Water Treatment Plant Operator Practice Exam

The fusible metal plug on a chlorine cylinder is specifically designed to open within the temperature range of 157°F to 162°F. This safety feature is crucial for preventing the buildup of pressure within the cylinder due to temperature increases. Chlorine gas, like other compressed gases, can expand significantly when heated, leading to dangerous conditions if not properly managed. When the ambient temperature exceeds the specified range, the fusible metal melts, allowing gas to escape in a controlled manner. This helps to prevent the risk of an explosion or rupture of the cylinder. The chosen temperature range is carefully determined to ensure safe handling and storage of chlorine, which is a toxic and reactive substance. Therefore, the correct answer reflects the specific engineering and safety standards established for chlorine gas safety protocols in water treatment facilities.