Barlow's formula

The Barlow's Formula calculator computes the pressure that a pipe can withstand based on the allowable stress, wall thickness and outside diameter.

INSTRUCTION: Choose units and enter the following:

• (S) Allowable Stress
• (t) Wall Thickness
• (D) Outside Diameter of Pipe

Pressure (P): The calculator returns the pressure in pascals (Pa).  However, this can be automatically converted to compatible units (e.g., pascals) via the pull-down menu.

The Math / Science

Barlow's formula relates the internal pressure that a pipe can withstand to its dimensions and the strength of its material. The Barlow formula is:

   P=(2•S•t)/D

where: 

• P = pressure based on Barlow's formula
• S = allowable stress
• t = wall thickness
• D = outside diameter

This formula figures prominently in the design of autoclaves and other pressure vessels. 

References

Wikipedia (https://en.wikipedia.org/wiki/Barlow%27s_formula)