How many common classes of working pressure in water mains are recognized?

The correct answer indicates that there are four recognized common classes of working pressure in water mains. Understanding these classes is essential for ensuring the safe and effective operation of water distribution systems. Each class corresponds to a specific range of working pressures that water mains must be designed to withstand to safely transport potable water.

Water mains are typically classified based on their pressure rating, which affects the materials used, the design of the system, and the necessary maintenance protocols. The classification helps in determining how much pressure the pipes should handle during normal operation and under peak flow conditions.

By recognizing four distinct classes of working pressure, operators are better equipped to make informed decisions about the design, installation, and maintenance of water mains, thereby improving the reliability and longevity of the water supply system. This classification system ultimately contributes to public health and safety by reducing the risk of pipeline failures that could lead to contamination or service interruptions.