What Is a Bunding Wall?
A bunding wall is an enclosure around tanks, drums or other storage containers to stop hazardous liquids escaping into the ground or surface water in case of tank failure. It is a requirement of most site permits and waste licences.
Bund walls must be made from a material that is impervious to the stored chemicals, or chemically resistant masonry. The walls should be designed to withstand a hydrostatic head (water pressure) of at least 6 times the total storage capacity.
Traditional bunds consist of concrete, brick or block walls and floors. In many cases the concrete and mortar are not chemically resistant which can lead to the leaking of the chemicals into the bund. Alternatively the masonry is permeable and allowing the chemicals to soak through into the floor which is then compromised and can also leak into the ground or surface water.
Ensuring Safety: Importance of Proper Bund Wall Construction
In general, the height of the bund walls should be adequate to allow emergency workers access to operate a truck or other vehicle. This will vary with each site but a balance should be struck. Very low wall heights will aid worker accessibility but may lead to chemical contamination in the event of a sudden pressurized vessel failure higher up in the stack.
A common issue with bund walls is the growth of vegetation. This is often due to cracks or damaged regions in the wall. The growth of plants or shrubs can cause the wall to fail as it allows moisture, fungus or bacteria into the walls and corners. The solution to this is to sandblast and dehydrate the exposed face of the bund walls before applying a chemically resistant or watertight protective lining.
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