Remote Field Eddy Current Testing (RFET)

Remote Field Eddy Current Testing is a specialized electromagnetic inspection technique used primarily for inspection of ferromagnetic heat exchanger tubes. RFET is particularly effective for detecting internal and external defects in carbon steel and low-alloy steel tubes, where conventional eddy current testing is limited.

RFET enables reliable detection of wall loss, corrosion, and cracking throughout the tube wall thickness.

Why RFET Is Required

Inspection of ferromagnetic tubes presents unique challenges due to magnetic permeability effects. RFET overcomes these limitations by using remote field electromagnetic principles, allowing detection of defects on both the internal and external tube surfaces.

RFET is critical for evaluating carbon steel heat exchanger tubes operating in corrosive environments where external corrosion or under-deposit corrosion may occur.

Scope of Inspection

RFET is applicable to:

Carbon steel and low-alloy steel heat exchanger tubesBoiler tubes and economiser tubesFerromagnetic condenser and cooler tubes

Inspection Methodology

RFET inspection is carried out by inserting a probe that generates a low-frequency electromagnetic field through the tube. The field travels through the tube wall, propagates along the outer surface, and re-enters the tube at a remote location where it is detected.

Changes in wall thickness or defects affect the remote field signal, allowing identification of corrosion, thinning, and cracking. Inspection data is analysed to determine defect location and severity, and results are used to assess tube condition and integrity.

Key Benefits

RFET enables inspection of ferromagnetic tubes, detects both internal and external defects, provides reliable wall loss assessment, and supports integrity evaluation of ageing heat exchangers.

Industries and Applications

RFET is widely applied in refineries, power plants, petrochemical facilities, fertilizer units, and chemical industries operating carbon steel heat exchangers.

Remote Field Eddy Current Testing provides a reliable inspection solution for ferromagnetic heat exchanger tubes. By enabling accurate detection of wall loss and degradation, RFET supports safe operation, maintenance optimization, and long-term asset reliability.