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Watco Permatank Outside
BUILT THE WATCO WAY

STI PERMATANK® TRIPLE WALL

A triple-wall underground storage tank incorporating tertiary containment, engineered for environmental protection and structural durability.

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WATCO TANKS

PERMATANK® Triple Wall Features:

Triple-Wall PNG

 

Key Technical Advantages

Design Efficiency

Combines proven ACT-100® and Permatank® technologies to deliver advanced fuel storage while meeting the highest regulatory requirements for environmentally sensitive areas
Durability

Constructed with a primary steel tank, a secondary steel wrap built to UL 58 standards, and a tertiary wall featuring STI’s NextGen Permatank® with a corrosion-resistant coated steel jacket compliant with UL 1746 standards for long-term structural durability
Fuel Compatibility

Steel construction ensures compatibility with all hydrocarbons and can be configured for DEF and JetA/AV Gas applications, supporting a wide range of fuel storage requirements
Installation Considerations

Designed for installation in applications requiring advanced containment and regulatory compliance
Sustainability

Sustainable steel construction enables recycling and supports environmental responsibility, making it suitable for use in environmentally sensitive locations
Built-in-Safety

Independent secondary and tertiary monitoring pipes prevent cross-communication for enhanced safety, while opposing vacuum technology ensures structural integrity across all containment layers
Capacity Range

Available in capacities up to 35,000 gallons, with braced double bulkhead compartments that provide increased versatility for advanced fuel storage applications
Watco Tanks Strength in Layers

Permatank® Triple Wall Steel Tank

Advanced Triple Wall Containment: Tertiary corrosion resistant wall featuring Watco’s Next Generation Permatank jacketed design,
meets UL 58, UL 1746 and ULC‐5603.1

Triple-Wall Layers (2)

Triple Wall Design Specifications

Standard Dimensions and Tank Capacities

Diameter Capacity Length +/- 2" Weight +/- 5%
96" 8,000 gal 21'-9" 16,000 lbs
96" 10,000 gal 27'-2" 18,000 lbs
96" 12,000 gal 32'-7" 21,000 lbs
96" 15,000 gal 40'-8" 25,000 lbs
96" 20,000 gal 54'-5" 36,000 lbs
120" 10,000 gal 17'-4" 18,000 lbs
120" 12,000 gal 20’-10”  20,000 lbs
120" 15,000 gal 26'-0" 23,000 lbs
120" 20,000 gal 34'-8" 29,000 lbs
120" 24,000 gal 41'-8" 338,000 lbs
120" 26,000 gal 45'-2" 40,000 lbs
120" 30,000 gal 52'-1" 45,000 lbs
126" 30,000 gal 46'-9" 44,000 lbs
126" 32,000 gal 49'-11" 46,000 lbs
126" 34,000 gal 53'-0" 49,000 lbs
138" 30,000 gal 39'-0" 43,000 lbs
138" 35,000 gal 45'-6" 49,000 lbs
PERMATANK® Triple Wall

Installation

  • Cost saving backfill material options such as pea gravel, earthen dirt, or clean-washed crushed stone
  • Optional Watco deadman system available to ensure safe loading and unloading of materials
  • Designed shorter than fiberglass tanks of the same capacity, reducing the cost of installation and increasing site layout flexibility
  • Features a durable non-slip OSHA-level grip strength for superior safety
  • Reliable delivery scheduling with coordinated support
  • All tanks are proven tight throughout installation via third-party certification by interstitial vacuum test
Triple Wall 2 (1)

Proven Quality Through Independent Oversight


Each PERMATANK® Triple Wall tank is certified to meet UL 58, UL 1746, and ULC-S603.1 standards for steel underground tanks. This triple-wall design meets the highest regulatory requirements and has been approved by the Edwards Aquifer Authority and TCEQ since 2011. All tanks are backed by STICO Mutual’s 30-year limited warranty.

Watco Tanks undergoes independent third-party inspections by UL and STI, including eight unannounced audits annually. Since the inception of the inspection program over 25 years ago, Watco has maintained a flawless record — one of only three STI-certified manufacturers to do so.
Triple Wall 1 (1)
Slice 3 (76)
Protect The Environment - Buy Recyclable Steel Tanks
Compatible with a wide range of fuels and chemicals, including biodiesel and ethanol

Permatank® Triple Wall Guideline Specification

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

Labeling
  1. Tanks shall bear the Steel Tank Institute Permatank® label.
  2. Underground tanks shall bear the appropriate Listing label.

Manufacturer
  1. Manufacturer shall be a licensed member company of the Steel Tank Institute and subject to Steel Tank Institute’s Quality Assurance program.
Product Description
  1. Tanks shall be manufactured per Steel Tank Institute Specification for Permatank®.
  2. Tanks shall be manufactured and listed following 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.

Trusted Watco Tanks Affiliates

Watco Tank Manufacturing Shot

Top U.S. Producer of STI Technologies

Watco Tanks was recognized as the largest U.S. producer of STI Technologies in 2021 and the second-largest worldwide, with over 5 million gallons built in 2021 and over 6 million gallons each in 2022 and 2023.

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