Comparison of flange standards

The pressure ratings used are different, right? The American standard uses pounds, while the European standard uses PN (MPa).

European pressure ratings are more detailed, with ten different pressure levels, while American standards have only six pressure levels.

The units used to express nominal pressure vary, and the eye spacing is also different. Basically, those larger than DN100 cannot be used interchangeably

1. A flange connection or flange joint refers to a detachable connection that consists of a flange, gaskets, and bolts working together as a combined sealing structure. A pipe flange is the flange used for piping in pipeline systems, while one used on equipment refers to the inlet and outlet flanges of that equipment. 2. Several international systems for pipe flange standards 1) European flange system: German DIN (including the Soviet Union) a. Nominal pressure: 0.1, 0.25, 0.6, 1.0, 1.6, 2.5, 4.0, 6.4, 10.0, 16.0, 25.0, 32.0, 40.0 MPa b. Nominal diameter: 15–600 mm c. Flange types: butt-welded plate type, butt-welded ring loose-type, folded loose-type, butt-welded folded loose-type, butt-welded ring loose-type, butt-welded type, necked threaded connection type, integral type, and flange cover d. Flange sealing surfaces: flat surface, concave surface, male-and-female surface, tenon-and-socket surface, rubber ring connection surface, lens surface, and diaphragm welding surface e. The OCT pipe flange standard issued by the Soviet Union in 1980 is similar to the German DIN standard, so it will not be discussed further. 2) American flange system: American ANSI B16.5 “Steel Pipe Flanges and Flanged Fittings” a. Nominal pressure: 150 psi (2.0 MPa), 300 psi (5.0 MPa), 400 psi (6.8 MPa), 600 psi (10.0 MPa), 900 psi (15.0 MPa), 1500 psi (25.0 MPa), 2500 psi (42.0 MPa) b. Nominal diameter: 6–4000 mm c. Flange types: strip welding, socket welding, threaded connection, loose-type, butt-welding, and flange cover d. Flange sealing surfaces: concave surface, male-and-female surface, tenon-and-socket surface, metal ring connection surface 3) Japanese JIS pipe flanges: These are generally used only in utility systems within petrochemical plants; they have little influence internationally and do not form an independent system on the global scale. 3. The **standard system for steel pipe flanges in China is GB 1): Nominal pressure: 0.25 Mpa to 42.0 Mpa. a) Series 1: PN1.0, PN1.6, PN2.0, PN5.0, PN10.0, PN15.0, PN25.0, PN42 (main series). b) Series 2: PN0.25, PN0.6, PN2.5, PN4.0. Among these, the flange sizes for the 6 grades of PN0.25, PN0.6, PN1.0, PN1.6, PN2.5, and PN4.0 belong to the European flange system represented by German flanges, while the rest belong to the American flange system represented by American flanges. In GB standards, the highest nominal pressure class for those belonging to the European flange system is 4 Mpa, while for those belonging to the American flange system, the highest nominal pressure class is 42 Mpa. 2) Nominal diameter: 10mm–4000mm 3) Types of flange structures: Integral flanges, Unit flanges; a) Threaded flanges, b) Welded flanges – Butt-welded flanges, Necked flat weld flanges, Necked socket weld flanges, Plate flat weld flanges; c) Loose-flange types – Butt-weld ring loose-necked flanges, Butt-weld ring loose-plate flanges, Flat weld ring loose-plate flanges, Plate type with loose flange; d) Flange covers (blind hole flanges) 4) Flange sealing surfaces: Flat surface, Concave surface, Eccentric surface, Tenon-and-socket surface, Ring joint surface. II. Common standard systems for pipe flanges used in instrumentation 1. DIN standard 1) Common pressure grades: PN6, PN10, PN16, PN25, PN40, PN64, PN100, PN160, PN250 2) Flange sealing surfaces: Raised face (DIN2526C), Grooved face (according to DIN2512N). 2. ANSI standard 1) Common pressure grades: CL150, CL300, CL600, CL900, CL1500 2) Flange sealing surfaces: ANSI B 16.5 RF flanges – Raised face flanges. 3. JIS standard: Not commonly used 1) Common pressure grades: 10K, 20K. III. How to recommend appropriate flange and pipeline standards to customers 1. When the customer requests drawings for manufacturing matching flanges: For example, a customer selects an vortex flow meter with the model number 70FS80-E0A00A1B100. The specifications are: PN40, DIN2501, raised face, DIN2526C. The customer requests drawings for manufacturing matching flanges. Solution: Three standard drawings are involved here – DIN2501 refers to the female flange, while DIN2526C specifies the type of flange surface (raised face); therefore, DIN2635 should be used. DIN2635 uses DIN2501 as the base flange standard, with the mating flange standard being DIN2526C; simply fax this diagram to the customer. 2. When selecting a vortex flow meter and using the ANSI standard, it is necessary to pay attention to the difference between Sch80 and Sch40, and to ensure that it matches the standard of the pipes used; that is, if the meter is chosen as Sch80, then the pipes should also be Sch80, so as to avoid any discrepancy in diameter between the pipes and the meter. Piping size series: Imperial pipes, Metric pipes. Imperial pipes: A piping series commonly used internationally. Metric pipes: A series of outer diameter sizes for steel pipes that have been widely used in China’s chemical industry and other industrial sectors for decades. Piping series, pipe flange standards, and pressure rating values: PN0.25, 0.6, 1.0, 1.6, 2.5, 4.0 Mpa correspond to the German pipe flange series; GB9112~9125-88. PN2.0, 5.0, 10.0, 15.0, 25.0, 42.0 Mpa correspond to the American pipe flange series. For imperial pipes, SHJ406-89 is applicable, as per the “Engineering Construction Standards of Sinopec”. PN2.0, 5.0, 6.8, 10.0, 15.0, 25.0, 42.0 Mpa correspond to the American pipe flange series. For metric pipes, HG5003~5028-58 and JB75~86-59 are relevant; PN0.25, 0.6, 1.0, 1.6, 2.5, 4.0, 6.4, 10.0, 16.0, 20.0 Mpa correspond to the Soviet pipe flange series from the 1950s, which is similar to the German pipe flange series. Table of Contents
Standard Flange Dimensions

