Barlow`s Formula
![barlows](https://webarchive.library.unt.edu/dentonfracking/20141030114038im_/http://tridentsteel.com/wp-content/uploads/2013/04/barlows-300x108.png)
Where:
P = ID pressure (psi)
T = Wall thickness (in)
OD = Outside Diameter (in) *Must be a decimal*
SF = Safety factor (generally 1.5 – 10, 1 for collapsing pressure)
S = Material strength (psi) *Minimum yield strength*
*Disclaimer: Formulaic calculators are provided purely for illustrative purposes, and should not be relied upon for any technical, engineering, or application-specific purpose. For technical information, consult a licensed petroleum engineer.