Calibration of Vertical oil storage tank

The tank is filled at its present location with the product to be stored to its working capacity or with water to its equivalent height, and such product or water has been held in the tank for atleast 24 hours to allow for settling.

Tank calibration is mainly done by strapping and internal measurements. When the tank drawing and measurements is available from the manufacturer, it is checked for correctness. Then calibration tables are prepared and the capacity is found.



The complete calibration data is entered on the Tank Measurements Record Form. It contains -

Tank No, Owner's Name, Plant or property name, Location, Manufacturer, Erected by, Description, tank contents, average temperature, Hydrometer reading, type of roof, weight of floating roof, type of bottom, No of joints, elevation, Deadwood details, Height, shell Circumferences, height or depth of crown etc.

The overall height shall be measured, using dip tape and dip weight, from the dipping datum point to the reference point on the dip hatch. This overall height shall be recorded and marked on the tank at the dip hatch.

Equipments required : Steel rule, Spirit level, Awl and scriber, marking crayon, record paper, plumb line, positive displacement bulk meter, Rope, hooks, safety belts, ladders etc.