What is the correct GPM and tip pressure for a 2 1/2" smoothbore with a 1 1/8" tip?

For a 2 1/2" smoothbore nozzle with a 1 1/8" tip, the calculation for the flow rate and tip pressure reveals that 260 gallons per minute (GPM) at 50 pounds per square inch (psi) is accurate.

The flow rate of a smoothbore nozzle is primarily determined by the orifice size and the pressure at which water is flowing through it. In general, for a 1 1/8" tip, the standard GPM is derived using the formula that suggests approximately 265 GPM at 50 psi. This aligns closely with the choice indicating 260 GPM at the same pressure.

The importance of the correct pressure should also be noted; 50 psi is a common operating pressure for smoothbore nozzles, allowing for effective water delivery and optimal reach when extinguishing fires. The 1 1/8" tip is designed to maximize flow while maintaining manageability for the user.

In contrast, other choices present different combinations of GPM and pressures which do not align with standard operation guidelines or the physics of fluid dynamics as it relates to nozzle design, leading to suboptimal performance in practical firefighting scenarios.