Piping Design by Rigorous Analysis may provide some savings but the calcs are time consuming (remember the Nukes). But I would definitely NOT reduce the inherent Safety Factors in the code since as can be seen in this forum and elsewhere, numerous UNqualified personnel work in this industry.

Piping Designers ENGINEER piping systems and many CAESAR II Engineers QUALIFY piping systems. Scary stuff.

Also there are many more piping systems in a plant than vessels.