ASME B16.47-2017 Large Diameter Steel Flanges NPS 26 Through NPS 60 Metric/Inch Standard

what is ASME B16.47?

ASME B16.47 2017 is a standard published by the American Society of Mechanical Engineers (ASME) that provides specifications for large diameter steel flanges in sizes NPS 26 through NPS 60. The full title of the standard is "Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard."

The ASME B16.47 2017 standard provides information on materials, dimensions, tolerances, markings, and testing requirements for these large diameter steel flanges. The standard also includes provisions for the design and construction of flanges used in pipeline applications, including pressure-temperature ratings, bolted joint assembly procedures, and gasket seating stresses.

ASME B16.47 covers pressure–temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60. Included are flanges with rating class designations 75, 150, 300, 400, 600, and 900 with requirements given in both SI (Metric) and U.S. Customary units, with diameter of bolts and flange bolt holes expressed in inch units. 

This Standard is limited to 

(a) flanges made from cast or forged materials 

(b) blind flanges made from cast, forged, or plate materials (see Tables 1 and 2) Also included in this Standard are requirements and recommendations regarding flange bolting, flange gaskets, and flange joints.

What is the difference between ASME B16 47 Series A and Series B?

ASME B16.47 provides two series of flange dimensions. 

ASME B16.47 Series A specifies flange dimensions for general use flanges. 

ASME B16.47 Series B specifies flange dimensions for compact flanges that, in most cases, have smaller bolt circle diameters than Series A flanges. 

These two series of flanges are, in general, not interchangeable. The user should recognize that some flanged valves, equipment bolted between flanges, and flanged equipment may be compatible with only one series of these flanges.

Similar Flanges： MSS SP-44 covers similar Class 150, 300, 400, 600, and 900 flanges for use with high strength pipe made from materials having yield strength greater than 276 MPa (40,000 psi) resulting in large inside pipe diameter and thinner pipe wall.

The main difference between Series A and Series B of ASME B16.47 is the pressure ratings. Series A flanges have a smaller pressure rating than Series B flanges. The pressure rating of Series A flanges ranges from Class 150 through Class 900, while the pressure rating of Series B flanges ranges from Class 75 through Class 1500.

Another difference between Series A and Series B flanges is the number of bolt holes. Series A flanges have fewer bolt holes than Series B flanges, which makes them lighter and easier to handle.

Series A flanges are typically used in lower pressure and temperature applications, while Series B flanges are used in higher pressure and temperature applications.

It is important to note that the selection of Series A or Series B flanges should be based on the specific requirements of the application, including pressure, temperature, and material compatibility.