Application of statistical quality control (SQC) in the calibration of oil storage tanks

Abstract

Calibration of storage tanks is an exact means of determining the accurate capacity of storage tanks at a given incremental level. When calibrating a certain number of oil storage tanks having the same dimensions, it is assumed that if the specified tank dimensions are within the statistical control limits, a calibration chart generated for one tank can be used for the other tanks. This study used X-bar and R-control chart to investigate the stability of the tank calibration process for some fabricated oil storage tanks. The method of control chart was used to check if the process is under control or not. The variables of the calibration process are Circumference of each course shell, Height of each course shell and Elevations for the bottom profile. Results revealed that the calibration process was statistically stable and under control with no special or assignable cause of variation. Process capability conducted also showed that the calibrated tanks met the pre-set limits.