A Practical Guide for Owners and Operators
Bunney’s Inc. provides expert API 653 inspection and repair services for aboveground steel storage tanks (ASTs), helping facility managers extend asset life, reduce risks, and maintain compliance. API 653 is the industry-recognized standard for in-service inspection, maintenance, repair, alteration, and reconstruction of welded, riveted, or bolted ASTs operating at or near atmospheric pressure. Applying it correctly ensures tanks remain safe, compliant, and cost-effective throughout their lifecycle.
Serving industrial and utility facilities across Arizona.
What API 653 Covers—and Why It Matters
API 653 complements new-build standards like API 650 by defining how to:
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Evaluate tank condition and trend metal loss
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Determine fitness-for-service and calculate remaining life
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Execute and document compliant repairs, alterations, or reconstruction
Following this standard helps facilities avoid unplanned downtime, minimize environmental risks, and provide defensible records for regulators, auditors, and insurers.
Inspection Types & Frequency
API 653 inspection programs combine routine external inspections, periodic internal inspections, and targeted NDT:
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External inspections: Shells, roofs, coatings, appurtenances, foundations, settlement, and leak paths.
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Internal inspections: Floor evaluation, UT readings, weld assessments, and lining integrity.
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Frequency: Risk-based—driven by product stored, historical corrosion rates, and environmental conditions. Trending UT datasets helps right-size inspection intervals.
NDT Methods in API 653 Programs
Non-destructive testing ensures accurate, defensible results:
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Ultrasonic thickness (UT) mapping of shell, roof, and floor
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Magnetic particle (MT) and liquid penetrant (PT) for welds
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Radiography (RT) for critical welds if required
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Vacuum box or liquid testing for floor seams
Reliable NDT data underpins corrosion-rate calculations and lifecycle planning.
Repairs, Alterations & Reconstruction
API 653 outlines proper methods when degradation is found:
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Plate replacement (floor, roof, or shell)
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Local weld repair and nozzle reinforcements
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Internal linings/coatings to arrest corrosion
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Reconstruction/replacement for severe wall loss
Repairs must follow qualified welding procedures, use traceable materials, and pass NDT and hydro/pressure testing.
Fitness-for-Service & Remaining Life
Certified inspectors calculate remaining life using thickness data, corrosion rates, and operating conditions. Options include:
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Continuing service with monitoring
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Scheduling repairs proactively
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Decommissioning or replacing the tank
Regular UT trending shifts decisions from reactive to proactive lifecycle management.
Safety, Environmental Controls & Documentation
API 653 work must meet strict safety and environmental standards:
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Confined-space entry: gas monitoring, ventilation, PPE, trained staff
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Containment planning during repairs to prevent spills/releases
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Documentation: inspection reports, NDT data, weld maps, WPS/PQRs, MTRs, and test records—ready for regulators and insurers
Why Arizona Facilities Choose Bunney’s Inc.
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Certified inspectors & welders experienced in API 653 work
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Turnkey services: inspections, NDT, repairs, pressure testing, documentation
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Built for Arizona: practical solutions for heat, dust, and remote-site logistics
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Lifecycle value: Programs that extend service life, reduce emergency repairs, and minimize downtime
FAQs
1) How often should I schedule an API 653 internal inspection?
Intervals are risk-based, influenced by stored product, corrosion rates, and prior findings. UT data trends set the correct timing.
2) Can tanks with leaking floors be repaired or must they be replaced?
Many floor issues can be repaired through plate replacement or weld repairs, depending on extent. Replacement is reserved for severe degradation.
3) What documentation will I receive after API 653 work?
Expect full inspection reports, UT maps, repair drawings, MTRs, weld/NDT records, and test certificates.
4) Do repairs always require downtime?
Not always. Some external work can be done in-service, but floor and internal repairs usually require an outage. We help minimize downtime with careful planning.
5) Why hire Bunney’s Inc. instead of a generic contractor?
Our team combines API-certified inspectors, qualified welders, and decades of AST experience—ensuring safe, code-compliant work with defensible documentation.
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