What is Companion Flange and Why Do We Use Them?

16 Jun.,2025

 

What is a Companion Flange? | BOP Products, Houston TX

Oil and gas drilling involves a lot of plumbing, including pipe connections that require companion flanges. So, what is a companion flange? A companion flange corresponds to another flange to create a joint that fits into pipe connections. It has bolt holes that align with other flanges for quick jointing. As a result, it creates a pressure-tight seal.

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Companion flanges are vital in oil drilling operations. They help oilfield operators to assemble and disassemble pipe connections quickly. Besides, the flanges have bolt-hole patterns that align with other flanges to secure pipe joints. As a result, they make oil and gas pipes repair and maintenance services easy.

What is a companion flange, and how does it work in tandem with your oil rig set up? Learn how a companion flange can change your rig. Share on X

What Does a Companion Flange Do?

The companion flange is usually attached to another pipe’s flange, and the pipeline gets assembled to create a tight fit between the two flanges. You can also use the flange in a pipeline section you may want to remove in the future, mainly when changing pipe size.

All you need to do is place a flange in the pipeline and use a gasket to seal the sections tightly. As a result, the joint offers quick access during an emergency. The companion flange also allows convenient pipeline expansion for future construction additions.

Type of Flanges

Companion flanges come in different types, depending on the materials they are made of. Therefore, blending two or more pipes into a single system is easy without replacing the whole of it. For instance, you can add copper flanges to plastic plumbing systems.

Iron pipes can also blend well with brass flanges. However, blending different materials requires a matching flange and gasket. Besides, you need to use an anti-seize compound on the fasteners of different flange materials to prevent oxidation and rust.

Some types of flanges you should know based on design include:

  • Blind flange
  • Lap joint flange
  • Slip-on flange
  • Socket weld flange
  • Threaded flange
  • Welding neck flange 

What is Best?

Companion flanges are vital in sealing inspection openings to provide access points within plumbing lines. For that reason, a closed flange is often used to seal open pipes. Thankfully, you can change out the closed flange in the future when necessary. Also, the flanges make future additions or substractions within the pipelines easy.

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Let BOP Products Help

Companion flanges are essential in the oil industry. If you want your oil rig to have a lot of longevity, a companion flange will allow you to change out your pipe size easily. Looking for this piece of equipment? Check out our products to see what we have for you! 

What is a Companion Flange? | BOP Products, Houston Texas

If you work in a drilling site, you may wonder, “What is a companion flange?” You are perhaps familiar with other flanges, but not this type of flange. Well, a companion flange connects a flange yoke to another connection to allow proper torque transfer. It is common in drilling operations to improve the efficiency and performance of drilling tools.

Companion flanges are essential in pipe works and related equipment to quickly assemble and disassemble connected components. Notably, most flanges used in oilfield operations have bolt-hole patterns to secure the joints and a gasket to provide a pressure-tight seal. So, it makes repair and maintenance effortless.

What is a companion flange? Learn what it is, its application, and its importance in pipeline systems in the following blog post. #BOPProducts #oilandgas #APIEquipment Share on X

What is the Difference Between a Flange and a Companion Flange?

The primary difference between a flange and a companion flange is that the latter has a hub that’s either threaded or socket to attach to a pipe. But, flanges are solid in the middle allowing you to bolt to the companion flange to terminate a line. In other words, a flange doesn’t have a hub.

Where is it Used? 

In most cases, this piece of equipment gets attached to another pipe’s flange, and the pipeline gets assembled to fit between the two flanges. You can also use a threaded companion flange on plastic pipes when inserting threaded iron pipes into them. That makes this tool a vital component of a plumbing or pipeline system.

Why is it Important?

When building a plumbing system, it’s vital to install access points into the plumbing line to facilitate the removal of clogs. That’s where the companion flange comes in handy to help. It seals open pipes to form a closed flange, which can get changed in the future when a need arises. For that reason, it offers easy access for a plumbing emergency. 

API Equipment with BOP Products

Some API documents categorize companion flanges as “loose flanges” or “loose connectors,” The types of flanges that fall in that category are blind, test, threaded, and weld neck flanges. Since this piece of equipment is a vital component of the pipeline system, you need to get them from a reliable manufacturer, such as BOP Products.