Which component is not used in a sprinkler system as part of the fire pump?

The cross main is a crucial part of the water distribution system in a fire sprinkler system, but it does not function directly as part of the fire pump itself. The primary role of the cross main is to connect various sprinkler branch lines and distribute water throughout the system to ensure adequate coverage and pressure across different areas. It serves as the conduit for transporting water but does not engage in pump mechanics or functions.

In contrast, both the jockey pump and the booster pump are integral components of the fire pump system. The jockey pump maintains the pressure in the system by automatically activating when it detects a drop in pressure, primarily due to minor leaks or fluctuations. The booster pump, on the other hand, is designed to enhance the pressure of the water supplied to the sprinkler system, ensuring that sufficient water flow is available during an emergency.

Additionally, the gravity tank plays a critical role in providing a reliable source of water for firefighting activities. It functions by relying on gravitational forces to supply pressurized water to the system.

Thus, the cross main's role is focused on distribution rather than the actual pumping mechanism, distinguishing it from the components that are actively involved in the pumping process of the fire protection system.