STANDARD · ASME-B16-47-B

ASME B16.47 Series B Flange Dimensions

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

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

ASME B16.47 Series B is the former API 605 large-diameter flange standard, covering NPS 26 to NPS 60 in classes 150 to 900. Its outside diameters are smaller than Series A for the same size and class, which makes it attractive where space or weight is constrained.

Series B is dimensionally different from Series A and from B16.5. Always quote the series explicitly, and check the mating flange before ordering — a Series B flange will not bolt to a Series A flange of the same nominal size. B16.47 covers weld-neck and blind flanges only, 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	867	87.3	737	803.1	32 × Ø34.9	702	143	181 kg	Spec sheet
28″DN700	Class 300	921	87.3	787	857.2	36 × Ø34.9	756	148	204 kg	Spec sheet
30″DN750	Class 300	991	92.1	845	920.8	36 × Ø38.1	813	156	249 kg	Spec sheet
32″DN800	Class 300	1054	101.6	902	977.9	32 × Ø41.3	864	167	311 kg	Spec sheet
34″DN850	Class 300	1108	101.6	952	1031.7	36 × Ø41.3	917	171	340 kg	Spec sheet
36″DN900	Class 300	1171	101.6	1010	1089.2	32 × Ø44.5	965	179	381 kg	Spec sheet
38″DN950	Class 300	1222	109.5	1060	1140	36 × Ø44.5	1016	190	415 kg	Spec sheet
40″DN1000	Class 300	1273	114.3	1115	1190.8	40 × Ø44.5	1067	197	449 kg	Spec sheet
42″DN1050	Class 300	1334	117.5	1168	1244.6	36 × Ø47.6	1118	203	515 kg	Spec sheet
44″DN1100	Class 300	1384	125.4	1219	1295.4	40 × Ø47.6	1173	213	560 kg	Spec sheet
46″DN1150	Class 300	1460	127	1270	1365.2	36 × Ø50.8	1229	221	667 kg	Spec sheet
48″DN1200	Class 300	1511	127	1327	1416	40 × Ø50.8	1278	222	714 kg	Spec sheet
50″DN1250	Class 300	1562	136.7	1378	1466.8	44 × Ø50.8	1330	233	776 kg	Spec sheet
52″DN1300	Class 300	1613	141.3	1429	1517.6	48 × Ø50.8	1383	241	835 kg	Spec sheet
54″DN1350	Class 300	1673	135.1	1480	1577.8	48 × Ø50.8	1435	238	898 kg	Spec sheet
56″DN1400	Class 300	1765	152.4	1537	1651	36 × Ø60.3	1494	267	1041 kg	Spec sheet
58″DN1450	Class 300	1827	152.4	1594	1712.9	40 × Ø60.3	1548	273	1256 kg	Spec sheet
60″DN1500	Class 300	1878	149.4	1651	1763.7	40 × Ø60.3	1599	270	1302 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 B follows the former API 605 dimensions, with a smaller outside diameter and a different bolt pattern from Series A. Ratings are ASME classes 150, 300, 400, 600 and 900, with allowable pressure from the B16.47 tables.

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.