The test consists of attaching sensors to the outside of the tank and monitoring for emission resulting from active corrosion of the floor. Noise sources are eliminated by sophisticated pattern recognition methods, and experienced operators.
MISTRAS engineers go through a rigorous training and certification program and have to pass written and practical exams as well as meeting minimum experience requirements. All work is conducted under an ISO-9002 documented procedure and a site report is given following the test, and results and records are reviewed by a MISTRAS Level III prior to final report issue.
Correlation of the TankPAC overall grade with actual follow-up internal inspection shows the reliability of the method. In this case, the inspection/repair result is rated as follows:
TANK FLOOR GRADING SCALE
A - No Damage, No Repair
B - Minor Damage, No Repair
C - Damage, Some Repairs
D - Major Damage, Many Repairs
E - Severe Damage, Many Repairs, New Tank Floor
Careful review of all the TankPAC information, and not just the "overall", improves the reliability. The method is being continually refined and improved as a result of the customer feedback. It is best suited to tanks that are in the same service long-term. Additional monitoring may be needed if the conditions in the tank are subject to changes as these may start/stop the corrosion process.
Cost savings depend upon tank condition. Saving the cleaning costs on 50% of your crude tanks can amount to millions, and on very clean product tanks, where many need no repair, savings can be huge when the overall cost of shutdown, cleaning, and internal inspection are taken into account.
ADVANTAGES
Significant money savings; No money wasted for opening of good tanks.
Maintenance prioritization; The most severely damaged tanks are programmed for internal inspection first.
Ideal tool for application of risk-based inspection plans.
Prevention of environmental losses; Early identification of potential leaks.
Very fast, low-cost inspection with minimal interruption of operations and tank usage.
