What is one type of commonly used overfill-prevention device?

One type of commonly used overfill-prevention device is a vent-restriction device. These devices are designed to manage the flow of vapor and liquid in a tank system, specifically to prevent overfilling during tank filling operations. They work by restricting the venting of vapors, which provides an indication of the tank's fill level. When a tank is filled, the vapors can’t escape freely, causing a rise in pressure and triggering a shut-off mechanism or alarm, thereby preventing further flow until the situation is safe.

Overfill prevention is critical in underground storage tank operations not only for compliance with regulatory requirements but also for safeguarding the environment from potential spills or leaks that can occur if a tank is overfilled. The combined functionality of vent-restriction devices helps mitigate risks, ensuring that tanks operate within safe limits.

While other devices, such as pressure relief valves, flow meters, and temperature sensors, are essential components in tank management systems, they serve different purposes. Pressure relief valves manage internal pressure, flow meters measure the quantity of liquid, and temperature sensors monitor temperature variations, but they do not directly prevent overfilling during the filling process.