CWEA Maintenance Technologist Practice Test

What is the head loss in psi for a 2000ft section of 10" cast iron pipe with a flow of 650 GPM?

1. 1.50

2. 2.12

3. 3.05

4. 2.75

The correct answer is: 2.12

To determine the head loss in psi for a specific section of a pipe with given flow conditions, the Darcy-Weisbach equation is typically used, along with the appropriate friction factor for the type of pipe and flow characteristics. For this scenario, you'd first need to calculate the velocity of the water flowing through the 10” cast iron pipe. The flow rate of 650 GPM can be converted to cubic feet per second (CFS) for further calculations. The area of the pipe’s cross-section, based on its diameter, can also be calculated, allowing you to find the flow velocity: 1. Convert GPM to CFS: \[\text{Flow rate (CFS)} = \frac{650 \text{ GPM}}{448.831} \approx 1.45 \text{ CFS}\] 2. Calculate the pipe's cross-sectional area: \[\text{Area} = \pi \times \left(\frac{10 \text{ in}}{12}\right)^2\] \[\text{Area} \approx 0.544 \text{ ft}^2\] 3. Calculate the flow velocity: \[\text{Velocity} = \frac{\