Tank Inspection Services

Tank Inspection Services

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Aboveground Storage Tank Inspection Service Overview

Since 1994, CommTank has provided comprehensive aboveground storage tank inspection services for clients throughout Massachusetts, New Hampshire, Connecticut, and Rhode Island.

As a certified tank inspection company, our support for all types of tanks is unequaled in New England.  We design, build, install, repair, remove and inspect tanks.

This firsthand experience with the complete lifecycle of aboveground storage tanks ensures that you gain expert support that only a full-service company can provide.

AST tank inspection photo.

Tank inspection by certified AST tank inspector in Boston, Massachusetts.

CommTank is also one of the very few companies in Massachusetts and New England with qualified tank inspectors who are API 653 certified by the American Petroleum Institute® and STI SP001 certified by the Steel Tank Institute.

That's important, because your permit to operate an AST hinges on complying with state laws that require an annual inspection by a certified professional inspector.

We know the aboveground storage tank inspection requirements, and stand ready to serve as your AST inspector.

AST Inspection Requirements by State

Massachusetts AST Inspection Requirements

In Massachusetts, the law applies to any AST that holds over 10,000 gallons of fluid other than water.

    • 502 CMR 5.00 – Massachusetts Permit and Inspection Requirements of Aboveground Storage Tanks of More than 10,000 Gallons Capacity.

Rhode Island AST Inspection Requirements

In Rhode Island, the Department of Environmental Management maintains an AST Resources page that requests completion of an Aboveground Storage Tank Registration Form by operators with a single or combined AST capacity of 500 gallons or greater. The state maintains and enforces Oil Pollution Control Regulations (250-RICR-140-25-2).

New Hampshire AST Inspection Requirements

In New Hampshire, the NH Code of Administrative Rules outlines the definitions, requirements and standards for AST installation, inspection, operations and removal.

Tank Inspection Certification and Licensing

With every tank certification inspection we perform, our team’s outstanding reputation grows. Our goal is to provide you with peace of mind and assurance that your tanks are completely reviewed, with all concerns noted.

You gain a thorough report that details what was inspected, what passed and failed, and photographs of problem areas. You also receive a written summary of our findings regarding the interior and exterior condition of your tank.

CommTank supports your team’s safety and productivity by keeping your tanks durable and compliant with local, state and federal laws.

Our Tank Inspection Licenses

    • API 653 – American Petroleum Institute AST Inspector
    • STI SP001 – Steel Tank Institute Aboveground Tank Inspector
    • API 510 – American Petroleum Institute Pressure Vessel Inspector
    • API 570 – American Petroleum Institute Pipeline Inspector
    • IEE - Asbestos Inspector Certification #20-2786-102-213648
Tank inspector in Hartford, CT.

The tank inspector uses a holiday tester to check for lining pinholes at a Connecticut manufacturer.

Types of Aboveground Storage Tank Inspections CommTank Performs

Facility owners and managers throughout New England entrust CommTank with their needs for compliant, quality AST inspection.  Below you’ll find examples of the types of ASTs we inspect and the types of integrity tests we perform.  We also discuss how we inspect tanks, and share AWWA recommendations.

Above Ground Storage Tank Types

    • Petroleum Storage Tanks
    • Chemical Storage Tanks and Pressure Vessels
      • Sulfur, Anhydrous Ammonia, etc.
    • Marine Fuel Tanks
    • Fire-Water Tanks
    • Fire Suppression Tanks
    • Linen Wash Tanks
    • Food Storage Tanks
    • Potable Water Tanks
    • Frac Tanks

Tank and Piping Integrity Tests

    • Visual Inspection
    • Ultrasonic Thickness Testing
    • A-Scan and B-Scan
    • Magnetic Flux Leakage Testing (MFL scan)
    • Hydrostatic Testing
    • Inert Gas Leak Testing
    • Magnetic Particle Testing
    • Vacuum Box Testing
    • Diesel Fuel Testing
Aerial tank inspection

A remote-controlled drone captures video footage of a large AST for a tank inspection report.

