What are the size standards for flanges?

The size standard of flanges varies according to different countries or regions, different industries and different application requirements. Here are some common flange size standards:

First, international general standards

American Standard Flange (ANSI/ASME B16.5)

Size range: 1/2 inch to 60 inch.

Small diameter flange thickness: 1/16 inch to 1/4 inch.

Medium diameter flange thickness: 5/16 “to 3/8”.

Large diameter flange thickness: 7/16 “to 1/2”.

German standard Flange (DIN)

Size range: DN10 to DN4000.

Small diameter flange (DN10 to DN125) Thickness: 4mm.

Medium diameter flange (DN150 to DN600) thickness: 6mm to 8mm.

Large diameter flange (DN700 or more) thickness: 10mm.

Japanese standard flange (JIS)

Size range: 10A to 1500A.

Small diameter flange (10A to 200A) thickness: 5mm to 12mm.

Large diameter flange (250A to 1500A) thickness: 15mm to 28mm.

British Standard Flange (BS)

Size range: 1/2 inch to 80 inch.

Small diameter flange thickness: 1/16 inch to 1/4 inch.

Medium diameter flange thickness: 5/16 “to 3/8”.

Large diameter flange thickness: 7/16 “to 1/2”.

Second, China’s national standards

GB/T9119-2024(or other latest version of the national standard)

Size range: Covers flanges with pipe diameters DN10 to DN1400.

Flanges are divided into flat welded flanges and neck flanges, each size of the flange has a clear outer diameter, hole number, aperture, hole circle diameter and other technical parameters.

Third, other industry or application-specific standards

In addition to the above general international and national standards, there are also a number of industry or application-specific flange size standards. For example, the petrochemical industry, the power industry, the shipbuilding industry, etc., have their own flange size standards. These standards are usually developed according to the special needs and working environment of the industry to ensure the suitability and safety of flanges in the industry.

In summary, the size standards of flanges are very diverse, and the user should determine the appropriate standard according to the specific application needs and working environment when choosing. At the same time, it is also necessary to pay attention to the compatibility and interchangeability between different standards to ensure the correct installation and use of the flange.