Storage Tanks: API 653 and Its Basis in API 650

API 653 is a standard published by the American Petroleum Institute (API) that governs the inspection, repair, alteration, and reconstruction of aboveground storage tanks (ASTs) used in the petroleum and chemical industries. This standard is crucial for ensuring the continued safe and reliable operation of tanks throughout their service life. Notably, API 653 is fundamentally based on API 650, which provides the design, materials, and construction standards for new aboveground storage tanks. Understanding the relationship between API 653 and API 650 is essential for appreciating how these standards contribute to the lifecycle management of storage tanks.

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1. Relationship Between API 653 and API 650

API 650, titled "Welded Tanks for Oil Storage," outlines the specifications for the design and construction of new welded steel tanks used to store petroleum and other liquids. It addresses factors such as tank design, materials, welding, and construction techniques. API 653, titled "Tank Inspection, Repair, Alteration, and Reconstruction," builds upon API 650 by focusing on the ongoing management of existing tanks. Essentially, API 653 provides a framework for maintaining the integrity of tanks that were constructed in accordance with API 650.

The key relationship between the two standards lies in the fact that API 653 is designed to ensure that tanks, once constructed per API 650, continue to meet safety and performance criteria over time. This means that API 653 often references API 650 specifications, as that is where the foundation for evaluating and maintaining tanks is derived from.

2. Basis of API 653 on API 650

API 653’s basis on API 650 manifests in several key areas:

- Design Principles: API 653 relies on the design principles outlined in API 650 to assess the condition of tanks. Since API 650 covers the initial design and construction, API 653 uses these parameters as benchmarks when inspecting tanks. For instance, API 653 inspection procedures compare the current condition of the tank to the initial design criteria, such as tank capacity, structural integrity, and materials.

- Material Specifications: API 653 references the material specifications provided in API 650. The original construction of tanks must adhere to the materials and construction methods detailed in API 650. During inspections and repairs, any replacement or repair materials must be compatible with the original specifications from API 650. This consistency helps maintain the tank’s structural integrity and operational reliability.

- Welding and Fabrication: API 650 sets forth standards for welding and fabrication during tank construction. API 653 builds on these standards by specifying how to address welding issues that may arise over time. Inspections include checking welds for signs of deterioration or failure, with repair procedures designed to conform to API 650 welding standards.

- Corrosion and Damage Assessment: API 650 includes guidelines for corrosion allowances and tank maintenance during construction. API 653 uses these guidelines to evaluate the extent of corrosion or damage during inspections. By referencing API 650, it ensures that any detected issues are assessed against the initial design parameters and that appropriate repair methods are employed.

3. Inspection and Maintenance Protocols

API 653 provides detailed protocols for the inspection, repair, alteration, and reconstruction of tanks, with a strong emphasis on maintaining the standards set by API 650.

- Inspection Procedures: API 653 outlines the procedures for inspecting tanks, including methods for evaluating the tank's shell, roof, bottom, and internal components. These procedures are designed to identify deviations from the original API 650 standards. For example, inspections may focus on checking for signs of corrosion or structural damage that could compromise the tank’s integrity, with reference to the original construction requirements.

- Repair and Alteration: When tanks are found to have issues during inspections, API 653 provides guidelines for repairing or altering them. These guidelines are aligned with the design and construction standards of API 650 to ensure that repairs do not compromise the tank’s structural integrity. Repairs must meet or exceed the standards of the original construction to ensure continued compliance and safety.

- Reconstruction: API 653 includes provisions for the reconstruction of tanks that may need extensive repairs or modifications. This aspect ensures that any reconstruction efforts are carried out in accordance with API 650 standards. The goal is to bring the tank back to a condition that is equivalent to or better than its original state, maintaining the safety and reliability of the tank.

4. Compliance and Documentation

Compliance with both API 650 and API 653 is critical for ensuring the ongoing safety and performance of storage tanks. API 653 mandates thorough documentation of inspections, repairs, and alterations, ensuring that all activities are recorded and traceable. This documentation often references API 650 specifications to verify that all actions taken are in line with the original design standards. Compliance with these standards helps prevent potential issues related to safety, performance, and regulatory adherence.

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5. Benefits of Using API 653 Based on API 650

The integration of the two standards offers several benefits:

- Consistency: By using API 650 as a basis, API 653 ensures that the ongoing management of tanks remains consistent with the original design and construction standards. This consistency helps maintain the tank’s integrity and operational performance throughout its lifecycle.

- Enhanced Safety: API 653’s focus on adhering to API 650 standards during inspections and repairs helps ensure that tanks remain safe to operate. Regular inspections and adherence to established standards reduce the risk of accidents and environmental hazards.

- Operational Efficiency: Following the guidelines set forth in API 653 ?helps prevent costly failures and unplanned downtime. Proper maintenance and timely repairs ensure that tanks continue to operate efficiently and effectively.

- Regulatory Compliance: Adhering to API 653 helps ensure compliance with industry regulations and standards. This compliance is crucial for avoiding regulatory penalties and maintaining operational licenses.

Conclusion

API 653 is intricately based on API 650, reflecting a continuity from tank design and construction to ongoing inspection and maintenance. By leveraging the design principles, material specifications, welding standards, and maintenance protocols established in API 650, it ensures that aboveground storage tanks remain safe, reliable, and compliant throughout their operational life. This relationship underscores the importance of a holistic approach to tank management, where initial construction standards are seamlessly integrated with ongoing maintenance practices to achieve long-term operational success and safety.

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Written by: Javier Tirenti

For more information:

API 650 | Design of Aboveground Storage Tanks

API 653 | Inspection & repair of storage tanks