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Above Ground Storage Tanks & Tank Base Sealing. Tank Base Sealing Types of Tank. Fixed Roof Tanks. - Least Expensive to construct For storing “Low Vapour Pressure” Products ( below 2 psi. ). Tank Base Sealing Types of Tank. Fixed Roof Tanks Least Expensive to construct
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Above Ground Storage Tanks & Tank Base Sealing
Tank Base Sealing Types of Tank Fixed Roof Tanks • - Least Expensive to construct • For storing “Low Vapour Pressure” • Products ( below 2 psi. )
Tank Base Sealing Types of Tank • Fixed Roof Tanks • Least Expensive to construct • For storing “Low Vapour Pressure” • Products ( below 2 psi. ) Floating Roof Tanks • - To prevent evaporation loss • More expensive to build and maintain
Tank Base Sealing Types of Tank • Fixed Roof Tanks • Least Expensive to construct • For storing “Low Vapour Pressure” • Products ( below 2 psi. ) • Floating Roof Tanks • To prevent evaporation loss • More expensive to build and maintain Silos • - Ash (Fly ash) • - Used for Storing “dry” products • Variety of construction materials
Tank Base SealingTank Base Construction Large Tanks 1. Trench preparation for perimeter wall 2. Reinforced concrete containment wall 1 3. First sections of tank wall positioned Large Storage Tanks – Typical Construction 3 2 2 3
4 6 5 Tank Base SealingTank Base Construction Large Tanks 4. Liner installed when required 5. Sand – bitumen foundation laid 6. Tank base installed
Tank Base SealingTank Base Construction Large Tanks 7. Walls constructed 8. Roof welded in place 7 9. Tank completion 9 8 9 8
Tank Base SealingTank Base Construction Small Tanks 1. Foundations prepared 2. Base and plinths constructed 1 3. Tanks installed 3 2
Tank Base SealingProblem Areas – Tank Base • Corrosion of tank wall and chine angle • Determination seal • Corrosion of tank base
Tank Base SealingProblem Areas – Tank Base Conventional methods to seal tank base
Tank Base SealingProblem Areas – Tank Base • Mastics • Asphalt & Bitumen
Tank Base SealingProblem Areas – Tank Base • Bonded Rubber
Tank Base SealingProblem Areas – Tank Base • Steel Skirts
Chine Angle Tank Base SealingProblem Areas – Tank Base Corrosion at the Chine Angle • Failure of Bitumen Seal - Corrosion of wall / base / metal thinning • - Contents to be emptied • Tank requires to be gas free – man entry • Sludge needs to be removed / disposed of - Tank needs to be lifted up
Tank Base SealingProblem Areas – Tank Base • Corrosion at the Chine Angle • Tank needs to be cut open for plate entry • New base needs to be built • Base welded into position • Hydro Test needs to be conducted • Approx. Costs ( 90 foot tank ) • $40,000 for cutting and entry / base removal • $8,000 for sand-bit floor screed replacement • $10,000 for flexible liner • $40,000 for new bottom plates • $100,000 for inspection and Hydro Test • -------------- • $198,000 • Plus : • Tank cleaning / waste disposal costs • Tank out of service for 3 months
Tank Base Sealing Storage Tank Base Associated Problems No grout or sealing measures Failed grout
Tank Base Sealing Storage Tank Base Associated Problems Failed grout Cracked Concrete Base
Tank Base Sealing Conventional wisdom states: Replace failed system with more of the same sealants Replace failed system with similar sealants Switch sealing system to other conventional sealing methods
Tank Base Sealing unconventional PROVEN ^ LONG TERM, COST EFFECTIVE SOLUTIONS ARE AVAILABLE
Tank Base Sealing Membrane systems for long term sealing of chine angle Epoxy grouts for concrete ring repair and grout sealing Urethane coatings for tank exterior
Tank Base SealingKey Features and Benefits • Weatherproof & Waterproof - Prevents ingress of water and provides long term corrosion protection • Seamless Encapsulant – Seals around irregular contours and is easily repaired if accidentally damaged
Tank Base SealingKey Features and Benefits • Maintains High Adhesion – Ensuring long service life • Fire Resistant Systems Available • Flexible & UV Resistant – Long lasting and tolerant of movement through climatic variations unlike conventional sealants
Tank Base SealingKey Features and Benefits • Durable & Tough – Long lasting and tolerant of industrial environments • Microporous – Allows trapped moisture to escape • Cold Applied – No hot work required ensuring safety in use where fire is a concern
Tank Inspection Requirements API 653 ( American Petroleum Institute ) BS 2654 ( British Standard ) EEMUA 159 ( Engineering an Equipment Materials Users Association ) PA DEP 245 (Department of Environmental Protection) Requirement for all Tank users to Inspect and ensure integrity of their Structures Frequency : 1 Year visual / 5 Year integral
Storage Tank Containment Issues Before repair/coating After repair/coating
Tank Base Sealing Maintain environmental compliance Maintain asset integrity Minimize headaches with preventative maintenance
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