API 653 inspector: what the credential covers, and what it leaves to others

An API 653 inspector is a person certified by the American Petroleum Institute to inspect aboveground storage tanks under API Standard 653. The certification belongs to the individual, not to the firm that employs them. That single fact shapes how a proposal should be read: a firm can be excellent, but the report is only as valid as the certification of the person who signs it.

How the certification is obtained

API runs it through its Individual Certification Programs. Candidates must meet a combination of education and experience requirements set by API, then pass an examination on the standard and the documents it references. The certification is issued for a fixed period and must be renewed under API’s conditions. The detail of what the certification means is set out in what API 653 certification means.

What the inspector is responsible for

The inspector plans and performs the inspection the standard requires, evaluates the findings against the standard’s acceptance criteria, and sets the next inspection interval based on measured corrosion rates. The interval is the most consequential number in the report. It is the inspector’s judgment, documented and signed, and it is what the owner relies on until the next inspection.

What the inspector does not do alone

Many measurements in an API 653 inspection are made by technicians: ultrasonic thickness readings, magnetic flux leakage scans of the floor, vacuum box testing of welds. Those technicians are qualified under their own schemes, typically employer certification against ASNT guidelines. The inspector relies on their data and remains responsible for the evaluation. A proposal should say who does what.

API 653 is not STI SP001

Shop built tanks are commonly inspected under STI SP001, which has its own inspector certification administered by the Steel Tank Institute. An API 653 inspector is not automatically an SP001 inspector, and the reverse is also true. If your facility has both kinds of tanks, check that the proposal covers each with the right credential.

How to check a certification

API publishes a directory of certified individuals. Searching it by name takes a couple of minutes and shows whether a certification is current. It does not show competence on a particular kind of tank, and it does not show whether the person will actually be on site. The steps are on verify an inspector. Ask for the certificate number in the proposal and check it before the work starts, not after the report arrives.

Experience that the certificate does not show

Certification proves a baseline. It does not tell you whether the inspector has worked on tanks like yours: floating roofs, insulated tanks, tanks in heated service, very large diameters. Asking for two or three comparable jobs, with the owner’s permission to name them, is a reasonable request and often the most informative part of the selection.

Reading the signature on a report

The report should carry the inspector’s name and certification number, and the inspection it describes should match the scope of an API 653 inspection: external, internal or both, with the data that supports the interval. A report signed by someone whose certification was not current on the inspection date is a report you may have to redo.

Keep a copy of the directory search result with the report. It takes a minute on the day, and it answers the question for good if anyone later asks whether the person who signed was certified when they signed.

Questions worth putting in the request for proposal

Ask for the name and certification number of the inspector who will sign, and whether that person will be on site or will review data collected by others. Ask which technicians will make which measurements, and under what qualification. Ask how the next inspection interval will be calculated and what data it will rest on. These questions cost nothing to ask, and the way a firm answers them says a great deal about the report you will receive. A proposal that cannot name its inspector before the contract is signed is a proposal that has not decided who will do the work.