STANDARD · ASME-B16-47-A

ASME B16.47 Series A Flange Dimensions

ASME B16.47-2025 · ASME B16.47 Series A

ASME B16.47-2025North America, Middle Eastpressure class

ASME B16.47 covers large-diameter flanges from NPS 26 to NPS 60. Series A preserves the former MSS SP-44 dimensions and is the series most often specified for large-bore oil and gas, water and process piping.

Series A and Series B use different outside diameters and bolt patterns for the same size and class, so the series must be stated on the purchase order. A Series A flange will not bolt to a Series B flange, and neither will bolt to an ASME B16.5 flange of the same nominal size. B16.47 covers weld-neck and blind flanges only — slip-on flanges above NPS 24 are made to drawing — and Class 900 is published up to NPS 48.

Base materialASTM A105

Size notationNPS (inch)

Material options5 groups

Reference data5 topics

DIMENSIONS

Dimension tables

One row per specification. Open a size for the drawing, pressure ratings and printable A4 sheet.

Weld Neck 84 Blind 84

Weld Neck: Butt-welded to the pipe with a tapered hub; used for high pressure, high temperature and cyclic service. 84 specifications.

18 specifications

Size	Rating	Outside Ø D	Thickness C	Raised face D2	Bolt circle K	Bolting	Hub A	Length H	Weight
26″DN650	Class 400	972	88.9	749	876.3	28 × Ø47.6	727	194	295 kg	Spec sheet
28″DN700	Class 400	1035	95.3	800	939.8	28 × Ø50.8	783	206	356 kg	Spec sheet
30″DN750	Class 400	1092	101.6	857	997	28 × Ø54	837	219	411 kg	Spec sheet
32″DN800	Class 400	1149	108	914	1054.1	28 × Ø54	889	232	483 kg	Spec sheet
34″DN850	Class 400	1206	111.3	965	1104.9	28 × Ø54	945	241	544 kg	Spec sheet
36″DN900	Class 400	1270	114.3	1022	1168.4	32 × Ø54	1000	251	608 kg	Spec sheet
38″DN950	Class 400	1206	124	1035	1117.6	32 × Ø47.6	1003	206	424 kg	Spec sheet
40″DN1000	Class 400	1270	130	1092	1174.8	32 × Ø50.8	1054	216	494 kg	Spec sheet
42″DN1050	Class 400	1321	133.4	1143	1225.6	32 × Ø50.8	1108	224	540 kg	Spec sheet
44″DN1100	Class 400	1384	139.7	1200	1282.7	32 × Ø54	1159	233	624 kg	Spec sheet
46″DN1150	Class 400	1441	146.1	1257	1339.8	36 × Ø54	1213	244	692 kg	Spec sheet
48″DN1200	Class 400	1511	152.4	1308	1403.4	28 × Ø60.3	1267	257	812 kg	Spec sheet
50″DN1250	Class 400	1568	157.2	1362	1460.5	32 × Ø60.3	1321	268	885 kg	Spec sheet
52″DN1300	Class 400	1619	162.1	1413	1511.3	32 × Ø60.3	1372	276	964 kg	Spec sheet
54″DN1350	Class 400	1702	169.9	1470	1581.2	28 × Ø66.7	1425	289	1163 kg	Spec sheet
56″DN1400	Class 400	1753	174.8	1527	1632	32 × Ø66.7	1480	298	1229 kg	Spec sheet
58″DN1450	Class 400	1803	177.8	1578	1682.8	32 × Ø66.7	1530	306	1465 kg	Spec sheet
60″DN1500	Class 400	1886	185.7	1635	1752.6	32 × Ø73	1584	319	1733 kg	Spec sheet

REFERENCE

Pressure ratings, materials and tolerances

Transcribed from ASME B16.47-2025 with table and page references.

Pressure-temperature ratings

ASME B16.47-2025 pressure–temperature ratings (Group 1.1)

Table 3 (SI, bar) and Table 3C (U.S. customary, psig) of ASME B16.47-2025 give the maximum working pressure o…

Open reference Material groups

ASME B16.47-2025 material groups (Table 1)

ASME B16.47-2025 sorts every permitted flange material into a numbered group, and the group number — not the …

Open reference Tolerances

ASME B16.47-2025 flange tolerances (Section 7)

Section 7 of ASME B16.47-2025 sets the permissible manufacturing deviations for large-diameter flanges: raise…

Open reference Marking

ASME B16.47-2025 marking requirements (Section 4)

Section 4 of ASME B16.47-2025 defines the identification markings that must appear on every large-diameter fl…

Open reference Edition changes

ASME B16.47-2025 changes and record numbers

ASME B16.47-2025 was approved by the American National Standards Institute on 4 March 2025 and issued on 30 M…

Open reference

How to read the pressure class

Series A follows the former MSS SP-44 dimensions. Ratings are ASME classes 150, 300, 400, 600 and 900, with allowable pressures read from the B16.47 pressure–temperature tables for the material group and design temperature.

Edition and verification

Dimension values on this page have been checked against ASME B16.47-2025 (SI tables, cross-checked against the U.S. Customary tables). The 2025 edition prints exact metric equivalents of the inch dimensions rather than the old 5 mm-rounded values (for example 36.50 in is printed as 927 mm, not 925 mm), and defines flange thickness as excluding the raised face. Both corrections are reflected here; Series B NPS 38 and above follows Series A per the standard’s General Note (h).

Data imported 2026-11-05 08:05.