Storage Tank Inspection Procedures

Tanks are inspected to the standard to which they were built.  For most internal AST audits, tanks must be taken out of service, cleaned, and made ready for the inspector to enter the tank.

We inspect potable water storage tanks while the tank is in service using our remote-operated vehicle (ROV). In situations with limited storage tank roof access, we perform the visual inspection using drones.

AWWA Recommendations for AST Inspection

The American Water Works Association (AWWA) is a non-profit organization that provides water management education and advocates to preserve water as a resource.

Among its members are utilities that supply roughly 80 percent of the drinking water and treat nearly half of the wastewater in the U.S.

As outlined in Section 3.3 of the document titled Finished Water Storage Facilities prepared by the AWWA for the EPA Office of Ground Water and Drinking Water Standards and Risk Management Division:

The AWWA Manual M42 (1998) recommends that tanks be drained and inspected at least once every 3 years or as required by state regulatory agencies. Most states do not recommend inspection frequencies thereby leaving it to the discretion of the utility. States that do have recommendations include [among others listed] New Hampshire (5 years), and Rhode Island (external once per year; internal, every five years).  Kirmeyer et al. (1999) recommend that comprehensive inspections be conducted every 3 to 5 years for structural conditions and possibly more often for water quality purposes.

Tank inspection company equipment photo.

CommTank AST Tank Inspection Equipment

We own, operate and maintain our own AST inspection equipment.  This saves our clients time and money because we can mobilize quickly and pass on the cost savings generated by not outsourcing equipment.

Tank Inspection Robots (Underwater Remote Operated Vehicles)

Robotic inspection is performed using an unmanned remotely operated vehicle (ROV) in an AST full of water.  It is typically performed in potable water tank inspections and fire water tank inspections.  The ROV can identify tank imperfections and other issues that may require the tank to be drained for repairs and further review.

Many municipalities now require large facilities to maintain their own fire water tank (typically an AST in the penthouse/roof level), instead of tying into the city’s water system.  A tank can be inspected either robotically with an ROV; a scuba tank inspection by a diver when the tank is full of water; or after the tank is drained (and water stored) to enable inspector entry.

Tank Inspection Drones (Aerial Remote Operated Vehicles)

API and STI Standards require visual inspection of an AST.  A remotely-operated aerial drone with a mounted camera performs visual overhead reviews and takes photos.  Previously, ladder or crane access was required to inspect from overhead.

Remote Cameras for Pipe Inspection

STI Specifications require up to the first flange or fitting of aboveground storage tank piping to be inspected. Since this distance can be up to 50 feet, CommTank inspectors use remote cameras to probe for interior pipe corrosion or damage.

Fuel tank inspector photo.AST Tank Repairs

CommTank has the experience, expertise, and equipment to deliver comprehensive single-source support for your facility’s aboveground storage tanks – including full inspection, repair, and restoration services.  

All work is performed by our in-house staff of certified technicians and divers, experienced welders, and skilled equipment operators.

As a reputable tank inspection company, we self-perform all blasting and coating work, which limits our clients’ tank downtime to 24 -48 hours in many cases. 

For example, we restored a chemical tank in-place in just four days by repairing, welding, and coating it for a safe return to service.

We also provide the service of fuel storage in temporary tanks while we rebuild and restore ASTs.

Above Ground Storage Tank Inspection Checklists

Through our decades of experience with inspecting aboveground tanks, we know that the process is no longer driven solely by API or STI standards, but also by insurance coverage standards. 

Based on this experience, we’ve developed our own robust CommTank aboveground storage tank inspection checklists and now routinely inspect things not traditionally required, to meet the highest level of commercial and industrial insurance standards.

