Positive Shutoff Overfill Prevention Valves and Drop Tubes
Overfill prevention is currently required by the Federal EPA to eliminate any chance of overfilling the UST. The approved methods for overfill prevention include a positive shut-off valve or a slow-down device (ball float). A positive shut-off valve is installed into the drop tube of the UST. The EPA allows a positive shutoff valve to fill a UST to 95% of its capacity. When the UST is filled close to 95% full, the overfill prevention valve will engage and shut off the fuel delivery. A positive shutoff overfill valve is much easier to install when upgrading an existing UST because a drop tube can be easily accessed without excavation. Overfill prevention valves can be used in non Stage I, Dual Point and Coaxial Stage I systems.
