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Status Needs review
Workspace AutoPIPE Vessel
Created by Guest
Created on Oct 23, 2025

Manufacturing tolerance for heads

Add manufacturing tolerances for heads, in accordance with standards NF E81-100 to NF E81-104 (and other national standards).

Or be able to define a manufacturing tolerance as a percentage rather than a fixed value.

  • Guest
    Mar 24, 2026

    “Minimum After Forming” (M.A.F.). This describes the amount by which the head thickness is reduced at the knuckle area, where the largest deformation occurs when forming the head from a flat plate.

    A common rule of thumb is that M.A.F. is approximately 15% of the nominal thickness. This is not the same as corrosion allowance or tolerance, so it requires a separate entry.

    When performing strength calculations, this value should be added to corrosion allowance and tolerance. However, it should be excluded from weight calculations, which should not take M.A.F. into account.