Which formula can be used to estimate the flow of water in gallons-per-minute in a smooth/solid bore nozzle?

The correct formula to estimate the flow of water in gallons-per-minute for a smooth/solid bore nozzle is found in option B, which is expressed as 29.7d² x NP. In this formula, "d" is the diameter of the nozzle in inches, and "NP" is the nozzle pressure in psi (pounds per square inch).

This formula works because it accounts for both the nozzle's diameter and the pressure at which water is being discharged. The constant 29.7 converts the calculated flow from cubic feet per second to gallons per minute, which is essential for fire service operations since flow rates are typically expressed in GPM for firefighting purposes.

Understanding this relationship is crucial for fire apparatus operators as it allows them to determine the appropriate flow rate needed for various fire suppression tactics, ensuring they can effectively manage water supplies during operations. Other formulas do not specifically relate to nozzles or might not provide clear conversions suitable for the context of firefighting operations.