Pipe Schedule Calculator

Calculate the required pipe wall thickness from internal pressure, allowable stress, and pipe diameter using the Barlow formula.

MPa
mm
MPa
mm

Minimum Wall Thickness

7.19 mm

Barlow Thickness (no CA)6.10 mm

Minimum Wall Thickness vs Design Pressure (P)

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Formula

## Pipe Wall Thickness Design The required pipe wall thickness depends on the internal pressure, pipe diameter, material allowable stress, and safety factors. The Barlow formula provides the starting point. ### Barlow Formula **t = P × D / (2 × S × E)** The ASME B31.3 modified version: **t = P × D / (2 × (S × E + P)) + CA** where P is pressure, D is outside diameter, S is allowable stress, E is weld joint efficiency, and CA is corrosion allowance.

Esempio Risolto

A 6" Sch pipe (OD=168.3 mm) at 10 MPa, S=137.9 MPa, E=1.0, CA=1.5 mm.

  1. 01Barlow: t = 10 × 168.3 / (2 × 137.9 × 1.0) = 1683 / 275.8 = 6.10 mm
  2. 02ASME modified: t = 10 × 168.3 / (2 × (137.9 + 10)) + 1.5
  3. 03t = 1683 / 295.8 + 1.5 = 5.69 + 1.5 = 7.19 mm