A 78 metre Diameter COS Tank was required to have a robotic Tank Floor Inspection conducted to extend the endorsement as the tank was due major overhaul but could not be removed from service due to operational ullage requirement.
COS Tank 256 Feet – SONAR Online
OUTCOME
Just over 1 year later the tank was removed from service and internally inspected. The results of the
two inspections were as follows:
The In-Service Robotic Inspection of the 78m Crude Oil Tank with sludge up to 3m in some locations provided data that when projected forward to the time of the Out of Service Ultrasonic Readings was deemed to be incredibly accurate and comparable.
The difference between the two methodologies of 0.59 mm thickness 8.5% of nominal were derived with basic EVA statistics rather than the upgraded statistics used today.
