06-Aug-2025
Flanges (法蘭) are crucial components in piping systems, used to connect pipes, valves, pumps, and other equipment. Selecting the right flange standard ensures compatibility, safety, and long-term performance—especially for projects involving international specifications.
In this post, we break down the three most common flange standards:ANSI (ASME) from the U.S., DIN from Germany, and JIS from Japan. We’ll also highlight their sub-specifications and usage differences.
🔧 1. ANSI / ASME Flange Standards (🇺🇸)
ANSI (often in practice referred to as ASME, the American Society of Mechanical Engineers) is the most widely used flange standard in the oil & gas, petrochemical, and industrial sectors.
✅ Key Features:
· Inch-based sizing
· Designed for high-pressure, high-temperature environments
· Commonly used in heavy industry
· Compatible with NPT (threaded pipe) systems
✅ Key Sub-Standards:
Spec
Description
ASME B16.5
Flange dimensions, pressure-temperature ratings, materials, and testing (½”–24”)
ASME B16.10
Standardized face-to-face and end-to-end dimensions for valves
ASME B16.34
Design criteria, wall thickness, and pressure-temperature ratings for valves
🔹 Pressure Classes:
150, 300, 600, 900, 1500, 2500 lbs
🔹 Common Materials:
Carbon steel, stainless steel, alloy steel
🔩 2. DIN Flange Standards (🇩🇪)
DIN (Deutsches Institut für Normung) flanges are widely used in Europe and internationally, especially in chemical processing and mechanical engineering.
✅ Key Features:
Metric system (millimeters)
Pressure-based classification (PN)
Excellent for precision manufacturing and process industry usage
✅ Common DIN Standards:
Spec
Description
DIN EN 1092-1
Flanges and their joints (European standard)
DIN 2501
Flange dimensions based on pressure rating (older standard)
DIN 2631–2638
Weld neck flanges for different pressure classes
🔹 Pressure Ratings (PN):
PN6, PN10, PN16, PN25, PN40, PN64, PN100, PN160…
✅ Note: "PN" (Pressure Nominal) = pressure in barsE.g., PN16 = 16 bar ≈ 232 psi
🔧 3. JIS Flange Standards (🇯🇵)
JIS (Japanese Industrial Standards) are commonly used in Japan and Southeast Asia, especially in HVAC, plumbing, food, and general industry.
✅ Key Features:
Uses metric measurements
Pressure classification is in K (kgf/cm²)
✅ Common JIS Flange Standards:
Spec
Description
JIS B2220
Steel pipe flanges (main JIS flange standard)
JIS B2238
Cast iron flanges
JIS B2239
Copper alloy flanges
🔹 Pressure Ratings:
5K, 10K, 16K, 20K, 30K
✅ Note: 10K ≈ 10 kgf/cm² ≈ 142 psiJIS flanges typically have a lighter design than ANSI or DIN.
📐 ANSI vs DIN vs JIS: Comparison Table
Feature
ANSI (ASME B16)
DIN (EN / DIN)
JIS (B2220)
Origin
USA
Germany
Japan
Units
Inches
Millimeters
Millimeters
Pressure Classes
150–2500 lbs
PN6–PN160
5K–30K
Industry Usage
Industrial, Oil & Gas
Chemical, Mechanical
HVAC, Plumbing, Marine
Some of customers might confuse,"Can ANSI and JIS flanges be connected directly?"
❌ No. Flanges from different standards—such as ANSI and JIS—are not dimensionally compatible, even if they share the same nominal pipe size (NPS).Key differences include:
· Bolt hole patterns
· Bolt circle diameters
· Center bore dimensions
These variations mean that direct connection is not possible without using an adapter flange or making modifications to the piping design.
🧠 Conclusion: Choosing the Right Flange
Whether you're engineering a plant in the U.S., Europe, or Asia, understanding flange standards is essential for ensuring compatibility and compliance. Here’s a quick guide:
✅ Use ANSI/ASME for oil & gas or heavy industry
✅ Use DIN for European manufacturing and process systems
✅ Use JIS for light-duty or Asian plumbing/HVAC applications
🛠 Need Help?
If you're unsure which standard suits your project, our engineering team is ready to help.Contact us today for flange sizing, material selection, and technical support!
📧 Email us at: sales@ansonflow.com
🌐 Visit: https://www.ansonflow.com/