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 300	972	78	749	876.3	28 × Ø44.5	721	183	274 kg	Spec sheet
28″DN700	Class 300	1035	84.3	800	939.8	28 × Ø44.5	775	195	338 kg	Spec sheet
30″DN750	Class 300	1092	90.7	857	997	28 × Ø47.6	827	208	395 kg	Spec sheet
32″DN800	Class 300	1149	97	914	1054.1	28 × Ø50.8	881	221	456 kg	Spec sheet
34″DN850	Class 300	1206	100.1	965	1104.9	28 × Ø50.8	937	230	519 kg	Spec sheet
36″DN900	Class 300	1270	103.4	1022	1168.4	32 × Ø54	991	240	578 kg	Spec sheet
38″DN950	Class 300	1168	106.4	1029	1092.2	32 × Ø41.3	994	179	315 kg	Spec sheet
40″DN1000	Class 300	1238	112.8	1086	1155.7	32 × Ø44.5	1048	192	381 kg	Spec sheet
42″DN1050	Class 300	1289	117.6	1137	1206.5	32 × Ø44.5	1099	199	431 kg	Spec sheet
44″DN1100	Class 300	1353	122.4	1194	1263.6	32 × Ø47.6	1149	205	479 kg	Spec sheet
46″DN1150	Class 300	1416	127	1245	1320.8	28 × Ø50.8	1203	214	560 kg	Spec sheet
48″DN1200	Class 300	1467	131.8	1302	1371.6	32 × Ø50.8	1254	222	626 kg	Spec sheet
50″DN1250	Class 300	1530	138.2	1359	1428.8	32 × Ø54	1305	230	694 kg	Spec sheet
52″DN1300	Class 300	1581	143	1410	1479.6	32 × Ø54	1356	237	753 kg	Spec sheet
54″DN1350	Class 300	1657	150.9	1467	1549.4	28 × Ø60.3	1410	251	930 kg	Spec sheet
56″DN1400	Class 300	1708	152.4	1518	1600.2	28 × Ø60.3	1464	259	977 kg	Spec sheet
58″DN1450	Class 300	1759	157.2	1575	1651	32 × Ø60.3	1514	265	1030 kg	Spec sheet
60″DN1500	Class 300	1810	162.1	1626	1701.8	32 × Ø60.3	1565	272	1120 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.