Question:

DNV suggesting that we should apply the "free corrosion" version of the fatigue curves used. I'm aware SACS uses "Norsok" to designate the standard DNV curves, I assume they are "with cathodic protection".  We have currently applied the ISO ITJ (Norsok version would be curve "T") and Norsok F3 curves to the relevant areas.  DNVGL-TP-C203 provides values that define the "free corrosion" version of these curves (see images attached) but is there an inbuilt option to account for these versions of the standard curves or must the curves be manually defined?

Answer:

The S-N curves with cathodic protection can be entered in column 33-35 of the FTOPT line. You can enter the splash zone in FTOPT2 line. If you like to have a free corrosion S-N curve, you need to enter your own user defined S-N curve.