Aboveground storage tanks (ASTs) are large metal tanks that store liquids and gases such as petroleum products, crude oil, chemicals, water, acids, and fertilizers. These bulk tanks come in various sizes and shapes and are a common sight in manufacturing across the United States.

Due to the environmental impact of potential leakage, there are mandatory regulations on the installation of containers and secondary containment requirements for aboveground storage tanks. In the absence of proper secondary containment, industrial units could face challenges related to spillage and subsequent monetary penalties.

Aboveground Storage Tanks: Containment Challenges

Corrosion

Internal corrosion of plates lining the bottom of the tank is one of the foremost reasons for the failure of ASTs. This type of corrosion slowly weakens the structure, resulting in either leaks or a rupture, causing spills in storage areas.

Plumbing Failure

Pipes that go in and out of the tanks can also corrode and face mechanical breakdown. This is especially true for tanks that store acids or other corrosive chemicals. Without regular maintenance and plumbing, they can break and cause leaks.

Sub-standard Maintenance

ASTs need regular inspection and maintenance. Replacing fuel filters and keeping the surroundings clean is key. Lack of regular maintenance and poor management of containers will jeopardize reliability and ultimately lead to leakage. A faulty leak detection system can also lead to tank failure.

Dispensing Failure

Faulty valves, leaking pipes, and human error can cause entire tank systems to fail.

Delivery Problems

A massive aboveground tank is essentially a bulk storage container that many operators might want to fill to the brim, which could cause the tank delivery system to fail.

Physical Safety

Despite necessary safety measures, aboveground tanks that sit unguarded are susceptible to vandalism or damage caused by storms, hurricanes, and floods.

Leaked liquids from large ASTs can be hazardous for human health and detrimental to groundwater and surface water. This calls for a collection or secondary containment system with an aboveground storage tank.

Types of Secondary Containment for Aboveground Tanks

Commonly, containment areas and systems are referred to as release prevention barriers (RPBs). Here are some methods for preventing spills from aboveground storage tanks:

Dike Tanks

Dike tanks are steel secondary containment solutions that cover the main tanks, piping, and associated equipment. Any spill from the main tank goes into the dike, preventing release into the surrounding area.

Containment Sumps

Made of high-resistance polyethylene or PVC, containment sumps can withstand harsh, corrosive environments. You can enclose storage tanks for oil, chemicals, petroleum products, fuel, and other hazardous materials inside containment sumps to prevent leaks. Sumps usually have a capacity of 360 to 1,000 gallons.

Berms

Berms offer flexible containment systems that prevent oil and chemicals from spilling and are available in various sizes. Some examples include utility trays, foam wall spill berms, drive-over spill berms, and economy L-bracket berms. They are generally used with frac tanks, tanker trucks, or intermediate bulk containers (IBCs).

Rooms with a Sealed Floor

Sealed-floor rooms provide an airtight space in which to house the main tank. In the event of leakage, they prevent any liquids from spilling beyond the room itself.

Elevator Pits

Positioned in the ground below the surface of the lowest level of the tank, these pits will capture and hold any liquid that flows out of the tank.

Containment Pallets

Containment pallets are essentially elevated platforms that hold drums containing liquid. These pallets are capable of supporting drums weighing up to 500 kg. In case of spillage or leaks, the pallets prevent the liquid from flowing and contaminating the surrounding environment. The pallets are fully recyclable, chemical and UV-resistant, and compatible with most pallet trucks and forklifts.

Double-Walled Steel Tanks

Often oriented horizontally, these steel storage tanks are housed inside another steel tank, giving you the advantage of a secondary containment solution in one unit.

Obviously, containment units should be impervious to the stored liquid. To accomplish this, these units are made of steel, concrete, asphalt, clay, or plastic. Your containment system should be able to contain 100 percent of the liquid stored in the largest tank. This includes precipitation, such as ice, snow, rain, and stormwater runoff.

Containment for Maintenance of Large ASTs

Regular maintenance is essential to preventing accidental leaks and for the longevity of the tank. During maintenance, you may need to transfer all the contents to another temporary tank. An ideal solution is to buy or rent closed-top frac tanks to safely store liquids.

