ASME B16.47: Differences Between Series A & Series B Flange
ASME B16.47 is a standard for large-size flanges of ASME (American Society of Mechanical Engineers). It is divided into two types: Series A and Series B. Before explaining the difference between the two, let’s first understand some basic information.
Currently, ASME standards are divided into B16.47 and B16.5. B16.5 is for small sizes (24 inches, that is, below NPS 24), while B16.47 is for large sizes (26 inches to 60 inches, that is, between NPS 26 – NPS 60).
The B16.47 standard is divided into Series A and Series B, and covers blind flange and welding neck flange. Below is a comparison chart of the differences between Series A & Series B:
| Series A | Series B |
|---|---|
| Formerly known as MSS SP-44 flange. Note: ASME B16.47 Series A flanges (> NPS 26) are MMS SP-44 flanges. MSS SP-44 also covers NPS 12 to NPS 24 flanges which are equivalent to ASME B16.5. | Equivalent to API 605. Note: API 605 has been cancelled. |
| Series A flanges are typically thicker and heavier than Series B flanges and are used in high-pressure applications. Series A covers pressure class from 150 to 900. (Class 150, 300, 400, 600, 900) | Series B covers pressure class from 75 to 900. (Class 75, 150, 300, 400, 600, 900) |
| Series A flanges have a larger bolt circle diameter, meaning they use fewer bolts but in larger sizes. | Series B flanges have a smaller bolt circle diameter, so they require more bolts but in smaller sizes. |
| Series A flanges are typically able to handle more external loads than Series B flanges due to their increased thickness and weight. | Series B flanges are relatively weaker and are able to handle fewer external loads. |
| Series A flanges are typically more expensive than Series B flanges, which is usually due to the higher steel content and thicker design. | Series B flanges are less expensive due to the reduced steel weight. |
| Series A flanges are typically used in new piping projects or equipment installations, especially in applications that require stronger pressure resistance and heavier construction. | Series B flanges are more often used in renovation or replacement work because the cost is more manageable. |
ASME B16.47 And ASME B16.5
ASME B16.5 and ASME B16.47 are two different flange standards developed by the ASME (American Society of Mechanical Engineers). The ASME B16.5 standard covers flanges from NPS 1/2 inches to NPS 24 inches, with pressure classes from 150 to 2500. And the ASME B16.47 standard covers larger flanges, ranging from NPS 26 inches to NPS 60 inches, with pressure classes including 75 to 900.
Both standards include provisions for pressure, temperature, materials, dimensions, tolerances, marking and testing. In addition, ASME B16.5 defines more flange types, such as weld neck flanges and blind flanges.
To help you remember better, just look at the following:
Differences Between Series A & Series B
ASME B16.47 is further subdivided into two series:
Series A: Flanges are thicker, heavier, and able to handle greater external loads. These flanges are often used in new piping projects or critical applications because they require a more robust structure and are generally more expensive than Series B flanges.
Series B: Flanges are lighter, less expensive, and are used in non-critical applications. Series B flanges require more but smaller fasteners and are generally used in pipeline renovations or projects with limited budgets.
ASME B16.47 FLANGE CLASSES
Choose The pressure class below
Overall
Both ASME B16.47 Series A and Series B are important for ensuring the safety, reliability, and compatibility of flanges in piping systems. They are widely used in industries such as oil, gas, chemicals, power, and water treatment.
Author: Lewis Liu
Hello, my name is Lewis Liu, and I’m a professional sales engineer with over a decade of expertise in the flange fittings sector.
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If you have any queries or concerns concerning flange fittings for your pipelines, whether they are about selection, material choice, specification requirements, or anything else, please contact me at any time. I am dedicated to providing expert advice and assistance to help you make educated decisions and reach your objectives.
