What is ANSI Flange And How Does it Works

What is ANSI flange?

ANSI flange is a standard produced by the American National Standard Institute (ANSI) that specifies the appearance, size, and pressure level of flanges. ANSI flanges are those that have been constructed in accordance with ANSI specifications. The widespread use of ANSI flanges is due to their standardization and compatibility, which ensure consistency and interchangeability across many industrial applications.

Because these flanges are available in a number of sizes, pressure levels, and materials to fulfill a wide range of application needs, they are frequently employed throughout industries and applications.

Why is it important to use ANSI standard flanges?

The following factors primarily demonstrate the significance of ANSI flanges:

Standardization and compatiability: ANSI flange standards guarantee uniformity and interchangeability across diverse industrial applications, enabling the seamless connection of diverse systems and equipment to enhance system dependability and productivity.
Wide range of applications: ANSI flanges are widely used in a variety of industrial fields, including but not limited to petroleum, chemical, power, water treatment, etc., because of their diversity and applicability.
Quality and performance assurance: ANSI flanges are made in compliance with stringent standards, guaranteeing their quality and performance and enhancing the overall stability and safety of the system.
Cost-effectiveness: By using ANSI flanges, you can cut production costs, design and manufacturing errors, and the cost of replacement and maintenance down the road.

Because of their standardization, compatibility, broad range of applications, and assurance of quality and performance, ANSI flanges are essential to the industrial sector.

Something you should know

The role and standard setting of ANSI (American National Standards Institute)

ANSI (American National Standards Institute) is a private non-profit organization established on October 18, 1918, responsible for the management and coordination of voluntary standardization and conformity assessment systems. ANSI’s mission is to improve the global competitiveness of American business and the quality of life of the American people by promoting and assisting voluntary and consistent standards and conformity assessment work and maintaining their integrity.

ANSI itself rarely formulates standards, but through the appointed group law and the solicitation of opinions law, it selects standards that are of great significance to the country from the standards formulated and issued by various professional groups, and promotes them to national standards after review, and gives them the ANSI code.

Currently, there are more than 180 standard-setting organizations accredited by ANSI, with a total of 37,000 standards, accounting for 75% of non-governmental standards. A small number of them are approved by ANSI as national standards. Of the 11,000 standards formulated and issued by ANSI, only 1,600 are formulated by it itself.

ANSI’s roles and responsibilities include:

Coordinate the standardization activities of domestic institutions and groups.
Review and approve American national standards.
Represent the United States in international standardization activities.
Provide standard information consulting services.
Cooperate with government agencies.

ANSI is headquartered in New York and has more than 250 professional societies, associations, consumer organizations and more than 1,000 companies (including foreign companies) participating. Representatives of federal government agencies participate in their activities in their personal capacity and do not accept government funding. ANSI is the official U.S. representative to the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), and serves as the official U.S. representative to the International Electrotechnical Commission (TEC) through the U.S. National Committee. In addition, ANSI also represents the United States at the Pacific Area Standards Conference (PASC) and the Pan American Standards Committee (COPANT).

Common types of ANSI standard flanges

ANSI/ASME B16.5

This is the most widely used ANSI flange standard, with widths ranging from NPS 1/2 to NPS 24 with pressure ratings of 150, 300, 400, 600, 900, 1500, and 2500. This standard specifies the size, material, tolerance, labeling, testing technique, and nomenclature for flange holes.

It comprises a variety of flanges such as butt welding necks, socket welding, threaded connections, loose sleeves, butt welding, and flange covers.

B16 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24, Metric/Inch Standard

ANSI/ASME B16.47

This standard specifies the dimensions, materials, and testing requirements for large steel flanges ranging in nominal diameter from NPS 26 to NPS 60.

It is separated into two series: flanges with elevated faces (Series A) and flanges with flat faces (Series B).

B16 – Large Diameter Steel Flanges: NPS 26 through NPS 60, Metric/Inch Standard

ANSI/MSS SP-44

This standard is specialized to steel pipeline flanges, with sizes ranging from NPS 12 to NPS 60 and pressure levels of 150, 300, 400, 600, and 900.

It defines the pressure-temperature rating, materials, dimensions, tolerances, marking, and testing standards for flanges.

Weld neck flanges must be constructed of forged steel, whereas blind flanges can be made of forged steel or steel plates.

How do we classify flanges?

