When calculating total pressure loss in hose assemblies, what factor must always be considered?

When calculating total pressure loss in hose assemblies, the length of the hose is a crucial factor to consider. Pressure loss occurs due to friction as water flows through the hose, and this frictional loss is directly proportional to the length of the hose. The longer the hose, the greater the surface area that the water interacts with, resulting in increased friction and, consequently, more pressure loss. This relationship emphasizes the importance of accounting for hose length in any calculations related to pressure loss in firefighting operations.

While other factors such as the size of couplings, the number of bends, and the flow rate do influence pressure loss, the length of the hose remains a primary and unchanging variable that must always be included in total pressure loss assessments. Each of these other factors can contribute to additional losses, but without considering the hose length first, accurate predictions of total pressure loss would be incomplete.