Abstract

In the oil and gas industry, the above-ground storage tanks play a significant role in the continuous movement of petroleum products. Oil is a valued product; the storing tank must undertake regular maintenance. Characteristic AST inspection can be conducted under its usual operation, but the floor of large AST is challenging to access during in-service. Due to the inaccessibility of the floor, tanks need to be emptied and made out-of-service for inspection and repair. This is a known expensive way both in terms of earning and the maintenance procedure itself. In this paper, the review of this condition and procedure of the AST is discussed with the present limitation and possible improvements in inspection methods. The inspection of the floor is the main focus, because it is a prime factor that characterizes the out-of-service time. The petrochemical industry's main aim is not only to minimize the frequency and time of out-of-service interval, but can also shift towards in-service defect detection methods. In-service methods can save major time and expense of not entering the tank for inspection. Both in-service and out-of-service strategies are discussed for inspection of the floor to achieve the objective goals. 

Keywords

above ground tanks (AST), non-destructive-testing (NDR), in-service, out-of-service, life cycle