What term refers to the decrease in pressure that occurs due to the physical properties of the hose or pipe?

The term that refers to the decrease in pressure occurring due to the physical properties of the hose or pipe is friction loss. This phenomenon arises as water flows through a hose or pipe, where friction between the moving water and the internal surfaces of the hose or pipe results in a loss of pressure. It is critical to understand that the amount of friction loss can vary depending on factors such as the diameter of the hose, the type of material, the length of the hose, and the flow rate of the water.

Friction loss is particularly important for firefighters and apparatus engineers to consider when planning and implementing fire ground operations. Proper calculations of friction loss help ensure that adequate water pressure is maintained at the nozzle, allowing firefighters to effectively combat fire and other emergencies.

In contrast, terms like hydraulic loss generally encompass various losses including friction and elevation losses, static loss relates to potential energy due to elevation changes without movement, and residual loss typically addresses the pressure remaining in a system after certain losses have occurred or during dispatch. These distinctions clarify why friction loss is the most accurate descriptor for the pressure decrease due specifically to the hose or pipe's properties.