For Primary stresses the ASME B31.3 Code Default is to use 0.75xSIF.

But now, we have the SSI for primary type of stress, I will quote from Dorin Daniel reply:

"The ASME B31.3 Sustained Stress Indexes (SSIs) are NOT equal to Primary Stress Intensification Factors. The ASME B31.3 SSIs are calculated based upon limit load analyses."

Any other opinion is greatly appreciated.

Cheers!!!