Basic Firefighter Written Practice Exam

What is the term for the part of total pressure that is lost while forcing water through hoses and appliances?

1. Static pressure

2. Friction loss

3. Dynamic pressure

4. Residual pressure

The correct answer is: Friction loss

The term that refers to the part of total pressure lost while forcing water through hoses and appliances is friction loss. This phenomenon occurs because of the resistance the water encounters as it flows through the internal surfaces of hoses, fittings, nozzles, and other equipment. The flow of water creates friction against these surfaces, leading to a loss of pressure. Understanding friction loss is vital in firefighting operations since it directly impacts the effective pressure available at the nozzle. Firefighters must consider this loss when calculating how much pressure is needed to deliver water effectively to a fire, ensuring that the flow is sufficient to suppress the flames. In contrast, static pressure refers to the pressure present in a system when no water is flowing, dynamic pressure pertains to the pressure of water that is actively flowing, and residual pressure represents the pressure remaining in the system at the outlet after some flow has occurred. These terms, while relevant to understanding water dynamics, do not specifically describe the pressure loss caused by the friction between water and the hose/appliance surfaces like friction loss does.