ANSI stands for the American National Standards Institute, which is a private, non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. ANSI does not itself write standards, but instead accredits organizations that do, such as the American Society of Mechanical Engineers (ASME).

ASME is a professional organization of mechanical engineers that promotes the art, science, and practice of mechanical engineering and allied sciences. ASME develops codes and standards for boilers, pressure vessels, piping, and other mechanical equipment.

How are ANSI and ASME involved in flange specifications?

The current ANSI/ASME flange specifications of B16.5 and B16.47 trace their roots to the old B16.1 specification from decades past, which consisted primarily of cast iron. This specification in turn was developed from the original AESC/ASA committee B16 in the 1920s. These modern specifications are the result of countless hours of engineering and design to form a standard which could be utilized worldwide.

ANSI stands for “American National Standards Institute”

ASME Stands for “American Society of Mechanical Engineers”

These organizations play different roles in the development of flange specifications:

ANSI accredits ASME as a standards developing organization (SDO). This means that ASME has met the requirements of ANSI to develop standards that are fair, open, and balanced.

ASME develops the technical content of the flange specifications. ASME has a number of committees of experts who volunteer their time to develop and revise the specifications.

ANSI approves the final flange specifications. Once ASME has developed a new or revised specification, it is submitted to ANSI for approval. ANSI makes sure that the specification meets all of its requirements before it is published.

Why are ANSI/ASME flange specifications important?

ANSI/ASME flange specifications are important because they help to ensure the safety and reliability of piping systems. By using flanges that meet these specifications, engineers can be confident that they are using high-quality components that will not fail under pressure.

Flange applications

Our most commonly requested flange specification, ANSI/ASME flanges continue to be the most widely used type of steel flange across various industries. The pressure vessel and fabrication sectors use these in abundance in their pressurized applications to retain and transport air, water, and a variety of other chemicals. Often found in refineries, ANSI/ASME flanges are a critical component in their infrastructure, and are primarily used to connect piping, valves, and other fittings which compose the bulk of a piping assembly. The 150# class of steel flanges is the most popular for low pressure and vacuum applications, as the design has proven to be effective in applications which require an occasional fluctuation in the temperature and pressure of the environment.