B31.3 allows for the reduction in MDMT without impact testing of piping material if specific conditions are met (See Fig 323.2.2B).

Per note 3 under the graph, it states that stress intensification factors are not to be included in the calculation.

Question: Is there a method to get CAESAR II to report stress ratios without SIFs included?

Quick edit: Would be nice if CAESAR II could determine the MDMT without impact testing from this graph if provided a pressure value.

As a first aid, I think you may overwrite the SIFs in a separate file.

However, I think that reduction in MDMT is more explicit addressed in API 579-1 and they are rather asking for an "operating longitudinal stress" (they are saying "combined stress") calculated without any stress intensification factor- which is exceeding B31.3.

API 579-1:

"Guidelines for stress calculations are as follows:

a. The circumferential stress should be calculated based on the nominal wall thickness minus the metal loss, future corrosion allowance, mechanical allowances, and the manufacturing mill tolerance.

b. The longitudinal stress should be calculated based on the combined stress resulting from pressure, dead weight, and displacement strain. In calculating the longitudinal stress, the forces and moments in the piping system should be determined using section properties based on the nominal dimensions adjusted for metal loss and future corrosion allowance, and the stress should be calculated using section properties based on the nominal dimensions minus the metal loss, future corrosion allowance, and mechanical allowances. Stress intensification factors associated with pipe bends, elbows, tees, etc., do not need to be included in the longitudinal stress calculation. The thermal stress does not have to consider a full design range, such as would result from a system with a high design temperature. It should best reflect the actual stress imposed at low temperature."

Best regards.

There is no built-in facility to ignore SIFs to address Section 323.2.2b. As Mariog states above, the only way to accomplish this would be to make a copy of the job file, then manually specify all the SIFs as "1.0".

Thank you both for your responses.

I think it might be easier to export CAESAR II local loads to Excel and calculate your own "non-SIF" stresses there.

I think you are right.

In addition, I understand it's not only a "non-SIF" stress, it's an operating stress which "should best reflect the actual stress imposed at low temperature."

Best regards.