Enercon Pipe & Fittings Industries

Enter any three numeric values:

psig

in.

in.

psi

Barlow's Formula is Used to Determine:

• Internal Pressure at Minimum Yield
• Ultimate Bursting Pressure
• Maximum Allowable Operating Pressure
• Mill Hydrostatic Test Pressure

The Formula is Expressed as P=2St/D, Where:

• P = pressure, psig
• t = nominal wall thickness, in inches (i.e. .375)
• D = outside Diameter in inches
• S = allowable stress in psi, which depends on the pressure being determined utilizing Yield or Tensile depending on what is trying to be determined

For Example:

• Internal Pressure at Minimum Yield:
  S= SMYS - minimum yield for grade of pipe

Ultimate Bursting Pressure:

• S = SMTS - minimum tensile strength for grade of pipe

Maximum Allowable Operating Pressure:

• S = SMYS - reduced by a design factor

Mill Hydrostatic Test Pressure:

• S = SMYS - reduced by a design factor depending on OD and grade