Forex Seminar Blog

Introduction

The definition of the word ‘demolish’ is deliberate and controlled collapse of a structure. In the late 1970’s Fred Dibnah became the most well-known steeplejack in Britain when his work on demolishing high chimneys without having the requirement for explosives was shown on Tv. Fred was a fascinating personality and became popular as a specialist on repairing tall chimneys, so when it came to taking them down he knew the best way to do it. He normally would chop an alcove at the bottom of the chimney, then place wooden props to underpin the structure. By very carefully setting the props, the chimney would be likely to collapse in the correct place when the wood was set alight and burned away. Once he was almost killed because he miscalculated slightly, demonstrating just how dangerous demolition work truly is.

The particular term to demolish only came to exist in 1570, and was used from then on to mean the deliberate taking down or destroying of a building or structure. Though in reality the job of demolition, in some form or other, has been taking place for millenia. Structures have been completely destroyed either by natural disturbances of the Planet’s crust or in the course of battles or attacks on villages for as long as there have been structures. The left over ruins would be removed and rebuilt or used for other structures in the area and must be early examples of recycling.

Preserving History - Preparing the Future.

To preserve Britain’s history of agriculture the farm land between the built up areas of the villages and towns is shielded from growth of urban sprawl. This acreage is called Green Belt and it’s preserved for farming which is essential to the ongoing economic system of the country. By protecting the Green Belt, urban areas are now being squeezed to supply housing, so developers have to be much more resourceful to find suitable sites.

Great Britain is a country with an extremely dense population per square mile. The amount of land readily available for construction is restricted when compared to other countries. For that reason there’s always a healthy need for space on which to build. Taking down aged and unused buildings and replacing them with new is an excellent method to attempt to counter this general shortage.

Land that may be disused industrial and commercial sites, but may very well be contaminated with harmful waste or pollution, are classified as Brownfield sites. Once the land has been cleaned up they are potentially valuable for redevelopment. Both Glasgow and South Wales constructed gardens using old industrial sites and installed Shopping centres to attract tourists and generate income.

Greyfield sites are completely different from Brownfield sites in that they don’t have the environmental issues of toxic waste materials. The term greyfield originates from the massive areas of asphalt which often had once been car parks of commercial urban units. Their significance is in the fact that the facilities like roads, electricity, water supply, sewerage, and gas is already in place. These urban areas which end up under-utilised or abandoned and are important simply because they require very little remedial work to be renovated. Cities including Leeds and Manchester have experienced an enormous programme of transforming the existing warehouses or factories into homes, retail establishments and eating places, keeping the main shell and refurbishing the interior into valuable accommodation.

The Demolition Process

An experienced demolition contractor will have made a careful plan of the sequence of events.

The construction type and actual physical dimensions of the structure.
What products have re-use value?
What will the cleaned site’s re-use be intended for?
Where are the waste material by-products going to be disposed?
What precautions need to be made with regards electricity, water, sewerage and gas mains.

Hydraulic excavators and bulldozers can be used to weaken the walls at the roots, so the building will topple; at the same time controlling the manner and course of the fall. Questions of safety are paramount, and clean-up systems are taken into consideration when determining the way the building is to be demolished.

Traditional Demolition

At one time the traditional way of demolishing a building was quite primitive. As soon as the services were turned off, the men and machinery would go ahead and simply knock down the walls. Then the entire building would fall and then the ensuing wreckage could be piled on lorries and be dumped in land fill sites. Concrete footings would be cracked by pneumatically-driven tools and then the site could be cleared of rubbish ready for the new work to start. However nowadays demolition procedures are subject to stringent planning, safety and monitoring laws and are highly governed by the local council. The way in which a building is constructed means that one area depends on another for stability and toughness. For example the roof of a building isn’t fastened down apart from fixing roof tiles with nails to prevent them sliding. The roof stays in position with its own weight as the beams are laid on top of the walls rather than being fixed into them as they used to be for much older properties. The cross beams and purlins then link the entire thing together to secure the frame of the roofing. To this slats are laid as a frame for laying on the tiles or slates. Other sections of a building are also interdependent so when it comes to demolition these aspects are considered in the sequence of deconstruction. In a sense, like Fred Dibnah you need to be a specialist in construction to understand how to perform the deconstruction.

Deconstruction and Recycling

The newest system of demolishing buildings is called deconstruction - a green approach. Landfill sites are in limited supply and so the aim when demolishing a property is to minimise the quantity of waste material remaining.

Small structures for instance two or three storey homes may be taken apart relatively easily. The project can be a painstaking task of dismantling by hand - brick by brick - or beam by beam but by going thoroughly valuable elements are conserved for re-use. The beauty of deconstruction is that 90% or even more of waste materials is saved from going straight into landfill sites and reclaimed resources can be re-used and recycled for future buildings. The farmer opposite my family home sold his barns inside the farm yard for construction; when the builder demolished the barns he cleaned up the bricks and reused them to make the wall around the farmhouse thus keeping the character of the place.

Contemporary specialist techniques and machinery enables demolition contractors to successfully segregate waste material varieties on or off-site. Construction resources are recycled and re-used whenever practical in the new structure making significant financial savings in project costs not to mention being good for the environment.

