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 600	1016	108	749	914.4	28 × Ø50.8	748	222	426 kg	Spec sheet
28″DN700	Class 600	1073	111.3	800	965.2	28 × Ø54	803	235	481 kg	Spec sheet
30″DN750	Class 600	1130	114.3	857	1022.4	28 × Ø54	862	248	549 kg	Spec sheet
32″DN800	Class 600	1194	117.3	914	1079.5	28 × Ø60.3	917	260	624 kg	Spec sheet
34″DN850	Class 600	1245	120.7	965	1130.3	28 × Ø60.3	973	270	699 kg	Spec sheet
36″DN900	Class 600	1314	124	1022	1193.8	28 × Ø66.7	1032	282	773 kg	Spec sheet
38″DN950	Class 600	1270	152.4	1054	1162	28 × Ø60.3	1022	254	667 kg	Spec sheet
40″DN1000	Class 600	1321	158.8	1111	1212.8	32 × Ø60.3	1073	264	739 kg	Spec sheet
42″DN1050	Class 600	1403	168.1	1168	1282.7	28 × Ø66.7	1127	279	921 kg	Spec sheet
44″DN1100	Class 600	1454	173	1226	1333.5	32 × Ø66.7	1181	289	980 kg	Spec sheet
46″DN1150	Class 600	1511	179.4	1276	1390.6	32 × Ø66.7	1235	300	1093 kg	Spec sheet
48″DN1200	Class 600	1594	188.9	1334	1460.5	32 × Ø73	1289	316	1295 kg	Spec sheet
50″DN1250	Class 600	1670	196.9	1384	1524	28 × Ø79.4	1343	329	1510 kg	Spec sheet
52″DN1300	Class 600	1721	203.2	1435	1574.8	32 × Ø79.4	1394	337	1615 kg	Spec sheet
54″DN1350	Class 600	1778	209.6	1492	1632	32 × Ø79.4	1448	349	1778 kg	Spec sheet
56″DN1400	Class 600	1854	217.5	1543	1695.4	32 × Ø85.7	1502	362	1941 kg	Spec sheet
58″DN1450	Class 600	1905	222.3	1600	1746.2	32 × Ø85.7	1553	370	2105 kg	Spec sheet
60″DN1500	Class 600	1994	233.4	1657	1822.4	28 × Ø92.1	1610	389	2268 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.