What are the standards for flanges?

Speaking of flanges, in addition to connecting or sealing pipes, when using pumps, flanges are also mainly used for connection. After understanding the basic types, sealing surface forms and applications of flanges, we also need to pay attention to the specification and standard classification of flanges, their ability to withstand pressure, flange disk thickness, applicable countries and so on.

Flange is mainly divided into two systems: European system and American system, and the flange standards of various countries and ISO organizations are basically derived and revised.

It has a wide influence, and the commonly used standards are European Union standards, American standards, Chinese national standards, China Ministry of Chemical Industry standards, China Ministry of Machinery standards, China Petrochemical standards, ISO standards, Australian standards and Japanese standards.

What are the applicable standards for flanges?
Common flange standards are ANSI (American Standard), DIN (German Standard), JIS (Japanese Standard) and GB (National Standard). ANSI is commonly used in America, DIN is commonly used in Europe, JIS is commonly used in Japan, and GB is commonly used in China. The international flange standards are mainly ANSI and DIN, but the flange connection dimensions of these two standards are completely different and cannot match each other.


1. ANSI standard
Common pressure grades: 150 LB, 300 LB, 400 LB, 600 LB, 900 LB, 1500 LB and 2500 LB.
Flange forms: sliding flange, welded flange, threaded flange, loose sleeve flange, socket welding flange and blind flange.
Flange sealing surface: plane, convex surface, concave-convex surface, tenon-groove surface and ring connection surface.


2. DIN standard
Common pressure grades: PN6, PN10, PN16, PN25, PN40, PN64, PN100, PN160, PN250, PN320 and PN400.
Flange forms: sliding flange, welded flange, threaded flange, loose sleeve flange and blind flange.
Flange sealing surface: convex surface, concave-convex surface, tenon-groove surface and ring connection surface.


3. JIS standard
Common pressure levels: 5K, 10K, 16K, 20K, 30K, 40K and 63K(K is the pressure level used in Japan. )
Flange forms: sliding flange, welded flange, threaded flange, loose sleeve flange, socket welding flange and blind flange.
Flange sealing surface: plane, concave-convex surface and tenon-groove surface.


4. GB national standard
Common pressure grades: < series I/ main series/large outside diameter >: pn 1.0, PN1.6, PN2.0, PN5.0, PN10.0, PN15.0, PN25.0 and PN42.0.
< series II/ small outside diameter >: pn 0.25, PN0.6, PN2.5, PN4.0.
European flange systems: PN0.25, PN0.6, PN1.0, PN1.6, PN2.5 and PN4.0.
Flange forms: sliding flange, welded flange, threaded flange, loose sleeve flange and blind flange.
Flange sealing surface: plane, convex surface, concave-convex surface and tenon-groove surface.

5.American flange system: PN 2.0, PN 5.0, PN 10.0, PN 15.0, PN 25.0, PN 42.0.
Flange forms: sliding flange, welded flange, threaded flange, loose sleeve flange, socket welding flange and blind flange.
Flange sealing surface: plane, convex surface, concave-convex surface, tenon-groove surface and ring connection surface.

6.Main standard number of EU standards:
EN 1092-1-2007 Flanges and their connections Circular flanges for PN-marked pipes, valves, fittings and accessories Part 1: Steel flanges
EN 1092-2-1997 Flanges and their connections Circular flanges for PN-marked pipes, valves, fittings and accessories Part 2: Cast iron flanges
EN 1092-3-2003 Flanges and their connections Circular flanges for PN-marked pipes, valves, fittings and accessories Part 3: Copper alloy flanges
EN 1092-4-2002 Flanges and their connections Circular flanges for PN-marked pipes, valves, fittings and accessories Part 4: Aluminum alloy flanges
EN 1759-1-2000 Flanges and their connections Circular flanges for pipes, valves, fittings and accessories marked with C lass Part 1: Steel flanges, NPS 1 /2～24 ~ 24.
EN 1759-3-2003 Flanges and their connections Circular flanges for pipes, valves, fittings and accessories marked by C lass Part 3: Copper alloy flanges
EN 1759-4-2003 Flanges and their connections Circular flanges for pipes, valves, fittings and accessories marked by C lass Part 4: Aluminum alloy flanges