The choice of fuel oil storage tanks that are offered can be quite confusing, but if you answer a few simple questions you will soon be well on your way to finding the right tank for your needs.
There is no one-size-fits-all solution when it comes to fuel oil tanks. The space you have available for a tank, the amount of heating oil your property consumes and the size of your budget will all have a bearing on your decision.
Let’s start with the basics:
a) Is the oil storage tank for a domestic or commercial property?
A commercial property may have a greater choice of where the tank can be sited as aesthetics are likely to be less of an issue but the UK Government’s Oil Storage Regulations also vary between domestic and commercial installations.
b) Where can you site an oil tank on the property?
It isn’t enough to find a space with sufficient footprint and headroom for an oil tank. It will also need to be accessible to delivery vehicles and have enough room around it for maintenance and servicing. You will want it to be near enough to the property to make connection to your system easy, but far enough away to satisfy fire safety regulations. You will also need to make sure it is far enough away from any watercourse to prevent pollution in the event of a leak or spillage.
c) How much storage capacity will you need?
You want to be sure your oil tank is large enough to cope with demand; constantly paying for the tank to be refilled is heavy on the pocket and the environment. On the other hand, while a larger tank might empower you to benefit financially by buying in larger quantities, it will cost more to buy and install the tank and take longer to recoup the extra through oil price savings.
You should now be forming a picture of what you need. Let’s look at some other important questions:
How should your fuel oil tank be constructed?
Single-Skin Oil Tanks
Heating fuel oil tanks were traditionally a single-skin steel fabrication; just a single layer of steel stood between the oil in the tank and the big, wide world. As you can imagine, this didn’t provide much protection against oil leaks, particularly if the tank was damaged or rust started to eat through the steel.
One way of protecting the environment against oil pollution is to sit the tank in a sealed reservoir or ‘bund’ that captures any oil that leaks from the tank. Oil-absorbent materials can be used to soak up the leaking oil and safely dispose of it.
With the advent of oil storage tanks made from moulded plastic, the single-skin tank became lighter to move, cheaper to manufacture and corrosion-free. However, plastic is also not as strong as steel and is at greater risk of impact damage.
Single-skin oil tanks are still permitted for domestic use in England and Scotland, under certain circumstances and provided specific conditions are met (only bunded oil tanks are legally permitted in Wales).
Before deciding on a single skin oil tank, we strongly recommend you thoroughly read the Oil Storage Regulations and pay for an OFTEC-approved engineer to carry out a risk assessment.
Bunded & Double-skinned Oil Tanks
Bunded oil tanks take the concept of a single-skin tank in a bund and amalgamate them into a single, double-skinned tank. The inner skin functions as a receptacle for the oil while the outer skin protects the inner skin (and the oil) against impact damage. It also acts as a second line of defence should the inner skin develop a leak, containing any spilt oil between the two layers.
Bunded and double-skinned oil tanks are essentially similar in design: the term ‘bunded tank’ is used for aboveground storage while ‘double-skinned tank’ is used for underground storage.
Bunded oil tanks are understandably more expensive to manufacture and purchase than single-skin tanks, but even in England and Scotland, a bunded oil tank is the only legally permitted option for oil storage above a given capacity (3,500 litres in England and 2,500 litres in Scotland).
However, even if you don’t live in Wales and you’re storing less than the permitted maximum for a single skin tank, a bunded tank gives so many additional benefits that the extra outlay at the beginning is worthwhile.
- For a start, it is easier to get permission to install a bunded oil tank than a single-skin oil tank.
- Manufacturers also tend to offer longer warranty periods on bunded tanks than on single-skin tanks, so you can effectively repay the additional purchase cost over a longer period.
- Bunded tanks are also designed to prevent rainwater from entering the inner tank and degrading the oil quality.
- In the unfortunate event of the inner skin of a bunded tank springing a leak, the oil can be retrieved from the bund and reused (oil spilt from a single skin tank can only be discarded).
What oil tank profile is best for you?
As the size and shape of the available space varies from one installation to the next, oil tanks are manufactured in a choice of profiles.
Vertical oil storage tanks
Where height and aesthetics aren’t critical and capacity is important, vertical oil storage tanks are the most popular choice as they offer the highest storage capacity per square metre of footprint.
They are most commonly found in commercial, agricultural and industrial environments where oil consumption is highest. However, vertical oil tanks can be unsightly and hard to conceal in many situations.
