Standards Reference
DIN and EN 1092-1 Flanges
When the project documents come in metric and the pressure class is written as PN, you are in EN 1092-1 territory. This is the European standard for steel pipe flanges, descended from the older DIN series. It uses Pressure Nominal (PN) ratings, metric dimensions, and a numbered type system that maps cleanly to the usual flange configurations.
PN Pressure Ratings
PN stands for Pressure Nominal, expressed in bar. EN 1092-1 covers a wide range of pressure classes, from low-pressure utility service up through severe-service applications. The full set includes:
PN 6
PN 10
PN 16
PN 25
PN 40
PN 63
PN 100
PN 160
PN 250
PN 320
PN 400
Each PN rating represents nominal pressure in bar at a reference temperature, typically 20 degrees C. Actual allowable working pressure derates with temperature and material, similar to ASME ratings but with a different reference curve.
Rough Comparison to ASME Classes
PN ratings and ASME pressure classes are not directly interchangeable, but the rough alignment helps when a project mixes European and American specs. Bolt patterns, OD, and face dimensions do not match - this is for pressure regime only, not mechanical compatibility.
| DIN / EN PN | Rough ASME Class | Notes |
|---|---|---|
| PN 10 / PN 16 | Class 150 | Common low-pressure overlap |
| PN 25 / PN 40 | Class 300 | Standard process service |
| PN 63 / PN 100 | Class 600 | Higher-pressure process |
| PN 160 | Class 900 | Approximate alignment |
| PN 250 | Class 1500 | Severe service |
| PN 400 | Class 2500 | Top of the standard range |
Reminder: a PN 40 flange will not bolt up to a Class 300 flange. Bolt count, bolt circle, hole diameter, and OD are all different. The pressure regime aligns; the mechanical interface does not.
EN 1092-1 Flange Types
EN 1092-1 numbers each flange configuration. The most common types you will see on European specs:
TYPE 01
Plate Flange (Flat)
Flat plate flange for welding to pipe. The simplest configuration, used at lower pressures where a hub is not required.
TYPE 02
Loose Flange with Weld Neck Collar
Two-piece arrangement. The flange rotates freely on a collar welded to the pipe. Allows easy alignment of bolt holes during assembly.
TYPE 04
Loose Lap Joint Flange
Backing flange used with a lap joint stub end. Equivalent to the ASME lap joint configuration. Common when the line is an expensive alloy and the flange can be carbon steel.
TYPE 05
Blind Flange
Closes off the end of a line. Solid disc with bolt holes, no bore. Functionally identical to an ASME B16.5 blind.
TYPE 11
Weld Neck Flange
The European weld neck. Long tapered hub welded butt-joint to pipe. The default for higher-pressure service. Equivalent in role to a B16.5 weld neck.
TYPE 12
Hubbed Slip-On Flange
Hubbed slip-on configuration. The pipe slides through, the flange is fillet welded on both faces. Equivalent to a B16.5 slip-on.
Materials per EN 1092-1
EN 1092-1 references European material specifications that often cross-reference to familiar ASTM grades. The common ones:
P250GH
Carbon steel for elevated temperature service. Roughly analogous to ASTM A105 for many applications.
P265GH
Higher-strength carbon steel for pressure equipment. Common on PN 25 and above in larger sizes.
16Mo3
Molybdenum-alloyed steel for moderate elevated temperature service. Comparable in role to ASTM A182 F1.
A105 Substitution
On many North American projects with European spec callouts, ASTM A105 is accepted as an equivalent to P250GH with appropriate documentation.
When You Will See DIN / EN 1092-1
European engineering contractors building US projects, ISO-aligned facilities, equipment skids fabricated overseas, and any project where the line list or P&ID came out of a European EPC. Pharmaceutical, food and beverage, and certain chemical projects use EN 1092-1 by default even on US soil because the upstream equipment was sourced from Europe.
We source DIN and EN 1092-1 flanges in the standard PN ratings and type configurations to match what your spec calls for. For cross-spec projects with both ASME and EN piping, we will help confirm the right adapter or transition strategy.
DIN or EN 1092-1 on the Spec Sheet?
Send the schedule with PN ratings, types, and materials. We will source to spec and confirm the dimensional package matches your mating equipment before anything ships.