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Trends with Shop-Fabricated Storage Tanks. Wayne Geyer Steel Tank Institute November 18, 2013. Who and What is STI/SPFA?.
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Trends with Shop-Fabricated Storage Tanks Wayne Geyer Steel Tank Institute November 18, 2013
Who and What is STI/SPFA? • Association of 180 fabricating and affiliate companies of steel construction products – shop-fab tanks, field erect tanks, pipe, pressure vessels and other special fabricated products • STI members account for nearly all of the total shop fabricated underground steel storage tank production capacity in North America
2012 Annual Product Awards:Steel Fabricated Products www.steeltank.com
What does the Steel Tank Institute do? • UST and AST tank technologies • Industry standards and recommended practices • License manufacturers to build tanks to STI specifications • Quality control • Information resource • Certification 4 – 50,000 Gallon Permatanks Installed at Northwestern Univeristy
STI Tank Registration • Every tank built with an STI labeled is inspected by tank fabricator to meet STI specification • Tank is “registered” with STI • STI maintains database with over 400,000 entries
Tank Performance Evaluation • All STI labeled UST’s subject to 3rd party warranty • STICO Mutual has strong claims management program • STI gets feedback on quality and performance
STI Certification Programs • 927 Certified SP001 Aboveground Storage Tank Inspectors • 484 Certified Cathodic Protection Testers • Over 130,000 sti-P3 tanks tested for cathodicprotection through WatchDog program • NEW: On Line Learning Program • T*I*M Tank Integrity Management
STI Shop-Fabricated Tank Programs • > 100 tank shops licensed and inspected • 14 tank fabrication standards • 19 recommended practices for testing, installation and inspection • NEW: R111 Storage Tank Maintenance • Under Development: SP131- UST Inspection, Repair, & Modification
Underground Storage Tanks • Primarily used at service stations today • Tanks are getting larger • STI Database • Average capacity in 2013 for jacketed tank exceeds 15,000 gallons • 25 years ago, the typical UST at a service station was 8000 – 10,000 gallons
Compartment Tanks • Compartment tanks have become very common for both UST’s and AST’s • Multiple fuel types can be stored within one tank unit • Provides user/owner versatility as more fuels develop
Underground Storage Tanks • UL 58 is the principle standard for steel tank construction – single wall and double wall steel • UL 1746 is the principle standard for corrosion control and for jacketed (non-metallic outer wall) tank construction
Underground Storage Tanks • Regulations require all tanks incorporate secondary containment • Today, jacketed tanks are favored by many buyers as outer containment provides a corrosion barrier and secondary containment • Other corrosion systems use two walls of steel
Fabricating Steel Secondary Containment • After the primary tank is built and tested, the outer wall is fabricated atop the primary tank. • The second wall is intimately wrapped atop the primary tank wall.
Testing the Interstice • Most fabricators will test the interstice by bleeding air from a 3-5 psi pressurized inner tank into the secondary tank. The volume of the interstice is very small and can get pressurized rapidly. • Access to the interstice can be fabricated in different ways
Production Test to Verify Both Walls are Tight • Upon completion of production testing of the interstice with positive air pressure, and soap testing the welds of the secondary containment, all air is released. • Then a vacuum is pulled within the interstice and monitored by the fabricator for tightness over time.
Preparing the Tank for Delivery • After ancillary equipment installed, coatings applied, etc. the tank is made ready for shipment. • Fabricators apply a vacuum into the interstice of secondary containment tanks.
Interstitial Vacuum • After the vacuum is applied, the tank is held in storage until it is made ready for delivery • The vacuum remains on the tank during storage, delivery, and during much of the installation. • An easy view of the vacuum gauge to verify retention of the vacuum assures that both walls remain tight.
Tank Compatibility - Biofuels • E10, E15, E85, B2, B20, B100 • Steel Tank Manufacturer Certification Statements • STI Web Site • Performance • Tanks are Cleaner – Sludge • Biodiesel Shelf Life • Water Concerns • Phase Separation - Ethanol
Recent EventsBiofuels • Sumps • EPA ORD Research • NIST Research • Publications • “Compatibility of UST Systems with Biofuels,” • Published by ASTSWMO • Case Studies • Research and Work Groups • Underground tanks storing E85
Corrosion of metal components within FRP tanks storing ULSD • Clean Diesel Fuel Alliance supported research from Battelle Labs - completed in 2012 • Further studies under consideration • STI Research • Tanknology hired to visually examine the insides of steel and FRP ULSD tanks • Fuel samples extracted and tested • Example – Las Vegas service station tanks under same owner • FRP tank vapor control fitting – top right photo • Steel tank vapor control fitting – bottom right photo Ultra Low Sulfur Diesel Issues
Inspection and Maintenance STI R111 Storage Tank Maintenance STI SP001 AST Inspection
Cylindrical Rectangular Vertical Horizontal Double Wall Diked Fire-protected Gen-Base FieldErected Aboveground Storage Tanks
Aboveground Storage Tanks • Most popular choice for shop-fabricated tanks for: • Fleet motor vehicle fueling applications • Fuel for emergency power generators • Bulk oil and chemical storage • Secondary containment
Aboveground Storage Tanks • UL 142 is the principle standard for steel tank construction – single wall and double wall steel. • UL 2085 is the principle standard for two hour fire protected tank construction.
Aboveground Storage Tanks • Secondary contained shop-fabricated steel tanks are preferred: • Serves as spill control to meet fire codes • Meets SPCC rules with proper use of overfill prevention equipment • Double wall construction preferred over diking
Protected AST’s • Protected aboveground tanks preferred when: • Installed in close proximity to buildings & property lines • Dispenser mounted on tank • Minimize fire safety hazards • Meet codes for motor vehicle fuel dispensing
SPCC – AST Inspections • EPA references STI SP001 standard for smaller tank inspection and integrity verification • Category 1 preferred • Double wall tanks can be easily tested with vacuum to prove containment integrity Category 3 – Higher Risk to Environment
Release Prevention Barrier (RPB) • Liquid containment barrier • Under the AST • Diverts leaks toward the perimeter of the AST where they can be easily detected
Risk Matrix Concept – SP001 More Risk More Risk
Category 1 – Secondary Containment and CRDM Double-wall Tank Tank in a with Overfill Prevention Concrete Dike
Wayne Geyer WGeyer @ steeltank.com 847-438-8265 www.steeltank.com