Horizontal oil storage tanks
If a greater footprint area is available, a horizontal oil storage tank can be a good solution for high-capacity storage. Benefits of a horizontal tank include greater stability, a more even weight loading across a wider area and a lower height reducing its visibility. Access to the top of the tank is also easier and safer if required.
Low-profile oil storage tanks
Similar in design to horizontal oil tanks, low-profile tanks (as the name suggests) feature an even lower tank height, making them easier to conceal behind a wall or fence. They can be useful for domestic heating oil requirements where there is a sufficient footprint and aesthetics are important.
Slimline oil storage tanks
These compact oil storage tanks feature a tall, narrow design that enables the tank to be installed in confined spaces such as alongside a path or to provide oil storage without encroaching unnecessarily on areas such as driveways or gardens.
What material do you want your oil tank to be made from?
We have already mentioned that fuel oil tanks can be made from steel or plastic. Let’s now look at their pros and cons, and consider an innovative alternative: plastic in steel!
Plastic oil storage tanks: the pros and cons
Plastic tanks are cheaper to manufacture than steel tanks, making them a better option if you’re working to a budget. They also weigh less, making them easier (and therefore cheaper) to transport and install.
They are made from hard-wearing UV-stabilised polymers that are proof against corrosion and offer high resistance to weathering. The polymer is also a better insulator than steel, so is better at protecting the oil against extremes of temperature.
As they are rotationally moulded as a single component, they don’t have any seams or joins that could potentially become leak points.
However, plastic is not as robust as steel and doesn’t have the same resistance to impact damage. It is also potentially more vulnerable to fuel theft.
Due to their rotational moulding manufacturing process, plastic tanks are only available in a limited range of sizes and shapes, and the total oil storage capacity is restricted by the strength of the plastic.
Steel oil storage tanks: the pros and cons
Steel tanks are more suited to commercial and industrial applications, where they offer greater protection against impact damage and weathering. While corrosion is a potential problem, a well-maintained steel tank should be able to outlast a plastic tank.
Steel tanks also offer a greater level of security, as their harder material offers better resistance to fuel theft by drilling through the tank and siphoning the fuel, while their increased weight acts as a further deterrent to tank theft.
As steel tanks are fabricated to order, they can be manufactured to specific dimensions and larger storage capacities.
While steel tanks require de-rusting and repainting to maintain them in good condition, this also means they can be painted in any shade to match corporate colours, stand out to reduce the risk of damage caused by manoeuvring vehicles, or blend more naturally with their surroundings if aesthetics are important.
As with plastic tanks, they also have drawbacks. One of these is that steel tanks are more expensive to manufacture and cost more to transport and install due to their weight.
External corrosion can weaken the tank’s structure, particularly at welded seams and joints, and this requires regular maintenance. Corrosion can also accumulate inside the tank, clogging filters.
While steel is more resistant to impact it is also less forgiving; welds and seams can crack, resulting in leaks, environmental pollution and expensive repairs.
Steel is also an excellent heat conductor; in hot weather, this heat can quickly transfer to the oil and develop an oil-degrading bacterial bloom.
Plastic in steel fuel oil tanks – the best of both
As we have already seen, plastic and steel fuel oil tanks both have advantages and disadvantages. With our innovative plastic in steel design, we have combined valuable features from plastic and steel to make a tank that offers the best of both options.
Using an off-the-shelf plastic tank for the inner tank ensures leakproof quality at a cost-effective price and reduces the overall weight of the tank, while the welded steel outer tank creates a bund between the two to capture any oil spilt in the unlikely event of the plastic tank leaking.
With plastic in steel oil tanks, you get the higher strength and security of the steel outer tank with the flexibility and corrosion resistance of the plastic inner tank. The steel outer layer protects the plastic inner against deterioration caused by UV and weather while the plastic inner layer acts as heat insulation to protect the contents against bacterial growth.
A plastic in steel tank also offers the opportunity to have your tank painted in corporate colours. If you are installing it at home and in a position where it can be seen, you can even get creative and use paints to camouflage it or turn it into an art installation with a design of your choosing!
Making your decision
We hope that this guide clarifies why there are so many options available to you, and helps you make a decision you are happy with when choosing a new or replacement fuel oil tank for your property. Of course, our storage tank experts are always on hand to help you with further advice and answer your questions; call us on 01953 665940 or email info@tanks-uk.com.