Which plumbing fitting prevents siphoning by providing an air break?

The fitting that prevents siphoning by providing an air break is the air gap. An air gap is a physical separation between the end of a pipe and the level of the water it discharges into, such that no water can bridge the gap and create a path for backflow. This design is crucial in plumbing systems, particularly in waste disposal or drainage scenarios, as it effectively eliminates the risk of contaminated water being siphoned back into the potable water supply.

In instances where an air gap is utilized, it creates a clear division between different water sources, significantly enhancing health and safety standards by ensuring that non-potable water cannot negatively impact potable water systems. This mechanism is particularly important in kitchens and laboratories, where cross-contamination of water supplies must be vigilantly avoided.

The other options, while related to plumbing, do not serve the specific function of preventing siphoning through an air break. For example, a trap is designed to hold water and prevent sewer gases from entering the living space but does not prevent siphoning due to its design. A vent valve allows air into the plumbing system to prevent vacuum conditions but does not offer a physical separation like an air gap. Lastly, a check valve allows flow in one direction but does not create an air