Everything You Need to Know About Underground Storage Tank Management

Commercial underground storage tanks are common, but there is a need to maintain and utilise these tanks properly to get the most benefit from this solution. There are some very manageable safety risks that require the right amount of attention and maintenance to keep tanks safe and working optimally.

One of these risks is that of spills or releases, these can be very hazardous regardless of the contents.

The majority of UST (Underground Storage Tank) releases are caused by corrosion of components, inappropriate installation, piping system failure, improperly engineered fuel delivery resulting in spills and overfills, and improper operation and maintenance of the UST system. UST leaks can spread quickly across the soil and endanger drinking water sources and building foundations.

Many USTs in the public sector are former petrol tanks that are anything from 20 to 80 years old, single skinned and certainly well beyond their design life.

In this article, we seek to create a comprehensive guide for commercial fuel tank storage owners and managers to get a broad scope of the management practices that go into underground tank management, in particular fuel tank storage.

What is tank management?

Storage tank management refers to the set out and regular responsibilities of the owner for the oversight of their underground tanks that are used for the storage of fuels, oils, and chemicals. There are strict requirements for these tanks to protect both the people that use them and the environment. The goals of storage tank management are to minimise the risks at hand when dealing with tanks and the volume of material stored to ensure installations meet regulatory requirements and remove tanks that are at risk of causing environmental damage.

What are the broad types of tank storage?

Aboveground Fuel Tanks

Aboveground fuel tanks (AST) are quite popular because of their lower long-term maintenance and upfront costs. These tanks are more cost-effective to install compared to underground tanks since you don’t need to spend on backfilling, deep excavation, pavement, or more involved piping. Aboveground fuel tanks offer greater ease of maintenance compared to below-ground tanks. You can check them easily for leaks and access for repairs. This is the reason aboveground fuel storage tanks are preferred for storing fuels and Adblue.

Underground Storage Tanks

At least 10% of the tank’s stored capacity is buried underground in an underground storage tank (UST). Tanks used to store fuels are regulated by the Groundwater Protection Code and the Blue Book (4th Edition), in the case of petrol tanks. These tanks are ideal for customers who wish to optimise their property’s area and/or value. Underground storage tanks can be installed beneath transport yards, out of sight. These tanks are arguably safer because the possibility of an explosion is quite low. However, because these tanks cannot be inspected regularly, the possibility of leakage and contamination increases.

The various types of commercial storage tanks available

Bunded Steel Tanks

Bunded storage tanks are adaptable, long-lasting, and cost-effective. They are constructed from mild steel. These tanks are available in a variety of sizes and may be modified to fit individual project requirements.

Stainless steel

Stainless steel storage tanks are efficient and long-lasting and are the most expensive option. They are an alternative to plastic for Adblue storage.

Fibreglass

Fibreglass underground fuel tanks were tried at the end of the last century but mostly abandoned following product failures. They are not commonly used for above-ground fuel storage.

Bunded plastic

The cheapest storage tanks on the market are polyethylene storage tanks. They have to be bunded if they are going to contain fuel and they are commonly used for home heating oil and Adblue. There have been some failures in the past because of UV damage and they are not recommended for large volumes of storage, greater than 10,000 litres.

How long do underground fuel tanks last?

Steel tanks

Steel underground storage tanks can be a source of concern for owners because no tank lasts forever. The typical life expectancy of a single-skin underground steel storage tank is  15 to 20  years, however numerous elements influence the storage tank’s lifespan projection. These issues include stray electrical current, steel grade and thickness, soil PH level, and many more. Since 2000 underground fuel storage tanks have been double-skinned with leak detection systems. The design life of these tanks is 25 to 30 years.

The rate of corrosion and tank failure is completely dependent on tank type, installation, and site circumstances. In practical use, a UST life span is typically 15 to 20 years. In recent years, however more stringent standards for leak detection and tank longevity have been implemented. If you are worried about your UST, the most important factors to consider are: 

• Age of tank – Is it more than 15 years old?
• Quality of tank/wall thickness / protective coating
• Quality of installation/piping/corrosion protection system
• The moisture content of soil or surrounding materials

What problems do leaking underground storage tanks cause?

Spills from faulty underground storage tanks in commercial sites and petrol stations pose the single greatest hazard to groundwater quality. Petroleum products include contaminants that are extremely difficult to clean to drinking water standards. Because of the health and environmental risks presented by the compounds that can seep from leaking underground storage tanks, they have come under increased regulatory attention across the world. Petroleum fuels and other dangerous substances are commonly stored in these tanks. 

