Bund walls are the safety catch that ensures major (and even minor) storage tank failures do not turn into catastrophe. They contain the liquid to a level below the tank or drum so that any leaks can be contained without spreading to the surrounding area.

Ideally, they are made of brick/mortar or concrete that is chemical resistant and can withstand the pressure exerted by the stored material. If the liquid being held within is above boiling point then additional insulation such as vermiculite mortar should be included in order to reduce the rate of evaporation. Bund walls should be located close enough to the road fence battery limit of process plants in order to allow mobile firefighting vehicles to easily get to a site if required. They should also be able to provide a good vantage point from which firefighters can observe tank fires. Access roads over bund walls into large compounds are also useful for facilitating the movement of equipment and personnel.

Bund Walls Explained: Functions and Varieties

Most traditional site-built permanent bunds are constructed from brick/block walls standing on concrete floors. They are designed to be liquid-tight and can withstand a full hydrostatic head. Walls should be constructed such that in cross-section they have a slope of not less than 1 in 1.5 and that the flat section is not more than 1 m wide. The height of the wall should be a minimum of 15 m above the road fence battery limit.