Pipe Wall Thickness Calculator

Formula overview

Keep units consistent, e.g., P (MPa), D and t (mm), S (MPa).

t = (P · D) / (2 (S·E·W + P·Y)) + corrosion allowance, per ASME B31.3 pressure design.

Worked example

Example: P = 2 MPa, D = 168.3 mm, S = 138 MPa, E = 1, W = 1, Y = 0.4, c = 1.5 mm
t = (2 × 168.3) / (2 × (138 + 2 × 0.4)) + 1.5
t = 336.6 / 277.6 + 1.5 ≈ 1.21 + 1.5 = 2.71 mm → Select a thicker schedule after accounting for 12.5% mill tolerance.

Common mistakes

• Forgetting to add corrosion allowance and deduct the 12.5% mill tolerance.
• Using allowable stress at the wrong temperature.

FAQ