ANSI flange standards exist to ensure compatibility and uniformity in industrial piping systems. By adhering to these standards, industrial operations benefit from increased efficiency, reliability, and safety.
The American National Standards Institute (ANSI) is a non-profit private organization dedicated to developing standards across a range of industries, such as industrial flanges developed under the American Society of Mechanical Engineers (ASME). Specifically, ANSI flange standards apply to a flange’s design, size, material grade, and dimensions. Because ANSI flanges are compatible with components from other manufacturers, most industries go by ANSI flange standards rather than other less stringent standards.
Learn more about ANSI flange standards and how they can influence your flange selection.
The ANSI B16.5 Standard
One of the most popular standards is the ANSI B16.5 standard, which applies to food processing, oil and gas, water treatment, chemical, and other systems. This standard specifically informs the development of flanged fittings and pipe flanges consisting of stainless steel, carbon steel, alloy steel, and other materials.
Class Ratings and Dimension Tables
The pressure class and size of the pipe needed will determine which flange dimensions are ideal. ANSI B16.5 standards are based on those published by other organizations, such as ASME, Manufacturers Standardization Society (MSS), and the American Petroleum Institute (API).
Flanges Covered by ANSI B16.5
Different types of ANSI flanges fall under this particular standard, such as:
- Slip-on
- Blind
- Lap joint
- Socket weld
- Weld neck
- Threaded
This standard also applies to flanges for pipes measuring 1/2″ to 24″ and in pressure classes from 150 to 2500.
Other Relevant ANSI Standards
In addition to ANSI B16.5, the following are more standards that dictate ANSI flange dimensions, fabrication, and use.
ANSI B16.1 for Cast Iron Flanged Fittings and Pipe Flanges
This standard covers cast iron pipe flanges and flanged fittings in pressure classes 25, 125, and 250. It governs:
- Materials
- Pressure-temperature ratings
- Gaskets and bolting
- Marking
- Tolerances and dimensions
- Pressure testing
- Sizes and methods of designating openings of reducing fittings
ANSI B16.47 Series A and B
If pipe flanges are larger, they may fall under this standard, which applies to 26″ to 60″ pipe flanges with pressure class ratings of 75, 150, 300, 400, 600, or 900. This standard is further sectioned into Series A or Series B. Series A flanges are stronger, heavier, and thicker than Series B flanges. While Series A flanges can bear more external loading, they are also more expensive than Series B flanges.
ANSI B16.36 for Orifice Flanges
This standard covers orifice flange unions that typically work with orifice meters for liquid or gas flows via either socket weld or tapped meter connections on the flange’s exterior.
ANSI B16.9 for Factory-Made Wrought Steel Butt-Welding Fittings
Pipe fittings under this standard provide high precision. Covered fittings comprise socket-welded and butt-welded tees and elbows, eccentric and concentric reducers, and others of varying forms, materials, and dimensions.
ANSI B16.11 for Forged Steel Fittings (Threaded and Socket-Welded)
This standard governs threaded and socket-welded forged steel fittings, including those made of alloy steel, carbon steel, and stainless steel. The threaded end fittings are also referred to as class 2000, 3000, or 6000, while the socket weld end fittings are also called Class 3000, 6000, or 9000.
ANSI Flanges from Coastal Flange
For high-quality ANSI flanges that meet any of the above standards, Coastal Flange has the products you need. We distribute and manufacture pipe flanges from ½” to 200” OD that meet ANSI, ASME, AWWA, or other specialized standards.
Contact us today for more information about our offerings, or request a quote to find the right solution for your application.