JIS vs ANSI Flange Standards: Key Differences You Should Know

In the world of industrial piping and fluid systems, flanges are critical components that allow for the connection, maintenance, and pressure management of pipelines. However, not all flanges are created equal — especially when you’re dealing with international projects. Two of the most widely used flange standards are JIS (Japanese Industrial Standards) and ANSI (American National Standards Institute).

At Hebei Leading, we manufacture and supply flanges according to JIS, ANSI, DIN, EN, and other global standards. In this article, we’ll explain the major differences between JIS and ANSI flanges, helping you make the right decision for your piping project.

What Is a Flange Standard?

A flange standard defines the dimensions, pressure class, face type, bolt hole patterns, and materials used for a specific type of flange. It ensures interchangeability and compatibility between pipeline components, regardless of the manufacturer.

Flange standards are important because:

• They determine connection size and pressure rating

• They affect installation tools and torque values

• Using the wrong flange type can lead to leakage or mechanical failure

Overview: JIS and ANSI Flange Standards

JIS Flanges

• Full Name: Japanese Industrial Standards

• Pressure Ratings: 5K, 10K, 16K, 20K, 30K

• Units Used: Metric (mm, kg/cm²)

• Common Applications: Asia-based industries, marine piping, water treatment

JIS flanges are often used in countries like Japan, South Korea, Taiwan, and in systems that were originally built with metric standards.

ANSI Flanges

• Full Name: American National Standards Institute

• Also Known As: ASME B16.5 flanges

• Pressure Ratings: CL150, CL300, CL600, CL900, CL1500, CL2500

• Units Used: Imperial (inches, PSI)

• Common Applications: Oil & gas, petrochemical, power generation, US-based projects

ANSI flanges dominate in North America and are commonly used worldwide for API pipelines, high-pressure steam, and industrial machinery.

Key Differences Between JIS and ANSI Flanges

Here’s a side-by-side comparison table to highlight the technical and dimensional differences:

Why It Matters: Compatibility Issues

You cannot directly connect a JIS flange to an ANSI flange because of:

• Different bolt circle diameters

• Varying thickness and pressure ratings

• Inconsistent gasket size requirements

If mismatched, it can lead to:

• Leaks

• Bolt misalignment

• Unsafe pressure containment

To connect JIS and ANSI systems, you must use adapter flanges or custom-machined transition pieces — which can be costly and time-consuming.

Application Examples

Example 1: Water Treatment Facility in Japan

A municipal water system uses JIS 10K flanges for stainless steel pipe lines. The system operates under low to medium pressure, and all valves and pumps are JIS-compatible.

Example 2: Oil Refinery in the U.S.

A high-pressure steam pipeline uses ANSI CL600 flanges, built according to ASME B16.5 standards, designed for temperatures up to 538°C (1000°F).

Hebei Leading has supplied both types of systems, offering custom flange solutions for international EPC projects and retrofit systems.

Hebei Leading: One-Stop Flange Supplier

At Hebei Leading, we manufacture and export flanges according to JIS, ANSI/ASME, DIN, BS, and EN standards. Our flange products cover:

• Materials: Carbon Steel (A105), Stainless Steel (304/316), Alloy Steel

• Sizes: ½" to 48"

• Types: Slip-on, Weld neck, Blind, Socket weld, Threaded, Lap joint

• Face Types: RF, FF, RTJ

• Pressure Ratings: From 5K to CL2500

 Services We Offer:

• Custom flange machining (hole drilling, surface finish)

• Material certification (EN10204 3.1)

• Third-party inspection support (SGS, BV)

• Seaworthy wooden packing and international shipping

Visit our Product Page to explore flange categories and specifications.

Final Advice: Choosing the Right Standard

Here’s how to decide:

• ✔ If your project is in Japan or East Asia, or connects to metric components → use JIS flanges

• ✔ If your system is ANSI/ASME-based or used in oil, gas, or power → go for ANSI flanges

• ❌ Never mix both without using specially engineered adapters

Still unsure which flange type you need? Contact Hebei Leading's engineering team for expert advice, drawings, and quick quotations based on your application needs.

Conclusion

Understanding the difference between JIS and ANSI flange standards is crucial for international project success. While both are reliable in their own right, their technical specifications and dimensional requirements are not interchangeable.

With Hebei Leading, you gain access to a global flange supplier that understands regional standards, ensures compliance, and delivers with precision.

Let us help you simplify your flange procurement today — reliable quality, technical support, and fast delivery are just a message away.