Eaglestar Underground Fuel Storage Tank – Frequently Asked Questions (FAQ)

1. What is an Underground Storage Tank (UST) system?

An underground storage tank (UST) system is a tank (or a combination of tanks) and connected underground piping that has at least 10 percent of its combined volume underground. The system includes the tank, underground connected piping, underground ancillary equipment, and any containment system. Federal UST regulations apply to systems storing either petroleum or certain hazardous substances.

The Eaglestar Underground Fuel Storage Tank is a premium SF double-wall UST system engineered specifically for service stations and commercial fuel depots, with capacities ranging from 1,000L to 75,000L.

2. What types of tanks are exempt from UST regulations?

Not all underground tanks are regulated. The following types are typically exempt from federal UST regulations:

• Farm and residential tanks of 1,100 gallons or less capacity holding motor fuel for noncommercial purposes

• Tanks storing heating oil used on the premises where stored

• Tanks on or above the floor of underground areas (basements, tunnels)

• Septic tanks and stormwater/wastewater systems

• Flow‑through process tanks

• UST systems of 110 gallons or less capacity

• Emergency spill and overfill tanks

Note: Some state or local agencies may include these exempted tanks in their own regulations—always check with your local authorities.

3. Why are double-wall USTs required? What is an SF tank?

Double-wall construction has become the global standard for new UST installations. The Eaglestar UST features an SF (Steel + FRP) double-wall design:

• Inner tank: High-strength Q235B carbon steel (5/6/8mm thickness)

• Outer tank: Fiberglass Reinforced Plastic (FRP) outer shell – corrosion-resistant, no cathodic protection needed

• Interstitial space: The gap between inner and outer walls allows for continuous leak monitoring

Double-wall tanks provide secondary containment – if the inner wall leaks, the outer wall holds the fuel and directs it to the interstitial monitor, preventing soil and groundwater contamination.

4. How does leak detection work for a double-wall UST?

The Eaglestar UST is equipped with an interstitial leak detector installed in the space between the inner and outer tank walls, enabling 24/7 automatic monitoring.

Key regulatory requirements for interstitial monitoring include:

• The interstitial monitor must be checked at least once every 30 days

• Annual testing of the leak detection equipment is required

• The system must be capable of detecting a release through the inner wall in any portion of the tank that routinely contains product

If any liquid (fuel or water) is detected in the interstitial space, the system triggers an immediate alarm – allowing you to address leaks before they become environmental incidents.

5. What are the installation requirements for a UST?

Installing an underground storage tank requires careful planning and regulatory compliance. Key requirements include:

Installation requirements vary by jurisdiction – always consult your local regulatory agency.

6. How long does an underground fuel storage tank last? What affects its lifespan?

The lifespan of a UST depends on its construction and environmental conditions:

Key factors affecting lifespan:

• Corrosion protection: FRP outer shell eliminates corrosion risk

• Installation quality: Improper installation can damage protective coatings

• Regular maintenance: Annual inspections and leak detection testing extend service life

7. What are the costs associated with owning a UST?

Owning a UST involves several cost categories:

Installation costs – Underground tank installation typically costs 15–25% more than aboveground tanks due to excavation, backfilling, and site restoration requirements. For a typical steel UST in the 1,000–5,000 gallon range, costs can range from $1,300 to $8,000 for the tank alone, with total installed costs often reaching tens of thousands of dollars.

Operational costs – Annual fees, testing, and preventive maintenance are required. Operation and maintenance costs are typically estimated at around 5% of the initial investment per year.

The cost of non-compliance – One real-world example: a single-wall steel tank corroded and leaked, resulting in an environmental cleanup bill of $47,000 – more than three times the cost of the double-wall system that should have been installed from the start.

8. What certifications should a UST have? Is Eaglestar certified?

The Eaglestar Underground Fuel Storage Tank is manufactured by a company with over 22 years of experience in fuel equipment manufacturing, with CE and UL certifications ensuring compliance with international safety and quality standards.

📋 Quick Reference: Eaglestar UST Specifications

For more information on specific capacity requirements, customization options, or regulatory compliance in your region, please contact our team.