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 600	889	111.3	727	806.4	28 × Ø44.5	698	181	249 kg	Spec sheet
28″DN700	Class 600	952	115.9	784	863.6	28 × Ø47.6	752	190	295 kg	Spec sheet
30″DN750	Class 600	1022	125.4	841	927.1	28 × Ø50.8	806	205	367 kg	Spec sheet
32″DN800	Class 600	1086	130	895	984.2	28 × Ø54	861	216	431 kg	Spec sheet
34″DN850	Class 600	1162	141.3	952	1054.1	24 × Ø60.3	914	233	547 kg	Spec sheet
36″DN900	Class 600	1213	146.1	1010	1104.9	28 × Ø60.3	968	243	608 kg	Spec sheet
38″DN950	Class 600	1270	152.4	1054	1162	28 × Ø60.3	1022	254	—	Spec sheet
40″DN1000	Class 600	1321	158.8	1111	1212.8	32 × Ø60.3	1073	264	—	Spec sheet
42″DN1050	Class 600	1403	168.1	1168	1282.7	28 × Ø66.7	1127	279	—	Spec sheet
44″DN1100	Class 600	1454	173	1226	1333.5	32 × Ø66.7	1181	289	—	Spec sheet
46″DN1150	Class 600	1511	179.4	1276	1390.6	32 × Ø66.7	1235	300	—	Spec sheet
48″DN1200	Class 600	1594	188.9	1334	1460.5	32 × Ø73	1289	316	—	Spec sheet
50″DN1250	Class 600	1670	196.9	1384	1524	28 × Ø79.4	1343	329	—	Spec sheet
52″DN1300	Class 600	1721	203.2	1435	1574.8	32 × Ø79.4	1394	337	—	Spec sheet
54″DN1350	Class 600	1778	209.6	1492	1632	32 × Ø79.4	1448	349	—	Spec sheet
56″DN1400	Class 600	1854	217.5	1543	1695.4	32 × Ø85.7	1502	362	—	Spec sheet
58″DN1450	Class 600	1905	222.3	1600	1746.2	32 × Ø85.7	1553	370	—	Spec sheet
60″DN1500	Class 600	1994	233.4	1657	1822.4	28 × Ø92.1	1610	389	—	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.