Minnesota Class D Water Operator Certification Practice Exam 2025 – Your All-in-One Guide to Exam Success!

To prevent freezing, the recommended maximum chlorine usage from a 150-pound cylinder is based on the balance between usage and the potential for pressure drop and freezing conditions. When chlorine is released from a cylinder, it expands and cools down, which could lead to freezing if the usage rate is too high.

Using 42 pounds per day strikes a balance by allowing sufficient usage without creating conditions that could lead to freezing. This amount ensures that the system can operate efficiently while maintaining appropriate pressures that prevent the formation of ice inside the cylinder or the delivery system.

This approach is designed to ensure safety and operational efficiency, especially in colder environments where chlorine gas might freeze if used too rapidly. It's important for operators to manage chlorine delivery rates carefully to avoid operational issues, making 42 pounds a practical guideline for daily usage in preventing freezing conditions.