ASME B31.3 Process Piping Design Factor

Calculate ASME B31.3 metal pipe diameter, minimum wall thickness and pressure design thickness from pipe schedule or user defined diameter and wall thickness (ASME B31.3 section 304.1).

Select the pipe schedule (NPS or ISO), pipe diameter and wall thickness, or use the user defined option. Use the Result Table option to display the pipe schedule with nominal wall thickness, minimum wall thickness and pressure design wall thickness for the selected diameter.

Tool Input

• schdtype : Schedule Type
• diamtype : Diameter Type
  • ODu : User Defined Outside Diameter
  • IDu : User Defined Inside Diameter
• wtntype : Wall Thickness Type
  • tnu : User Defined Wall Thickness
• ttoltype : Wall Thickness Fabrication Tolerance Type
  • txu : User Defined Negative Wall Thickness Fraction
  • tfu : User Defined Negative Wall Thickness Allowance
• c : Wall Thickness Corrosion Allowance

Tool Output

• ID : Nominal Inside Diameter
• OD : Nominal Outside Diameter
• OD/tn : Diameter Over Wall Thickness Ratio
• tf : Wall Thickness Fabrication Allowance
• tm : Minimum Wall Thickness
• tn : Nominal Wall Thickness
• tp : Pressure Design Wall Thickness
• tx : Wall Thickness Fabrication Fraction

Calculate the pipe weld joint reduction factor W from the maximum temperature (ASME B31.3 table 302.3.5). For carbon steel the weld joint reduction factor is 1.0.

For other materials, the weld joint reduction factor is calcuated from a straight line equation for table 302.3.5 (the table values are truncated to two decimal places).

Note : The calculated weld joint factors may not be valid if the metal temperature is greater than the temperature range in appendix A for that particular material.

Tool Input

• wfactype : Weld Factor Type
  • Wu : User Defined W Factor
  • Tcr : User Defined Creep Temperature
• T : Design Temperature

Tool Output

• W : Weld Factor