A quote from the article by Cole and Gautrey which is part of this months edition of NDT.net :
'...TANKPAC is the only non-invasive on-line maintenance-planning tool available for above ground storage tanks,...'
Just to keep NDT.net an up to date source of information : a couple of years ago already a second non invasive tank floor inspection tool has been developed, which uses a combination of acoustic emission (advanced waveform based and only for leak detection, as supported by the American Petroleum Institute) and electrochemical testing (corrosion assessment technology validated by Lloyds Register of Shipping). The use of two separate and independent techniques adds reliability to the technology. More information can be obtained through www.METALogic.be or by contacting me by email.