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Bunding, also called a bund wall, is the area within a structure designed to prevent inundation or breaches of various types. Image File history File links Broom_icon. ... A flood (in Old English flod, a word common to Teutonic languages; compare German Flut, Dutch vloed from the same root as is seen in flow, float) is an overflow of water, an expanse of water submerging land, a deluge. ...

Liquid containment

The term can also refer to dikes, but it is frequently used to describe liquid containment facilities that prevent leaks and spillage from tanks and pipes, though sometimes any barrier is referred to as bunding. Frequently, the liquids in tanks and pipes are toxic, but bunding is used to prevent the liquid from causing damage (either by force or its chemistry. If a large tank has a catastrophic failure, the liquid alone can cause extensive damage. Afsluitdijk, a 32 km dike in the Netherlands. ... Pipe is a tube or hollow cylinder for the conveyance of fluid. ... Toxic redirects here, but this is also the name of a song by Britney Spears; see Toxic (song) Look up toxic and toxicity in Wiktionary, the free dictionary. ... In physics, force is an influence that may cause a body to accelerate. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ...

If built properly, bunding is large enough and strong enough to contain the contents of an entire tank, though regulations may require it to be up to a third larger. When multiple tanks share a bund, the capacity is based on the largest tank. One of the most common designs for large tanks is a concrete or masonry wall around the tank with a concrete floor. The outside of the wall may be reinforced with an earth berm. Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ... Masonry is the building of structures from individual units laid in and bound together by mortar. ... Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ... A berm is a level space or shelf separating two features. ...

Concrete works very well for many liquids, but it is unsuitable for some applications like containing strong acids. Using earth berms for bunding is not recommended for most situations, though liners can be used to decrease permeability. Smaller tanks often use containers made of steel or plastic. The material used depends on cost, the chemical properties of the liquid and its density. Plastic tanks cannot hold very dense liquids at high wall levels. Large, exposed bunding will need a sump pump or some other system to remove precipitation, though it may also be used to transfer spilled liquid into another container. Rainwater must be treated if the liquid being stored is toxic because there may be small amounts of it surrounding the tank. Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acids: Strong acids Weak acids Bases: Strong bases Weak bases edit A strong acid is an acid that dissociates completely in an aqueous solution, or in other terms, with a pKa < −1. ... The steel cable of a colliery winding tower. ... This article or section does not adequately cite its references or sources. ... Wikipedia does not yet have an article with this exact name. ... In physics, density is defined as mass m per unit volume V. Mathematically, it is expressed as where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is the volume of the substance... A sump pump is a pump used for drainage that removes accumulated water from a sump pit. ...

The bund may have a roof to prevent precipitation from getting in, but steps must be taken to provide adequate ventilation when storing flammable liquids. If the wall is over a meter high, it may require a ladder or steps to allow people to escape quickly. Another design uses a channel that drains the liquid to a secondary container. Return inlet (left)Supply outlet (right). ... Flammable or Flammability refers to the ease at which a substance will ignite, causing fire or combustion. ...

When the risk of tank failure is not as likely or when it would not cause extensive damage, the bunding may be designed to merely contain small leaks from hoses and valves. This bunding may not be able to contain the entire volume of the tank. Plastic and steel are used, but another common method is making a hump or lip around the perimeter of a concrete floor. Some bunding is temporary, such as short-term chemical storage in the field. A hump or slope type bunding is helpful when vehicles need access to the area. There is also a type of bunding that compresses when a vehicle passes over and expands once it has past. Plastic hoses. ... These water valves are regulated by handles. ... Categories: Disambiguation | Software stubs | Data compression software ...

Bunding is a legal requirement in many countries particularly around tanks, storage vessels and other plant that contain liquids which may be dangerous or hazardous to the environment.

Particular examples which receive specific attention in the UK, the rest of Europe and the USA are oil and fuel storage tanks and transformers at electricity sub-stations which are filled with oil for cooling and insulation purposes.

It is reasonably easy to construct a "water-tight" bund around the base of a tank or vessel. A concrete base and a sealed wall of masonry, brickwork, concrete or even prefabricated steel provides the holding capacity.

Holding Capacity Almost all regulations require a holding capacity of 110% of the capacity of the maximum capacity of the biggest tank within the bund or 25% of the total capacity of all the tanks within the bund whichever is the greatest. In addition further guidelines in some countries (egg. the UK) recommend additional measures such as providing sufficient "freeboard" or height of wall above the maximum holding capacity to accommodate dynamic factors such as surge in situations of major tank failure or storm driven waves in larger bunds. As a rule (and unless specific local laws prevail) most operators work to the 110% capacity guide.

Unwanted Water Build-up and Removal As noted above, electricity sub-station transformers contain significant amounts of oil. An 110KV transformer may have up to 40,000 litres of cooling/insulating oil contained within the body of the transformer and its associated coiling radiators and storage tanks. Unlike ordinary fuel storage tanks these are complex structures and there is a much higher propensity for leakage of the oil. Using the UK as an example; as electricity industry privatisation took place in the 1980s and 1990s the new electricity companies were made aware of their environmental responsibilities. Most area and national companies realised that they had several thousand transformers many of which had been gently leaking into the ground below them for many years. The companies embarked on an upgrading programme involving the construction of "water-tight" bunds to retain any oil leakage and to prevent further pollution and contamination.

They immediately encountered the problem of water build-up from rain being retained by the now "Water-tight" bund and this unwanted rain-water reduces the holding capacity of the bund. Once the water level reaches more than 10% of the holding capacity of the bund it is no longer fit for purpose and the water must be removed. The problem is that the water is also likely to be. At best, moderately contaminated with a small film of oil on the top of it or, at worst, substantially contaminated by a thick layer of oil. This is worse on older, leakier transformers. This also can apply to any oil storage tank

Oil floats on water and, if still clean enough to see through, has a different refractive index than the water below making the oil/water interface difficult to judge. This makes manual pumping difficult and unsafe. Removing the entire contents for disposal as hazardous waste is expensive and environmentally unacceptable however in the UK at least, the latest regulations (DEFRA Oil Storage Regulations England and Wales 2001) require some formal method to be put in place for the removal of the rainwater. One of the systems recommended is an automatic pump system which is able to discriminate between oil and water. A good system should work continuously and automatically and must fail to safety (egg. not pumping). It should also provide alarms for conditions such as high water (indicative of pump or system failure) and high oil to warn that action to skim off the waste oil should now be done. These automatic pump systems are usually referred to as "BundGuards". There are very few manufacturers of these systems and the main one in the UK and Europe is Andel Ltd of Huddersfield, England.

Ianpogson 12:00, 7 March 2007 (UTC)