During pumping operations, what should the driver/operator maintain on the master intake gauge?

Maintaining a residual pressure of at least 20 psi on the master intake gauge during pumping operations is crucial for ensuring adequate water supply and system performance. This pressure level provides a balance that allows sufficient water to be delivered to the firefighting operation while also preventing cavitation in the pump. Cavitation occurs when the pressure in the pump drops below the vapor pressure of the water, leading to the formation of vapor bubbles which can cause damage to the pump components and decrease effectiveness.

By maintaining a residual pressure of at least 20 psi, the driver/operator ensures that the pump operates within its optimal range, providing enough pressure to support fire suppression efforts while safeguarding the equipment. This standard is backed by operational guidelines and best practices in firefighting that emphasize the importance of maintaining pressure to achieve reliable and effective water delivery to the incident scene.

Higher residual pressure values, while potentially beneficial in some scenarios, may not be necessary for all conditions, and can also risk overwhelming the system or leading to wasteful resource usage. Thus, 20 psi is recognized as a practical minimum under typical operational conditions.