Overview of API 653 and API 570
API 653: Aboveground Storage Tanks
API 653 is a standard by the American Petroleum Institute that outlines how Aboveground Petroleum Storage Tanks should be inspected, repaired, altered or reconstructed when used to store petroleum products, chemicals, and other liquids. API 653 is critical in ensuring that the tanks are safe and last longer with compliance to the industry code of regulation all the time.
Key focus areas of API 653 include:
- Inspection intervals and procedures for ASTs
- Evaluation of tank integrity and corrosion
- Repairs, alterations, and reconstruction of ASTs
- Ensuring compliance with API 650 (tank construction standard)
API 653 is generally used on tanks constructed to API 650 but it is relevant on tanks developed prior to the issuance of API 650. It applies the tanks that are welded or riveted, and aims at safety, protection of the environment and productivity of the process.
API 570: In-Service Piping Inspection
API 570 is the standard for the inspection, rating, repair and alteration of in-service piping systems used in process industries. Operating stresses in piping systems in oil refineries, chemical plants and gas processing facilities such as high operating temperatures, system working pressures and corrosive service environment cause deterioration with a passage of time.
Key focus areas of API 570 include:
- Inspection procedures for piping systems
- Assessment of corrosion and erosion damage
- Repair and maintenance of in-service piping systems
- Ensuring compliance with construction standards like ASME B31.3 and B31.4
API 570 is particularly for piping which transport fluids, gases and hydrocarbons to and from equipment and it gives help to the inspectors in identifying and managing probable failure facets that may harm the piping system.
Scope of API 653 and API 570
Scope of API 653
API 653 focuses on the inspection and testing of AST which are storage tanks that are utilized above the ground level. These tanks are normally employed to retain vast quantities of fluids such as petroleum, chemical and water. API 653 is not exclusive to new tanks, it also encompasses new tanks but mainly deals with procedures of evaluating the structural soundness, corrosion protection and fitness for continued use of existing tanks.
API 653 covers:
- External and internal inspections of the tank shell, bottom, and roof
- Tank foundation inspections
- Thickness testing to assess corrosion rates
- Recommendations for repairing or replacing damaged components
- Tank settlement evaluations
The standard is for tanks fabricated with different materials such as carbon steel, stainless steel and aluminum materials. API 653 also has special requirements for welding repairs, alterations and tank re-construction.
Scope of API 570
API 570 is centered on inspection and maintenance of in-service piping systems, which transport some fluid, gas, or hydrocarbon, in refineries, chemical plants and other process facilities. Some of these piping systems are components that assume vital roles in the performance of industrial tasks and while undergoing these tasks, problems can occur in the form of safety concerns, leakage or spills which may cause harm to the environment or complete shut down of operations.
API 570 covers:
- External and internal inspections of piping systems
- Corrosion and erosion monitoring
- Thickness testing and corrosion rate analysis
- Identification and management of corrosion loops
- Recommendations for repairing or replacing damaged piping components
API 570 allows piping structures of different materials such as carbon steel, steel, alloys and stainless steel. This standard is applied together with ASME codes and specifications like ASME B31.3 Process Piping, ASME B31.4 Pipeline Transportation Systems for Liquids or ASME B31.8 Gas Transmission and Distribution Piping Systems.
Inspection Procedures: API 653 vs. API 570
API 653 Inspection Procedures
API 653 presents the inspection procedures both internal and external in regards to storage tanks. The inspection process is comprehensive and includes the following:
- External Inspection: Also sees the condition of the tank shell, roof and nozzle for corrosion, deformation, leakage and any other defects.
- Internal Inspection: Tends of the inspection involve checking for corrosion, pitting and other forms of wear on the tank bottom, shell, and internal fittings. Other forms of testing include Non-destructive examination (NDE) for example ultrasonic thickness testing (UTT).
- Settlement Assessment: Checks if the tank has landed out of level which could endanger the structural of the tank.
- Leak Testing: Checks the liquid tightness of the tank by doing a pressure test or vacuum box testing.
Different for API 653 depends on the size, materials and operating conditions allowed, usually internal inspection is needed after 5 to 20 years.
API 570 Inspection Procedures
API 570 outlines several inspection methods for piping systems, depending on the system’s risk level, material of construction, and service environment:
- External Inspection: An assessment of the exterior surface of the piping system and insulation, supports, fastening devices: straps, hangers, brackets, and other related components for signs of corrosion, leakage, or deformation.
- Thickness Testing: The assessment of remaining wall thickness and corrosion rates employ ultrasonic thickness testing. This is particularly important for services that are at elevated pressures or temperatures of the piping system.
