Final answer:
The rod diameter for supporting 5-inch horizontal piping can only be accurately determined by referring to applicable building codes or standards, which provide guidelines based on various factors such as load and material. Without specific code references, an exact size cannot be given.
Step-by-step explanation:
When supporting horizontal piping that is 5-inches in diameter with hangers, you need to consider the appropriate rod diameter for supporting the weight and ensuring proper installation and safety. In standard practices, hanger rods are sized not just by the pipe diameter but also based on the load they are to carry, the type of material from which they are made, and local building codes. None of the information provided directly indicates the exact rod diameter required for a 5-inch diameter pipe. To find this information, you would typically refer to building codes or standards such as the American Society of Mechanical Engineers (ASME) B31.1 Power Piping Code or the B31.3 Process Piping Code, which provide guidelines for piping support elements. Without specific reference to these codes, determining the rod diameter would be speculative and could lead to an incorrect and unsafe setup.