What are the standard sizes of pipe flanges?

Overview of pipe flange size standards:

In the piping system, flange connection is the most common connection method, and the pipe flange size standard has come into being. Flange connection is to connect a flange at both ends of the pipe, and then bolt the two flanges together to form a tight pipe connection. Different types of pipes require different flange size standards to ensure the safety and stability of the pipeline system.

Common pipe flange size standards:

There are quite a few standards that specify pipe flange sizes. The most common ones are ANSI, ASME, DIN, BS, and JIS. For example, ANSI flanges are based on American National Standards Institute sizes, while JIS flanges follow Japanese Industrial Standards. The standard used depends on where the pipe is manufactured and installed. Choosing the right pipe flange for the application means choosing the right standard, pressure rating, diameter, bolt pattern, and end face type.

1. American standard flange size standard: American standard flange size standard is a commonly used flange size standard in the United States. It includes different types of flanges, such as welding neck flanges, blind flanges, butt welding flanges, etc. The following table lists some commonly used American Standard flange size standards and their parameters.

Flange type	Pipe size	Flange thickness	Number of holes	Number of bolts
Welding Neck	1/2"~24"	STD/SCH40/SCH80	4~24	4~24
Slip On	1/2"~24"	STD/SCH40/SCH80	4~24	4~24
Blind	1/2"~24"	STD/SCH40/SCH80	4~24	4~24
Socket Welding	1/2"~24"	STD/SCH40/SCH80	4~24	4~24

2. Japanese standard flange size standard: Japanese standard flange size standard is a flange size standard commonly used in Japan. It also includes different types of flanges, such as SORF flange, BLFF flange, WNRF flange, etc. The following table lists some commonly used Japanese standard flange size standards and their parameters.

Flange type	Pipe size	Flange thickness	Number of holes	Number of bolts
SORF	10A~1500A	5K/10K/16K/20K/30K/40K	4~32	4~64
BLFF	10A~1500A	5K/10K/16K/20K/30K/40K	4~32	4~64
WNRF	10A~1500A	5K/10K/16K/20K/30K/40K	4~32	4~64

3. German standard flange size standard: German standard flange size standard is a flange size standard commonly used in Germany. It also includes different types of flanges, such as welding flange, blind flange, butt welding flange, etc. The following table lists some commonly used German standard flange size standards and their parameters.

Flange type	Pipe size	Flange thickness	Number of holes	Number of bolts
Welding Neck	DN10~DN1000	PN6/PN10/PN16/PN25/PN40	4~48	4~48
Slip On	1/2"~24"	PN6/PN10/PN16/PN25/PN40	4~24	4~24
Blind	DN10~DN1000	PN6/PN10/PN16/PN25/PN40	4~48	4~48

With so many choices, it can be confusing! But most systems only need a few common sizes.

Typical sizes used for flanges in piping systems:
For many industrial water, steam, and gas systems, you will typically see pipe flanges in sizes 1/2", 3/4", 1", 1-1/2", 2", 3", 4", 6", 8", 10", 12", 14", 16", 18", 20", 24". Of course, larger pipes require larger pipe flanges, but the ones listed are just some of the more common versions. You may notice that these sizes sound familiar - they correspond to standard pipe sizes. That's because the flanges are designed to fit the outside diameter of SCH 40 pipe and SCH 80 pipe. The flange size matches the pipe size, making installation simple.

Conclusion:

The flange size standards used in piping systems vary from country to country, and the correct selection and installation of pipe flanges is critical to the safe operation of pressurized piping systems. Trillions of cubic feet of natural gas and hundreds of billions of tons of liquid petroleum products need to be safely transported each year, thanks in part to well-designed flanges. When you want to buy pipe flanges for the oil and gas industry, please contact us now: sales@hu-steel.com

Read more: How to choose pipe flange material?