Integrity Matters: Topside & Underwater Inspection

Offshore and marine structures are constantly exposed to harsh environmental conditions, leading to material degradation, corrosion, and structural fatigue. Regular topside and underwater inspection is essential for maintaining the integrity of assets such as offshore oil and gas platforms, subsea pipelines, ships, and wind farms. Advanced inspection techniques help identify potential failures before they become critical, ensuring safety, compliance, and cost-effective maintenance. However, these types of asset they require very different inspection methods according to whether you are inspecting above or under the water. 

Key Inspection Techniques

Both topside and underwater inspections rely on a range of Non-Destructive Testing (NDT) methods to assess the condition of structures. Some of the most commonly used techniques include:

1. Topside Inspection Techniques

Topside inspections focus on above-water structures such as platforms, risers, and jackets. Inspectors use a combination of different NDT methods to assess welds, coatings, and material conditions. The NDT methods that are commonly used are:

• Visual Inspection (VT): The first line of assessment, used to detect open to surface and geometrical imperfections such as cracks, corrosion, and coating failures
• Magnetic Particle Testing (MT): Ideal for detecting surface and near-surface discontinuities in ferromagnetic materials
• Ultrasonic Testing (UT): Identifies any internal discontinuities and can measure with high precision the wall thickness loss due to corrosion or erosion
• Eddy Current Testing (ET): Used for detecting cracks and corrosion in conductive materials, especially around welds

1. Underwater Inspection Techniques

Underwater inspections are carried out by divers or Remotely Operated Vehicles (ROVs) to assess subsea structures, pipelines, and ship hulls. The techniques used are adapted for the underwater environment and require specialised training.

• Flooded Member Detection (FMD): A key technique for checking structural members for water ingress, which indicates potential cracks or failures
• Cathodic Protection Surveys: Used to evaluate the effectiveness of corrosion protection systems, such as sacrificial anodes or impressed current systems
• Alternating Current Field Measurement (ACFM): Detects cracks in welds and metal surfaces without requiring surface preparation, making it ideal for underwater use
• MPI (Magnetic Particle Inspection): Used for sub surface or near surface defects

Certification and Training for Inspectors

To perform topside and underwater inspections, professionals must undergo specialised training and obtain industry-recognised certifications. TWI offers a range of courses designed to equip engineers, inspectors, and technicians with the necessary skills. As with the inspection methods used, so the certification differs according to whether it is topside or underwater-related.

Some key topside qualifications include:

• BGAS-CSWIP Certification: Covers painting, welding, and coating inspection for offshore and onshore structures
• NDT Certification (VT, UT, MT, ET, ACFM): Ensures competency in accordance with ISO 9712 in NDT methods used for asset integrity management

Key underwater qualifications include:

• CSWIP 3.1U/3.2U Underwater Inspection Certification: Designed for commercial divers conducting subsea inspections
• CSWIP 3.3U-3.4U Inspection Certification: Designed for topside inspection controllers

The Growing Demand for Inspection Professionals

As industries continue to expand into offshore energy production, the need for skilled inspectors is rising. The oil and gas, wind energy, and maritime sectors all rely on certified professionals to maintain asset integrity, prevent failures, and optimise maintenance schedules.

By investing in quality training, professionals can build a rewarding career in asset inspection while ensuring the safety and efficiency of critical infrastructure.

Explore TWI’s topside and underwater inspection courses today and take the next step in your career. For further information, please see here.