Ken Tesh Water Distribution Operator Exam 1 Practice

The air and vacuum relief valve is specifically designed to prevent a pipe from collapsing when it is drained. When water is rapidly removed from a pressurized system, a vacuum can form in the pipe, potentially leading to its structural failure. The air and vacuum relief valve allows air to enter the system, thereby equalizing the pressure and preventing the negative pressure conditions that cause collapse. This ensures the integrity of the pipeline during draining operations.

In contrast, other options serve different functions. An air release valve is used to allow trapped air to escape from a pipeline, thereby helping maintain efficiency and flow, but it does not specifically address vacuum conditions. A pressure reducing valve (PRV) regulates downstream pressure and is not designed to handle vacuum scenarios. An altitude valve manages water levels in tanks or reservoirs but does not provide the necessary protection against pipe collapse during drainage situations.