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 deg F (-196 deg C), whether erected on the premises or factory assembled, except as specifically excluded in the following paragraphs. Users are advised that other piping Code Sections may provide requirements for refrigeration piping in their respective jurisdictions. This Code shall not apply to: (a) any self- contained or unit systems subject to the requirements of Underwriters Laboratories or other nationally recognized testing laboratory: (b) water piping; (c) piping designed for external or internal gage pressure not exceeding 15 psi (105 kPa) regardless of size; or (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.