What happens to friction loss if the hose diameter is decreased?

When the diameter of a hose is decreased, friction loss increases due to the principles of fluid dynamics. This phenomenon occurs because a smaller diameter hose restricts the flow of water, leading to a higher velocity as the same amount of water is forced through a narrower opening. According to the Hazen-Williams equation, which is commonly used to calculate friction loss in pipes and hoses, friction loss is directly related to the velocity of the water. As flow velocity increases, there is an increase in the surface area of contact between the water and the hose, resulting in greater friction loss.

Additionally, the narrower diameter creates a greater amount of turbulence within the flow, which further contributes to increased friction loss. This principle is very important for firefighters, as understanding friction loss is crucial for effective flow management and for ensuring that adequate water pressure is maintained during firefighting operations.