Barlow’s Formula

Barlow Formula Equation:

 
P = Fluid Pressure (psi or MPa)
T = Pipe Wall Thickness (in or mm)
OD = Pipe Outside Diameter (in or mm)
SF = Safety Factor (General Calculations 1.5, 2, 3, 4, 5, 6, 7, 8,9, 10, Use 1 For Calculating Bursting Pressure)
S =  Material Strength or Allowable Stress (psi or MPa)
Ultimate Tensile Strength (U.T.S) or Yield Strength (Y.S) can be used. U.T.S should be used to determine the bursting pressure. Y.S. can be used to estimate the pressures at which permanent deformation begins.
When calculating, please pay attention to the consistency of units, i.e. Imperial (inch, psi), Metric (mm, MPa).