What are two main reasons for using valves in piping systems?

Using valves in piping systems primarily serves two essential functions: starting and stopping fluid flow, as well as regulating the flow rate to meet operational requirements. These functions are vital for maintaining the desired performance and efficiency of the system.

Starting and stopping flow is crucial for operational control; it allows for precise management of when fluids move through the system, which is necessary for safe operations and maintenance. For instance, in scenarios where maintenance must be performed, valves facilitate the isolation of sections of the piping system.

Regulating flow is equally important as it ensures that the system operates within specific parameters, preventing issues such as overpressure or flow rates that could lead to inefficiencies or damage. By adjusting the valve, operators can control the amount of fluid flowing through the system, which directly affects processes reliant on fluid dynamics.

The other options explore various functions that valves may influence indirectly or fall under different categories altogether. While preventing corrosion and reducing noise are important considerations in piping systems, they do not represent the primary functions of valves. Similarly, measuring flow and handling emergencies are tasks that might involve other devices or systems rather than being central to the basic operation of a valve. Thus, the correct answer focuses on the fundamental control functions that valves provide in a piping system.