The oil and gas industry heavily relies on tanks for storing and transporting substances such as crude oil, gasoline, and natural gas. Tanks are crucial for safe and efficient operations, but they can become damaged or corroded over time. Tank repair is one of the methods to ensure the tanks are restored to their original condition. In this article, we will discuss tank repair, alteration, reconstruction, and all the relevant information regarding storage tank handling.

What Is Storage Tank Repair? 

Storage tank repair is the process of fixing and restoring storage tanks that have been damaged or have developed faults over time. Over time, storage tanks can experience corrosion, leaks, cracks, or other forms of damage. Such damage can compromise the tank’s structural integrity.

Thus, storage tank repair involves identifying and fixing these issues to restore the tank’s functionality and safety. When a storage tank is found to repair during an inspection, the repair process should be carried out according to the guidelines and requirements outlined in API 653. This ensures the repaired tank remains structurally sound and meets the necessary safety standards for storing petroleum materials.

How To Regulate Repairs, Alterations & Reconstruction of Storage Tanks?

API 653 sets forth detailed requirements and procedures for regulating repairs, alterations, and reconstruction of storage tanks. These measures include:

  1. Conduct a thorough inspection and assessment of the tank’s current condition to identify defects or deficiencies before any repairs or alterations.
  2. Defining the scope of the necessary repairs, alterations, or reconstruction based on the inspection findings, including the materials and procedures required to restore the tank’s structural integrity and functionality.
  3. Providing guidelines for selecting welding procedures and qualifying welders as welding is a common repair method for storage tanks.
  4. Implementing quality control measures to ensure that repairs and alterations adhere to the required standards. Non-destructive testing of welded joints is mandatory to verify their quality.
  5. Documenting and reporting all repair, alteration, or reconstruction work according to API 653 requirements, including inspections, repair procedures, testing results, and any other pertinent information.

What Are Storage Tank Relocation and Re-erection?

Tank relocation under API 653 is regulated by several requirements, including evaluating the new tank location, inspecting and testing the tank, safely removing and transporting the tank, and reinstalling it in the new location by API 653 standards.

Tank relocation requires careful planning, evaluation, and execution to ensure that the tank is safely and effectively relocated while maintaining compliance with industry standards.

The re-erection of the storage tank is not specified under API 653. However, the standard does provide guidance on proper tank dismantling procedures, such as appropriate material and equipment handling, and cleaning and inspecting tank components prior to reassembly.

API 653 mandates that any modifications or repairs to a tank must be examined and authorized by a qualified engineer or inspector and that the tank must undergo testing and inspection before being put back into service. These requirements apply to all repair or alteration activities, including the re-erection of a tank.

How Are Storage Tanks Repaired According to API 653?

API 653 inspection for petroleum and petrochemical tank inspection
External Inspection of Aboveground Storage Tanks (Credit: Freepik)

1. Replacement of Tank Bottom, Hot Tapping on Tank Shell.

Under API 653, the instructions on how to replace tank bottoms and perform hot tapping on tank shells are discussed. Tank bottom replacement is a significant repair that requires the removal of the existing bottom and the installation of a new one.

Hot tapping on tank shells is a repair method that involves drilling a hole into the tank wall while it is still in use to enable the installation of new equipment or access to the tank contents. API 653 provides information on the necessary equipment and materials for hot tapping, as well as the safety measures and procedures that must be followed to avoid accidents or incidents.

It is essential to note that any tank repairs or modifications must be examined and authorized by a qualified storage tank inspector in compliance with API 653. The tank must also undergo testing and inspection before it is put back into service to ensure that it meets the standard’s requirements and is safe to use.

2. Material Corrosion and Degradation (API 571)

API 571 is a recommended practice for evaluating damage mechanisms. Though API 571 is a whole different standard compared to API 653, it plays an important role in ensuring the safety and reliability of storage tanks and equipment in the oil and gas industry.

Material corrosion and degradation is a major damage mechanism covered by API 571. Material corrosion is the gradual deterioration of a material due to its interaction with the environment, while degradation refers to any other form of damage that occurs in materials. API 571 provides guidance on how to identify and evaluate the different types of material corrosion and degradation using various inspection techniques.

API 653 Tank Inspection, Repair, Alteration, and Reconstruction - Oil and Gas Training by PetroSync

3. NDT of Tank Repairs

The procedure of NDT (Non-Destructive Testing) for repairing tanks is employed to assess the soundness of a storage tank while avoiding any damage to the tank. It encompasses several methods like ultrasonic testing, radiographic testing, magnetic particle testing, and visual inspection.

