The inspection of protected welded steel structures for fatigue cracks during their service life creates a set of problems which can be minimised by the efficient use of eddy current NDT techniques.
The oil industry has been cautious to adopt the techniques until the reliability of the equipment, the profiency of the personnel and the validity of the procedures have been demonstrated.
During the last five years SSNDT has provided a total package of support, by training and certifying technicians, by measuring the performance of equipment, and by devising and checking procedures in conjunction with industrial partners, details of which will be presented.
Over the last 18 months an industrial sponsored project has measured the limits of performance of eddy current equipment. The project work has specialised in the application of manual eddy current equipment ou fatigued and coated welds where the performance of the technician is a major contributing factor to overall reliability.
A method has been devised to provide a framework for the comparison of alternative manufacturers equipment and the validity of the basic measurements.
The latest results of the project will be described and include the limit of attainable performance of the inspections and the procedures which have become industrial standards.