7 Facts About How Bunding Works

Due to environmental laws and industry regulations, the use of bunded storage systems or bunded tanks has become a necessary requirement for any business requiring fuel or other liquids to be stored on site. The strength and reliability of a self bunded tank has proven itself to be a safe and effective storage system. But how does a bunded tank work? Below are 7 facts about bunding and how it is applied in self bunded tanks.

1.Bunding is a wall or structure within a containment system or storage tank designed to prevent spillage of the liquids. Bunding is also known as a bund or a bund wall. Bunding, as a form of liquid containment, can also refer to dikes or any barrier that prevents liquids from spilling through the structure. In a storage system such as a tank, bunding can be simply described as a tank within a tank.

2.The use of bunding in storage of liquids is a legal requirement in many countries, particularly for industries that use storage facilities or tanks to contain hazardous liquids, chemicals and wastes. As many of these liquids are environmental hazards, bunding acts as a durable double wall that prevents leakage of the liquids contained, thus minimising or eliminating pollution and injury to individuals.

3.The materials used for bunding must be impervious to and compatible with the liquids contained in order to avoid harmful chemical reactions. Concrete is generally recommended as it is durable and mostly impervious; however it may cause dangerous reactions to liquids containing strong acids. In this case, an additional coating that is acid resistant must be used.

4.Bunding should be large and durable enough to hold the contents of an entire tank. The bund height should be able to hold 100% of the capacity of the tank. When two or more tanks share a bund, the bunding of the largest tank should be at least 10% higher, for a total holding capacity of 110%. Some regulations may also require bunding to be a third larger to accommodate displaced liquids, but as general practise operators follow the 110% capacity guide.

5.When transferring liquids from a tank vehicle, the capacity of the bunding should be greater than 100% of the largest compartment of any tank vehicle filling it.

6.To prevent rainwater from entering and mixing with the liquids contained, the bunded area should be stored in a roofed facility. If this is not possible, proper disposal of rainwater as prescribed by regulations should be observed. Facilities should be provided to bunded tanks to transfer rainwater to the sewer or to a rainwater drainage system.

Rainwater reduces the holding capacity of the bunding and can also become contaminated when it comes in contact with the stored liquid, so preventing it from entering the bunded area or removing it safely is crucial.

7.Bunding is applied to self bunded tanks. An ordinary metal or steel tank requires additional bunding facilities such as linings, drums or spill pallets to be placed inside the tank, to act as the bund wall. In a self bunded tank already has built-in bunding inside the tank, eliminating the need for additional bunding facilities.

A self bunded tank is manufactured to meet industry and statutory requirements of bunding, making it a complete storage facility for fuel and other liquids. Because of its durability, versatility and cost effectiveness, the self bunded tank has become the preferred liquid storage system in many industries.