Out of service MFL floor scanning using the latest generation FloormapVS2 mapping system.


Specialized Inspections Co. Ltd offers Magnetic Flux Leakage (MFL) inspection of Bulk Liquid Storage Tank Floor using Silverwing FloormapVS2 system. It is suitable for the inspection of floors made of mild steel up to 20mm thick including floors with non-magnetic coatings up to 6mm thick.

The FloormapVS2 is designed for maximum results and minimum operator dependency ensuring complete corrosion detection and monitoring.

Tank bottom inspection using the Handscan and FloormapVS MFL systems


The custom designed data acquisition software not only captures all the MFL signals but analyses and displays the location and severity of the corrosion in real time. All captured data, over 20% loss of the nominal plate thickness as sized by the on-board software, is re-analyzed in the off-line reporting software, using dynamic filters which automatically detect the type of corrosion whether it is pipe, conical or lake type. Depending on the defect profile the dynamic filters adjust the estimated material loss either up or down as required in relation to the peak amplitude loss estimation generated by the on-board software.

The combination of dynamic filtering plus amplitude analysis ensures enhanced defect sizing even on badly corroded floors where small diameter deep pits may otherwise have been undersized. The severity level of the corrosion can filtered, displayed electronically and printed as a hard copy to simplify location of repairable defects and as an aid to calculating remaining life of individual plates or even complete floors.

A comprehensive statistics package which can be configured for the whole tank or individual plates is included in the electronic reporting package as is a patch plate design function. Additional data from visual, ultrasonic, vacuum box and magnetic particle inspection can be added to the report generating a full fingerprint of the tank floor including the annular plates.

An innovative feature of the software allows subsequent inspection data to be overlaid and corrosion growth identified. Now the Tankage Engineer can produce a full current fingerprint of his tank floor, no matter what age, carry out immediate repairs as required and then re-inspect at a set time interval to produce accurate corrosion growth patterns and so predict future maintenance requirements.

The Tank Inspection report shall include a drawing of the floor plan showing the Tank Datum, plate and annular numbering system and the position of man ways, sumps, Pipe work and obstructions.

The co-ordinates of all pitting equal to or greater than the reporting level for each plate together with the percentage loss or remaining wall thickness shall be shown on a diagram for each affected plate. Results from areas that have been inspected by Hand scan and Ultrasonic's shall be inserted manually into the FloormapVS2 results




Tank Inspection Limitations


The sensitivity of the above systems varies with increasing floor thickness - please contact us for limits. Similarly there are limitations to the maximum thickness of coating through which satisfactory inspection can be carried out as floor thickness increases. The FloormapVS2 system is only suitable for floors up to 12.5mm thick. However above this thickness, the system can be used in Manual Mode.

As with all inspection methods the effectiveness of inspection is affected by the cleanliness and preparation of the floor. In particular, magnetic debris and weld spatter can lead to false indications.

Each of the tank floor inspection systems has a physical limit to the proximity to lap welds and shell to annular welds that can be achieved. There is also a square in each corner of a floor plate that cannot be inspected. These untested areas will be inspected using the Ultrasonic's.

Tank Floor Inspection (MFL)