Tank company inspecting pipe.CommTank Inspects Beyond Typical API or STI Checklist Items

For example, many large insurance firms now require building owners with large boiler systems to upgrade their equipment above and beyond what STI or API standards require.

This is because many insurance companies have researched factors that typically create risk or liability regarding ASTs, and now seek to mitigate that risk.

Some insurance firms require secondary containment around piping, even when the code indicates that double walls for exposed piping aren’t necessary.

For example, on the roof of a building running single-walled pipes full of oil, an insurance company may require double-walled containment. 

The benefit of our tank inspection company is that when we inspect aboveground exposed pipe, either single or double-walled, we call out what insurers typically require, based on our experience with mission-critical buildings throughout New England.

This promotes a smooth process of obtaining or maintaining insurance coverage, since we provide our clients with comprehensive tank inspection reports that address what insurance companies look for.

What We Look For When We Inspect a Tank

Examples of issues we look for when we inspect an AST:

    • Coating Failure
    • Condition of Repairs, Patches
    • Corrosion
    • Cracking
    • Declivity
    • Deformations
    • Dents
    • Distortions
    • Leak Detection
    • Pitting
    • Settlement
    • Signage
    • Site Drainage
    • Spalling
    • Water in Tank

Tank Inspection Protocols: STI SP001 and API 653

No matter the type of AST, routine inspection protocols are required for all tanks larger than 55 gallons. This ensures compliance with federal EPA regulations, and state and local building and fire codes.  It also helps to reduce the risk of leaks, spills, and contamination that can lead to product loss, costly cleanup and liability concerns.

Spill Prevention Control and Countermeasure (SPCC) Regulation

The Spill Prevention Control and Countermeasure (SPCC) rule was developed by the EPA under 40 CFR part 112 to help prevent facilities from discharging oil into local navigable bodies of water or adjoining shorelines. It requires any facility that stores more than 1,320 gallons of oil in containers 55 gallons or greater to create, maintain and execute an SPCC plan if a spill from their facility could reach navigable waters.  An SPCC plan requires that aboveground storage tanks be regularly inspected.

SPCC 40 CFR 112. 8(c)(6) Indicates testing and inspection of aboveground containers for integrity in accordance with industry standards.

Learn more about the SPCC Regulation in the EPA publication, A Facility Owner/Operator’s Guide to Oil Pollution Prevention.

Tank inspection in Rhode Island.

Tank inspector inspecting tank in North Kingstown, RI.

STI versus API Inspection Types

Federal regulations such as SPCC, as well as state and local rules, created the need to regularly inspect aboveground storage tanks.  STI and API standards were created to ensure compliance with federal and state regulations.

Traditionally, STI inspections were conducted on smaller, shop-fabricated tanks, and API inspections were performed on larger, field-constructed tanks, as outlined below.

Traditional Inspection Protocols Per Tank Standard

    • Field-built tanks built to API 650 Standard typically undergo an API 653 Inspection
    • Shop-built tanks built to UL 142 Standard typically undergo an STI 001 Inspection

Today, however, it has become common for tank owners or facility managers to request or require API protocols for shop-fabricated tanks with less than 50,000-gallon capacities.

This is usually because API is a more stringent protocol, and provides a more thorough report.  Correspondingly, STI protocols are also now being conducted on larger tanks with 50,000 to 75,000-gallon capacities.

Throughout New England, STI tank inspections are more common than API, which are more commonly performed in large fuel storage areas.

Comparison of STI SP001 vs. API 653

Regulatory Compliance:  Both standards provide compliance for tank integrity inspection for SPCC and local environmental regulations.

Risk-Based Benefit:  Both standards provide a reduction in audit frequency for use of release prevention barriers for reduced spill risk.


    • STI SP001 – Applies to all configurations of shop-built tanks and smaller field-erected tanks.
    • API 653 – Applies to field-erected tanks (welded or riveted). Includes guidance for repair, alteration, relocation and reconstruction.

