The Alternating Current Field Measurement – or ACFM – technique was specifically developed to detect and size surface-breaking defects on and around rough welds through several millimetres of non-conductive coating. This is a key advantage because just the costs associated with paint removal, post-MPI re-blasting, and recoating are typically four or five times more expensive than the MPI itself.
While the main failure point in storage tanks is corrosion in the floor plates, from either the top surface or from the underside, the welded sections are also a direct source of damage mechanisms. ACFM is proving itself as the most cost-efficient and trusted method for inspecting storage tank welds to supplement corrosion mapping, successfully detecting large cracks often missed by MPI.
You can’t deny the cost savings of ACFM over MPI; overall, ACFM jobs are typically six times less expensive than their MPI counterparts while providing the added value of a more reliable inspection with data-rich information to pass along to the asset owner.