Large Diameter Flanges — ASME B16.47
NPS 26 through NPS 60 in two series that in general do not interchange. Series A comes from MSS SP-44 and is the heavier; Series B comes from API 605 and is the lighter.
The two series do not mate, with one exception. In Classes 75, 150 and 300, and in NPS 36 and smaller in Classes 400, 600 and 900, a Series A and a Series B flange of the same NPS and class have different bolt circles and bolt counts. At NPS 38 and larger in Classes 400, 600 and 900 the two series have the same dimensions. Specifying “NPS 36 Class 150 B16.47” without the series is an incomplete specification.
Series and class coverage
| Series and class | Derived from | Sizes | On PipeData |
|---|---|---|---|
| Series A Class 150 | MSS SP-44 | NPS 26 through NPS 60, Class 900 through NPS 48 | Full table |
| Series A Class 300 | MSS SP-44 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series A Class 400 | MSS SP-44 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series A Class 600 | MSS SP-44 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series A Class 900 | MSS SP-44 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 75 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 150 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 300 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 400 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 600 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not tabulated here |
| Series B Class 900 | API 605 | NPS 26 through NPS 60, Class 900 through NPS 48 | Not 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?
In general, no. In Classes 75, 150 and 300, and in NPS 36 and smaller in the higher classes, the two series have different outside diameters, bolt circles and bolt counts. At NPS 38 and larger in Classes 400, 600 and 900 the two series have the same dimensions. Always state the series on the requisition.
Which B16.47 series should I specify?
The standard describes Series A as the series for general use and Series B as the compact one. Series A is heavier and more rigid. Series B is lighter and cheaper, and is often chosen to match API 605 flanges already in a plant. The project specification decides.
What sizes does ASME B16.47 cover?
NPS 26 through NPS 60 in both series, in even sizes, with Class 900 published through NPS 48 only. It covers welding neck and blind flanges. Below NPS 26, flanges are covered by ASME B16.5 instead — the two standards meet at NPS 24/26 with no overlap.