What is swivel flange and its applications in offshore pipelines

What is a Swivel Flange?

A swivel flange is a specialized type of flange designed to facilitate easier alignment and installation in piping systems. Unlike traditional fixed flanges, a swivel flange consists of two main components:

The rotating ring – A loose flange ring that can rotate around the hub or pipe end.

The hub or welding neck – A fixed component that is welded to the pipe.

This design allows for easier bolt hole alignment, reducing installation time and stress on the piping system, especially in offshore and subsea applications where precise alignment is crucial.

swivel flange

How Does a Swivel Flange Differ from Other Common Flanges?

Compared to other flange types, the swivel flange offers unique advantages:

Swivel vs. Weld Neck Flange (WN Flange) – While weld neck flanges provide strong and stable connections, they do not allow for rotational adjustment, making bolt alignment more challenging.

Swivel vs. Slip-On Flange – Slip-on flanges are easier to install but lack the structural strength required for high-pressure offshore applications. Swivel flanges provide both strength and adjustability.

Swivel vs. Blind Flange – Blind flanges are used to seal off pipeline ends, while swivel flanges are designed to connect and adjust alignment between pipes or equipment.

Applications of Swivel Flanges

Swivel flanges are widely used in industries where precise alignment, high-pressure resistance, and corrosion protection are required. Common applications include:

Offshore Oil & Gas Pipelines – Used in subsea pipeline connections and riser systems for easier installation.

Floating Production Storage and Offloading (FPSO) Units – Enables flexible and secure connections between floating platforms and pipelines.

Subsea Manifold and Christmas Trees – Used in deepwater production systems where high pressure and corrosion resistance are critical.

High-Pressure Process Piping – Applied in refineries, chemical plants, and other industries where ease of alignment is necessary.

Swivel Flange in Offshore Pipelines

In offshore pipeline engineering, installation and maintenance are significantly more challenging than onshore systems due to harsh marine environments, high pressure, and deepwater conditions. Swivel flanges play a crucial role in overcoming these challenges by:

Reducing installation time – Their rotational capability simplifies the bolting process, even in difficult underwater conditions.

Minimizing stress on pipelines – Misaligned flanges can cause unnecessary strain; swivel flanges allow for adjustments to prevent stress points.

Enhancing corrosion resistance – Often made from materials such as Super Duplex Stainless Steel (A182 F55) or Nickel Alloys, which provide excellent corrosion resistance against seawater exposure.

Haihao Group: A Trusted Supplier of Swivel Flanges for Offshore Projects

With decades of experience in offshore pipeline engineering, Haihao Group is a leading manufacturer of swivel flanges and other pipeline components. Our products meet stringent international standards, including:

✅ ABS (American Bureau of Shipping) Certification

✅ DNV (Det Norske Veritas) Certification

✅ BV (Bureau Veritas) Certification

✅ RINA, RS, and more

We have supplied high-quality flange solutions for various offshore and subsea engineering projects, including FPSO units, offshore drilling platforms, and deepwater pipelines. Our expertise and certifications ensure that our products provide reliable performance in extreme marine conditions.

For more information on our swivel flanges and offshore pipeline solutions, feel free to contact Haihao Group!  Email:sales@haihaogroup.com