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

What are the common classes of working pressure in water main pipes?

1. 50/100/150/200

2. 75/100/150/200

3. 100/150/200/250

4. 150/200/250/300

The correct answer is: 100/150/200/250

The common classes of working pressure in water main pipes are established to specify the pressure rating that a pipe can safely handle during operation. The correct choice identifies a range of pressure classes that are relevant and widely accepted in the water distribution industry. Water mains typically require robust materials designed to withstand varying pressures based on the specifics of the system, including the elevation changes and distance the water needs to travel. The classes listed—100, 150, 200, and 250 psi—correspond to standard pressures that accommodate low to moderately high-pressure applications in municipal water service. Class 100 pipes, for instance, are suitable for lower pressure projects, while Class 250 would be indicated for systems that experience higher pressures, ensuring safety and reliability under different operational conditions. Other options provide either lower or higher pressure classes that do not align as closely with the commonly used classifications in the industry. For example, while options A and B mention lower pressure classes that are less common for main pipelines, option D includes a higher range that exceeds typical municipal requirements. Therefore, the range of 100 to 250 psi encapsulates the standard classes most encountering municipal water mains, making it the most accurate choice.