California ICC UST Inspector Practice Exam

Which device is NOT an approved overfill protection device for a UST system?

1. Alert the transfer operator when the tank is 90% full

2. Restrict delivery of flow to the tank at least 30 minutes before overfill

3. Provide positive shut-off of flow to the tank when 95% full

4. Has a ball float that restricts flow when the tank is 95% full

The correct answer is: Alert the transfer operator when the tank is 90% full

The correct answer indicates that the option suggesting to alert the transfer operator when the tank is 90% full is not an approved overfill protection device for a UST system. In UST systems, overfill protection devices are designed to ensure the safe management of fuel levels and prevent overfilling, which can lead to spills and environmental hazards. Effective overfill prevention measures typically involve physical mechanisms that intervene automatically at critical fill levels. The other choices highlight functions that actively engage to prevent overfilling just before it happens. For instance, restricting the delivery of flow at least 30 minutes before an overfill occurs is a proactive measure that automatically prevents excessive filling. Similarly, providing positive shut-off of flow when the tank reaches 95% full represents a fail-safe mechanism that directly stops the inflow of liquid, thereby averting overfilling. The option mentioning the ball float that restricts flow at 95% full describes a mechanical method of preventing overflow, which is a key characteristic of effective overfill protection. In contrast, simply alerting the operator at 90% full does not provide any immediate action or physical intervention to stop the flow of liquid, making it insufficient as an approved overfill protection mechanism. Therefore, it does not meet