What type of valve is used to manage water flow into a specific fixture?

The shut-off valve is specifically designed to manage water flow to individual fixtures within a plumbing system. This type of valve allows users to easily stop the flow of water to a fixture for maintenance or repair without affecting the water supply to other areas of the home. Shut-off valves are typically installed under sinks, behind toilets, and in other locations where individual control of water flow is necessary.

In contrast, the other types of valves listed have different functions. A pressure relief valve is primarily used to limit the pressure in a system, preventing potential overpressure situations. A flow control valve regulates the flow rate of water but does not necessarily serve as an on/off control for individual fixtures. An expansion valve is used in systems involving refrigerants, such as air conditioning, to manage the flow of refrigerant. Thus, the shut-off valve is the most appropriate choice for managing water flow into a specific fixture.