Texas Commission on Environmental Quality (TCEQ). Class C Water License Exam

What is the primary purpose of a thrust block in a water distribution system?

1. To increase water pressure

2. Prevent movement at pipe joints

3. Enhance water flow

4. Control water temperature

The correct answer is: Prevent movement at pipe joints

The primary purpose of a thrust block in a water distribution system is to prevent movement at pipe joints. Thrust blocks are specifically designed to transmit the forces exerted on the pipeline due to changes in flow direction or pressure fluctuations. When water moves through a pipe, especially when it changes direction at a fitting or bend, the pressure can create significant thrust forces that, if unrestrained, could cause pipe joints to displace or even fail. By effectively anchoring the pipe and distributing these forces to the surrounding soil or concrete, thrust blocks ensure that the pipe remains securely in place, thereby maintaining the integrity of the entire water distribution system. This stability helps to prevent leaks at the joints and reduces the risk of mechanical failure, ensuring reliable service and reducing maintenance costs. Other options like increasing water pressure, enhancing water flow, or controlling water temperature do not align with the specific mechanical role that thrust blocks play in the system.