Overview
EN 1092-1 is the European standard for steel flanges. Instead of the American "Class" system (e.g., Class 150), it uses the Nominal Pressure (PN) designation system (e.g., PN16, PN40), which roughly corresponds to the allowable pressure in bars at room temperature.
Scope & Applicability
Applies To Industries
Covers — European metric steel flanges:
- Sizes designated by DN (Diamètre Nominal), e.g., DN50 (approx. NPS 2).
- Pressure designations: PN 2.5, 6, 10, 16, 25, 40, 63, 100, 160, 250, 320, 400.
- Replaces legacy national standards like DIN (Germany), BS (UK), and NF (France).
Does NOT cover (exclusions) — the following are governed elsewhere:
- ASME Class designated flanges → ASME B16.5.
Key Requirements
EN 1092-1 categorizes flanges using specific Type numbers:
- Type 01: Plate flange for welding (Slip-on equivalent).
- Type 05: Blank flange (Blind).
- Type 11: Weld-neck flange.
- Faces: Uses a letter system (Type A = Flat face, Type B = Raised face, Type E = Spigot, Type F = Recess).
Technical Details
While the world of process piping is heavily dominated by ASME B16.5, European manufactured equipment (pumps, heat exchangers, packaged skids) will almost universally arrive with EN 1092-1 PN flanges.
EN flanges and ASME flanges are completely incompatible in terms of bolt circle diameter, number of bolts, and flange thickness.
Engineering Notes
A common mistake is assuming PN20 is exactly equivalent to Class 150, or PN50 to Class 300. While the pressure capacities are similar, the physical dimensions do NOT match. You cannot bolt an ASME B16.5 flange to an EN 1092-1 flange without a custom transition spool.
Source, Edition & Status
- Publisher
- EN
- Industries
- Chemical Plant, General Industry
- Last Reviewed
- 2026-07-01
- Last Updated
- 2026-07-01
- Verified By
- Engineering content reviewer
- Content Status
- reviewed