Cross Connection Practice Exam

What effect can undersized water service and distribution piping have when carrying water at high velocities?

1. It increases pressure

2. It causes backsiphonage due to the aspirator effect

3. It promotes faster flow

4. It reduces contamination risk

The correct answer is: It causes backsiphonage due to the aspirator effect

When water service and distribution piping are undersized, carrying water at high velocities can create a situation that leads to backsiphonage due to the aspirator effect. This occurs because the high velocity of water flowing through narrowed pipes can create a significant drop in pressure within the system. If the pressure decreases sufficiently, it can become lower than atmospheric pressure, resulting in a situation where contaminants from the surrounding environment can be drawn back into the system through cross connections. This is a critical concern in plumbing and cross-connection control, as backsiphonage can introduce harmful substances into the potable water supply when the protective measures are not in place. Undersized pipes can also create turbulence and flow disturbances, which can further exacerbate the risks of backsiphonage. Understanding the relationship between pipe size, flow velocity, and pressure is essential for maintaining a safe and reliable water distribution system.