Applies To
Product(s):	AutoPIPE
Version(s):	ALL;
Area:	Calculations
Date Logged & Current Version	Oct 2023 23.00.00.230

Problem:

How to calculate the Hoop stress and Hoop allowable for ASME B31.3-2020?

There is a difference in the Hoop stress values calculation from Autopipe and Hands on calculation.

Solution:

 The following was found on the General Model Options dialog:

To get the Hoop stress formula for B31.3 2020.
Go to Help > Reference information > Code Compliance calculations > ASME B31.3 (2020) > Hoop stress (ASME B31.3-2020)

As an Example, Hoop Stress Calculation:

Design pressure P = 7.7 N/mm²
Nominal outside diameter of the pipe D = 88.9mm
Nominal wall thickness t = 5.486mm
Corrosion c= 88.9mm
Mill tolerance tmil = 0.686mm
Reduced Thickness tred = t-c-tmil
Hoop stress factor Y = 0.4
Hoop stress Sh  = [P D / (2 x tred)] - (P x Y)

Hoop Stress = 187.067 N/mm²

As you can see in the screenshot below from the output summary the results are matching for Hoop stress Values i.e..187.02 N/mm²