The Plasteel® Double Wall Composite Tank
UL 58 and UL 1746 Certified Double Wall Underground Storage Tank
The Plasteel® Double Wall Composite
The Plasteel® Double Wall Composite Tank is a Double Wall Underground Storage Tank designed for safe and reliable underground fuel and chemical storage. In 1983, it became the first composite secondary contained tank to achieve UL Listing, setting the benchmark for durability and compliance in the industry.
This Underground Storage Tank is UL Listed and tested per UL Standard 58 and UL Standard 1746, Part II, Type I and Type II Secondary Containment, ensuring long-term protection in demanding applications.
The inner primary steel tank is assembled, welded, and tested for tightness to deliver the underground structural performance required for storage. Surrounding it, the outer steel secondary containment tank is welded 360° around the primary tank, creating an interstitial space for leak detection and containment. Encapsulating the entire system is an exterior fiberglass reinforced plastic (FRP) laminate, providing a UL-tested corrosion protection system that enhances long-term reliability.
Plasteel® Composite Underground Tank
Proven Peformance
The Plasteel® Double Wall Composite Tank has also been performance tested under the optional UL Standard 58 External Pressure Test (EPT), Paragraph 18. In this test, the empty primary tank withstood submersion under five feet of water without backfill materials and showed no structural deformation—demonstrating its proven strength.
Trusted across industries, these double wall tanks combine steel strength, secondary containment, and fiberglass protection to deliver a storage solution built for safety and performance.
Double Wall Composite Tank Features
This Double Wall Underground Storage Tank is engineered for long-term reliability, combining steel strength with fiberglass corrosion protection. It meets UL standards for underground fuel storage while offering safety, durability, and proven performance.
- 30 Years warranty
- Competitive pricing and lead times
- Certified Elutron®
- Corrosion resistent exterior fiberglass tank and steel primary tank
- Wide range of capacities and compartments
- Underwriters Laboratories listings, UL58, UL1746
- Compatible with all ethanol and bio-diesel fuels along with many other chemicals that can be safely stored with the application of internal linings approved by STI engineers
- There has never been a documented external corrosion failure of any Plasteel® tank.
Plasteel® Composite Underground Tank
Potential Industries & Markets
Aviation
IT / Data Centers
Retail
Medical
Previous Projects
UL1746 / UL58
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