Check valves are used to prevent what in piping systems?

Check valves are specifically designed to allow fluid to flow in one direction only, thereby preventing any backflow or reversal of flow within piping systems. When the fluid moves in the intended direction, the valve opens, allowing passage. However, if there is an attempt for the fluid to flow back, the valve closes, effectively blocking the reverse movement. This function is crucial in various applications, such as maintaining system pressure, ensuring safety, and protecting equipment from damage caused by unintended backflow.

The other options relate to issues that check valves do not directly address. For instance, while check valves can indirectly contribute to managing pressure conditions by preventing backflow, they are not primarily designed to prevent pressure buildup, overflow, or leaks. These functions are typically managed by other types of equipment or valves designed specifically for those purposes.