HomePipingWall thickness calculator
    Piping & Stress Analysis

    Engineering tool

    Pipe Wall Thickness

    Wall thickness of a straight pipe under internal pressure, by the relation of ASME B31.3 para 304.1.2(a). The calculation carries through the allowances and the mill tolerance to the nominal thickness you actually have to order, and states whether the relation is still inside its own validity range.

    Nominal size

    Outside diameters from ASME B36.10M / B36.19M. Enter D directly in the field below for sizes outside the list.

    Line & design condition
    Material

    S, E, W and Y are read from the standard, because they depend on the material, the design temperature and the edition in force. They are inputs here on purpose: a materials table written from memory is exactly what would make this tool untrustworthy.

    Allowances & tolerance
    Thickness check

    Set to 0 to skip the check. The schedule wall thicknesses are in ASME B36.10M.

    Minimum nominal thickness to order

    4.82 mm

    Minimum required tm = 4.21 mm, before allowing for the mill tolerance on the delivered pipe.

    Selected thickness is adequate

    T = 7.11 mm leaves 6.22 mm after mill tolerance, against tm = 4.21 mm. Margin +2.01 mm.

    Intermediate resultValueRelation
    Pressure design thickness1.213 mmt = P·D / (2·(S·E·W + P·Y))
    Sum of allowances3.00 mmc = c_corr + c_mecc
    Minimum required thickness4.213 mmtm = t + c
    Minimum nominal thickness to order4.815 mmT ≥ tm / (1 − tol)
    Selected thickness after mill tolerance6.221 mmT · (1 − tol)
    Validity — thickness ratio0.0072 –t / D < 1/6 = 0.1667
    Validity — pressure ratio0.0145 –P / (S·E·W) ≤ 0.385

    What this does not cover

    Internal pressure on a straight pipe is only one of the checks B31.3 asks for. It says nothing about external pressure and collapse, bends and branch connections, sustained and displacement stresses, supports, or the thickness needed simply to handle and install the line. It is a screening calculation, not a verification, and carries no warranty.

    Need the full line check?

    Send us the line list and the isometrics and we will run the stress analysis, the supports and the thickness verification together, to B31.3 or EN 13480.

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