Florida Wastewater Practice Test

What device prevents explosions due to excessive pressure in a chlorine tank?

1. Pressure gauge

2. Fusible plug

3. Safety valve

4. Emergency shut-off

The correct answer is: Fusible plug

A fusible plug is a crucial safety device used in chlorine tanks and other pressurized systems to prevent the dangers associated with excessive pressure, such as explosions. It operates by melting at a specific temperature, which is usually set below the threshold where a dangerous rise in pressure could occur. When the fusible plug melts, it creates a venting pathway, allowing chlorine to escape safely and reducing pressure within the tank. This mechanism serves to prevent catastrophic failures that could arise from over-pressurization. In the context of the other options, a pressure gauge is important for monitoring but does not actively intervene to release pressure. A safety valve can also relieve excess pressure by opening at a predetermined set point, but it functions differently compared to a fusible plug, which operates based on temperature rather than just pressure. An emergency shut-off, while crucial in containing a situation, generally serves to stop flow rather than managing pressure levels directly. Thus, the fusible plug is specifically designed to address the risk of excessive pressure in a chlorine tank directly by providing a fail-safe response.