Pipe Wall Thickness Calculator

ANA›Life Services Authority›National Calculator Authority›Pipe Wall Thickness Calculator

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Pipe Wall Thickness Calculator

Calculate the minimum required pipe wall thickness based on internal design pressure using the ASME B31.3 Process Piping formula.

Pipe Outside Diameter (mm)

Internal Design Pressure (MPa)

Allowable Stress S (MPa)

Weld Quality Factor E

1.0 — Seamless pipe 0.95 — ERW (Electric Resistance Welded) 0.85 — Furnace Butt Welded 0.80 — Double Submerged Arc Welded

Temperature Coefficient Y

0.4 — Ferritic steel ≤ 482°C 0.5 — Ferritic steel 510°C 0.7 — Ferritic steel ≥ 566°C 0.4 — Austenitic steel ≤ 566°C 0.5 — Austenitic steel ≥ 621°C

Mill Tolerance (%)

Corrosion Allowance c (mm)

Calculate

function pipCalc() { var D = parseFloat(document.getElementById('pip-od').value); var P = parseFloat(document.getElementById('pip-pressure').value); var S = parseFloat(document.getElementById('pip-stress').value); var E = parseFloat(document.getElementById('pip-quality').value); var Y = parseFloat(document.getElementById('pip-ycoeff').value); var mill = parseFloat(document.getElementById('pip-mill').value); var c = parseFloat(document.getElementById('pip-corr').value);

var res = document.getElementById('pip-result');

// --- Input validation --- if (isNaN(D) || D ⚠ Outside diameter must be a positive number.'; return; } if (isNaN(P) || P ⚠ Internal pressure must be zero or positive.'; return; } if (isNaN(S) || S ⚠ Allowable stress must be a positive number.'; return; } if (isNaN(mill) || mill = 100) { res.innerHTML = '⚠ Mill tolerance must be between 0 and 100%.'; return; } if (isNaN(c) || c ⚠ Corrosion allowance must be zero or positive.'; return; }

// --- ASME B31.3 formula --- // t_min = (P * D) / (2 * (S * E + P * Y)) var denominator = 2 * (S * E + P * Y); if (denominator ⚠ Denominator is zero or negative — check inputs.'; return; }

var t_min = (P * D) / denominator;

// Add corrosion allowance var t_with_corr = t_min + c;

// Add mill tolerance: t_ordered = t_with_corr / (1 - mill/100) var millFactor = 1 - mill / 100; if (millFactor ⚠ Mill tolerance must be less than 100%.'; return; } var t_ordered = t_with_corr / millFactor;

// Inside diameter var ID = D - 2 * t_ordered;

// Pressure check: ensure t = D / 2) { res.innerHTML = '⚠ Calculated thickness exceeds pipe radius — thin-wall formula not applicable. Consider thick-wall analysis.'; return; }

if (ID ⚠ Calculated wall thickness exceeds pipe radius — check inputs.'; return; }

res.innerHTML = '### Results ' + '' + 'Pressure design thickness (t)' + t_min.toFixed(3) + ' mm' + '+ Corrosion allowance (' + c.toFixed(2) + ' mm)' + t_with_corr.toFixed(3) + ' mm' + 'Minimum ordered thickness (mill tol. ' + mill.toFixed(1) + '%)' + t_ordered.toFixed(3) + ' mm' + 'Resulting inside diameter' + ID.toFixed(3) + ' mm' + '' + 'Select the next standard schedule with wall thickness ≥ ' + t_ordered.toFixed(2) + ' mm.

'; }

#### Formula — ASME B31.3 Clause 304.1.2

Pressure design thickness:

t = (P × D) / (2 × (S × E + P × Y))

Minimum ordered thickness (accounting for corrosion and mill tolerance):

tordered = (t + c) / (1 − mill% / 100)

Where:

#### Assumptions & References

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References

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