California ICC UST Inspector Practice Exam

Which of the following is not considered a valid overfill prevention method?

1. Spill bucket

2. ATG with audible/visual alarm

3. Ball float valve

4. Flapper valve

The correct answer is: Spill bucket

Overfill prevention methods are crucial components in maintaining the safety of underground storage tank (UST) systems by preventing spills and leaks. Each method plays a specific role in ensuring that a tank does not exceed its capacity during filling operations. A spill bucket is designed to catch any spillage that may occur during the filling process, but it does not prevent overfilling from happening in the first place. Its primary function is to contain spills instead of preventing them, which disqualifies it as a valid overfill prevention method. The key characteristic of effective overfill prevention devices is their ability to notify the operator of an imminent overfill condition, allowing them to take corrective action before an actual overflow occurs. On the other hand, an automatic tank gauge (ATG) with audible and visual alarms actively monitors the tank levels and alerts the operator if the level approaches the tank's capacity, thereby preventing overfilling. Similarly, a ball float valve is designed to automatically shut off the flow of fuel into the tank when the float reaches a certain level, offering a reliable means of preventing overfill. A flapper valve can also help prevent backflow but is generally not a primary method for overfill prevention. In summary, the spill bucket's role is reactive rather