Concrete can now be quickly broken up using a huge guillotine.

Creating 6f2 recycled material is very cost effective as it avoids the expense of hauling the building waste to landfill sites.

Copper pipes, lead, roof tiles or slates, floor tiles, wiring and doors, and wooden panelling are valued objects which might be conserved for recycling to be re-used. Many specialist firms offer up reclaimed old or vintage building supplies in most towns and cities.

Taller Buildings

Tower blocks and chimneys are the kind of tall buildings that may need to be demolished. The demolition of tall structures necessitates specialist approaches. The highest building to be demolished lawfully was in 1967/8 for the Singer Building in New York. The fall of the World Trade Centre after the 9/11 assault in 2001 shows the horrible devastation that develops if the demolition is out of control and haphazard.

In the demolishing of high buildings and larger structures a wrecking ball on a crane can be utilised, but is hardly ever used as the swinging ball is somewhat uncontrollable. The closeness of other buildings is a deciding issue which prevents the usage of explosives to implode a tall building. So ‘High Reach’ demolition excavators are used wherever other solutions will not be possible to demolish the highest part of a tall building. Once it is down to a manageable height demolition can continue in the usual way. The various methods of demolishing tall buildings are by implosion using explosives, controlled collapse and piecemeal. To control the dust produced in demolition, water hoses and spray equipment are sometimes used and then it is called a wet demolition.

Explosions

The use of explosives in demolition is very specialist work and getting it wrong would be catastrophic. If for example there exists atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards as opposed to upwards resulting in the wave of energy and sound to break glass windows. If the implosion is not prepared correctly the risk might be destruction of surrounding properties where flying debris could cause harm to spectators.

For most people when they consider demolition they might have in mind the usage of explosives in the dramatic collapse of a tall building. This method is actually called implosion using explosives. Implosion is vital for dense urban areas since it brings down a tall building so that the surrounding environment is damaged as little as possible. The collapse takes only a few moments for the building to fall into its footprint.

Due to the dangers of working with explosives they are only used when other methods are too costly or impractical. Where there’s a partial collapse of a building and there are still primed explosives that didn’t go off, workers will be in great danger because the remaining structure is extremely unstable. On the other hand the demolition needs to carry on and secure the safety of the site.

Health and Safety

The work of demolition is an infinitely more technical and complicated process than most people would appreciate. The job is highly dangerous and requires experienced and skilled operators to handle the work. It is crucial that personnel working in the market are adequately trained. Health and safety awareness is crucial in demolition services so it is advisable for operatives to have gained a certificate of Competence in Demolition to ensure safety for both workers and public alike. All demolition work is regulated by Construction, Design and Management Regulations.

Prior to any demolition of a building in Birmingham occurring, your demolition company must demonstrate they have adhered to a similar process as the above in order to gain demolition planning permission.

Sequence of Demolition

An incorrect sequence of dismantling can lead to premature collapse of a building because the stability of any structure is reliant on the interdependence of its component parts. Think of a house of cards and what the results are if one of the supporting cards is taken away.

There’s a strict sequence of events before any demolition will take place. Councils across the country have their own specific list for planning approval in their area, but a typical order could be as follows:-

Provision of information
Information must be provided about the design of the structure to be demolished. Details of its previous use and also the appropriate demolition methods to be used, including disposal of hazardous substances, have to be submitted by the demolition company.

Survey of Demolition
A thorough survey of the site to identify any structural problems, as well as risks associated with hazardous or flammable substances, should be discussed in detail with the authorities. (E.g. A disused garage where petrol was stored is often a potential fire hazard so preventative measures will have to be taken).

Preferred and Safe Method of Work
A professional demolition company should be able to select the correct way of disposal showing the outline dismantling process. Planning is essential for vigilant monitoring. The authorities will demand an in depth statement of the safety procedures to used, and all parties involved need to agree the methods before any demolition can take place.

Preparation and Planning
Issues such as asbestos abatement, rodent baiting, dealing with hazardous substances, disconnecting utilities, and making safe any electric, gas or other services need to be shown in the planning stage. There is a lot of preparation to be done before even starting work on demolishing the property itself.

Protection of the Public
Safety cannot be compromised so wherever you can find heavily populated areas surrounding the demolition site the protection of the public is paramount. Any health risks should be assessed and temporary services arranged, and people affected will need to be informed.

Conclusion

The goal in demolition is to eliminate an unwanted building as safely and quickly as possible also in our modern environment efforts are made to recycle or re-use the majority of the old material. This is not a new idea although the word itself is relatively modern. On the borders between England and Scotland after the Romans left, a significant portion of Hadrian’s Wall was hauled away and use was made of the beautifully dressed stone to construct the new buildings in the towns and villages nearby and some remain standing today.

Demolition work by its nature is an extremely risky business and demolishing any building is a complex and skilled process. The next time you observe demolition work occurring on a building give a thought to the individuals who work in a dangerous situation daily and how much is associated with the meticulous planning, regulations compliance, care and skill that goes on to carrying out the project to clear the path for our future.

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