Final answer:
The appropriate flow diagram to determine the category of fluid service design when the owner requires metal piping is the Process Flow Diagram (PFD). This diagram helps categorize the fluid service design based on the nature and properties of the fluid being transported.
Step-by-step explanation:
When the owner requires metal piping to be used and does not specify the category of fluid service design, the appropriate flow diagram to determine the category can be the Process Flow Diagram (PFD). The PFD is a schematic representation of the major equipment and flow paths in a process. It provides a visual overview of the process and helps identify the category of fluid service design.
For example, if the metal piping is intended for carrying water, the flow diagram might indicate a Category D fluid service design, which is for non-hazardous fluids under relatively low pressure and temperature. On the other hand, if the metal piping is intended for carrying hazardous chemicals, the flow diagram might indicate a Category M fluid service design, which is for hazardous fluids under high pressure and temperature. The PFD helps categorize the fluid service design based on the nature and properties of the fluid being transported.
By using the appropriate flow diagram, engineers can determine the category of fluid service design and make informed decisions about the materials, equipment, and design considerations that are necessary for the specific application.