STI SP001 Standard 

The scope of the STI SP001 Standard includes evaluation and testing of the following types of tanks:

    • Aboveground shop-fabricated tanks
    • Small field-erected tanks
    • Portable containers
    • Associated secondary containment

ASTs are inspected to identify their condition and record any changes, and to evaluate and determine suitability for service.

The Steel Tank Institute/Steel Plate Fabricators Association (STI/SPFA) provides STI SP001 related information, including links to download SP001 Checklists.

Components of an STI SP001 Above Ground Tank Inspection

    • Primary tank thickness determination
    • Secondary tank (if present)
    • Tank foundation, supports & anchors
    • Tank gauges & alarms
    • Overfill valves & alarms
    • Insulation covering
    • Tank appurtenances
    • Non-emergency vents
    • Emergency vents
    • Release prevention barriers
    • Spill control systems
    • Piping (Tank valves & connections)
API 653 Standard

The scope of the API 653 standard for inspection of aboveground storage tanks includes:

    • Assessment of suitability for continued use
    • Assessment of brittle fracture risk
    • Recognizes fitness-for-service assessment concepts

This type of audit applies to steel storage tanks built to API 650 or older API 12C. It is performed to ensure minimum requirements for maintaining a tank’s integrity after it is placed into service.  It also addresses the repair, alteration, relocation, and reconstruction of ASTs.

Components of an API 653 Tank Inspection
    • Tank Foundation
    • Bottom (flaw & thickness detection)
    • Shell (flaw & thickness detection)
    • Brittle Fracture/Failure Assessment
    • Structure
    • Roof
    • Attached Appurtenances
    • Nozzles to face of 1st flange, 1st threaded joint, or 1st welding-end connection
Tank inspector testing tank.

AST tank inspector inspecting tank in Portsmouth, NH.

Inspection Frequency for Aboveground Storage Tanks

Municipal fire codes generally mandate minimum requirements for fire protection storage tank inspection programs in accordance with National Fire Protection Association (NFPA) 25.

NFPA 25 requires external AST inspections every 3 years and internal AST inspections every 5 years for water-based aboveground storage tank systems. Insurance policy conditions also reference NFPA 25 and may recommend a more frequent cycle.

Local Requirements for AST Inspection Frequency

Local regulations require that the tank owner or his or her designated personnel knowledgeable in-tank system operation inspect their AST either weekly, monthly or quarterly. 

State Requirements for AST Inspection Frequency

State regulations require that the tank owner hire a certified technician to regularly inspect (monthly, quarterly, or annually). Traditionally, daily tank-sticking was required to monitor the level of fuel or other tank contents, but modern electronic tank management and control systems now provide continuous monitoring.

As part of the required annual AST review, the components of these electronic systems must be reviewed by a technician certified to inspect the branded tank and equipment.

STI Recommendations for AST Inspection Timing

STI provides a reference chart for tank owners to follow, that indicates when tank components should be inspected. 

API Recommendations for Tank Inspection Timing

API recommendations are based on a tank’s life expectancy. For example, if degradation is found after five years, this data is used to calculate future timing.

API 653 Frequency Protocols: 

    • Routine In-Service Inspections – Conducted monthly by owner personnel knowledgeable in-tank system and operation
    • External Inspections – Conducted every 5 years by an authorized API 653 inspector, while the tank is in service, including ultrasonic thickness inspection
    • Internal Inspections – Calculated according to the API 653, Section 6.4.2 (corrosion rate determination); performed by an authorized API 653 Inspector; while the tank is out of service; including assessment of tank bottom condition
    • Initial Internal Inspections Intervals – 10 yrs. from initial service date, or based on Risk-Based Inspection (RBI) Assessment criteria
Fuel inspectors in on tank in Massachusetts.

Fuel tank inspection of fuel oil tank in Boston, MA.

