Type of Flanges Used in the Oil and Gas Industry - Edgevarsity Blog Edgevarsity
Type of Flanges Used in the Oil and Gas Industry

Type of Flanges Used in the Oil and Gas Industry

The Oil and Gas industry is well-known for its gigantic infrastructure. The foundation of this vast infrastructure lies in the articles and equipment used. When we talk about the articles, we also consider the supporting framework. Supporting frameworks serve the bigger purpose as they carry out the major load-bearing activities. One such crucial supportive framework is the Flange. 

What are Flanges?

Before proceeding, let us remember one fact about flanges. They are the second most used joining method after welding. Flanges are used to connect equipment to a piping system or two piping spools so that these connections can be dismantled as and when required. 

Why do we need a flange?

As you might know, absolutely permanent connections or joints of pipes could be welded, but joints or links that need to be removed once in a while are mostly done through flange connections.

Now that you know the basic functionality of flange, let’s see the types of flange connections.

Type of Flanges

According to the type of construction, pressure-bearing capacity etc., the flanges are classified into different categories. You must remember that Flanges are not a one-type-for-all sort of solution. It is essential to consider matching the ideal flange design that would sync with your piping system. It will serve the intended purpose, help to ensure reliable operation, a long service life, and appropriate pricing.

The most commonly used flanges in the industry are:

  1. Slip-on flange
  2. Socket flanges 
  3. Threaded flanges 
  4. Weld neck flange
  5. Stub end and Lap joint
  6. Blind flanges

Slip-On Flange

This flange is designed to serve its purpose for processes that accommodate low temperature and low pressure. Here, the inside diameter of the flange that needs to be inserted is slightly more than the outer diameter of the pipe. As the name suggests, this ensures that the flange can easily slip over the pipe to increase its strength and prevent leakage.

Socket Flanges

Socket flanges are also recommended for low pressure and low-temperature processes, as the static strength of socket weld is equal to a Slip-on flange. Socket weld flanges are usually designed to be used for operations where small-bore piping is required. However, due to corrosion issues, these flanges are avoided in some processes.

Threaded flanges

These flanges are similar to the socket flange, but the only difference lies in the fact that the inner portion is threaded instead of the socket in threaded flanges. As a result, the mating pipe will have suitable male threads. Welding is not necessary in the case of threaded flanges. This type of flange is generally used in small bore piping for utility air, instrument air and galvanized drinking water lines.

Weld neck flanges

Weld neck flanges are primarily used in high-pressure environments. They are easily recognized due to their tapered hub, and they go well when the process involves repeat bending conditions. These flanges are attached to a piping system using butt welding. Since butt weld gives good strengths and quality, weld neck flanges are commonly used for good quality piping.

Lap joint and Stub End

The Lap joint flange is a particular type of flange with a two-part attachment. The lap joint flange has a structure similar to the slip-on flange, along with a stub end fitting. The lap joint flange freely rotates around the stub end. This type of flange is mainly used in those processes where the primary requirements are frequent dismantling and space constraints.

Blind flanges

Blind flanges or Blinds, as the name suggests, are used to blind or block off the end of a piping system, valves or even pressure vessel openings. For example, a blind flange can block the dummy nozzles of static equipment. It is also used for hydro testing the piping spools. Blind flanges could also be used together with any other flange to isolate a piping system in the oil and gas industry. The blind flanges are made for the high-pressure application. Therefore, the materials used in the manufacture of blind flanges should have high tensile strength and good mechanical and corrosion resistance properties.

This information was just a brief of what flanges are and their types and functionalities. You need to dive deeper into the concepts for strengthening your hold in this subject.
If you aspire for a suitable job-oriented course after graduation in the oil and gas industry, check out the Oil and Gas Piping engineering course for more details.


by Debashree P

Debashree is an Aeronautical engineer by education and a curious researcher by passion. She is passionate about engineering and technology. She is an avid technology writer who has a knack for developing content for websites, newsletters, blogs, articles, advertising and marketing materials based on the requirements. Technologies of her interest include Aviation, Oil & Gas and AI.