What can be attached to a 2 ½" discharge to prevent vacuum loss?

The correct answer is the option involving a garden hose or nozzle, as these attachments can help maintain pressure and prevent vacuum loss. When using a 2 ½" discharge, managing flow and pressure is crucial for effective firefighting operations. If a discharge line is open and incorrect attachments are added, it can create conditions where air enters the system, potentially leading to a vacuum condition which can impede water flow.

Using a garden hose or a nozzle at the end of the discharge maintains a controlled flow, and allows the discharge to work more efficiently without risking an air leak. This allows for better management of water output and pressure retention. In scenarios where you want to keep the system pressurized and avoid vacuum loss, maintaining a smooth flow path with the right attachments is essential, and a nozzle can appropriately manage that flow by restricting and directing it effectively.

Other options, like a larger diameter hose or a pump extension, may change the dynamics of the flow without ensuring that vacuum loss is mitigated. A pressure gauge, while useful for monitoring system pressure, does not actively prevent vacuum loss; it simply indicates the pressure levels within the system.