How far off the bottom must an anti-vortex plate be installed at a minimum?

The correct answer is that an anti-vortex plate must be installed a minimum of 6 inches off the bottom. This specific distance is crucial for preventing the formation of vortices in the water supply systems. Vortices can cause issues such as decreased water flow and potential air entrapment, which can lead to equipment damage or operational inefficiencies.

Installing the anti-vortex plate at least 6 inches above the base of the tank or basin helps ensure that it operates effectively. This distance is designed to allow smooth water flow while providing enough depth to mitigate the swirl or funnel effect that could impede water intake. Adhering to this guideline supports the overall performance and safety of the sprinkler system by promoting proper water movement and intake.