In industrial piping systems, selecting the correct flange dimensions is essential to ensure accurate alignment, leak prevention, and safe operation. However, different regions and industries use different standards – the most common being JIS (Japan), ANSI (USA), and DIN (Europe).
In this article, Sunjin Metals Vina (SJM Vina) will guide you through the differences between flange standards and how to read standard dimension charts correctly.

1. Why do flange dimensions vary by standard?
Each international standard defines:
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Outer Diameter (OD)
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Inner Diameter (ID)
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Number and diameter of bolt holes
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Pitch Circle Diameter (PCD)
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Flange thickness
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Facing type (Raised Face, Flat Face, RTJ)
Using the wrong flange standard can result in:
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Misaligned bolt holes → can't install
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Poor sealing → leakage
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Extra costs and downtime for modifications
2. JIS Standard – Common in Asia (Japan, Vietnam, Korea)
JIS (Japanese Industrial Standards) are widely used in Vietnam and other Asian countries. Common pressure ratings include:
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JIS 5K – low pressure
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JIS 10K – most popular
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JIS 16K, 20K, 30K – higher pressure
Example:
JIS 10K flange – DN100:
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Outer Diameter: 210 mm
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Number of bolt holes: 8
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Bolt hole diameter: 19 mm
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PCD: 175 mm
✅ Applications: Water supply, wastewater, HVAC systems, light industry
3. ANSI Standard – Used in inch-based piping systems
ANSI/ASME B16.5 is the American flange standard, using inch units and classified by pressure ratings:
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Class 150, 300, 600, 900, 1500, 2500
Example:
ANSI B16.5 Class 150 – NPS 4" (DN100):
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Outer Diameter: 229 mm
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Number of bolt holes: 8
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Bolt hole diameter: 19 mm
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PCD: 190.5 mm
✅ Applications: Oil & gas, chemical plants, power generation, heavy industries
4. DIN Standard – Common in Europe
DIN (Deutsches Institut für Normung) is the German/European standard, using metric units. Common types include:
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DIN 2576 – slip-on flange
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DIN 2633 – welding neck flange
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DIN 2501, DIN 2527, DIN 2642 – blind or loose flanges
Example:
DIN 2633 – DN100, PN16:
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Outer Diameter: 220 mm
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Number of bolt holes: 8
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Bolt hole diameter: 18 mm
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PCD: 180 mm
✅ Applications: Food processing, pharmaceuticals, EU-standard projects
5. Comparison Table – DN100 Flange Dimensions by Standard
| Standard | Type/Class | Outer Diameter | Bolt Holes | PCD (mm) | Hole Diameter |
|---|---|---|---|---|---|
| JIS | 10K | 210 mm | 8 | 175 mm | 19 mm |
| ANSI | Class 150 | 229 mm | 8 | 190.5 mm | 19 mm |
| DIN | PN16 (DIN 2633) | 220 mm | 8 | 180 mm | 18 mm |
PCD = Pitch Circle Diameter (distance between center of bolt holes)
How to Select the Right Flange Dimensions
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✅ Identify the standard used in your piping system
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✅ Confirm the DN (Diameter Nominal) or NPS size
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✅ Choose the correct pressure rating (PN or Class)
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✅ Double-check PCD and number of holes before purchase
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✅ Work with suppliers offering full technical support and size charts
Sunjin Metals Vina – Trusted Supplier of JIS – ANSI – DIN Flanges
Sunjin Metals Vina (SJM Vina) supplies a full range of steel and stainless steel flanges according to global standards:
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JIS 5K – 10K – 16K – 20K – 30K
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ANSI B16.5 – Class 150, 300, 600...
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DIN 2576, 2633, 2527, 2642...
✔️ Available stock from DN15 to DN600
✔️ Materials: Carbon steel, Stainless 304/316, Alloy steel
✔️ Complete documentation: CO, CQ, drawings, dimension charts
✔️ Technical support for EPC projects, factories, piping systems
📍 Address: 628 Le Hong Phong, Ward 10, District 10, Ho Chi Minh City, Vietnam
📞 Hotline: +84 33 4233 127
📧 Email: sjmvina@sunjinmetal.com
🌐 Website: www.sjmvina.com.vn
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