Why You Need to Schedule Routine Industrial Tank Inspections

Engineer inspecting industrial storage tank

In the industrial sector, routinely inspecting chemical storage, fuel, and water tanks is crucial for maintaining safety and efficiency. As a general rule, industrial tanks should be professionally inspected annually. However, that frequency will change depending on the tank’s age and condition, what type of liquids the tank is storing, the type of environment it’s in, and if the tank has a documented history of issues. The frequency of inspections may also increase in scenarios where there is a higher risk of corrosion, leakage, or contamination.

If you have an industrial tank or more than one industrial tank on your property, keep reading to learn more about the benefits of scheduling professional routine inspections, the regulatory bodies that oversee these inspections, and what generally happens during one.

Preventing Compliance Issues

Team inspecting the inside of an industrial storage tank

Arguably, the most important benefit of scheduling routine tank inspections is staying compliant and avoiding costly penalties. Industrial tanks are governed by stringent regulations to ensure safety and environmental protection. The EPA and OSHA enforce the primary regulations, but each state may have additional requirements for industrial tank inspections and safety protocols. The Steel Tank Institute, American Petroleum Institute, the National Fire Protection Association, and The American Society of Mechanical Engineers also have standards on tank inspections, which we’ll cover later.

By regularly examining the condition and functionality of tanks, businesses can identify and resolve any potential non-compliance issues early on.

Lowering Environmental Risks

Regularly examining the condition of your tanks, particularly those storing hazardous substances, helps identify any potential leaks, mitigates the risk of soil, groundwater, and air contamination, and reduces material wastage.

These inspections also help maintain the integrity of secondary containment systems that help prevent tank spills, which is especially important in sensitive ecological areas where a spill could have devastating effects on local ecosystems.

Mitigate Future Leaks

During routine tank inspections, the tank’s condition is thoroughly evaluated. This includes assessing its physical structure, testing for integrity and stability, identifying signs of deterioration like rust or metal fatigue, and reviewing its protective coatings and linings, which help prevent corrosion. Routine inspections also involve checking the operational aspects of the tank, including valves, pipes, and fittings. Any malfunction in these components can lead to leaks.

By identifying and resolving potential issues early on, you can prevent small problems from escalating into significant leaks, which impact environmental safety and result in costly cleanups and operational disruptions.

Reduce Costs & Downtime

As mentioned in the previous sections, routine inspections allow for early detection of potential problems like minor leaks, corrosion, and wear and tear, which will only worsen over time. When you identify issues early on, you can perform targeted repairs before the problem becomes more severe and costly. This approach is much more proactive than reacting to a major failure, which could result in expensive emergency repairs and significant material loss.

Additionally, these inspections help prolong the lifespan of tanks, ensuring they remain operational for longer periods. Prolonging the lifespan of your tanks means fewer replacements, which are significant capital expenses.

Lastly, you’ll minimize operational disruptions and improve process efficiency by preventing major incidents, such as large-scale leaks or tank failures. Downtime is not only extremely costly but also results in potential penalties and loss of customer trust.

Not All Tank Inspections Are the Same

Huge oil, gas and liquid storage tanks in open air field at factory

Many regulatory bodies oversee inspections of different types of tanks. Each regulatory body has its own set of specific requirements. Understanding these requirements is crucial for ensuring compliance and safety.

The most prevalent regulatory bodies include:

The Steel Tank Institute (STI)

STI offers standards for inspecting welded steel tanks often used for storing flammable and combustible liquids. STI’s SP001 standard requires that any businesses using shop-built welded steel aboveground fixed storage tanks must have them inspected annually by a certified inspector and monthly by the tank owner’s inspector.

This standard does not include tanks that hold less than 5,000 gallons of liquid, heating oil tanks, or tanks at farms and construction sites.

The standard also requires 20-year inspections for tanks that hold over 5,000 gallons of liquid. These inspections must be performed by an individual with an STI SP001 certification or an API 653 certification with an SP001 adjunct certification.

Please visit the STI’s website to learn more about this standard.

American Petroleum Institute (API)

API 653

The most common API tank inspection standard is 653, which provides comprehensive guidelines for inspecting, repairing, altering, and reconstructing aboveground storage tanks used in the petroleum industry.

Per API 653, the frequency of tank inspections is based on the age of the tank and the materials it stores.

Generally, in-service tanks under 10 years old should be inspected every five years. If they’re in-service and over 10 years old, they should be inspected every three years. If the tank is out of service, it should be inspected before being returned to service. Lastly, if the tanks are newly constructed, they should be inspected before being placed into service.

