Which hydrant valve allows immediate charging of a supply hose while permitting a second engine connection?

The four-way valve is designed to allow for the immediate charging of a supply hose while also permitting the connection of a second engine. This is achieved through its configuration, which includes multiple ports. With two outlets for engines and at least one inlet for the water supply, the valve can efficiently handle multiple engine connections without disrupting the flow of water.

This capability is crucial in firefighting scenarios when multiple resources are needed simultaneously - such as when additional hose lines need to be deployed or when multiple units need to draw from the same water source without impediment to water flow. In contrast, the other types of valves do not offer the same flexibility for multiple connections, thus making the four-way valve the optimal choice for such operational needs.