Health and Safety Procedures in Demolition
Introduction
The definition of the term ‘demolish’ is deliberate and controlled collapse of a structure. In the late 70′s Fred Dibnah took over as the most celebrated steeplejack in The UK when his work on demolishing large chimneys without having the requirement for explosives was displayed on Television. Fred was an entertaining individual and became popular as a specialist on restoring tall chimneys, so when it came to taking them down he knew precisely how to do it. He normally would cut an alcove at the base of the chimney, and place wooden props to hold the structure. By carefully positioning the props, the chimney would be likely to collapse in the right place once the wood was set alight and burned away. Once he was nearly crushed because he miscalculated somewhat, showing just how dangerous demolition work really is.
The actual expression to demolish only came to exist in 1570, and was used there after to mean the deliberate taking down or destroying of a building or structure. Even though in reality the task of demolition, in some mode or other, has been occurring for millenia. Properties were demolished either by natural disruptions of the Planet’s crust or during battles or attacks on communities for as long as there have been buildings. The surviving ruins would be removed and rebuilt or used by other structures in the area and must be early examples of recycling.
Preserving the Past – Preparing the Future.
To preserve Britain’s history of farming the acreage between the built up regions of the villages and towns is protected from growth of urban sprawl. This acreage is recognized as Green Belt and it’s preserved for farming that is vital to the continuing economic system of the country. By protecting the Green Belt, urban areas are being squeezed for the provision of housing, so developers end up being much more resourceful to uncover acceptable sites.
Britain is a nation with a very dense human population per square mile. The amount of land for development is small when compared to other countries. Therefore there’s always a high need for space on which to build. Taking down aged and abandoned buildings and replacing them with new is another way to combat this general shortage.
Land that is disused industrial and commercial sites, but could be polluted with harmful waste or pollution, are classified as Brownfield sites. Once the land has been cleaned up they can be potentially valuable for redevelopment. Both Glasgow and South Wales constructed gardens out of disused industrial sites and put in Shopping centres to attract holidaymakers and visitors and generate income.
Greyfield sites are totally different to Brownfield sites in that they do not have the environmental problems of dangerous waste materials. The expression greyfield comes from the massive areas of asphalt which had once been car parks of industrial urban properties. Their value is incorporated in the indisputable fact that the commercial infrastructure like roads, electricity, water supply, sewerage, and gas is already in position. These kinds of urban areas that become under-utilised or abandoned and are valuable because they require very little remedial work to be renovated. Cities including Leeds and Manchester have experienced an enormous programme of converting the old warehouses or industrial facilities into apartments, retail establishments and restaurants, retaining the main shell and renovating the interior into desirable accommodation.
The Demolition Process
Office and building demolition requires careful consideration to the following points.
• The construction type and actual physical size of the structure.
• What products have re-use value?
• What will the cleared site’s re-use be for?
• Where are the waste by-products likely to be disposed?
• What considerations need to be made with regards electricity, water, sewerage and gas mains.
Hydraulic excavators and bulldozers can be used to undermine the walls at the bottom, so that the building will topple; at the same time managing the manner and path of the fall. Issues of safety are extremely important, and clean-up tactics are usually taken into account when choosing how a property will be demolished.
Old fashioned Demolition
In the old days the traditional way of demolishing a building was quite crude. As soon as the services were turned off, the men and equipment would go ahead and just knock down the walls. Then the entire framework would fall and the resulting rubble would be stacked onto trucks and be dumped in landfill sites. Concrete footings would be broken up by air-driven tools and the site would be cleaned of waste ready for the new work to commence. However today demolition practitioners are at the mercy of stringent planning, safety and inspection regulations and are also highly controlled by the local authority. How a building is constructed will mean that one area is dependent on the other for solidity and sturdiness. For example the rooftop of a house is not really fastened down apart from fixing tiles with nails to stop them dropping. The roof stays in place using its own weight because the beams are laid on top of the walls rather than being fastened into them as they used to be for much older houses. The cross beams and purlins then link the whole thing together to tie down the frame of the roofing. To this slats are laid to provide a frame for laying on the tiles or slates. Other sections of a building may also be interdependent so when it comes to demolition these aspects are taken into consideration in the sequence of deconstruction. In this way, like Fred Dibnah you have to be an expert in construction to know how to carry out the deconstruction.
Deconstruction and Recycling
The modern approach to demolishing buildings is called deconstruction – an environmentally friendly approach. Landfill sites are in short supply so the aim when demolishing a structure is to reduce the volume of waste materials leftover.
Smaller constructions like 2 or 3 storey houses can be disassembled relatively easily. The work can be a slow task of dismantling manually – brick by brick – or beam by beam but by going carefully costly materials are safeguarded for re-use. The additional value of deconstruction is that 90% or more of waste is prevented from going directly into landfill sites and reclaimed products can be re-used and recycled for upcoming buildings. The farmer opposite my new home sold his barns within the farm yard for housing; when the builder demolished the barns he cleaned up the bricks and reused them to make the wall around the farmhouse hence keeping the character of the farm.