I. ANSI 150, 300, 400, 600, 900, 1500, 2500RF Flange Dimensions
Table1 ANSI 150RF
Table2 ANSI 300RF
Table3 ANSI 400RF
Table4 ANSI 600RF
Table5 ANSI 900RF
Table6 ANSI 1500RF
Table7 ANSI 2500RF

II. ANSI 150, 300, 600, 900, 1500, 2500RJ Flange Dimensions
Table8 ANSI 150RJ
Table9 ANSI 300RJ
Table10 ANSI 600RJ
Table11 ANSI 900RJ
Table12 ANSI 1500RJ
Table13 ANSI 2500RJ

III. JIS 10K, 16K, 20K, 30K, 40K, 63K, RF, FF Flange Dimensions
Table14 JIS 10K, RF, FF
Table15 JIS 16K, RF, FF
Table16 JIS 20K, RF, FF
Table17 JIS 30K, RF, FF
Table18 JIS 40K, RF, FF
Table19 JIS 63K, RF, FF

IV. JPI 150, 300, 600RF, RJ Flange Dimensions
Table20 JPI 150RF
Table21 JPI 300RF
Table22 JPI 600RF
Table23 JPI 150RJ
Table24 JPI 300RJ
Table25 JPI 600RJ

V. German DIN Standard Flange Dimensions
Table26 PN16 (1.6 MPa)
Table27 PN40 (4.0 MPa)

VI. Chinese JB Standard Flange Dimensions
1. Raised-face integral steel pipe flanges (JB/T79.1-94)
Table28 PN1.6 MPa
Table29 PN2.5 MPa
Table30 PN4.0 MPa

2. Raised and recessed-face integral cast steel pipe flanges (JB/T79.2-94)
Table31 PN4.0 MPa
Table32 PN6.3 MPa
Table33 PN10.0 MPa
Table34 PN16.0 MPa
Table35 PN20.0 MPa

3. Tenon-and-socket face integral cast steel pipe flanges (JB/T79.3-94)
Table36 PN4.0 MPa
Table37 PN6.3
Table38 PN10