PERMATANK® double‐wall jacketed underground storage tank features an inner steel tank coupled with an exterior corrosion‐resistant fiberglass tank. A unique standoff material separating the inner and outer tanks creates a uniform interstitial space ensuring rapid and accurate leak detection.

PERMATANK ® features:

Meets EPA Leak Detection Requirements for Underground Storage Tanks

  • Meets UL 58, UL 1746 and ULC‐S603.1
  • All tanks proven tight throughout installation, via
    third party certification, by interstitial vacuum test ‐
    13 inches Hg minimum
  • Provides many options to meet EPA leak detection
    requirements for interstitial monitoring, including the
    Permatank Precision Vacuum Monitor
  • Steel provides complete compatibility with all blends of
    ethanol and biodiesel fuels
  • Impermeable to all petroleum products and vapors

Additional features:

  • Steel inner tank provides structural strength, while its
    exterior wall of fiberglass reinforced plastic prevents
  • Designed shorter than an all‐FRP tank of the same
    capacity, reducing the cost of installation and
    increasing site layout flexibility
  • Capacities range up to 60,000 gallons

PERMATANK ® Benefits:

  • Steel construction allows for recycling
  • Various backfill options allow for money‐saving
  • Low cost compartments and customization
  • Built to nationally‐recognized STI standards with
    strict third‐party quality control inspection program

Compatible With a Wide Range of Fuels and Chemicals, Including Biodiesel and Ethanol

PERMATANK® is available from a large network of STI Licensed Manufacturers •

Permatank® Double-Wall Jacketed Underground Steel Storage Tanks

  • Steel Tank Institute Permatank® and UL Labeled
  • Compatible with alternative fuels
  • Low cost compartments and customization
  • Flat ends reduce installation costs
  • Provides safe and effective secondary containment
  • Capacities range up to 60,000 gallons

Permatank® Guideline Specification

A) General

1. Provide Permatank® double‐wall jacketed steel‐fiberglass underground storage tanks.


B) Labeling

1. Tanks shall bear the Steel Tank Institute Permatank® label.

2. Underground tanks shall bear the appropriate Listing label.


C) Product Description

1. Tanks shall be manufactured in accordance with Steel Tank Institute Specification for Permatank®.

2. Tanks shall be manufactured and listed in accordance with Underwriters Laboratories UL 58, Steel
Underground Storage Tanks for Flammable and Combustible Liquids and UL 1746, External Corrosion
Protection Systems for Steel Underground Storage Tanks or ULC‐S603.1, Standard for Corrosion Protection
for Steel Underground Tanks for Flammable and Combustible Liquids.

3. All tanks shall provide testable secondary containment and access for interstitial leak detection monitoring.


D) Manufacturer

1. Manufacturer shall be a licensed member company of the Steel Tank Institute and subject to Steel Tank
Institute’s Quality Assurance program.

Permatank® is available from an extensive group of Steel Tank Institute fabricators who participate in the STI Quality Assurance Program.
Under the program, independent quality control inspectors make unannounced visits to STI members, ensuring fabrication to the highest possible standards