Swiss Approval Advanced NDT based in UK, manages all activities related to NDT inspection services, with use of Pulsed Eddy Current (PEC) Testing, in order to measure percentage variations in steel thickness. Our Advanced NDT Laboratory operations, are conformed with ISO 17025 requirements.

Working Principle

PEC is an advanced electromagnetic technique used to assess corrosion in ferromagnetic structures such as carbon steel and cast iron. A pulsed magnetic field is induced into the material using a coil. As this magnetic field interacts with the conductive material, it generates eddy currents. These eddy currents are sensed by the probe; their characteristics depend on the material properties and thickness of the sample. The received electromagnetic signals are compared with reference signals from known calibration blocks, and this way are related to the thickness of the component. PEC is practical and provides quantitative results on corrosion, determining the average wall loss with the footprint area.

Key Advantages

PEC is practical and provides quantitative results on corrosion. In particular PEC:

-Does not require insulation removal (up to 100 mm thick insulation)

-Does not require surface preparation of rough surfaces

-Does not require surface preparation of dirty surfaces

-High temperature inspection up to 120°C in direct contact with the probe

Testing Applications

PEC is commonly used for a wide range of applications, each with its own specific requirements. To increase probability of detection and improve the overall inspection, optimized probes are employed for each application. PEC is utilized in:

• Corrosion under insulation
• Corrosion under fire proofing
• Corrosion under scabs
• Flow accelerated corrosion
• Repair wraps
• Monitoring; repeat surveys
• Offshore structures (splash zone)
• Underwater inspections
• Ship tank inspections

Limitations

PEC is a screening tool. It is has low sensitivity to small defects, such as small pitting.