Newer specialist techniques and equipment permits demolition contractors to effectively segregate waste material groups on or off-site. Building items are recycled and re-used when practical within the new construction making considerable financial savings in project costs not to mention being good for the environment.
Concrete can now be easily broken up using a large guillotine.
Demand increases daily for 6f2 recycled material because it is an excellent aggregate for foundations of road and new buildings. as it provides a viable alternative to disposing of the demolished building remnants to landfill. Crushed material from the demolition can be used as a sub-base for the new building foundations or used on other sites where construction is underway.
Copper pipes, lead, roof tiles or slates, floor tiles, wiring and exterior doors, and wooden panelling are useful artifacts which might be saved for recycling to be re-used. Countless specialist firms provide reclaimed old or vintage building supplies in most towns and cities.
Tall Buildings
Tower blocks and chimneys are the kind of tall architectural structures which may need to be demolished. The demolition of tall architectural structures necessitates expert approaches. The highest building to be demolished lawfully was in 1967/8 of the Singer Building in New York. The collapse of the World Trade Centre after the 9/11 attack in 2001 shows the terrible devastation that occurs if the demolition is uncontrolled and haphazard.
In the demolishing of tall properties and larger structures a wrecking ball on a crane may be used, but is rarely attempted since the swinging ball is relatively uncontrollable. The proximity of other structures is often a deciding issue which often forbids the usage of explosives to implode a tall structure. So ‘High Reach’ demolition excavators are employed where alternative methods are not appropriate to demolish the top section 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
Using explosives in demolition is incredibly specialist work and getting it wrong would be catastrophic. If for instance there is atmospheric pressure from low cloud above the implosion site, the shockwave may spread outwards instead of upwards causing the wave of energy and sound to break windows. If an implosion isn’t prepared correctly the risk may be destruction of surrounding properties where flying debris may cause harm to spectators.
For many individuals when they think about demolition they might have in mind the employment of explosives in the spectacular collapse of a tall building. This method is really called implosion using explosives. Implosion is vital for dense urban areas as it brings down a tall building so that the surrounding environment is damaged as little as possible. The collapse takes only seconds for the building to fall into its own footprint.
Because of the hazards of dealing with explosives they are only used when other methods are too costly or impractical. Where there’s a partial collapse of the building and there are still primed explosives that didn’t go off, workers will be in great danger since the remaining structure is very unstable. Concurrently the demolition must carry on and secure the safety of the site.
Health and Safety
The task of demolition is a much more technical and complicated process than most people would appreciate. The work is highly dangerous and requires experienced and skilled operators to handle the task. It is vital that personnel working in the industry are thoroughly 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 jobs are regulated by Construction, Design and Management Regulations.
Your demolition contractor will need to have completed any necessary assessment for asbestos survey Nottingham to ensure planning approval has been granted for your building demolition.
Sequence of Demolition
An incorrect sequence of dismantling will result in premature collapse of a building as the stability of any structure is reliant on the interdependence of its component parts. Think about a house of cards and what the results are if one of many supporting cards is removed.
There is a strict sequence of events before any demolition will take place. Councils across the country have their specific list for planning approval within their area, but a typical order could be :-
• Provision of information
Information must be provided about the design of the structure to be demolished. Details of its previous use and the appropriate demolition methods to be employed, including disposal of hazardous substances, need to be submitted by the demolition company.
• Survey of Demolition
A thorough survey of the site to spot any structural problems, along with risks related to hazardous or flammable substances, will have to be discussed at length with the authorities. (E.g. A disused garage where petrol has been stored is a potential fire hazard so preventative measures will need to be taken).
• Preferred and Safe Method of Work
A reputable demolition company will be able to select the correct technique for disposal showing the outline dismantling process. Planning is essential for assiduous monitoring. The authorities will require an in depth statement of the safety procedures to used, and all parties involved have to agree the methods before any demolition can take place.
• Preparation and Planning
Issues like 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 great deal of preparation to be done before even starting work on demolishing the property itself.
• Protection of the Public
Safety cannot be compromised so where there are heavily populated areas around the demolition site the protection of the public is paramount. Any health hazards will need to be assessed and temporary services arranged, and individuals inconvenienced must be informed.
Conclusion
The goal in demolition is to eliminate an unwanted house as safely and quickly as possible also in our modern environment attempts are made to recycle or re-use most of the old material. This isn’t a new idea although the word itself is relatively modern. On the borders between England and Scotland after the Romans left, a large section 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 several are still standing today.
Demolition work by its nature is an extremely hazardous business and demolishing any building is a complex and skilled process. Next time you observe demolition work occurring on a building offer a thought to the individuals who work in a dangerous situation daily and how much is involved in 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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