EN1092-1 is a European standard that mainly covers the design and manufacturing requirements for various flanges, including slip on flanges, butt weld flanges, blind flanges, lap joint flanges and so on. According to different connection methods and application scenarios, EN1092-1 standard provides a variety of flange types, each with its unique structural characteristics and applicable environment. Understanding these different types of flanges can help users choose the most suitable products according to their needs and ensure the safety and reliability of the piping system.
EN1092-1 Standard System:
EN1092-1 is the core standard for steel pipe flanges developed by the European Committee for Standardization (CEN), and is known as “Flanges and their connections – Circular flanges for pipes, valves, fittings and accessories, PN designation – Part 1: Steel flanges”. This standard forms the basis of the European PN (nominal pressure) flange system and has a wide influence in the global industry.
EN1092-1 applies to circular steel flanges with nominal pressures from PN2.5 to PN400 and nominal sizes from DN10 to DN4000. The standard specifies the following in detail:
•Types of flanges and their sealing face forms
•Size and tolerance requirements
•Bolt size and arrangement
•Surface finish standard of flange connection surface
•Material selection and performance requirements
•Calculation method of pressure-temperature rating
•Flange marking and quality control requirements
EN1092-1 Different Types of Flanges：
01 (Plate flange for welding）
02 (Loose plate flange for Types 32—37）
04 (Loose plate flange for Type 34）
05 (Blind flange）
11 (Weld-neck flange）
12 (Hubbed slip-on flange for welding）
13 (Hubbed threaded flange）
21 (Integral flange）
32 (Weld-on plate collar）
33 (Lapped end pipe）
34 (Weld-neck collar）
35 (Weldring neck）
36 (Pressed collar with long neck）
37 (Pressed collar）
Methods of manufacture：
| Type of Flange and Collar | Forged a | Cast | Made from flat products (plates) | Machined from rolled or forged bars and forged sectional steel | Bent and electric welded form bars, sectional steel or strip b, c, d, e | Pressed from welded or seamless pipes or flat products |
| 01 (Plate flange for welding) | yes | no | yes | yes | yes | no |
| 02 (Loose plate flange for Types 32— | yes | no | yes | yes | yes | no |
| 04 (Loose plate flange for Type 34) | yes | no | yes | yes | yes | no |
| 05 (Blind flange) | yes | no | yes | yes | no | no |
| 11 (Weld-neck flange) | yes | no | no | yes | no | no |
| 12 (Hubbed slip-on flange for welding) | yes | no | no | yes | no | no |
| 13 (Hubbed threaded flange) | yes | no | no | yes | no | no |
| 21 (Integral flange) | yes | yes | no | yes | no | no |
| 32 (Weld-on plate collar) | yes | no | yes | yes | yes | no |
| 33 (Lapped end pipe) | yes | no | yes | no | yes | yes |
| 34 (Weld-neck collar) | yes | yes | no | yes | yes | no |
| 35 (Welding neck) | yes | no | yes | yes | yes | no |
| 36 (Pressed collar with long neck) | yes | no | no | no | yes | yes |
| 37 (Pressed collar) | yes | no | yes | yes | yes | yes |
| a Seamless rolled, pressed, forged. b Only one radial weld is allowed under DN 1800. If using cut strips for manufacturing, the through thickness direction of the strip for type 11 and 34 shall be perpendicular to the flange centerline, for Type 01, 02, 04 and 32 in the direction of the flange centreline. c For welding: see 5.11. d Welded flanges allowed only for an application up to 370 °C in conformance with EN 13480–3:2002, D.4.4. e In case flanges are made by cold forming of a base material e.g. flat product, some mechanical properties, like elongation after fracture (A) and impact energy (KV), will be impaired due to cold forming without subsequently heat treatment. | ||||||
Surface finish：
| Flange type | Outer diameter | Centre bore diameter | Bolt holes | Spot facing | ||
| Ra max µm | Rz max µm | Ra max µm | Rz max µm | |||
| 01 (Plate flange for welding） | 25 | 160 | 25 | 160 | b | c |
| 02 (Loose plate flange for Types 32—37） | 25 | 160 | 25 | 160 | b | — |
| 04 (Loose plate flange for Type 34） | 25 | 160 | 25 | 160 | b | — |
| 05 (Blind flange） | 25 | 160 | n.a. | b | c | |
| 11 (Weld-neck flange） | 25a | 160a | 25a | 160a | b | c |
| 12 (Hubbed slip-on flange for welding） | 25a | 160a | 25a | 160a | b | c |
| 13 (Hubbed threaded flange） | 25a | 160a | See thread standard | b | c | |
| 21 (Integral flange） | 25a | 160a | 25a | 160a | — | c |
| 32 (Weld-on plate collar） | 25 | 160 | 25 | 160 | — | — |
| 33 (Lapped end pipe） | 25a | 160 | 25a | 160 | — | — |
| 34 (Weld-neck collar） | 25a | 160a | 25a | 160a | — | — |
| 35 (Weldring neck） | 25a | 160a | 25a | 160a | — | — |
| 36 (Pressed collar with long neck） | 25a | 160a | 25a | 160a | — | — |
| 37 (Pressed collar） | 25a | 160a | 25a | 160a | — | — |
| a Or up to PN 40 un-machined. b Bolt holes > PN 40 only drilled. c Chip machining spot facing for PN ≥ 63 (see 5.8.2). | ||||||
EN1092-1 Flange Materials：
| Carbon Steel | ASTM A105/A105N |
| low temperature steel | ASTM A350 LF2/LF3 |
| Pipeline steel | ASTM A694 F42/46/52/56/65/70 |
| Alloy steel | ASTM A182 F5/F9/F11/F12/F22/F91/F92 |
| Stainless steel | ASTM A182 F304/304L/304H、F316/316L、F317、F310S、F321、F347、F904L |
| Duplex stainless steel | ASTM A182 F51/53/55/60 |
Areas of Application：
Oil & Gas Industry
Petrochemicals
Power Industry
Water Treatment & Wastewater Management
Pharmaceuticals
Marine & Offshore Platforms
Chemicals & Hazardous Materials Transportation
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