ACOUSTIC
EMISSION & NDT SCIENTIFIC PUBLICATIONS
Condition
Monitoring for Tank Floors of Above-Ground Storage Tanks
Advanced
NDT Techniques (proceedings of MATEST 99 international conference),
CrSNDT, 23&24 September 1999, CAVCAT/CROATIA , pp.127-131
Dr.
Athanassios Anastassopoulos, Dimitrios Kouroussis
Tank floors are the most vulnerable
parts of atmospheric storage tanks. Predictive maintenance requires
corrosion assessment at regular intervals, so that repairs can take
place, in order to prevent leaking resulting in severe implications
to the environment and large amounts of lost product. Periodic tank
floor inspections, which require emptying of the tank regardless of
its condition, lead to significant losses of money and time because
of the unnecessary opening and emptying of tanks in good condition.
The Acoustic Emission (AE) NDT technique offers solutions to the
aforementioned problems. With the use of AE, the tank floor
condition can be assessed without the need to empty the tank. The
tank is monitored for 1-3 hours by an array of AE sensors placed on
the outside part of the tank wall which detect signals arising from
corrosion and/or leak. The result of this monitoring and post-processing
of AE signals is a tank floor grading, from A (no damage) to E (major
repair required) as well as graphs pinpointing the location of
corrosion on the tank floor. Thus, the unnecessary opening of tanks
in good condition is avoided, whereas high maintenance priority is
given to tanks with severe damage, resulting in considerable savings.
The present paper briefly outlines the AE method as applied in tank
floor inspection and the TANKPAC technology (developed through
thousands of tank bottom tests) by which tank floors are graded
based on the AE activity.