Remote Field Array Testing (RFA): Advanced Multi-Coil Inspection for Ferromagnetic Tubes
Remote Field Array (RFA) is an enhanced form of remote field technology designed for efficient and comprehensive inspection of ferromagnetic tubes. By combining traditional remote field coils with advanced array technology, RFA delivers both bobbin-style data and array mapping in a single scan. This results in higher resolution, improved defect characterization, and faster evaluation of tube integrity in industrial heat exchangers and boilers.
How It Works
Dual Bobbin Coils
RFA probes include two circumferential bobbin coils that generate a low-frequency magnetic field, penetrating through the tube wall and creating a remote field region outside the tube.
Array Sensors
Multiple array coils positioned along the probe capture detailed magnetic field variations, enabling circumferential coverage and improved defect localization.
Flaw Interaction
Both ID and OD defects—such as corrosion, pitting, erosion, and mechanical wear—alter the returning magnetic field.
Data Acquisition & Mapping
The system processes remote field signals and array sensor responses simultaneously, producing high-resolution data that helps accurately size and locate defects around the tube circumference.
Key Advantages of RFA
Single-Pass Dual Data Output
Provides both traditional bobbin data and array imaging in one inspection run.
Improved Defect Characterization
Array technology enhances the ability to differentiate between localized, circumferential, and axial defects.
High Coverage & Sensitivity
Increased sensitivity to both internal and external corrosion, especially in situations where conventional RFT may show limitations.
Faster and More Efficient
Reduces inspection time while delivering more detailed, actionable data for maintenance planning.
Ideal Applications
RFA is ideally suited for inspection of:
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Ferromagnetic heat exchanger tubes
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Boiler tubes
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Feedwater heaters
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Air coolers and fin-fan units
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Carbon steel and ferritic alloy tubing
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Facilities requiring rapid, high-resolution assessments (power plants, petrochemical, oil & gas)