Standards Reference
DIN EN 1092-1: European Metric Steel Flanges
DIN EN 1092-1 is the European answer to ASME B16.5. It covers steel flanges for pipework, valves, fittings, and accessories in the full nominal diameter range from DN 10 up through DN 4000, with pressure ratings designated PN 6 through PN 400. The dimensional system is metric. The pressure designation is in bar. The bolt patterns do not interchange with ASME without an adapter. For projects with European equipment, German pump packages, or imported skids, DIN is the standard the upstream documentation will reference.
How PN Ratings Work
PN stands for nominal pressure, expressed in bar at room temperature. PN 16 is roughly 232 psi cold working pressure. PN 40 is roughly 580 psi. PN 100 is roughly 1450 psi. The rating derates with temperature in much the same way an ASME class does, and the EN 1092-1 standard publishes a pressure-temperature table for every PN rating against the qualifying material groups.
The full PN ladder runs PN 6, PN 10, PN 16, PN 25, PN 40, PN 64, PN 100, PN 160, PN 250, PN 320, and PN 400. Not every PN is available in every DN size. The lower PN ratings dominate water and low-pressure utility service. PN 40 is the workhorse for general industrial piping. PN 100 and above appear in high-pressure hydraulic systems, chemical process, and high-pressure gas handling. PN 250, PN 320, and PN 400 are the heavy end of the standard, used in petrochemical and some specialized hydraulic service.
For a quick mental crosswalk, PN 16 roughly maps to ASME Class 150. PN 40 sits between ASME 150 and 300. PN 100 is in the same neighborhood as Class 600. PN 250 corresponds roughly to Class 1500. These are working approximations. The exact mating requires either matched pairs on both sides of the joint or a qualified transition flange between them.
PN to ASME Crosswalk
| DIN PN | Bar (cold) | PSI (cold) | Closest ASME Class |
|---|---|---|---|
| PN 6 | 6 | 87 | AWWA Class B / Class 125 cast iron |
| PN 10 | 10 | 145 | Below Class 150 |
| PN 16 | 16 | 232 | Approx Class 150 |
| PN 25 | 25 | 363 | Between Class 150 and 300 |
| PN 40 | 40 | 580 | Approx Class 300 |
| PN 64 | 64 | 928 | Approx Class 400 to 600 |
| PN 100 | 100 | 1450 | Approx Class 600 |
| PN 160 | 160 | 2320 | Approx Class 900 |
| PN 250 | 250 | 3625 | Approx Class 1500 |
| PN 320 | 320 | 4640 | Between Class 1500 and 2500 |
| PN 400 | 400 | 5800 | Approx Class 2500 |
Crosswalk values are approximate cold rating equivalents. Bolt patterns, outside diameters, and gasket geometries do not match between DIN and ASME. Do not mix the two on the same joint without a qualified transition.
Flange Types in EN 1092-1
The standard organizes flange shapes by type number, similar to the way ASME splits weld neck, slip-on, blind, threaded, and socket weld into named categories. Type 01 is a plate flange. Type 02 is a loose flange with weld-on collar. Type 04 is a loose flange with stub end, the metric cousin of a lap joint. Type 05 is a blind flange. Type 11 is a weld neck. Type 12 is a slip-on (now superseded in newer revisions). Type 13 is a hub slip-on. Type 21 is an integral flange.
On the majority of DIN piping, Type 11 weld neck dominates the higher PN ratings the same way it dominates ASME at Class 300 and above. Type 01 plate flanges appear in low pressure water service. Type 05 blind flanges close off the end of a header. The face options include type B raised face (default), type C tongue, type D groove, type E spigot, and type F recess, with ring joint variants for high pressure service.
DN Sizes and Their Inch Equivalents
DN is nominal diameter in millimeters. Common piping sizes run DN 15 (1/2 inch), DN 20 (3/4 inch), DN 25 (1 inch), DN 32, DN 40, DN 50 (2 inch), DN 65, DN 80 (3 inch), DN 100 (4 inch), DN 150 (6 inch), DN 200 (8 inch), DN 250 (10 inch), DN 300 (12 inch), DN 350, DN 400 (16 inch), DN 500 (20 inch), DN 600 (24 inch), and up through DN 4000 in large diameter water and penstock work.
The size designation is nominal. The actual outside diameter of a DN 100 flange in PN 16 is 220 mm. A DN 100 in PN 40 is 235 mm. The bolt circle, bolt count, and bolt hole diameter all shift with the PN rating, which is the practical reason DIN flanges of different PN do not bolt together even at the same nominal diameter.
Materials Under EN 1092-1
EN 1092-1 references material groups that parallel the ASME B16.5 material group system. Group 1E0 covers low and medium-strength carbon steel (P250GH, P265GH). Group 3E0 covers austenitic stainless (1.4404 / 316L, 1.4541 / 321). Group 5E0 covers chrome-moly creep-resistant grades (13CrMo4-5, 10CrMo9-10, equivalents to F11 and F22). The chemistry and mechanical properties of each EN grade map to a corresponding ASTM grade, and most mills publish the crosswalk on the MTR for projects that need both certifications.
For carbon steel projects, P250GH is the closest analog to A105. P265GH is the higher-strength grade often used in pressure vessel work. Stainless work follows the 1.4xxx number system, with 1.4571 (a stabilized 316Ti) being a common European preference for steam and high-temperature service. Confirm the grade callout against the project specification, especially when a US-based fabricator is sourcing flanges to a European equipment spec.
When You Need DIN, When You Need ASME
US-built piping defaults to ASME B16.5 and B16.47. Most North American refineries, chemical plants, and power stations spec ASME throughout. European-built equipment, German pumps and valves, and most LNG packages assembled in Europe come with DIN connections. When that European equipment lands in a US plant, somebody has to manage the transition.
The cleanest answer is a transition flange or a spool piece with a DIN flange on one end and an ASME flange on the other. We supply transition flanges in matched pairs when the project calls for them. The alternative is to convert the equipment connection itself, which is sometimes cheaper, sometimes more expensive, and almost always slower.
For projects shipping equipment overseas, the order frequently runs the other direction. Domestic fabrication using DIN-pattern flanges so the assembled skid drops into a European piping footprint without a transition on either side. We source DIN flanges from EU mills and from qualified Asian mills depending on the project documentation requirements.
Documentation and Sourcing
EN 10204 type 3.1 MTRs are the European standard for material certification and are equivalent in practical use to an ASTM-spec MTR. Type 3.2 adds independent third-party witness inspection, which some specifications require for high-pressure or critical service. Confirm the MTR type required by the project before the order goes out.
For US-flagged projects with Buy American exposure, DIN-pattern flanges from European mills will typically not qualify unless the project carries a specific waiver. Domestic plate-cut work in DIN dimensions is one workaround when the pattern is required but the procurement contract demands US melt origin. Call the sales desk to discuss the combination before the bid closes.
Need DIN Flanges Sourced?
Call (281) 484-8325 or email sales@texasflange.com with the DN size, PN rating, type, and material. We supply European-origin and qualifying domestic-origin DIN flanges depending on project documentation requirements.
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