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Blind Flange Calculator

Auto-select the PN class from EN 1092-1, calculate minimum thickness per EN 13445-3, and get a standard plate recommendation.

Open utility

What it does​

Select a DN, set operating and test pressures, temperature, and material grade. The tool uses EN 1092-1 flange dimensions and EN 13445-3 stress checks to compute minimum thickness and a recommended standard plate thickness.

When to use it (and when not to)​

Use it when:

  • You need a fast preliminary blind flange thickness for EN 13445 projects.
  • You want an automatic PN lookup instead of manual table checks.
  • You need a quick weight estimate for procurement or handling plans.

Avoid it when:

  • You need a fully certified calculation pack or third-party verification.
  • Your material grade or flange standard is not covered in the dataset.

Inputs and outputs​

Inputs​

InputDescription
DNNominal diameter for EN 1092-1 dimensions.
Operating pressureUsed to select the PN class.
Test pressureDefaults from operating pressure but can be overridden.
TemperatureUsed to pick temperature-dependent yield strength (deg C).
MaterialP265GH, P355GH, or 1.4404 (316L).
Corrosion allowanceAdded to the minimum thickness.

Outputs​

OutputFormatNotes
Recommended thicknessmmRounded up to a standard plate list.
Minimum thicknessmmFrom EN 13445-3 with corrosion allowance shown separately.
PN class and bolt dataOn-screenIncludes bolt count, size, and bolt circle.
Weight estimatekgBased on flange OD, thickness, and material density.

How to use​

  1. Choose DN and enter operating pressure.
  2. Confirm or override test pressure.
  3. Select temperature, material, and corrosion allowance.
  4. Read the recommended thickness, PN class, and bolt details.

Example dataset: DN 100, operating pressure 10 bar, test pressure 14 bar, temperature 20 C, material P265GH, corrosion 1 mm.

  • Expected output: Recommended thickness and PN class with bolt size and weight estimate.

Accuracy and verification​

  • The calculator is a preliminary sizing tool and does not replace full code verification.
  • Confirm flange class selection against project pressure ratings and gasket requirements.
  • Validate material properties, especially at elevated temperatures.
  • EN 1092-1 high-pressure ratings (PN160+) are only standardized for a limited DN range; unsupported combinations show “No data”.

FAQ​

  • How is the PN class selected? The closest PN class that meets or exceeds the operating pressure is chosen from EN 1092-1.
  • Can I override the test pressure? Yes. Editing the test pressure disables auto-updates.
  • Which materials are included? P265GH, P355GH, and 1.4404 (316L) with temperature-dependent yield data.
  • Does it upload my data? No. Everything runs locally in the browser.
  • Is this a final design check? No. Use it for preliminary sizing and verify against your project specs.

Changelog​

  • Initial documentation.

Feedback / bug report​

  • Open a GitHub issue
  • Email or DM with the slug blind-flange-calculator so we can reproduce the issue
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