Ontario Operator-in-Training (OIT) Practice Exam

What causes head loss in a piping system?

1. Water moving too slowly

2. Pressure increase in the system

3. Friction from the pipe walls

4. Excessive water temperature

The correct answer is: Friction from the pipe walls

Head loss in a piping system primarily results from friction between the fluid and the pipe walls as the fluid flows through the system. This friction occurs due to the interaction of the fluid particles with the surfaces of the pipe, which creates resistance to flow. The higher the velocity of the fluid and the roughness of the pipe's interior surface, the greater the frictional resistance, leading to increased head loss. Frictional head loss can be calculated using various formulas, like the Darcy-Weisbach equation, which considers factors such as the flow rate, the pipe's diameter, and the length of the pipe. Understanding this concept is crucial for engineers and operators as it impacts the design, efficiency, and operation of piping systems in various applications, including water treatment, distribution, and industrial processes. In contrast, options referring to water moving too slowly or excessive water temperature do not directly cause head loss in the same manner. A pressure increase typically indicates a more efficient flow or less resistance, which does not contribute to head loss. Therefore, friction from the pipe walls is the fundamental factor contributing to head loss in a piping system.