Suggestions from Development/Support:

For the 2017 Edition, specify reinforced dimensions for the OD and pipe thickness. If you Error Check the model, the software will display Note 553E that explains how to calculate the reinforced OD and pipe thickness.

If the model has mill tolerance specified, then it will use that value to convert the reinforced OD and thickness to the minimum reinforced DO and thickness, which are used in the stress calculations.

The corrosion allowance is not used by this piping code.

For the 2005 Edition, the software does not use the reinforced OD and thickness. It does however always use the corrosion allowance if specified.

In addition, the Hoop stress in the 2017 Edition does not use any stress multipliers, while the 2005 Edition does use a multiplier for tee and bend elements.

I can't tell if these differences are enough to cause the large differences that you have observed in the Hoop stress value, but I'm interested in taking a closer look if you can provide the job files.

I would be able to give precise answers to any questions involving differences between the two code editions, once I can review your job file.
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Regards,
Richard Ay - Consultant