Barlow's formula


Barlow's formula relates the internal pressure that a pipe can withstand to its dimensions and the strength of its material.
where
This formula figures prominently in the design of autoclaves and other pressure vessels.
The formula is named after Peter Barlow, an English mathematician.

Other formulations

The design of a complex pressure containment system involves much more than the application of Barlow's formula. For pressure vessels, design codes such as the ASME code stipulate the requirements for design and testing.
The formula is also common in the pipeline industry to verify that pipe used for gathering, transmission, and distribution lines can safely withstand operating pressures. The design factor is multiplied by the resulting pressure which gives the maximum operating pressure for the pipeline. This design factor is dependent on class locations which are defined in DOT Part 192. There are four class locations corresponding to four design factors: