Which of the following is NOT one of the four laws governing how friction loss behaves?

Friction loss in a fire hose is a critical concept for understanding how pressure changes as water flows through a hose. The laws that govern friction loss are well established in firefighting and hydraulics.

The correct answer highlights that friction loss does not vary in direct proportion to the diameter of the hose. In fact, the relationship between hose diameter and friction loss is not direct; rather, when hose diameter increases, friction loss actually decreases. This is because a larger diameter allows water to flow more freely, reducing the resistance caused by the hose.

In contrast, as the length of the hose increases, friction loss will increase due to the greater surface area in contact with the flowing water, which creates more resistance. Additionally, friction loss is influenced by the flow rate; as the flow rate increases, the velocity of water increases, which in turn increases the friction loss due to turbulence. Lastly, while the material of the hose can affect operational performance and durability, the fundamental behavior of friction loss does not remain constant: it may vary based on the material used but primarily depends on the internal diameter and the length of the hose, as well as the flow rate of the water.

Therefore, the assertion that friction loss varies in direct proportion to the diameter of the hose