What is the formula for calculating Friction Loss (FL)?

The formula for calculating Friction Loss (FL) is derived from the principles of fluid dynamics and is specifically designed for fire service applications. The correct formula, FL = C x (Q/100)² x (L/100), incorporates several key factors that affect friction loss in a fire hose or piping system.

In this formula, 'C' represents a coefficient that varies based on the type and diameter of the hose, while 'Q' stands for the flow rate in gallons per minute (GPM). The term (Q/100)² reflects how friction loss increases with the square of the flow rate; thus, as the flow rate increases, friction loss increases dramatically. Finally, 'L' denotes the length of the hose in feet, and dividing it by 100 standardizes the equation for easier calculations in typical scenarios encountered in firefighting.

Understanding this formula is crucial for firefighters and operators, as it helps them determine the appropriate measures needed to ensure sufficient water pressure is maintained at the nozzle for effective firefighting operations. This is especially important when dealing with long distance hose layouts, where friction loss can significantly impact the effectiveness of the water being delivered.

It's important to recognize that other options either address different aspects of fluid dynamics or are not specifically