- Corrosion Loop Analysis: Described as the process of defining areas of piping that are exposed to comparable corrosivity and sorting them into corrosion loops for the purpose of inspection.
- Risk-Based Inspection (RBI): By the process of evaluating risk, including risk of failure, and deciding about the application of inspection, the RBI can provide results that guarantee more effective and efficient inspections.
They recommend time intervals of the API 570 area between 3 to 10 years where the risk factor and prior assessment contributes to the analysis.
Repair and Alteration Guidelines
API 653 Repair and Alteration
API 653 gives extensive information on how to repair and alter storage tanks with the aim of increasing their useful service life while reducing key sector threats inherent in the manner. Repair procedures include:
- Welded Repairs: In case of the existence of corrosion or damage on the shell, bottom or roof of the tank. API 653 requires that one defines the nature of welding to be employed and testing to be conducted after repair work.
- Bottom Replacement: If the tank bottom has a high potential of corroding it may have to be replaced. API 653 also says how to remove and replace the bottom of the tank, which keeps the position stable.
- Roof Repairs: Corrosion and deformation are realignments that can require the roof of the tank to be either repaired or replaced. API 653 provides detail on these repairs to make sure that they continue to conform to industry standards.
API 570 Repair and Alteration
API 570 also provides recommendations on the piping system repair and alteration. Some common repair procedures include:
- Welded Repairs: Unfortunately, for those piping systems that have developed some extent of corrosion or damage, welded repair is usually the preferred mode of repair in the piping system.
- Hot Tapping: They come in handy especially when it is impossible to remove the piping system from service through traditional means of hot tapping enables repair or alteration to be made to line without having to stop working.
- Component Replacement: In some cases when certain components have suffered severe corrosion or damage, some portions of the piping may have to be replaced for the systems to be stable.
API 570 regards the repairs performed by qualified personnel, and all the works are to be examined and tested for compliance with the standards.
Certification and Personnel Requirements
API 653 Certification
API 653 certification is gained by fulfilling prescribed education and experience standards, as well as by passing the relevant test. Certification helps to guarantee that the inspectors will fully understand the inspection of storage tanks, how they can be repaired, and other essential industry requirements to follow.
Requirements for API 653 certification:
- High school study or the equivalent such as a modified certificate.
- At least one to five years’ experience in above ground storage tanks, based on educational background
- While it is important to understand the knowledge to pass the API 653 examination that focuses on the tank inspection methods, repair requirements, and the codes to adhere.
Of course, all the certified inspectors need to use their certification every three years by attending the continuing education and retesting.
API 570 Certification
Like in API 653, the certification process of API 570 involves assessment of certification bodies, exam format and the exam syllabi with the difference being that API 570 addresses in-service piping systems. Piping system construction and inspection criteria, construction documents, safety procedures, and repair practices are standards that must be displayed by inspectors.
Requirements for API 570 certification:
- General educational development/high school or equivalent
- Minimum of working experience of 1-5 years experience in piping inspection preferably with related educational background
- Successfully completing the API 570 exam, which deals with piping inspection practices, corrosion mechanisms, repair standards
Like API 653, API 570 certificate also expires after a period of three years.
Best Practices for Ensuring Compliance
API 653 and API 570 are standards that contain valuable information necessary to assess the fitness for service and careful inspections of critical structures. To ensure compliance with these standards, operators and inspectors should adhere to the following best practices:
- Follow Inspection Intervals: It is important to stick to the appropriate intervals of inspection in order to prevent worse problems from arising.
- Maintain Detailed Records: It helps to comprehensively record inspection history, repair or alteration of the concerned assets to monitor their status.
- Use Qualified Inspectors: This means that all inspection and repair work is conducted by licensed personnel who understand the prevailing standards.
- Implement Risk-Based Inspection (RBI): It is suggested here that RBI can be used to identify locations for inspection in relation to levels of risk of failure and potential impact and thus enhance the scheduling of inspections and use of inspection resources.
- Ensure Compliance with Construction Standards: In the case of tanks as well as the piping systems ensure that any repairs or alterations are made to conform to construction standards such as API 650 for tanks and or ASME B31.3 for the piping.
Conclusion
API 653 and API 570 on the other hand are very important standards which provide the guidelines needed in the storage tank and piping systems respectively. Both are best practice guidelines for the management of asset integrity, however, since tanks and piping present different problems this document is wider in scope, has different procedures for inspections and repair than the aforementioned.
It is important for anyone involved in the inspection, maintenance or repair of tanks and piping systems to fully appreciate these distinctions. To this end, through the implementation of these standards, industries shall be able to promote safe operations and Accident prevention and maintenance of key infrastructures for longer wear and tear.