STI P3® Underground Steel Tanks

An STI P3® Tank is a double‐wall underground storage tank that features a pre‐engineered corrosion protection system, providing ongoing monitoring for corrosion protection. The STI P3® system has provided reliable, long‐term performance for over a quarter million steel underground storage tanks. 30-year warranty.

Compatible with a wide range of fuels and chemicals, including biodiesel and ethanol.

UL 58 Underground Steel Tanks

Greer fabricates steel UL 58 underground tanks for the storage of flammable and combustible liquids. These are single wall tanks that come with a 1-year warranty.

Product Details

STI P3® Features & Benefits

Standard Features:
  • Meets UL-58, UL 1746-Part1 and ULC-S603.1.
  • The only UST design which allows for on-going monitoring of corrosion protection.
  • 10-year warranty plus 20-year extension available for internal and external corrosion
  • All models are alternative fuel compatible.
  • Steel striker plates below each tank opening to protect tank bottom
  • Openings are female NPT
  • Sacrificial lower Anodes
  • 2” – 4” threaded flanges with isolation kits.
  • Available only from STI ® Members.
Optional Features:
  • Can be customized for multi-product storage compartments with unlimited capacities.
  • Fittings placed as required.
  • Manholes can be installed.
  • Interior coatings
  • Can be designed as single or double-wall steel construction.
  • Bolt flanges are optional.
  • Steel construction allows for recycling
  • Low-cost compartments and customization
  • Built to nationally‐recognized STI standards with strict third‐party quality control inspection program

UL 58 Features & Benefits

Key Benefits:
  • Steel UL 58 underground tanks for flammable and combustible liquids.
  • Exterior paint is Jotun Black Mastic Epoxy
  • Interior is unpainted
  • Openings are female NPT
Optional Features:
  • Tie-downs
  • Custom Coatings (interior & exterior)
STI P3® Underground Tanks:
UL 58 Underground Tanks:

*LP – indicates “Low Profile”

STI P3® Guideline Specification

A. General:
  1. Provide STI P3® external corrosion and cathodically protected steel underground storage tanks.
B. Labeling:
  1. Tanks shall bear the Steel Tank Institute sti‐P3® identification label.
  2. Underground tanks shall bear the appropriate Listing label.
C. Product Description:
  1. Tanks shall be manufactured in accordance with Steel Tank Institute sti‐P3® Specification and Manual for External Corrosion Protection of Underground Steel Storage Tanks.
  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. Double‐wall tanks shall provide testable secondary containment on site and access for interstitial leak detection monitoring.
  4. Tanks shall be provided with the ability to monitor the corrosion protection system.
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.

STI P3® Underground Tanks

STI/SPFA – P3® Product Sheet

~ PDF (125KB)