PipeData

Large Diameter Flanges — ASME B16.47

NPS 26 through NPS 60 in two non-interchangeable series. Series A comes from MSS SP-44 and is the heavier; Series B comes from API 605 and is the lighter.

Series Afrom MSS SP-445 classes · NPS 26 through NPS 60Series Bfrom API 6056 classes · NPS 26 through NPS 60

The two series do not mate. A Series A and a Series B flange of the same NPS and class have different bolt circles and bolt counts. Specifying “NPS 36 Class 150 B16.47” without the series is an incomplete specification.

Series and class coverage

ASME B16.47 series and pressure classes.
Series and classDerived fromSizesOn PipeData
Series A Class 150MSS SP-44NPS 26 through NPS 60Full table
Series A Class 300MSS SP-44NPS 26 through NPS 60Not tabulated here
Series A Class 400MSS SP-44NPS 26 through NPS 60Not tabulated here
Series A Class 600MSS SP-44NPS 26 through NPS 60Not tabulated here
Series A Class 900MSS SP-44NPS 26 through NPS 60Not tabulated here
Series B Class 75API 605NPS 26 through NPS 60Not tabulated here
Series B Class 150API 605NPS 26 through NPS 60Not tabulated here
Series B Class 300API 605NPS 26 through NPS 60Not tabulated here
Series B Class 400API 605NPS 26 through NPS 60Not tabulated here
Series B Class 600API 605NPS 26 through NPS 60Not tabulated here
Series B Class 900API 605NPS 26 through NPS 60Not tabulated here

Coverage note. PipeData publishes the full dimensional table for Series A Class 150. The remaining series and class combinations are described here but not tabulated — read them from a current copy of ASME B16.47 rather than from a secondary source.

Common questions

Can a Series A flange bolt to a Series B flange?

No. At the same NPS and class the two series have different outside diameters, different bolt circles and different bolt counts. They are separate, non-interchangeable products that happen to live in the same standard. Always state the series on the requisition.

Which B16.47 series should I specify?

Series A is the heavier and the usual default for new North American refinery, power and pipeline work. Series B is lighter and cheaper but less rigid; it is normally chosen only to match existing API 605 flanges already in the plant.

What sizes does ASME B16.47 cover?

NPS 26 through NPS 60 in both series. Below NPS 26, flanges are covered by ASME B16.5 instead — the two standards meet at NPS 24/26 with no overlap.