Which code establishes rules for pressure or process piping that are not covered in B31.1?

The correct answer is the code that specifically outlines regulations for pressure or process piping not addressed in B31.1. B31.1 primarily deals with power piping, which includes piping systems in power plants. However, B31.3 focuses specifically on process piping used in chemical plants and other industrial facilities; thus, it covers a broader range of applications that are distinct from the power generation context of B31.1.

B31.2 pertains to gaseous fuel piping. While it establishes necessary guidelines, its scope does not overlap much with the broader pressure or process piping rules outside of gas applications. B31.4 deals with the transportation of liquids through pipelines, which is also outside the scope of the general power piping parameters defined in B31.1.

The understanding of different B31 codes is crucial for engineers and technicians in ensuring compliance with applicable standards for different types of piping installations. Thus, B31.3 would indeed provide the needed rules for pressure or process piping that are not specified within the framework of B31.1.