To calculate friction loss in 2-1/2" fire hose when the flow is near 100 gpm, which formula should be used?

The formula for calculating friction loss in fire hose is significant for ensuring efficient water flow and pressure management during firefighting operations. The correct formula, represented as FL = CQ^2L, is built on established principles of fluid dynamics, where:

• FL represents friction loss (in psi),

• C is a constant that depends on the diameter and type of the hose (specific to 2-1/2" fire hose),

• Q represents the flow rate (in hundreds of gallons per minute),

• L is the length of the hose (in hundreds of feet).

Using this formula allows operators to accurately determine the expected loss of pressure due to friction in the hose. As the flow rate increases, the friction loss increases exponentially, which is why the squared term (Q^2) is crucial. This relationship helps firefighters adjust their pressure needs based on both the flow rates and lengths of hose used.

The other formulas presented do not reflect the correct relationship or constants needed for calculations specific to 2-1/2" fire hoses at the flow rate indicated, making them less suitable for practical applications in this context. Using the correct formula ensures that operations are conducted safely and effectively under varying conditions encountered during firefighting efforts.