A bunded fuel tank is basically a tank within a tank. The idea is that if a tank is overfilled or splits for some reason, the material inside escapes, as a result, will be contained within the outer skin rather than spilling onto the ground and finding its way into the wider environment. Once the fuel gets into water or drains, it will be widely dispersed, inevitably leading to contamination and clean up charges (which you would be consequently liable for). This is why regulations have been put in place for the storage of oil.
Any tank in a domestic setting that has a capacity of more that 2500 litres must be bunded, regardless of its location to minimise any potential loss.
A tank of any size needs to bunded if, when it is being filled, the deliverer is not able to see the vent pipe from the fill point. This is also known as a “blind fill” and is not ideal, but this is designed to make the fuel delivery as safe as possible.
The idea is to avoid fuel getting into watercourses, so if your tank is within 50m of a well, borehole or spring or if it less than 10m away from what’s known as “controlled water” such as a ditch, soakaway, stream, river or even septic tank, it must be bunded.
What needs to be considered is whether any of the fuel from your tank could get where it shouldn’t in the event of an accident, however unlikely. Your tank may be 20m from a controlled water source, but if the tank sites on concrete and it slopes downhill towards the water, the fuel inside your tank will have nowhere else to go, especially in heavy rain or in the event of a large spill. In this scenario, it would not be wise to persuade anyone that a single skinned tank is appropriate.
Picture a scenario where you have lost 2000 litres of fuel; it’s gone down the drain and the authorities have managed to track the fuel back to you. You must be able to show that you did everything possible within regulations to avoid any contamination issues as a result of your stored fuel.
If you’re able to demonstrate that you have done everything within your power to prevent this, you will be looked on much more favourably by the bodies policing these matters and it could go towards mitigating large fines.
Even if this is of little to no concern to you, it’s also worth noting that single skinned tanks tend to only have up to 2 years warranty, while manufacturers are happy to guarantee bunded counterparts for as much as 10 years. To find out more about the benefits of a bunded fuel tank, contact us.