What is the formula for calculating the nozzle reaction of a solid-stream nozzle?

The formula for calculating the nozzle reaction of a solid-stream nozzle is NR = 1.57 x d² x NP. This equation reflects the factors that contribute to the reaction force generated by a nozzle when water is expelled at a specific pressure.

In this formula, "NR" stands for nozzle reaction, "d" represents the diameter of the nozzle in inches, and "NP" refers to the nozzle pressure in pounds per square inch (psi). The coefficient of 1.57 is derived from fluid dynamics principles and is specific to solid-stream nozzles, where the flow and pressure characteristics dictate this resultant force.

Understanding this formula is crucial for fire apparatus operators as it allows them to anticipate the reaction force exerted by the nozzle, which in turn helps in maintaining control of the hose during firefighting operations. Proper management of nozzle reaction enhances operational safety and effectiveness in delivering water streams.