Specialty Tanks






Flapper Valve

ATG Alarm & Warning Message

13.2.1 Overfill Alarms


UST systems must provide a means of warning the delivery operator or the UST owner/operator when an overfill of a tank occurs.  


Your Responsibility

As the Class B operator you are responsible to train the Class C operators for whom you have responsibility in regard to the overfill alarm method used at the facility where they work.   Consequently, you must identify the overfill alarm method for each facility that you are responsible.


What Are The Approved Overfill Alarm Methods?

There are three overfill alarm methods approved for use:


1.           Equipment that automatically shuts off the flow of product into tank when the tank is no more than 95% full.   An example of this equipment is the flapper valve.

2.           Equipment that restricts the flow of product into the tank or alerts the delivery transfer operator when the tank is no more than 90% full.   An example of this equipment is the ATG “Overfill Alarm”.

3.           Vent restriction devices (commonly referred to as “ball-float” valves) must be set higher than 95% when used in conjunction with a flapper-valve. Flapper-valves may not work properly if flow is restricted by the ball float.