Which of the following is required for marking gas pipes?

The correct choice specifies that gas pipes must be painted yellow every 1 inch and marked with "Gas" or "Propane." This requirement is important for safety and identification purposes. The consistent marking of gas pipes ensures that individuals can easily recognize these lines, which is critical in preventing accidental damage, informing maintenance work, and promoting safety in the vicinity of gas installations.

Painting the pipes yellow is a commonly accepted industry standard that is aimed at enhancing visibility and reducing the risk of accidental pipe strikes during construction or maintenance activities. Additionally, the specific marking with the terms "Gas" or "Propane" provides clear identification of the type of gas being transported, which is essential for emergency responders and technicians who may need to interact with the piping system.

This rigorous marking system is crucial for maintaining safety protocols and compliance with relevant codes and regulations that govern gas distribution.