Double-wall jacketed tank with inner steel tank and corrosion resistant secondary containment

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


  • 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
  • Steel inner tank provides structural strength, while its exterior wall of fiberglass reinforced plastic prevents corrosion
  • 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


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

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

PERMATANK® Publications

STI Tank Technologies

Aboveground Storage Tanks (AST)

Protected, thermally insulated secondary containment tank
Fire-tested, double-wall tank
Double-wall steel tank
Safe and sturdy support for your backup or emergency power
Open-top diked system

Underground Storage Tanks (UST)

Cathodically protected steel tank
Steel/FRP composite tank
Steel tank with an external urethane coating

Double‐wall jacketed underground storage tank

Gravity Oil Water Separators

Featured Affiliate

Commercial Metal Forming

Commercial Metal Forming is the nation’s leading manufacturer of tank heads and tank accessories. Contact us today to find out why we believe we are ahead of the curve.

“STI/SPFA membership has allowed us to promote and sell PERMATANK® in Southeast Asia and Asia Pacific.”

Supara Sinsamudpadung
Padungsilpa Engineering Co., Ltd.

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