What mathematical formula is used to calculate the reaction of a fog nozzle?

The correct formula for calculating the reaction of a fog nozzle is given as 0.0505 X GPM X √NP. This formula derives from the principles of fluid dynamics and is specifically tailored for calculating the reaction force produced by a fog nozzle during operation.

In this formula, GPM represents the flow rate in gallons per minute through the nozzle, and NP signifies nozzle pressure in pounds per square inch (PSI). The term √NP shows that the reaction force is influenced by the square root of the nozzle pressure, indicating that as the pressure increases, the reaction force does not increase linearly but rather at a diminishing rate.

The constant 0.0505 is a coefficient that adjusts the units so that the calculated reaction force is expressed in pounds, which is a necessary conversion for practical applications in firefighting. This formula allows firefighters to estimate the recoil force of the nozzle, helping them to effectively manage the operational challenges related to nozzle handling, especially in high-pressure situations.

Understanding this formula is crucial for effective fireground operations, as it enables operators to anticipate and prepare for the physical forces they will experience while using fog nozzles under various conditions.