Which code establishes minimum standards for repairing and servicing gas appliances?

The Natural Gas and Propane Installation Code is the correct answer because it specifically sets the standards for the installation, repair, and servicing of gas appliances and related equipment. This code is focused on ensuring safety and efficiency in the operation of gas appliances, addressing aspects such as proper installation techniques, necessary clearances, venting requirements, and the correct types of materials to be used. In doing so, it helps to prevent hazards such as gas leaks or improper venting, which could lead to dangerous situations.

While the other codes listed address important safety and installation standards in their respective areas, they do not pertain specifically to gas appliances. The Electrical Safety Code primarily deals with electrical installations and safety measures; the Building Code encompasses general construction practices and safety but does not focus specifically on gas appliances; and the Plumbing Code covers the installation and maintenance of plumbing systems. Therefore, none of those codes provide the targeted standards required for gas appliances that the Natural Gas and Propane Installation Code does.