Leaks can occur when transporting fuels to and from storage facilities. To prevent spills or leaks, you should use the following operation control measures:

• During the delivery of liquid hydrocarbon products to your tank during storage
• When you’re dispensing fuel
• When you’re removing waste from the site through drains
• During maintenance and repairs

The amount of danger to groundwater will be determined by your engineering and operational control methods, as well as the location of the tank. Ensure that the product is delivered securely. Spills can occur during the transfer of fuel to a tank, for example:

• During the uncoupling of delivery pipes
• Due to split hoses or leaks from offset fill pipes

You should have addressed the hazards to groundwater during delivery as part of your environmental risk assessment before installing your underground tank. To safeguard groundwater during delivery, establish the following provisions:

• The site has a separate tanker stand area
• The site’s drainage system can capture spills from the delivery point
• The interceptor has enough capacity and has been regularly maintained
• There are overfill prevention systems on the site
• Delivery pipes are clearly labelled
• That the correct delivery procedures are being followed

How common are leaking underground storage tanks?

Underground storage tank leaks can cause a huge disturbance to your business not only because of the damage it causes to the environment but as well as the enormous costs associated with eventual clean-up. This is why it is essential to know the causes of leaks to prevent this from happening. When it comes to damage and repairs, underground storage tanks, regardless of whether they are new service stations with modern double-walled, steel tanks and lines with spill protection devices or old, abandoned, single-walled steel tanks and lines with no-spill protection devices may have leaks which can be prevented. Here are some examples of spillage issues.

• STP pumps

Submersible transfer pumps (STPs) are used to transport products from the tank to the dispenser. These pumps’ fittings lie on top of the tanks, and the pump or manhole is created around the pump so that it may be operated. High-pressure breaches at the top of pumps cause significant spillage. Normally STPs are only found at larger service stations

• Steel tanks

Underground storage tanks are mainly composed of steel. Depending on the soil condition, some tanks can remain for decades without corroding, whereas, at other sites, corrosion happens within 10 years. New tanks are equipped with anti-oxidation technology, which increases their longevity and prevents leaks.

• Overfill and dispenser protection devices that leak

Newer overfill and spill prevention and detection systems function well. However, the seals in these devices might dry up and fracture as a result of this process. Because of the high percentage of ethanol in petro, the seal might become weak and collapse.

• Other causes of leaks

Other sources of leaks include unintentional conditions such as drilling through tanks or pipes during construction, a lack of maintenance, or a maintenance error. Furthermore, there is the risk of dealing with persons with criminal intent to cause leaks in your subterranean storage tank.

Tips for managing underground storage tanks

Staying on top of your storage tank maintenance is easy, you can create a tank-specific checklist that matches your UST facility. Once you identify your site-specific checkpoints, use them to perform operation and maintenance checks at your UST facility regularly. By using these checklists, you know you have done what was necessary to properly operate and maintain your UST system. Proper operation and maintenance activities are the leading aid in reducing the release of regulated substances into the environment.

Here are some tips to consider as you maintain your UST:

Keep up with the technology

New advances in storage tank technology are made every year, and as these advances are made in the world of storage tank maintenance, you must stay up to date on what’s going on, as solutions and preventions to problems are your ammunition against leakage, overflow, or any number of other problems. A great place to do this is the Metron Systems news page, constantly being updated with the content on the latest tech and debated in underground storage systems.

Check for leaks

You should constantly check the underground tanks at your site for leaks and other problems. Contaminants can add to the demise of a tank, which is another reason to have a regular cleaning programme. Single-skinned underground tanks and associated product pipes should be pressure tested every year at a minimum.

Clean the tank regularly

It’s usually a good idea to do this regularly to keep the interior of your tank clean. This prevents the build-up of bugs that can breed in hydroscopic biofuels. Fuel additives can also be used to kill bugs.

Fuel Reconciliation

It is good practice to reconcile fuel issues against stock levels. Online tank gauge systems and fuel management systems that record fuel issues can facilitate this. Discrepancies can be the first sign of a leak problem. Look at our Metron4 website for this type of equipment.

Consult a professional

Owning an underground storage tank takes specialist knowledge and solutions, so contact a professional and ask for advice. Not doing so may end up to the detriment of the environment and cost you money. Vectec Ltd is the UK’s leading fuel storage solutions provider, and you can visit our website or contact us today for expert advice and quality products.