Ensuring Industrial Safety: Advanced Techniques for Comprehensive Tank Inspections

Tank Inspection

In the realm of industrial safety and maintenance, the importance of NDT cannot be overstated. Sonomatic RAIS stands at the forefront of this critical field, pioneering advanced methods to ensure the integrity and longevity of storage tanks. These assets are vital components across various industries, from petrochemical plants to water treatment facilities, where their failure could result in catastrophic consequences.

This cover story delves into the sophisticated techniques and tools employed by Sonomatic RAIS to perform comprehensive inspections and maintain these essential structures, focusing on tank roof maintenance and internal and external NDT methodologies.

Tank Roof Maintenance Checks

Tank roof maintenance is an essential aspect of ensuring the overall health and functionality of storage tanks. Sonomatic RAIS conducts thorough inspections to detect and address potential issues before they escalate. These inspections are particularly crucial when the tank is at the top dip or, if performed below the top dip, necessitate the use of a breathing apparatus for safety. The following steps outline the meticulous process carried out by Sonomatic RAIS:

1. Drainage Sump Maintenance:

The inspection begins with the removal of the cover from the drainage sump, followed by clearing all debris and ensuring the sump is free from Obstructions.

2. NRV Operation Check:

The next step involves checking the operation of the non-return valve (NRV) to confirm it is functioning correctly.

3. Pontoon Inspection:

All pontoons are inspected for lower explosive limits (LELs) and liquid presence, securely refitted, and checked for proper installation.

4. Structural Integrity Checks:

Landing legs, gauging poles, and all associated pins and retaining clips are examined for signs of damage or corrosion.

5. ABV and Rim Vent Maintenance:

Ensuring all Automatic Bleeder Vents (ABVs) and rim vents are free of debris or damage is vital for proper ventilation.

6. Seal and Shunt Inspection:

The seal is checked for wear, corrosion, and distortion, while shunts are inspected to ensure contact with the tank shell.

7. RGA and Earthing:

Regular inspections of roof grounding assemblies (RGAs) and earthing arrangements are conducted to prevent static discharge hazards.

8. Tank Shell and Roof Ladder Condition:

Visible sections of the tank shell are inspected for scraping and damage, and the roof ladder, if present, is examined for signs of corrosion or structural issues.

9. Roof Plate Examination:

Roof plates are inspected for corrosion, damage, or cracking to maintain the structural integrity of the tank roof.

10. Continuity Check:

A continuity check between the tank roof and shell ensures protection against lightning and static electricity.

These comprehensive checks are meticulously recorded and reported to clients, ensuring transparency and proactive maintenance.

External and Internal NDT Methods

Sonomatic RAIS employs a range of sophisticated NDT techniques for both external and internal inspections of storage tanks. These methods ensure the detection of defects and corrosion, thus preventing potential failures.

A. External Inspections

• RMS 300: This tank shell crawler inspects the shell vertically, collecting data from bottom to top across a 300mm wide scan. This method ensures a thorough examination of the tank’s Exterior.

B. Internal Inspections

• Floormap?X: As the latest multi-technology Magnetic Flux Leakage (MFL) Array tank bottom solution from Silverwing, Floormap?X offers unmatched detection capabilities, especially in critical zones. Its patented STARS technology allows for top/bottom corrosion discrimination, making it highly efficient in inspecting tank bottoms. Floormap?X supports full floor mapping and Freescan? modes, enhancing efficiency and accuracy in tank bottom inspections.
• Vac-Box Inspection: This method is utilised to identify leaks or integrity issues in the tank bottom, ensuring a reliable assessment of the internal structure.

C. Both External and Internal Inspections

ACFM: Alternating Current Field Measurement (ACFM) is crucial for inspecting welds without removing paint coatings. It detects and sizes surface-breaking defects around rough welds, offering significant cost savings compared to Magnetic Particle Inspection (MPI).

• Ultrasonic Inspection (UT): Manual UT is used for thickness and volumetric inspections, providing precise measurements of the tank’s material condition.
• Radiography Inspection: This method uses X-rays or gamma rays to examine the internal structure of the tank, identifying hidden defects.
• Magnetic Particle Inspection (MPI) and Dye Penetrant Inspection (DPI): These methods are employed to detect surface and subsurface discontinuities in ferromagnetic materials.
• Phased Array Ultrasonic Testing (PAUT): This advanced technique is used for corrosion mapping and weld inspection, offering detailed images of the internal structure.
• Time of Flight Diffraction (ToFD): ToFD is a highly accurate method for detecting and sizing internal defects, particularly in welds.
• Eddy Current Testing (ECT): This method is effective for detecting surface and near-surface defects in conductive materials.

Throat Thickness Measurement: Ensuring the structural integrity of weld throats is vital for maintaining the strength of the tank.

ACFM: A Cost-Effective and Reliable Solution

ACFM has emerged as a highly efficient and cost-effective method for inspecting storage tank welds. Unlike MPI, which requires costly paint removal and recoating, ACFM can detect surface-breaking defects through several millimetres of non-conductive coating. This capability results in significant cost savings, making ACFM inspections typically six times less expensive than MPI while providing more reliable data.

The primary failure points in storage tanks are often the floor plates, where corrosion can occur on both the top and underside. Welded sections are also susceptible to damage mechanisms, and ACFM has proven to be a trusted method for detecting large cracks that MPI might miss. This reliability, coupled with cost savings, makes ACFM an invaluable tool in the arsenal of NDT techniques.

Silverwing Floormap?X: Breaking the Barrier

The Silverwing Floormap?X sets new standards in tank floor scanning, offering unparalleled probability of detection, resolution, and signal clarity. It combines enhanced MFL and STARS technologies in one system, supporting multiple scan modes and reporting options to meet diverse client requirements. The Floormap?X's advanced signal processing algorithms and smart hardware ensure efficient and accurate inspections, from data collection to report Submission.

Operators can control the system entirely without removing their hands from the control handles, thanks to software controls mirrored in hardware buttons. This design focuses on efficiency and accuracy making Floormap?X a game-changer in tank bottom inspections.

Conclusion

Sonomatic RAIS leverages cutting-edge technology and meticulous inspection protocols to ensure the safety and longevity of storage tanks. Through comprehensive tank roof maintenance checks and advanced NDT methods, Sonomatic RAIS provides clients with reliable data and cost-effective solutions while maintaining the highest standards of industrial safety and integrity.

In addition to these services for out-of-service tanks, Sonomatic also specialises in online tank cleaning and inspection. These services can be conducted while the tank is in service, eliminating the need for vessel entry through the use of Remote Internal Inspection (RII) Methods.

Sonomatic’s technicians are experienced in employing a wide variety of inspection techniques on various assets in diverse environments. As industries continue to demand more robust and efficient inspection techniques, Sonomatic RAIS remains at the forefront, driving innovation and excellence in NDT for tank inspections.