Internal versus External Inspections

Periodic AST Inspection

    • Required by: STI Standard   
    • Conducted by:  Tank Owner’s inspector (Qualified on-site person at facility)
    • Frequency: Monthly and Annually

Formal EXTERNAL (In Service) Inspection (FEI)

    • Required by: STI Standard, API Standard
    • Conducted by: Certified STI inspector or API inspector
    • Frequency: Every 5 years, or as determined by (#); E(20) = formal inspection every 20 yrs.

Formal INTERNAL (Out of Service) Inspection (FII)

    • Required by: STI Standard, API Standard
    • Conducted by: Certified STI or API inspectors
    • Frequency: As determined by (#); E(20) = formal inspection every 20 yrs.


    • Shop-Built/Fabricated AST – Horizontal or Vertical, Single or Double Walled
    • Steel Diked AST – Open or Closed
    • Concrete Exterior AST
    • Field-Erected AST – Smaller/Limited Size
    • Portable Containers – Drums, Totes (IBCs) – Plastic, Steel, Stainless

How Much Does an Aboveground Storage Tank Inspection Cost?

Depending upon several factors such as tank location, access, size, contents, and insulation, the cost of an STI inspection can vary within a range, and the cost of an API inspection can vary within a range.  CommTank inspectors have the expertise and experience to discuss your needs and provide you with a cost-effective estimate based on your project’s unique requirements.

Project Scope & Tank Configuration Factors that Affect Cost to Inspect

    • Tank location – for example, access to the 20,000-gallon capacity vertical ASTs located in vault rooms below the sidewalk in Boston’s Post Office Square necessitates a 50-ft drop into the tanks.
    • Tank interior access – for example, if your vertical tank has a near-edge opening that requires a 35 to 40-foot drop on wire on an angle to access the tank to inspect it.
    • Size of tank
    • Tank insulation
    • Tank contents

How to Track a Corrosion Rate Projection

The Corrosion Rate Prediction (sometimes referred to as a Corrosion Rate Projection) represents an estimate of the remaining life of the tank based on the observed corrosion rate. This rate is compared between inspections, to track whether it is accelerating.

Inspecting Potable Water Storage Tanks

As one of the northeast’s most sought-after above ground potable water storage tank inspection companies, CommTank follows stringent sanitizing protocols to protect potable water storage tanks from contamination.  We not only inspect potable water tanks; we also ensure each tank’s quick return to service by performing repairs and full specialty restoration using approved drinking water tank coatings.

Steel IBC Tank Certification and Re-test

Intermediate Bulk Containers (IBC) are manufactured to DOT-57 or UN31-A and must meet specific tolerances and material standards. The certification duration is limited so IBC containers must be re-tested every 30 months of service for proper UN/DOT labeling during shipment. IBC recertification is comprised of pressure tests, material thickness measurements, and exterior and interior visual inspections.

330-gallon IBC containers after compliance inspection

Intermediate bulk containers used in chemical storage are ready for shipment

Tank Inspection Frequently Asked Questions

AST Tank Inspection FAQs

Yes. CommTank is fully certified and licensed to inspect, repair, and coat tanks.  We have the trained in-house staff and professional equipment to get your aboveground storage tank back into service quickly, following safe and approved restoration procedures.

Yes. For fuel tank inspections, CommTank sets up temporary tanks and transfers your fuel out of your fuel tank while it’s being inspected.  This ensures that your facility remains fully functional and connected to a fuel source, to eliminate or minimize downtime.  Our expert fuel tank inspection technicians work to sequence and coordinate the connection, so you’re up and running in minutes.

CommTank makes it easy to maintain compliance with state laws by scheduling annual inspections for you. Regular checkups also drastically reduce your risk of noncompliance that could result in fines from other regulatory agencies, and helps to minimize your tank maintenance costs.

Periodic informal inspections of an AST can be done by a properly trained individual, usually an employee of the firm that owns the tank. However, when requirements call for a formal inspection to a specific standard, it should only be performed by a licensed and certified inspector.