What is the flow rate (GPM) and nozzle pressure (NP) for a 1 1/8" hand line tip?

For a 1 1/8 inch hand line tip, the correct flow rate and nozzle pressure combination is 266 GPM at 50 psi. This value is derived from the common formula used in fire service hydraulics that correlates nozzle size, flow rate, and nozzle pressure. Specifically, the flow from a smoothbore nozzle can be estimated using the formula:

Flow (GPM) = 29.7 × (D^2) × √NP

Where D is the diameter of the nozzle in inches and NP is the nozzle pressure in psi. Plugging in 1.125 inches (for 1 1/8 inch) and 50 psi into this formula gives approximately 266 GPM.

This combination is significant in fire operations because it balances effective fire suppression capabilities while ensuring that the firefighters can safely operate the line without excessive pressure, which can increase the risk of loss of control or injury. Understanding these figures helps in maintaining adequate firefighting tactics and achieving successful outcomes during fire suppression activities.