What does an overfill alarm indicate to the delivery personnel?

An overfill alarm indicates to the delivery personnel that the tank is 90% full. This alarm serves as a critical safety feature during the process of delivering fuel to underground storage tanks. When the tank reaches this designated capacity, the alarm alerts the delivery personnel to stop the flow of fuel to prevent overfilling, which could lead to spills and environmental hazards.

It's important for operators to be aware of this threshold, as it helps maintain compliance with environmental regulations and promotes safe fueling practices. The significance of the 90% mark stems from the need to provide an adequate buffer for potential expansion of the fuel due to temperature changes and other factors. Recognizing the importance of the overfill alarm is essential in order to execute responsible and safe operations when handling fuel deliveries.