Demolition manual national demolition association free download

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Richard Diven and Michael R. Taylor, CAE

Safe and efficient building demolition requires careful planning. Deter- mining how and when demolition work is to be done is especially crit- ical when extremely hazardous conditions or unique circumstances are present.

Since the dawn of civilization, people have demolished structures to make room for new structures, to rehabilitate existing ones, and to create new edifices with materials taken from existing structures. Cave dwellers began digging out adjacent earth and stone to expand their abodes. Later, demo- lition evolved into the removal of building parts to be used to build new structures. When the German archaeologist Heinrich Schliemann discov- ered the remains of Homer’s Troy, he found it was the seventh city built on the same site. In the time of the Egyptian pharaohs, it was a common prac- tice for the new ruler to tear down edifices built by his or her predecessor and to reuse the material to build a new palace or tomb. Portions of Hadrian’s Wall in northern England were recycled to build housing and commercial structures in Newcastle and other towns in the region. Today, demolition is a barometer of economic activity. When demo- lition occurs, it is usually a sign of coming growth, expansion, or renewal. Major cities in the United States and elsewhere are constantly renewed. Old factories are gutted and converted into new office spaces or residences. Industrial facilities are cleared to accommodate new machinery and equipment. Dilapidated housing is demolished to make way for new and more efficient residential uses. The Business of Architecture—2003 AIA Firm Survey reports that 44 percent of the work done by architecture firms nationwide in 2002 was classified as building rehabilitation—defined as additions or improvements to existing buildings. The survey also states that rehabili- tation represents a growing share of building construction activity. This trend indicates that architects are now planning, documenting, and specifying demolition work on nearly half their projects.

Excerpt from The Architect’s Handbook of Professional Practice, Update 2006

RICHARD DIVEN is a managing partner of R. J. Diven Consulting, LLC. He provides demolition consulting services to architects, engineers, contractors, and insurance companies. Diven has more than forty years of experience in the demolition industry. _{MICHAELTAYLOR}is executive director of the National Demolition Association. He is the principal author of the NDA’s Demolition Safety Manual and chairs the American National Standards Institute A10.6 Committee on Demolition Operations.

According to the National Demolition Association, annual spending for demolition in the United States today is about $3.5 billion.

Building demolition involves tearing down, breaking up, and razing whole buildings or parts of buildings and includes the removal of machinery or equipment from buildings. To ensure the work can be accomplished safely, demolition planning is undertaken. This process includes consideration of environmental, public, and worker safety and other mandatory requirements, as well as cost, time, and client goals. Demolition planning involves close collaboration and interaction between the client, demolition planner, archi- tect, engineers, regulatory agencies, contractors, and subcontractors.

Most building demolition planning can be addressed and adequately handled by the A/E project team. However, additional demolition planning expertise is sometimes warranted in some situations. For example, demolition planning is especially crucial for projects in which the removal of materials poses risks to the safety of people or adjacent property. For instance, the following situations may require a higher level of planning rigor and analysis:

At some point, the entire current stock of buildings will undergo some form of demolition work.

• A structure to be demolished is close to others (e.g., in highly congested down- town areas).

• A contaminated structure requires special demolition techniques and mate- rial handling to avoid exacerbating dangerous conditions.

• A structure to be demolished has historic significance.

• A building with special construction features requires special demolition techniques (e.g., post-tensioned concrete structures, buildings with signifi- cant structural damage, etc.).

• Portions of an existing facility must be kept in operation while demolition work is carried out in adjacent portions.

• Assets of high value are to be salvaged for sale or for reuse.

For these project situations, among others, demolition contractors ultimately determine which demolition methods and techniques are used.

Building demolition is achieved by a variety of means and methods, using many kinds of equipment and tools. Demolition experts can recommend which methods are appropriate for particular projects. For simplicity, demolition methods can be grouped under the cate- gories of mechanical, implosion, and special. MMeecchaniccal demmoolitioon. The most widely used method of building demolition today involves the use of various specialized mechanized equipment and tools. While the crane and wrecking ball have long been the symbol of large, high-rise demolition projects, demolition contractors employ a variety of high-reach excavators equipped with tools for crushing concrete and shearing steel at heights up to 120 feet. These machines can operate in confined work areas and can separate the building materials as they “chew” the building apart. Excavators equipped with special attachments, including hydraulic breakers, shears, and concrete processors, are also the machine of choice for demolishing foundations and handling debris and scrap metals. Interior demolition and selective demolition are most often accomplished with small, skid-steer loaders and small excavators equipped with a variety of hydraulic attachments that include breakers for concrete, shears for cutting small steel, and material-handling buckets and forks. In the last twenty years, effective remote-controlled machines have been developed that can be used in hazardous environments, confined spaces, areas that have been damaged or are structurally weakened, and areas that are sensitive to noise or vibration. These machines are also being used for selective demolition in radioactive environments. Impploosioon. Implosion methods are very effective for bringing down high structures that would be difficult to reach with equipment or too expensive to demolish one floor at a time. These methods use highly specialized explosives to undermine the supports of a structure so it collapses either within its own footprint or in a predetermined path. The

implosion process is especially suited for high-rise buildings (usually more than twelve stories) and a variety of special structures (e.g., cooling towers, nuclear reactor contain- ments, space launch towers, smokestacks, boilers, steel mill furnaces, and so on). Common explosives—usually various forms of dynamite and ammonium nitrate—are fre- quently used to blast heavy concrete such as that in bridge piers and machinery founda- tions. Only a handful of companies are qualified in this demolition method, and they almost always work as a subcontractor to a conventional demolition contractor. SSppeeccial ddeemoolitioonn. Certain types of demolition require specialized handheld tools for cutting, chipping, drilling, and breaking small amounts of materials (e.g., removing concrete for a new door in an active hospital, cutting and removing a specified pipe in a rack containing piping that is in use, removing a terra-cotta arch for reinstalla- tion, etc.). The tools for these tasks are mostly powered by hydraulic or pneumatic sys- tems and can usually be moved by two men. Special demolition projects are various. A typical project might require the con- tractor to remove partitions and suspended ceilings in a building area that is partially occupied, or cut new openings in concrete walls and floors for mechanical chases and doorways. Another special demolition type is careful removal of significant historic fabric in existing buildings. Often this is required when building systems are upgraded but the historic fabric (e.g., terra-cotta, windows, carved moldings, etc.) must appear to have been undisturbed afterwards. This process requires documentation prior to demolition and proper removal, cataloging, and storage of the historic building fabric.

Demolition deals largely with wrecking and dismantling services, but some projects may require some related services as well. Services that often come up in relation to demolition include hazardous material handling, material salvage and recycling, site work, utility work, and building decontamination and mold control. Some demolition firms are able to per- form some of these services, but often specialty contractors are used. Hazzarddoous mateerials hhanddlinngg. Some larger demolition firms can remove and dispose of hazardous materials such as asbestos-containing materials (ACM), polychlori- nated biphenyls (PCBs), mercury vapor from fluorescent lights, petroleum products, and other such materials. Often, however, other firms (usually as subcontractors to the demolition firm) must be used to access these services. The cost and time required to remove hazardous materials must be considered when developing cost estimates, sched- ules, and sequencing for virtually all types of demolition projects. Some demolition contractors and most general contractors are reluctant to assume lia- bility for handling hazardous materials. Therefore, when the need for abatement is known ahead of time, it may be prudent to have the client contract directly for this service. Mateerial reecyyclingg. The recycling of building materials has become important for several reasons. First, it can be less expensive to recycle than to haul materials to land-