacturer to have quality systems (e.g., ISO 9001) and conduct periodic plant audits to ensure production continues to meet standards and that traceability is maintained between each piece produced and the approved design.

And… if you still have any questions or need hands-on guidance for your project, get in touch and we’ll help you!