An API flange is a type of pipe flange that is designed to meet the specifications set forth by the American Petroleum Institute (API). The flange plays an important role in providing a secure connection between two pipes or other components. Let’s take a closer look at what an API flange is and why it’s so important.
What is an API flange?
API flanges are a special type of engineered connection originally developed by the American Petroleum Institute (hence the “API”) and they are widely used in industrial piping systems.
This unique fitting style is used most often for high-pressure applications and offers low-cost materials, minimal maintenance needs, and easy installation. The design consists of two ends that fit together, one side being set inside the other and fastened with a gasket or welded.
This connection method prevents damage caused by temperature extremes or vibration, providing an efficient option for quickly joining pipes and components.
API flanges are available for both above-ground and underground fittings and are preferred among many project engineers due to their durability, reliability, and cost-effectiveness.
The American Petroleum Institute (API) was founded in the 1930s with the intention of differentiating its flanges from those of the American Standards Association (ASA). The PSI requirements of API’s flanges exceeded that of ASA, meaning they couldn’t use the same type.
This spurred another development and eventually led to the American Society of Mechanical Engineers (ASME) and American National Standards Institute (ANSI) regulating and setting the standards for most flange systems used today. While both have their roots in API, the distinction remains clear between what they offer in terms of pressure ratings and durability.
How do API Flanges work
They provide a reliable method for joining piping components in defined pipelines, allowing liquids and gases to be safely transported over a long distance. An API flange consists of two end faces that are mated together using high-grade bolts, with the faces machined to mate tightly together.
This ensures that there is an optimal seal between the two mating surfaces, meaning it can hold up to extreme temperatures and pressures without being damaged or leaking. Once connected, these valves also maintain pressure or other parameters with an adjustable backflow mechanism.
In order to function properly, API flanges must meet stringent standards of manufacturing to ensure optimal strength and corrosion resistance. This is achieved by pairing the flange with a ring joint face, as well as a corresponding gasket for better seal integrity.
With greater safety features than traditional mechanical joints, API flanges offer oil and gas industry professionals an incredibly reliable component to keep their pipelines running smoothly.
What is the difference between API and ASME/ANSI Flanges?
The biggest difference between these API flanges and ASME/ANSI flanges is the amount of pressure they can handle. API flanges have a higher-rated operating pressure tolerance than ANSI/ASME flanges, making them ideal for use in applications where high pressure is present. Additionally, API flanges provide more options for sealing than ANSI/ASME ones, making them useful in systems that require extra protection from leakage.
Although sometimes both these 2 types of flanges use the same bolt circle and the same number of bolts, they have different pressure systems, in a resume:
- ASME evaluates class pressure based on materials of construction and design temperature
- API evaluates pressure based on acceptable materials and will give it a rating.
Although the dimensions – such as the circle and bolt holes – may be the same for API 6A and ANSI/ASME B16.5 requirements, they do not often share the same pressure rating system due to different standards in design, materials, and fabrication methods, as indicated in the table below.
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API vs. ASME/ANSI Flanges with the same Dimensions |
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| Flange | Pressure Class Rating (psi) |
Nominal Size Range (inches) |
||
| ASME/ANSI B16.5 | API 6A | ASME/ANSI B16.5 | API 6A1) | |
| Weld neck |
600 |
2000 |
1/2 – 24 |
113/16 – 11 |
|
900 |
3000 |
|||
|
1500 |
5000 |
|||
| Blind and Threaded |
600 |
2000 |
113/16 – 211/4 | |
|
900 |
3000 |
113/16 – 203/4 | ||
|
1500 |
5000 |
113/16 – 11 | ||
Great advantages of using API flanges
API flanges are a great choice for building projects because they provide many benefits that can help make construction faster, easier, and more efficient.
They can handle higher levels of operating pressure than other flanges, making them extremely beneficial in certain scenarios that require durable parts with excellent pressure-resistance properties.
Their construction also concentrates on guaranteeing their strength and enduringness when exposed to caustic solutions that could lead to corrosion or cracking damage. Seals and bolts are carefully selected to ensure the pipes remain sealed and are not prone to leaking or denting.
Additionally, API flanges have an industry-leading connection system which allows for quick dismantling and reassembly when required. All these factors combine to make API flanges a reliable option when it comes to constructing new buildings and structures.
How to choose the proper type of flanges for your project?
Flanges are key components in many operations, making the choice of which type to use for a specific application incredibly important. If the wrong type is used, it can lead to costly repairs and potential safety hazards.
When choosing the right flange, research is critical to ensure compatibility with project objectives, budgets, and timelines. You should consider things like pressure rating, temperature range, and material construction to ensure that the products you use will be strong enough to support your project requirements.
ASME flanges are often targeted toward industrial, architectural, and sanitary pipeline projects such as waterworks and building heating systems. They are the most popular choice amongst construction companies that require an affordable and reliable solution for difficult applications.
API flanges play an essential role in the oil and gas industries when processing high-pressure substances. It is often the only choice when it comes to refineries because of its capability to handle extreme pressures – something other pipes cannot provide.
As a result, API flanges have become increasingly popular with those operating in the oil and gas sectors, especially due to their superior strength and durability.
Conclusion
API flanges are widely used for applications that require high pressure, such as refineries and pipelines. They provide leak-free connections without the need for gaskets, making maintenance easier and eliminating the risk of environmental contamination.
API flanges come in various sizes, allowing them to fit any particular application, while their construction ensures that they are highly durable and resistant to corrosion. In conclusion, API flanges offer a reliable solution with numerous benefits over traditional alternatives.
Taiyuan Forging is a world-leading manufacturer of API flanges that are used in the oil & gas, and petrochemical industries. If you have any inquires, please don’t hesitate to contact us.