API-653 is the standard for 50-feet or taller tanks along with tanks that are greater than 30-feet in diameter. It covers the maintenance, inspection, alteration, and repair of steel and must be performed by a professional, licensed inspector.

An API-653 inspection reviews tank specifications, construction, release detection methods, and spill control. It allows different types of inspection to examine aboveground tanks components such as:

  • Visual
  • Ultrasonic
  • Liquid Penetrant
  • Magnetic Particle
  • Radiography
  • Vacuum Box
  • And more

When it comes to the structure of the tank, API-653 standards take into account minimum remaining thickness, minimum required thickness, and maximum corrosion rate. Some other factors assessed under API-653 to examine whether the tank is tilting or settling in the ground improperly include:

  • Out of plane
  • Rigid Body Tilting
  • Uniform
  • Dish Type
  • Edge Settlement
  • Localized Dispersions

An API-653 external inspection is required every five years while an API-653 internal inspection is required every ten years. Monthly, it is recommended under API-653 for site owner/operator’s inspector to thoroughly assess the overall tank condition without removing the aboveground tank from service.