DIN Flanges

Deutsches Institut fur Normung Pipe Flange Standards

What Are DIN Flanges?

DIN (Deutsches Institut fur Normung, or German Institute for Standardization) flanges follow European standards now largely superseded by EN (European Norm) standards. DIN flanges use metric dimensions and PN (Pressure Nominale) pressure ratings rather than the ASME class system. They are widely used in Europe, the Middle East, Asia, and international projects.

Pressure Ratings (PN)

DIN flanges use PN ratings: PN 6, PN 10, PN 16, PN 25, PN 40, PN 64, PN 100, PN 160, PN 250, PN 320, and PN 400. The PN number represents the approximate maximum working pressure in bar at 20°C. For example, PN 16 = 16 bar (~232 psi) at ambient temperature.

Key DIN/EN Flange Standards

  • EN 1092-1 (replaces DIN 2527-2637) — Steel flanges
  • EN 1092-2 — Cast iron flanges
  • EN 1092-3 — Copper alloy flanges

Common legacy DIN standards:

  • DIN 2527 — Blind flanges
  • DIN 2566 — Threaded flanges
  • DIN 2573-2576 — Slip-on flanges
  • DIN 2631-2638 — Weld neck flanges by PN class

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DIN vs ASME Flanges

Key differences: DIN uses metric dimensions (mm), ASME uses imperial (inches). DIN uses PN pressure ratings, ASME uses Class ratings. Bolt patterns, flange ODs, and thicknesses differ. DIN and ASME flanges of the same nominal size are NOT interchangeable. Sealing face types also differ (DIN Type B = raised face, Type A = flat face).

Common Materials

  • P245GH — Similar to A105
  • P250GH
  • 1.4301 — 304SS equivalent
  • 1.4401 — 316SS equivalent
  • 1.4571 — 316Ti

Related References