There are some significant design differences for piping designed to ASME B31.1 Power pipng code versus B31.3 Process pipng code. While CaesarII has a simple toggle switch to set the use of allowable stresses, the impact on design is more complex. Besides the allowable stresses, differences occur with SIF, allowed SA materials, required use of seamless pipe in areas, and minimum XS wall thickness for certain piping systems. The allowable cold strength Sc has less difference now after 3.5:1 change, but does anyone have an opinion whether there are design and project cost differences worth debating?

There is a solar plant study that has daily cycles, steel CL300 piping with pressure / temperatures below 750F, an unfired steam generator, and a small amount of steel CL600 piping to turbine generator. It is unlike a fired power plant that has alloy CL2500 piping running 95%+ baseload. What is probably the largest portion of piping would be the solar collector field with miles of piping and hundreds of expansion loops. The solar plant would seem to be a better fit for ASME B31.3 Process piping, but the owners and jurisdiction authorities have ASME Sec I and B31.1 code mentality. Some of the state regulations still have language pertaining to riveted steam drums! Does anyone have expeerience with an installation of a Sec VIII unfired boiler installation in a B31.3 plant vs B31.1 plant?

This question might be like the piping support span question that needs to be evaluated with specific details, but any experience of others would be appreciated.