The External Inspection Must-Dos for API 653 AST Owners

Storage TanksSeeing that aboveground storage tanks are widely used in many industries, particularly for those involved with petroleum, oil, gas, water, and chemical storage applications, it is a must for all AST owners to know and abide by the appropriate American Petroleum Institute (API) Standards. Failure to do so will not only cause major penalties, fines, and losses, but also catastrophes like the recent Caribbean Petroleum Refining Tank disaster that happened on the 23rd of October, 2009.

As for owners who have tanks classified under the API 653 Standard (ASTs with a height of more than 50 feet and a dimension of greater than 30 feet), it is a must to comprehend everything that the standard consists of.

What it covers

This is the standard used for ASTs that have the above-mentioned measurements. It also includes rules for the tank inspection, maintenance, repairs, and alterations. It also covers the regulations for the monthly, internal, and external tank inspections. For internal and external inspections, only API-licensed and -certified inspectors can conduct the job. Assessment of a tank’s brittle fracture problem also falls under this standard. Lastly, it also includes the correct welding procedures for tanks erected in the fields.

One of the most important inspections that AST owners should strictly follow is the external inspection.

What this type of inspection consists of

In most cases, the API requires external inspections for every 5 years. However, the licensed inspector may require the owner to conduct this process more frequently, depending on the overall status and integrity of the tank.

Certified inspectors of such tanks need to ensure that the ASTs’ overall condition and the state remain suitable for continued use.

The four crucial components of external inspections

Under this API Standard, the inspector needs to take into consideration four critical external inspection components. First, they need to thoroughly review and assess the previously conducted inspection checklists. Second, an inspection itself should include testing of the tank’s thickness, and third, verifying the initial thickness of the shell and determining its current thickness. The fourth involves the use of ultrasonic thickness testing that may then require ultrasonic testing scan (UTS).

For AST owners, meeting all these conditions will drastically reduce the risks of a catastrophe from happening.