Bunded Fuel Tanks

Bunded fuel tankBunded Fuel Tanks

Bunded fuel tanks are a more common feature on plant sites. The portable Fuelling Stations help reduce the cost of fuel used by generators and plant machinery. They are also part of farming lifestyle enabling farmers in remote locations to have access to fuel at a more continuous flow. The question is why do we use Bunded Tanks to store fuel or oil. Why cant we use and old container?

The answer is contamination. Bunded Storage Tanks are used to keep the environment safe from contamination. If oil, fuel or any other hazardous liquid seeps into the ground it could render the soil toxic. The problem would increase with rain spreading the contaminant deeper into the ground and possibly into local rivers and waterways. The law states that you are responsible for maintaining safe storage of any hazardous liquid from escaping into the environment at risk of huge financial penalty.

How does a Bunded Fuel Tank work?  A bund wall is a shell that contains a tank within.  The outer shell tank (which is also referred to as the second skin)  is usually 10% larger then the content of the smaller tank within.  The outer tank is there to protect liquid escaping from breaches in the internal tank.

Bunded tanks are now used for feed generator tanks to store diesel fuel safely and also as waste oil storage tanks. They can also be converted into portable fuelling station on building sites. This keep fuel safe from being spilled and endangering local wildlife and inhabitants.

You can buy a bunded fuel tank by simply using the Contact Form  at the bottom of the page.

Bunded Tanks

Bunded Tanks

Fuel and Oil Storage Regulations apply to all new installations in the UK (both domestic and commercial) of Fuel and Oil storage tanks. Oil is one of the leading contaminants in the UK, accounting for twenty five percent of all incidents. Guidelines are in place intended to help reduce ground contamination and pollution caused by incorrect storage of oil in above ground oil storage tanks.

Dependent upon your location, you will most likely be covered by either the Control of Pollution (Oil Storage)(England) Regulations 2001 or the Water Environment (Oil Storage)(Scotland) Regulations 2006. Wales and Northern Ireland are exempt but other legislation may apply (additional information below).

Your environmental controller or regulator can serve on you an ‘anti pollution works notice’ if your oil storage tanks gives rise to, or is at risk of giving rise to, pollution of surface waters or groundwater. This notice will require you to undertake remedial action.

Many drains lead directly to rivers, streams or lakes. If your oil storage tanks allow oil to enter these drains, it has the same effect as pouring it directly into the river.

Oil is toxic to fish and other wildlife and it smothers plants. Just two litres of oil could easily pollute the volume of fresh water needed to fill a full sized swimming pool and make it unusable.

You can be prosecuted and fined if oil from your site enters the ground or watercourses and you have failed to follow protocols. You could also be liable to pay substantial clean-up costs. The Oil Storage Regulations are in place to prevent contamination of ground and water via oil spills.

Does your installation require a Bunded Tank?

Is Secondary Containment Bunded tank (bund wall) a Legal Requirement?

Oil/fuel storage Regulations Definition: Secondary Containment, also often referred to as a bund wall or bunded tank, under the Oil Storage Regulations, an oil storage tank which qualifies should be contained within a secondary containment system totalling no less than 110% of the storage tanks full capacity, a bunded oil tank.

There is a lot of uncertainty as to whether you should ‘bund wall’ a storage tank or not, the new oil storage regulations stipulate that if you are either an institute (school) a commercial or an industrial site you should bund almost any oil or fuel storage tank exceeding 200 litres capacity. This means Bunded Fuel Tanks are a legal requirement.

You should always seek additional guidance from the environment agency if you propose to install bunded tanks in any location which is within 10 metres of inland coastal waters or 50m of a well or borehole.

Bunded Fuel Tanks

What are Bunds and Bunded Fuel Tanks

Bunds or Bund walls are generally used around storage tanks or drum storage areas where flammable chemicals  or toxic liquids are held usually Fuel or Oil containment are the major usage. Alternative measures may be earth dikes (usually for very large tanks), sumps and interceptors. Bunds are also sometimes used within plant buildings for reactors and other process vessels. For materials that are normally gases at ambient conditions, bunds are used where flash fractions are sufficiently low to merit them. Therefore they are often used for refrigerated gases but not for the same gases stored under pressure. Bunded Fuel Tanks are one of the best ways to store these liquids

It is normal to limit the number of tanks in a single bund to 60,000 m3 total capacity. However, incompatible materials should have separate bunds. Tanks often have individual bunds.

Bunds should be sized to hold 110% of the maximum capacity of the largest tank or drum. This will allow some latitude for the addition of foam during response to the emergency. There are no set rules on the ratio between wall height and floor area and codes vary greatly with respect to recommendations of bund wall height. Low wall heights (1-1.5 m) are often used to facilitate firefighting but are poor defence against spigot flow (where a leak in the wall of a tank passes over the bund wall) or the tidal wave effect of a catastrophic tank failure. In some cases bunds up to height of the tank are used, but these are quite unusual. For high walled bunds, consideration will need to be given to the possibility of tanks floating as the bund fills, causing catastrophic failure.

Bunds are generally fabricated from brick/mortar or concrete but where liquids are being stored above their boiling point additional insulation, e.g. vermiculite mortar, may be added as cladding to reduce the evaporation rate. Such materials provide adequate chemical resistance to most liquids.

Maintenance of bunds is an important aspect, often overlooked, particularly in remote locations. A system of inspection should be in place to ensure the integrity of the bund. Also due consideration should be given to drainage to allow the removal of rainwater. This is another reason that the popularity of Bunded Tanks has increased due to maintenance and portability. This is normally achieved by incorporating a drain at a low point of a sloping floor with a manual valve, normally kept closed. Operating schedules should include daily opening of the valve to remove accumulated water, this will also assist in identifying minor leaks. However, with this system there is the problem that the valve may be left open or fail, thus reducing the effectiveness of the bund if a tank failure occurs. Also in winter conditions, ice may form blocking the drain. Failure to remove rainwater will reduce the capacity of the bund and may result in overtopping and if the substance to be contained is incompatible with water e.g. oleum, may result in an increased airborne release. Consideration of these scenarios should be included in the Safety Report.

Placing your static Bunded Fuel tank

When positioning your Static Bunded Fuel Tank a minimum separation distance of 100mm is required between the tank and fire rated barrier unless a larger distance is specified by the tank manufacturer. In some situations, the oil storage tank can be sited inside a building such as a garage or outhouse. Installations of this type require the tank to be self contained within a 60 minute fire rated chamber. Your OFTEC registered technician can advise further on this type of installation. Don’t forget the support The need to provide a suitable base and support for your oil tank is of paramount importance for reasons of both safety and environmental protection.

The base for a Bunded Tank should be:
• Adequate for the weight of the tank;
• Non-combustible, imperforate and level;
• Constructed of concrete, paving stones or stonework;
• Large enough to extend 300mm beyond all sides of the tank.

If an oil storage tank is not adequately supported, the tank itself can be weakened leading to the eventual failure and escape of the stored fuel. During the life of an installation an oil storage tank base will need to provide continual structural support, even though ground conditions may alter from season to season and year to year.

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