By using these techniques, any faults or imperfections in the tank’s construction or welding can be identified, allowing for necessary repairs to be performed before a disastrous breakdown transpires.

4. Leak Testing

API 653 regulates the practice of leak testing to pinpoint and trace any seepages in above-ground storage tanks that have undergone repairs, alterations, or reconstructions. The standard lays down instructions on how to perform leak tests using diverse methods like the vacuum box technique, bubble leak testing, and hydrostatic testing. The tests hold significance in assuring that the tank is airtight and will not discharge harmful substances into the surroundings.

What Are API Recommended Steps for Storage Tank Repair or Reconstruction?

As mentioned in Section 7 of API 653, there are some recommended steps for doing the storage tank’s repair, alteration, and reconstruction. This section establishes clear requirements and guidelines for carrying out these activities. The key provisions outlined in Section 7 include:

1. Repair and Alteration Plan

Before starting any repair or alteration activities, it is crucial to create a thorough plan that specifies the work scope, procedures, materials, and any required calculations or analyses. This plan must undergo a review and approval process by a qualified engineer to ensure its accuracy and suitability for the task at hand.

2. Evaluation of Existing Conditions

Assess the current state of the tank, including its shell, roof, bottom, and foundation, to evaluate its condition. Consider factors such as corrosion, deterioration, settlement, and structural integrity to determine the necessary repairs or alterations needed and their extent.

3. Design Considerations

Ensure that any repairs or alterations adhere to the relevant codes, standards, and regulations in place. Take into account aspects such as the tank’s design, materials used, structural capacity, corrosion allowance, and compatibility with the materials stored within the tank.

4. Welding and NDT Requirements

Adhere to the specified guidelines for welding and non-destructive testing (NDT) when conducting repairs or alterations. This entails ensuring that welders possess the necessary qualifications and follow approved welding procedures. Additionally, employ suitable NDT techniques to evaluate the quality and integrity of welded joints.

5. Repair Methods

Choose suitable repair methods that align with the type and severity of the damage or deterioration observed. These methods may encompass options like patching, welding, plating, or other established repair techniques, in accordance with established industry practices and procedures.

6. Material Selection

Use suitable materials for repairs or alterations, considering factors such as compatibility, corrosion resistance, and mechanical properties. API 653 provides guidance on material selection, including specifications for steel plates, welding consumables, and coatings.

7. Quality Control and Inspection

Utilize appropriate materials for repairs or alterations, taking into account factors such as compatibility, corrosion resistance, and mechanical properties. The material selection should align with the guidelines provided by API 653, which include specifications for steel plates, welding consumables, and coatings.

8. Post-Repair Activities

After completing repairs or alterations, conduct appropriate tests and inspections to ensure the tank’s integrity. This may involve hydrostatic testing, NDT examinations, and other verification procedures.

9. Documentation

Keep comprehensive records of all repair and alteration activities, including plans, procedures, inspection reports, non-destructive testing (NDT) results, material certificates, and any other pertinent documentation. It is important to retain these records for future reference and to demonstrate compliance with the requirements outlined in API 653.

It’s important to refer to the specific provisions in Section 7 of API 653 for comprehensive guidance on repair, alteration, and reconstruction activities for storage tanks. Adhering to these requirements helps ensure the safety, integrity, and compliance of the tanks throughout their service life.

Storage tank repair needs specialized expertise and equipment. Additionally, repairs may require compliance with industry standards and regulations, which can add to the complexity of the repair process. If you want to master tank inspection, repair, alteration, and rerating, then taking the API 653 – Tank Inspection, Repair, Alteration, and Reconstruction training course should be your next step.

PetroSync’s specialized training is designed to equip you with the necessary knowledge and skills to perform storage tank inspections in compliance with industry standards and regulations. We offer in-depth materials where in-depth course materials, study guides, and practice exams that cover all aspects of the API 653 exam to help you prepare better for storage tank inspection.

We craft our 5-day training program with detailed discussions on engineering knowledge for in-service storage tanks with emphasis on API’s syllabus. The program covers six areas and includes practical case studies. Join PetroSync’s API 653 training and build your confidence in making informed decisions regarding storage tank inspection and maintenance with us. Reserve your spot now!

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