What is the primary function of the shut-off valve in a nozzle?

The primary function of the shut-off valve in a nozzle is to regulate water flow. This valve allows firefighters to start or stop the flow of water as needed, which is crucial for controlling the water supply during fire suppression efforts. By regulating the water flow, firefighters can adapt to different situations, manage pressure effectively, and ensure the right amount of water reaches the fire.

While other functions such as determining pressure levels, connecting to hose fittings, and controlling the spray pattern are important aspects of firefighting equipment, they are not the primary purpose of the shut-off valve. The valve's key role is to enable precise control over the water flow, ensuring that firefighters can operate efficiently and safely when combating fires.