EN 1092-1 is the European standard for circular steel flanges designated by PN (nominal pressure). It replaced the national standards DIN, BS 4504 and others, and is used across Europe and on many projects in the Middle East, Africa and Asia that follow European design. The standard fixes flange types, dimensions, facings, materials, pressure–temperature ratings and marking.
Raaj Fittings manufactures EN 1092-1 flanges from PN 6 to PN 400 at our two plants in India, in carbon, alloy and stainless steel, duplex and nickel alloys, for European plants, OEMs and EPC contractors.
| Type | Description |
|---|---|
| Type 01 | Plate flange for welding |
| Type 02 | Loose plate flange, used with a weld-on collar or lapped pipe end |
| Type 04 | Loose plate flange with weld-neck collar |
| Type 05 | Blind flange |
| Type 11 | Weld neck flange |
| Type 12 | Hubbed slip-on flange for welding |
| Type 13 | Hubbed threaded flange |
| Type 21 | Integral flange |
| Facing | Description |
|---|---|
| A | Flat face |
| B | Raised face (B1 and B2 finishes) |
| C / D | Tongue / groove |
| E / F | Spigot / recess |
| G / H | O-ring spigot / O-ring groove |
EN 1092-1 uses PN designations, from PN 2.5 to PN 400; PN is a reference number, and the allowable pressure at temperature depends on the material group of the flange. Materials are European grades, for example P250GH and P265GH carbon steel, 16Mo3 and 13CrMo4-5 alloy steel, and 1.4301, 1.4404 and 1.4571 stainless steels, or equivalent ASTM grades where the purchaser accepts them.
EN and ASME flanges are not interchangeable: outside diameters, bolt circles, bolt numbers and bolt sizes differ for most sizes even where PN and Class seem similar (for example PN 20 and Class 150, or PN 50 and Class 300). Always match the standard of the mating flange, valve or equipment.
Every EN 1092-1 flange is made from PMI-verified material, dimensionally inspected against the ordered standard and marked with material, size, rating and heat number. Orders are supplied with EN 10204 3.1 certificates; EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request.
PN (nominal pressure) is a reference designation, roughly the pressure in bar at ambient temperature for the basic material. The actual allowable pressure depends on the flange material group and the temperature.
EN 1092-1 replaced the DIN flange standards (DIN 2573, 2576, 2631 to 2638 and others). Many dimensions were carried over, but drawings should be checked when matching old DIN flanges.
Type 11 is the EN 1092-1 weld neck flange. Type 01 is a plate flange for welding, Type 05 a blind flange and Type 12 a hubbed slip-on flange.
Generally no, because the bolt circles and drillings differ in most sizes. Use flanges to the same standard on both sides of the joint.