TANK SETTLEMENT & ROUNDNESS

TANK SETTLEMENT & ROUNDNESS

Consider a steel tank like a plastic water bucket. When we pour water into the bucket, the plastic walls tend to expand and then return to their original shape. After filling the bucket completely, we may notice that the top rim is no longer perfectly circular but has become slightly elliptical. When we move our hand inside the water, we can also observe the bucket walls deforming.

The same phenomenon occurs in large steel tanks containing oil or chemicals. As these tanks are filled and emptied daily, their walls may deform, and pressure is exerted on the tank floor. In floating-roof tanks, the roof rim may also become distorted, which can affect the movement of the floating roof due to an uneven foam-seal gap.

Due to the enormous weight and liquid pressure exerted on the tank bottom, the floor may gradually settle. This can cause cracks in joints, make the tank tilt to one side, and gradually affect its centre of gravity. Uneven liquid-head pressure can also contribute to tank tilting.

These conditions are commonly referred to as tank out-of-roundness, tank tilt, and tank floor settlement. If these conditions are not properly studied and documented through a detailed report, serious safety and technical issues may arise. Identifying these problems early helps determine where maintenance or repairs may be required.

The overall condition of a tank should be assessed in accordance with the applicable requirements of API 653. Measuring, studying, analysing, and preparing accurate reports require specialised knowledge and experience.

With more than 22 years of experience in tank calibration projects worldwide, we have developed extensive expertise in assessing tank condition using accurate total stations, laser-based equipment, and experienced engineers.

After several years of operation, large tanks should be inspected for tank roundness, tilt, and bottom settlement. Our tank-health assessment can also include a detailed ultrasonic thickness measurement report for tank floors and shells, as these components may corrode over time, particularly in mild-steel tanks.

Whenever tanks are decommissioned for repair, maintenance, or cleaning, the above inspections should be carried out. We can prepare a detailed report covering roundness, tilt, and settlement surveys.

Your tanks are valuable assets, and oil is your lifeline. Contact us by phone or email to discuss your requirements. We are available to conduct these studies around the globe.

All it takes is one call or email to begin your tank-health assessment.