ANSI flanges can be classified according to pressure level, material, connection method, etc., for example:

Classification by connection method: welded flange, threaded flange, butt welding flange, etc.
Classification by material: carbon steel, stainless steel, alloy steel, etc.
Classification by pressure level: 150#, 300#, 600#, 900#, 1500#, 2500#, etc.

On our website, we have classified flanges in the following categories to help customers choose the right products. To view the flange products, simply click on any of the following:

Category	Options
Flange Standards	ANSI flange \| ASME flange \| EN Standard Flange \| Custom Type
Flange Types	Weld Neck Flanges \| Slip-On Flanges \| Blind Flanges \| Lap Joint Flanges \| Socket Weld Flanges \| Threaded Flanges
Flange Materials	Stainless Steel Flanges \| Carbon Steel Flanges \| Alloy Steel Flanges

How do we produce ANSI flanges?

At YANHAO, we manufacture flanges in the following steps. Of course, for different user requirements, we will make appropriate adjustments and upgrades to the production process in specific steps. Here, I will only briefly show the production process. If you are interested, you can click to view this article: How a Flange Is Made: The Flange Manufacturing Process.

Raw materials: Prepare raw materials by inspecting their appearance, mechanical properties, chemical composition, ensuring traceability, and adhering to international or domestic standards.
Sawing materials: Optimize the cutting process, reduce waste, increase efficiency, and maintain geometric dimensions and quality.
Heating: Use thermocouples or infrared thermometers to prevent overheating and ensure the temperature is appropriate.
Forging: Control the forging temperature, force, speed, and ratio to improve the microstructure and performance of the forging process.
Heat treatment: Adjust the heating and holding times, and choose annealing, normalizing, quenching, or tempering processes based on the product’s use.
Non-destructive testing: Non-destructive testing uses ultrasonic, magnetic powder, or radiographic technology to detect internal flaws.
Machining: Finishing enhances surface quality while controlling dimensional accuracy and tolerance.
Pickling and anti-corrosion: Chemical treatment removes oxide scale and impurities, while coating or electroplating increases corrosion resistance.
Acceptance of finished products: Inspect mechanical properties, dimensions, and surface quality in accordance with international or domestic standards.
Steel stamping and warehousing: This step involves using steel stamps to record specifications, materials, and furnace numbers, as well as tracking production and quality records using inventory management systems.

These steps make up the flange processing process. At YANHAO, we closely monitor and operate each step to ensure that the final product’s quality and performance meet customer expectations.

What are the common application areas of ANSI flanges?

ANSI flanges are widely used in various industrial applications due to their versatility and compatibility. ANSI flanges are available in a variety of sizes, pressure ratings, and materials to meet a variety of application requirements.

I believe that customers who are reading this article will have a basic understanding of the application scenarios of ANSI flanges. I will not go into details here. You can still learn about the specific places where our flanges are used through some of our cooperative customer cases.

Project Cases

Flange pipe fittings use cases in oil projects

Installation and maintenance of ANSI flanges

The installation and maintenance of ANSI flanges is a complex process. There is a set of installation and maintenance standards respectively. I will not elaborate here, but simply list some key points involving safety.

A worker is polishing the rusty flange — **Polishing the rusty flange**

When selecting matching flanges for equipment or valve components, attention should be paid to whether the flanges of the original equipment or valve components are consistent with the flange connection size used in the pipeline.
Ensure that the flange surface is free of damage, rust or other defects. Check whether the bolt holes are clean and the bolts can pass freely. Clean the contact surface between the pipeline and the flange to ensure that there are no foreign matter or impurities.
Select gasket materials suitable for the medium and operating temperature. Place the gasket between the flanges to ensure the correct position and avoid deviation.
Check the flange connection for signs of air or liquid leakage. Make sure all bolts are evenly stressed and the torque meets the specifications.
For flange connections of buried pipes, there should be inspection wells and anti-corrosion measures. If it must be buried, ensure that appropriate anti-corrosion measures are taken.

The above are just some simplified precautions, but you can also understand from these that these steps require professional personnel to install and regularly maintain. If you have any questions about this, you can contact YANHAO at any time, and we will arrange professional engineers for guidance.

Recommend Reading:

Corrosion-Resistant Flanges: Key Factors and How to Choose

Finally

The above is everything you need to know about ANSI standard flanges. At YANHAO, we provide various types of ANSI flanges and provide comprehensive pre-sales and after-sales services, such as flange installation guidance, maintenance tutorials, etc. If you need it, please feel free to contact YANHAO.

What is ANSI Flange And How Does it Works