ASME B16.47 covers large-diameter steel pipe flanges in sizes NPS 26 through NPS 60. This article summarizes its published scope, compares it with B16.5, and provides a historical table index from the official 2020 preview. [1] [2] [3]
Source review: 9 November 2026.
B16.47 scope at a glance
ASME B16.47 addresses steel pipe flanges in the nominal size range NPS 26–60. Its scope includes dimensional requirements, material requirements, tolerances, marking, testing and pressure–temperature ratings. ASME’s product description lists Classes 75, 150, 300, 400, 600 and 900. [1]
| Nominal size | NPS 26 through NPS 60 |
|---|---|
| Material forms | Cast or forged flanges; blind flanges may also use plate material. |
| Units | SI and U.S. customary requirements; bolt and bolt-hole diameters are expressed in inches. |
| Edition listed | B16.47-2025 on the ASME product page at the time of review. |
The listed classes describe the overall scope. They should not be read as a complete matrix of permitted size, class and configuration combinations.
B16.47 vs B16.5: size and class ranges
The following comparison summarizes the flange size and class ranges stated in the two ASME product descriptions. [1] [3]
| Standard | Nominal sizes and classes |
|---|---|
| B16.5 | NPS ½–24 for Classes 150, 300, 400, 600, 900 and 1500; Class 2500 covers NPS ½–12. Its scope also includes flanged fittings. [3] |
| B16.47 | NPS 26–60; the publisher lists Classes 75, 150, 300, 400, 600 and 900. [1] |
The ranges above summarize the published scope, not a complete size-by-class selection table.
Identify the edition before comparing data
At the time of checking, ASME’s product page displayed B16.47-2025. The separate 2020 preview gives an issuance date of 29 January 2021. In that document, the edition year differs from the year of issuance. [1] [2]
Series A and Series B: historical 2020 index
Edition note: This section describes the 2020 contents only. It does not establish the requirements of the 2025 edition.
The official B16.47-2020 table of contents lists separate dimensional-table entries for the two series. The index below helps a reader locate those entries without reproducing the standard’s dimensional data. [2]
| Series | Classes listed | Table numbers |
|---|---|---|
| A | 150, 300, 400, 600, 900 | 31–35; companion tables 31C–35C |
| B | 75, 150, 300, 400, 600, 900 | 36–41; companion tables 36C–41C |
In this 2020 index, Class 75 is listed under Series B, while the Series A dimensional-table entries start at Class 150. This is a description of the index, not a determination of dimensional interchangeability. [2]
Locate the original pages
The public PDF contains six pages of front matter and contents. The page numbers below refer to that PDF; printed page labels are included where present. [2]
- PDF page 3 — Issuance date for the 2020 edition.
- PDF page 4 · iii — Section headings, including ratings, marking, materials, dimensions, tolerances and testing.
- PDF page 6 · v — Series A and Series B dimensional-table headings.
Page anchors work in PDF viewers that support them. If the file opens at the beginning, use the viewer’s page selector.
References and editorial notes
- ASME. B16.47 — Large Diameter Steel Flanges: NPS 26 through NPS 60, Metric/Inch Standard. Publisher’s product listing and scope description; edition shown: 2025. Accessed 9 November 2026.
- ASME. ASME B16.47-2020: official public preview. Six-page preview: issuance date on PDF page 3; section headings on PDF page 4 (printed iii); Series A/B table headings on PDF page 6 (printed v). Accessed 9 November 2026. Historical edition; preview only.
- ASME. B16.5 — Pipe Flanges and Flanged Fittings: NPS ½ through NPS 24. Publisher’s scope description, including the Class 2500 size limitation. Accessed 9 November 2026.
Verification limits
This article was prepared with AI assistance from the public ASME materials linked above. The full 2025 standard was not reviewed, and no independent engineering review is claimed. Numerical dimensions, pressure ratings, bolt torque and Series A/B interchangeability are outside the verified scope of this article. The source descriptions and the historical table index are presented separately to avoid treating 2020 contents as verified 2025 requirements.
This page is not issued by or affiliated with ASME. References to ASME identify the source documents and do not imply endorsement.
