Model ATSTIP3 Specification

Provide and install _____ Anchorage Tank & Welding, Inc. Model STI-P3^® pre-engineered double wall cathodically protected steel Underground Storage tank(s). Tank(s) shall be _____ in diameter, long, having a total volume of ____gallons.

Design Criteria

The underground storage tank shall be fabricated in accordance with the STI-P3^® standard. The unit shall have the STl-P3^® corrosion control system and carry the STI-P3^® label.

Steel shell fabrication

Surface preparation, coating application, and the installation of galvanic anodes all take place at the manufacturer's plant. Anchorage Tank & Welding, Inc. is in good standing with, and licensed by, Steel Tank Institute.

Submittals

Provide shop drawings for the underground storage tank that show principal dimensions, materials, and location of fittings.

General Characteristics

An STI-P3^® tank has characteristics unique to the pre-engineered design for protection against corrosion:

Dielectric Coating

 Every STI-P3^® underground storage tank is protected with one of three generic types of coating that have been tested and approved by STI: coal tar epoxy, urethane, or isophthalic polyester resin. This first line of defense against corrosion completely covers the exterior surface of the tank. A coating is applied to a blast-cleaned, prepared surface.

Cathodic Protection

Sacrificial galvanic anodes made of either high-purity zinc or magnesium prevent corrosion of any exposed metallic surfaces, such as nicks or scratches in the coating that may occur during transportation or installation of the tank. Welded to the tank, these anodes control the direction of electrical current flow and will deteriorate in place of the steel.

Electrical Isolation: All tank openings are to be electrically isolated by the use of dielectric nylon bushings or flange isolators that will be compatible with stored product. This isolation, which

defines the area to be protected by anodes, is intact when shipped from Anchorage Tank & Welding, Inc. ALL STI-P3^® tanks must be electrically isolated from all metallic underground structures that will be exposed to back fill

Secondary Containment Tank Characteristics

The STI standard details double wall tank construction, which includes built-in Interstitial leak detection monitoring capability STI-P3^® double wall underground tanks can be constructed with Type I or Type II designs as defined by Underwriters Laboratories. Since the vast majority of USTs are Type I, this document addresses Type I double wall design only.

Primary Inner Tank

The primary inner tank shall be built with a minimum steel thickness of 10 gauge in strict accordance with UL^® 58. Steel striker plates at least ¼" thick shall be installed on the interior bottom below each tank opening.

Secondary Outer Tank

Construction of the steel outer wrap is separate from the inner wall, but intimate contact or face-to-face lay up will occur This intimate contact allows flow of liquid through the interstice to designated monitoring points, if an internal leak were to occur.

Interstitial Leak Detection Monitoring

STI-P3^® double wall tanks come with built-in interstitial leak monitoring capability. Interstitial monitoring options may be discussed with Anchorage Tank & Welding, Inc.

Installation

Illustrated installation instructions for STI-P3^® underground storage tanks (Document No. R821-93) are shipped with each tank It is important to assure that installers have the necessary knowledge, skills, and equipment to enable proper and safe underground storage tank installation. What follows is a summary highlighting key aspects of the installation process.

Excavating and Bedding

Bedding and back fill material shall be clean, homogeneous, granular material made of either sand, pea gravel, or No.8 crushed stone. The bottom of the excavation shall

extend a distance of 12 inches minimum clearance around the perimeter of the tank and between tanks. Initial Air Test: Before placing a double wall tank in service, an air pressure test must occur on both the inner tank and the secondary containment. Refer to R821-93 for complete procedural details

Tank Handling

To prevent damage to the tank, equipment to handle the vessel shall be of adequate size to lift and lower the tank without dragging or dropping.

Tank Storage

If the tank must be temporarily stored prior to installation, it should be placed in an area away from activity where tank damage could occur.

Anchoring Tank

Buoyancy restraint may be obtained by using properly designed hold-down straps in conjunction with concrete hold-down pads or dead man anchors. Straps must be isolated from the tank using SA rubber pads. The use of steel cable and round bar to hold down the tank is prohibited.

Final Back fill

Homogeneous back fill shall be deposited carefully around the tank up to the top of the tank and to a depth of at least one foot over the tank to avoid damage to the coating. Refer to National Fire Protection Association Code 30 [NFPA 30], Uniform Fire Code [UFC], and state and municipal codes for minimum depth of cover prior to allowing vehicular traffic over tanks.

Warranty

For installations in Alaska, STI-P3^® underground storage tanks are backed by a 10-year limited warranty against tank failure caused by cracking, breakup or collapse; corrosion caused by reaction of the tank with its soil environment; and internal corrosion for those tanks equipped with wear plates and used to store heating or motor fuels, including alcohol, and other compatible chemicals. In addition, Anchorage Tank & Welding, Inc. warrants the tank against failure due to defective materials and workmanship for one year following the delivery of the tank. Each STI-P3^® tank and its serial number is registered with STI. A copy of the complete STI-P3^® warranty is delivered with each tank.