Rules for this Code Section have been developed considering the needs for applications that include piping and heat transfer components for refrigerants and secondary coolants. This Code prescribes requirements for the materials, design, fabrication, assembly, erection, test, and inspection of refrigerant, heat transfer components, and secondary coolant piping for temperatures as low as -320°F (-196°C), whether erected on the premises or factory assembled, except as specifically excluded in the following paragraphs. This Code shall not apply to any of the following: (a) any self-contained or unit systems subject to the requirements of Underwriters Laboratories or other nationally recognized testing laboratory; (b) water piping, other than where water is used as a secondary coolant or refrigerant; (c) piping designed for external or internal gage pressure not exceeding 15 psi (105 kPa) regardless of size; (d) pressure vessels, compressors, or pumps, but does include all connecting refrigerant and secondary coolant piping starting at the first joint adjacent to such apparatus.