Which type of valve helps to ensure water supply lines are protected from back siphonage?

The type of valve that ensures water supply lines are protected from back siphonage is the check valve. Check valves are designed to allow fluid to flow in one direction only, preventing backflow that can occur due to a drop in pressure or a change in direction of flow. This is essential in plumbing systems to maintain the safety and integrity of the water supply, particularly in preventing contamination from back siphonage, where water flows backward and potentially introduces pollutants into clean water lines.

Check valves function by using a disc or flap that opens with forward flow and closes tightly when reverse flow occurs, effectively blocking it. This is particularly important in scenarios where water could be siphoned back into the supply system, such as when a hose is submerged in contaminated water or when a sudden drop in pressure occurs in the system.

Other types of valves mentioned, such as globe valves and ball valves, do not provide the same level of protection against back siphonage, as they do not inherently prevent reverse flow. An air gap, while crucial in preventing back contamination by creating a physical separation between the water supply and potential contaminants, is not a valve but rather a design feature or method used to safeguard drinking water supplies. Thus, the check valve is the specific component designed for