API 653 Aboveground Storage Tank Inspection

API 653 Aboveground Storage Tank Inspection is the standard for inspecting, repairing, and altering aboveground storage tanks (ASTs) to ensure their structural integrity and safe operation. In Malaysia, this inspection is critical for oil and gas terminals, petrochemical facilities, palm oil storage farms, and refineries to comply with DOSH (Department of Occupational Safety and Health) regulations. Regular inspections prevent tank failures, leaks, and environmental contamination, safeguarding both public safety and operational continuity.

Inspection intervals depend on the tank’s age, construction material, operating conditions, and service fluid. API 653 typically requires external visual inspections every 5 years and full internal inspections every 10 years, but DOSH or site-specific risk-based inspection (RBI) programs may require shorter intervals for tanks in corrosive or high-risk service.

An API 653 inspection includes external visual examinations, ultrasonic thickness measurements, floor plate inspections, roof structure assessments, settlement surveys, and weld integrity checks. It also involves checking nozzles, manways, shell plates, and annular plates for corrosion, pitting, or deformation. Advanced non-destructive testing (NDT) methods like Magnetic Flux Leakage (MFL) floor scanning are often used to detect corrosion under coatings.

DOSH enforces regulations on storage tank safety to prevent catastrophic failures and environmental hazards. API 653 inspections carried out by certified inspectors ensure that tanks meet the Factories and Machinery Act and Occupational Safety and Health Act requirements. Compliance not only avoids legal penalties but also supports insurance coverage and operational licenses.

Some external inspections and specific NDT techniques can be performed while the tank is in service. However, a complete internal inspection requires the tank to be emptied, cleaned, and made gas-free. This allows for a thorough assessment of floor plates, weld seams, and internal coatings, ensuring accurate evaluation of the tank’s condition.

Typical findings include bottom plate corrosion, pitting, weld cracks, roof deformation, settlement issues, and shell distortion. Early detection of these defects enables targeted repairs, extending the tank’s service life and preventing costly unplanned shutdowns.

CT Precise Engineering provides rapid mobilisation for API 653 Aboveground Storage Tank Inspection services across Malaysia, with the ability to respond to urgent requests within the same day. Whether your facility is in Johor Bahru, Kuantan, Penang, Klang Valley, or at offshore storage terminals, our API 653 certified inspectors are equipped with portable and advanced non-destructive testing (NDT) tools such as Magnetic Flux Leakage (MFL) floor scanners, ultrasonic thickness gauges, and settlement survey equipment.

For emergency scenarios—such as suspected bottom plate leakage, sudden settlement shifts, or significant corrosion progression—we prioritise immediate deployment to minimise downtime, environmental impact, and potential product losses. Upon arrival, our team conducts a comprehensive on-site risk assessment, initiates targeted NDT procedures, and delivers a preliminary findings report before the end of the inspection day.

We also coordinate closely with DOSH (Department of Occupational Safety and Health) to ensure that all inspection data and reports meet Malaysian regulatory requirements. This streamlined process helps expedite certification, repair approvals, and tank return-to-service timelines. For large tank farms or multi-tank inspection projects, we can mobilise additional teams and equipment simultaneously, ensuring that all inspections are completed efficiently without compromising accuracy or safety standards.