Out of service MFL floor scanning using the latest generation FloormapVS mapping system and Handscan unit for inaccessible areas Silverwing ME Ltd offers Magnetic Flux Leakage (MFL) inspection of Bulk Liquid Storage Tank Floors using Silverwing FloormapVS, Handscan systems. 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 FloormapVS is designed for maximum results and minimum operator dependency ensuring complete corrosion detection and monitoring.

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 manways, sumps, Pipework 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 Handscan and Ultrasonics shall be inserted manually into the FloormapVS results.

The Handscan MFL corrosion detection mini scanner is designed to compliment the FloormapVS floor scanner. With the combination of low profile and interchangeable long or short handles, the Handscan is an ideal tool for scanning otherwise inaccessible areas of storage tanks such as the shell to annular region and under pipe work or coils.

Even in such a small configuration the latest generation of permanent magnets enable localised magnetic saturation of the floor area under test. For sample surveys, complete surveys of small areas or complimentary inspection on major floor surveys, the Handscan is a versatile addition.

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 FloormapVS 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 Handscan unit and/or ultrasonics.

Please contact our sales office if you have an enquiry