API 653 Repair and Alteration 3

Question 1

Per API 653, what is required before welding a repair patch on a tank that has contained flammable product?

Accepted Answer

Gas freeing and atmosphere testing to safe levels

Answer

API 653 mandates that tanks be gas-freed and tested to confirm safe atmospheric conditions before any hot work such as welding.

Question 2

According to API 653, what is a 'major repair' compared to a 'minor repair' in the context of aboveground storage tanks?

Accepted Answer

A repair that restores the original design condition versus one that does not affect design function

Answer

API 653 classifies major repairs as those that restore original design intent or structural integrity, distinguishing them from maintenance-level minor repairs.

Question 3

When a tank bottom is repaired by installing a new bottom over the old one (lap-over-bottom), what is the minimum lap dimension per API 653?

Accepted Answer

1 inch

Answer

API 653 requires a minimum 1-inch lap when installing a new tank bottom over the existing corroded bottom.

Question 4

In API 653, what must be done when a repaired or altered tank is returned to service with a reduced maximum allowable working level (MAWL)?

Accepted Answer

The reduction must be documented and the tank must be marked with the new MAWL

Answer

API 653 requires that any MAWL reduction be documented in the tank record and physically marked on the tank to prevent overfilling.

Question 5

Which welding process is generally NOT acceptable per API 653 for structural repairs to tank shells without additional qualification?

Accepted Answer

Stud welding for structural attachments

Answer

Stud welding is not a recognized structural welding process for load-bearing repairs under API 653 without specific qualification and engineering approval.

(API 653) API 653 Aboveground Storage Tank Inspector Certification Practice Test

(API 653) API 653 Aboveground Storage Tank Inspector Certification Practice Test

API 653 Repair and Alteration 3