What’s the Difference Between DIN and ANSI Flanges?

DIN and ANSI flanges follow different standards and measurement systems. 

DIN flanges use the metric system and are common in Europe. 

ANSI flanges follow imperial measurements and are mainly used in North America. 

They aren’t interchangeable without modifications because their sizes, pressure ratings, and bolt patterns don’t match. 

Measurement System

DIN flanges use millimeters (mm) for size and bar (bar) for pressure ratings.

ANSI flanges follow inches (in) for size and pounds per square inch (psi) for pressure.

DIN is the standard in industries that use the metric system, while ANSI flanges fit systems built with imperial measurements.

Pressure Ratings

DIN flanges are rated as PN 6, PN 10, PN 16, and higher, which tells you how much pressure they can handle.

ANSI flanges follow Class 150, 300, 600, and 2500, based on ASME B16.5 standards.

Both systems are designed for high-pressure applications, but their classifications follow different testing methods.

Key Considerations for Choosing Between DIN and ANSI Flanges

Picking between flange DIN and ANSI flanges depends on factors like sourcing, compliance, and ease of installation. Here’s a quick guide to help you decide:

If you’re working on a European-based project, DIN flanges are likely the right fit. For U.S. and North American projects, ANSI flanges will integrate without modifications.

Can You Convert Between DIN and ANSI Flanges?

Not directly. The two systems have different bolt patterns, pressure ratings, and measurements, making them non-interchangeable without adjustments.

If you need to connect a DIN flange to an ANSI system, here are some options:

1. Use a Flange Adapter

Some manufacturers offer custom adapters that allow DIN and ANSI flanges to connect. These work but add cost and extra components to your system.

2. Modify the System

For some setups, an engineer may be able to adjust bolt holes or add spacers to align the flanges. However, this can weaken the connection if not done properly.

3. Choose a Hybrid Flange

Some suppliers offer flanges that meet both DIN and ANSI standards, making them easier to integrate without major modifications.

If you’re working with international projects, planning ahead will save you from compatibility headaches.

Conclusion

Mixing DIN and ANSI flanges in the same system isn’t as simple as swapping one for the other. The measurements, pressure ratings, and bolt patterns don’t match up, so picking the right standard from the start saves time and money.

If your setup follows European specs, flange DIN options will fit without modifications. If you’re working with North American equipment, ANSI flanges are the way to go. But if you need to connect both, adapters or custom fittings might be your best bet.

At Longan Flange, we manufacture precision-engineered DIN and ANSI flanges so you get the right fit without guesswork.