Flange Standards and Dimensions – ASME, JIS, and DIN Compared

Flange Standards and Dimensions – ASME, JIS, and DIN Compared

1. Introduction

Flanges connect everything — pipes, valves, filters, vessels — but people rarely look at the standard behind the bolt circle. Let’s break down how ASME, JIS, and DIN flanges differ in size, pressure class, and application.

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2. Major Flange Standards

Standard	Region	Pressure	ClassMaterial	RangeNotes
ASME B16.5	US	150–2500 lb	Carbon Steel, Stainless	Most common worldwide
ASME B16.47 A/B	US	75–900 lb	Large-diameter flanges	Used in vessel nozzles
JIS B2220	Japan	5K–40K	CS, SS	Common in Asia
DIN EN 1092-1	Europe	PN 6–PN 400	CS, SS, Alloy	Metric system standard

If you want a more detailed dimension table, please refer to the link below.

Flange Standards & Dimension Chart – ASME / JIS / DIN 

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3. Flange Face Types

Common flange types used in industrial piping systems

• RF (Raised Face) – Standard for process piping
• FF (Flat Face) – Cast iron or low-pressure systems
• RTJ (Ring Type Joint) – High-pressure, leak-free seal
• Tongue & Groove / Male & Female – For special sealing surfaces

Field Tip:
When someone orders “150A RF flange” without saying the standard — that’s your red flag. JIS 10K 150A ≠ ASME 150# 6".

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4. ASME B16.5 Flange Dimensions – Class 150 (RF Type)

NPS (inch)	Flange OD (mm)	Bolt Circle (mm)	No. of Bolts	Bolt Dia (mm)	Thickness (T, mm)	Hub Dia (H, mm)
1/2"	89	60.3	4	12.7	11	34
3/4"	98	69.9	4	12.7	12	38
1"	108	79.4	4	15.9	12	44
1-1/4"	117	88.9	4	15.9	12	51
1-1/2"	127	98.4	4	15.9	14	57
2"	152	120.7	4	15.9	15	64
2-1/2"	178	139.7	4	15.9	17	76
3"	191	152.4	4	19.1	17	89
4"	229	190.5	8	19.1	18	102
5"	254	215.9	8	22.2	19	127
6"	279	241.3	8	22.2	22	152
8"	343	298.5	8	22.2	24	203
10"	406	362.0	12	25.4	25	254
12"	483	431.8	12	25.4	27	305
14"	533	476.3	12	28.6	30	337
16"	597	539.8	16	28.6	32	387
18"	635	577.9	16	31.8	35	438
20"	698	635.0	20	31.8	37	489
22"	749	692.2	20	34.9	39	540
24"	813	749.3	20	34.9	41	591

(Data Reference: ASME B16.5-2020, Class 150 Raised Face Flange)

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5. Conversion Between Standards

Size (Nominal)	ASME (inch)	JIS (A)	DIN (DN)
1/2"	15A	DN15	150# / 10K / PN16
1"	25A	DN25	150# / 10K / PN16
2"	50A	DN50	150# / 10K / PN16
3"	80A	DN80	150# / 10K / PN16
4"	100A	DN100	150# / 10K / PN16
6"	150A	DN150	150# / 10K / PN16
8"	200A	DN200	150# / 10K / PN16
10"	250A	DN250	150# / 10K / PN16
12"	300A	DN300	150# / 10K / PN16
16"	400A	DN400	150# / 10K / PN16
20"	500A	DN500	150# / 10K / PN16
24"	600A	DN600	150# / 10K / PN16

 

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6. Field Notes

• JIS 10K and ASME 150# flanges look similar but bolt circle differs, so they don’t mate.
• DIN PN16 is close to JIS 10K dimensionally, but the bolt count and pitch circle can still mismatch.
• Always check OD + Bolt Circle + Bolt Size before ordering mixed-standard piping.

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7. Conclusion

Knowing the flange standard is the first step in avoiding mismatch headaches during fabrication.
Mixing ASME and JIS flanges isn’t just a measurement problem — it’s a leak waiting to happen.
Always confirm standard, pressure class, and facing type before fabrication or procurement.

Flange Standards & Dimension Chart – ASME / JIS / DIN Comparison