The API 653 standard includes different types of inspections, such as external, internal, bottom, roof, and shell settlement. Each inspection focuses on different components of the tank, looking for signs of corrosion, leaks, damage, and other structural issues. These inspection types also have recommended frequencies.

For example, internal inspections are required every 10 years, while external inspections should be performed every five years. The frequency may be adjusted based on operational conditions, previous inspection results, and other factors.

The standard also outlines specific testing practices, including visual inspections, hydrostatic testing, vacuum box testing, ultrasonic testing, and magnetic particle testing. It’s crucial to work with an inspector with an API 653 certification, as these types of inspections are extremely nuanced.

API 1631

The American Petroleum Institute also has a standard for underground storage tanks—API 1631. The API 1631 standard specifically provides guidelines for the interior lining and periodic inspection of existing steel and fiberglass reinforced plastic underground storage tanks, primarily used for storing petroleum-based motor fuels and middle distillates.

The API 1631 standard highlights procedures for vapor-freeing tanks, removing sediments, cleaning interior surfaces, and inspection methods to determine if a tank is suitable for lining.

National Fire Protection Association (NFPA)


The guidelines for inspecting, testing, and maintaining water storage tanks used for fire protection are outlined in the NFPA 25.

According to this standard, interior inspections should be performed every five years if the tank has corrosion protection. If the tank does not have corrosion protection, interior inspections should be performed every three years. Exterior inspections should be performed quarterly.

If tanks have a supervised water level alarm, the water levels should also be inspected quarterly. If the tanks don’t have alarms, they need to be inspected monthly.

Like the other standards mentioned in this article, the NFPA 25 also outlines specific processes for visual testing, including the use of underwater submersible remote-operated vehicles for in-service evaluations, traditional visual inspections for out-of-service tanks, and additional testing like ultrasonic thickness testing, adhesion testing, dry film thickness, wet sponge testing, spark testing, and vacuum box testing.


The NFPA also has another standard known as the Standard for Water Tanks for Private Fire Protection (NFPA 22), which permits tanks made of materials like steel, wood, concrete, or coated fabrics and categorizes tanks into types like elevated tanks, tanks at or below grade, and pressure tanks.

The American Society of Mechanical Engineers (ASME)

The ASME provides standards for the construction of boilers and pressure vessels, including certain types of storage tanks. These standards are widely recognized and followed globally. According to ASME standards, pressure vessels must be inspected and tested every five years. These inspections could include non-destruction evaluations and hydrostatic pressure testing. As always, it’s best to work with an ASME-certified inspector when getting a pressure vessel inspected, as there are many guidelines to follow.

What Happens During an Inspection

Industrial storage tank inspection

The exact process will vary based on what type of tank is being evaluated and what type of inspection is being performed.

Generally, a tank inspection involves:

  1. Pre-Inspection Preparation: In this step, the inspector ensures the tank is safely accessible and gathers the tools and equipment needed to perform the inspection safely and efficiently.
  2. External Inspection: The inspector checks for external signs of wear, corrosion, and damage, evaluates support structures, anchorage, and foundation, and verifies tank alignment and level.
  3. Internal Inspection (If Applicable): If the tank needs an interior inspection, the inspector will ensure the tank is empty and safe for entry. Then, they will review the interior for corrosion, pitting, and cracks and check welds, joints, and internal coatings.
  4. Roof & Manway Inspection: The inspector will examine the roof for structural integrity and corrosion and evaluate manways, hatches, and seals.
  5. Instrumentation & Accessory Inspection: The inspector will check gauges, meters, level indicators, valves, pipes, and fittings.
  6. Non-Destructive Testing (If Required): If the tank needs non-destructive testing, the inspector will most likely perform ultrasonic testing for thickness measurement and conduct radiographic or magnetic particle testing on welds.
  7. Final Assessment: The inspector will review all the findings, double-check compliance with relevant standards, and prepare a detailed inspection report with recommendations.

Schedule a Certified Inspection Today

If your tank is due for an inspection, it’s time to call Archview Services. We provide STI and API-certified inspections for underground and aboveground storage tanks and ASME-certified pressure vessel inspections to businesses throughout the Midwest. We always provide comprehensive reports to ensure you remain compliant with EPA regulations.

In addition to our certified inspections, we provide cleaning, repair, removal, and demolition services for residential and commercial storage tanks.

Please contact us today to learn more about our capabilities or to schedule a certified inspection.