Design of ASME B31.3

For those of you who work in chemical plants or who are related to the design, operation and repair of piping systems, of course you understand very well how important the calculation of pipe design according to the ASME31.3 pipe standard is.

One of these design factors is the minimum pipe thickness. The question now is, How to calculate the minimum pipe thickness according to ASME31.3? you can equip yourself with special software for pipe design then this will not be a problem. or we do manual calculations using excel sheet.

Alternatively, we can calculate the pipe thickness by using the online pipe thickness calculator. How to calculate the minimum pipe thickness using the online pipe thickness calculator?

One of them as provided by This site uses the ASME31.3 pipe standard as the basis for its calculations. see in this article

This pipe thickness calculator calculates required pipe thickness for a process pipe based on ASME B31.3 Code. Detail information about behind the back calculations is given at the end of this calculator.

This calculator calculates required thickness of a pipe under internal pressure based on criteria specified in section 302.1.1 and 302.2.2 of ASME B31.3 Pressure Piping Code.

Input Required:

  • Pipe material of construction.
  • Pipe NPD.
  • Pipe construction type : Seamless, EFW, ERW etc.
  • Design temperature.
  • Design Pressure.
  • Corrosion allowance for material and operating conditions.
  • Mechanical allowance.
  • Mill tolerance.

Explanation of the Pipe Thickness Calculator

ASME B31.3 tell us about how to use formula and guidelines to calculate of pipe under internal pressure. Even the formula is very simple, sometimes finding correct values of individual factors can be tricky.  Process pipe thickness calculator usually uses following formula to calculate the wall thickness requirement.

304.1.2 (a) equation 3a :

Seamless Pipes : Design Thickness t = (PD)/2(SE+PY)
Welded Pipes : Design Thickness t = (PD)/2(SEW+PY)

Where :

P : Internal Design Guage Pressure

D : Outside diameter of pipe

In this calculator, outside diameter is taken from American Pipe Standards for the selected nominal pipe diameter :

-ASME B36.10 : Welded and Seamless Wrought Steel Pipe.
-ASME B36.19 : Stainless Steel Pipes.

S : Allowable Stress value for material from Table A-1
These are allowable stress values for different materials at different temperatures. Provided in Table A-1 of ASME B31.3.


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Author Since: May 31, 2021

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