Preventing releases from underground storage tanks is an essential part of owning and operating storage tank units. Federal EPA regulations mandate release prevention practices for tanks, which are categorized into spill protection, overfill protection, correct filling practices, and corrosion. State regulations are used to supplement these practices, but the general rules they follow are the same. In this week’s blog, we’ll cover the four basic release prevention practices for underground storage tanks and how they work.
UST Release Prevention
Spill protection is used to prevent spills that can occur during deliveries to the tank. A spill bucket positioned around the fill pipe catches any liquid that escapes from the fuel hose after it is disconnected. The average hose will hold 14 gallons of liquid, which makes it necessary for the spill bucket to be properly sized so it can contain potentially the entire contents of the hose.
The liquid is removed from spill buckets by means of a pump or drain. Keeping the spill bucket clean is important, especially if the excess liquid is to be drained back into the tank. The accumulation of water and debris in the bucket can result in a mixture that is detrimental to the integrity of the fuel in the tank. Spill buckets can be drained and disposed of in accordance with hazardous waste disposal requirements.
Overfill protection devices are used to prevent the tank from overfilling during delivery. The three devices used to do this are automatic shutoff devices, overfill alarms, and flow restrictors. Small tanks that do not receive more than 25 gallons at a time do not require overfill protection, but most tanks require some form of overfill protection.
Correct Filling Practices
Improper filling during delivery is the case of many releases at underground storage tank sites. In order to prevent this, regulations require two standards to be met: “the volume available in the tank is greater than the volume of the regulated substance to be transferred to the tank before the transfer is made, and the transfer operation is monitored continuously.” Operators of storage tanks and delivery trucks must both be aware of the status of the delivery at all times in order to prevent releases. Though a few gallons from a delivery hose may not seem like much, the cumulative effects can be detrimental to the environment.
Corrosion of components is a common source of releases in storage tanks, which is why federal law mandates the use of noncorrodible materials such as fiberglass in tank construction. Metal components must be protected from corrosion with the use of corrosion-resistant coatings.