For hazardous materials, you can use double-wall frac tanks with internal spill containment systems.

How Much Does Secondary Containment for ASTs Cost?

The cost depends on the secondary containment method. You might need only a mud mound around the tank or a liquid-tight, epoxy-coated concrete slab. It will vary depending on site needs, but in most cases, an earthen dike system works well.

Regulatory requirements also contribute to costs for ASTs, as per the SPCC regulation (40 CFR Part 112) under the United States EPA. The costs also depend on the regulations for secondary containment solutions as defined in the RCRA Title 40 Code of Federal Regulations (CFR) Part 264.

Here are some factors to consider when determining secondary containment costs:

• Construction: The tank should not fail under pressure gradients, climate conditions, or the stress of daily operations.
• Containment volume: Larger tanks require bigger secondary containment solutions. The facility catchment basin should have sufficient capacity to hold the liquid from the largest container with enough freeboard to hold precipitation.
• Permeability of the containment liner: Reinforced polyethylene, RPP, and XR-5 are some liners used in the industry. Each differs in price, durability, and the contents they can handle.
• Properties of the liquid in storage: If the liquid is a highly corrosive chemical, the cost of meeting secondary spill containment requirements may be higher. The material of the tank and catchment liner should not corrode upon contact with the liquid.
• Environmentally sensitive sites: Costs increase when dealing with sensitive environmental conditions that require leak detection and monitoring systems.
• Insurance: For coverage in the event of environmental pollution.

Tanks need liquid-level alarms and audible and visual systems that communicate seamlessly between the container gauge and the pumping station via a constantly monitored surveillance station.

Contact us to determine the right containment solutions for your tanks.

A Quick Look at Some Secondary Containment Regulations for ASTs

Aboveground storage tanks (ASTs) that hold polluting liquids are subject to the Spill Prevention, Control, and Countermeasure (SPCC) regulation (40 CFR Part 112) under the United States Environmental Protection Agency (EPA). This mainly applies to on-shore oil storage and processing facilities.

The protocols for secondary spill containment fall under the Resource Conservation and Recovery Act (RCRA) Title 40 Code of Federal Regulations (CFR) Part 264.

• Section 40 CFR 264.175(b): Design and construction of secondary containment systems
• Section 40 CFR 264.175(c): Storage area for containers that hold non-liquid waste
• Section 40 CFR 264.175(d): Non-liquid waste where a storage system itself will not suffice and a secondary containment structure is required
• Section 40 CFR 264.193(b): Prevention of hazardous waste escaping from secondary containment into soil and groundwater
• Section 40 CFR 264.193(e): Liners used in containment systems

Facilities that store hazardous waste also needs to comply either with the Uniform Fire Code (UFC) or International Fire Code (IFC).

Note that regulations vary with location. Some states and municipalities in the United States have adopted the UFC from the National Fire Protection Association (NFPA), also known as NFPA 1.

Get in touch with Ironclad Environmental Solutions to explore containment solutions and regulations that apply to your location.

FAQs

What Are Some Common Leak-Management and Control Protocols for ASTs?

Defective internal heating coils that result in leakage must be monitored via the steam return and exhaust lines. These efforts will keep uncontaminated rainwater from leaking into storm drains and prevent effluents from draining into open waters.

If these liquids bypass your treatment system, you can look to following solutions:

• Seal the bypass valve
• Inspect retained rainwater to ensure that it will not lead to a discharge
• Supervise the opening and resealing of the bypass valve
• Maintain records of leaks and similar events

Who Regulates Aboveground Tanks?

ASTs fall under the Environmental Protection Agency (EPA) and Resource Conservation and Recovery Act (RCRA) Title 40 Code of Federal Regulations (CFR) Part 264.

How Often Should You Inspect an Aboveground Tank?

Monthly inspections are ideal. ASTs should be tested for integrity regularly and whenever you repair the tank. The frequency and type of testing must factor in tank size and design, such as floating roof, skid-mounted, elevated, or partially buried.

For detailed guidelines, refer to the SPCC program bulk-storage container inspection fact sheet by the effluent EPA.