The API 653 standard is a globally recognized guideline for the inspection, maintenance, repair, alteration, relocation, and reconstruction of aboveground welded storage tanks, particularly those holding 50,000 gallons or more. Developed by leading tank industry engineering experts, this standard ensures the safety, reliability, and compliance of tanks built to the API 650 Standard.
API 653 applies specifically to tanks 50 feet or taller or those with a diameter greater than 30 feet. It mandates inspections by licensed professionals to assess various tank components and conditions, such as minimum remaining thickness, maximum corrosion rate, and structural stability, including potential issues like tilting or settlement.
The standard outlines different inspection methods, including visual, ultrasonic, liquid penetrant, magnetic particle, radiography, and vacuum box inspections. External inspections are required every five years, while internal inspections are necessary every ten years. Additionally, monthly inspections by the site owner/operator are recommended to monitor the tank’s overall condition without taking it out of service.