Page 647 - Materials Chemistry, Second Edition

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618 Waste Management Practices: Municipal, Hazardous, and Industrial

FIGURE 21.6 Buildings undergoing demolition must be assessed for possible asbestos content.

Waste prevention techniques minimize the amount of materials used during construction and
renovation. For example, a technique from the homebuilding field, known as ‘optimum value engi-
neering’or ‘efficient framing,’reduces the amount of wood used in the framing process without sac-
rificing structural integrity (U.S. EPA, 2002).
Durable products are often more expensive and contain more material than their traditional coun-
terparts; however, they offer long-term benefits through lower maintenance and replacement costs.
Additionally, products that are more durable can enhance safety and prevent other building features
from deteriorating. The durability of a building is not simply a function of the actual construction
materials, but also from the quality of construction. For example, constructing a roof and window
frames to properly prevent water infiltration help ensure that interior walls and ceilings last longer.

21.6 DECONSTRUCTION

The amount of waste created by building demolition and removal can be minimized through waste
reduction techniques including a process known as “deconstruction.” This process maximizes the sal-
vage of building materials for reuse or recycling by selectively disassembling buildings.
Deconstruction concentrates on recovering items such as flooring, siding, windows, doors, bricks,
plumbing fixtures, ceiling tiles, and structural components. Some sites have demonstrated that enor-
mous amounts of demolition debris can be reused in new structures being built at the demolition site.
When the Seattle Kingdome was demolished in 2000, a total of 97% of the structural waste was recy-
cled into the new stadium complex, resulting in savings of more than $3 million. Additionally, truck
traffic to and from the site was reduced by about 4500 trips. Before constructing the Four Times
Square Office Tower in Manhattan, the contractor first removed six existing buildings. By salvaging
all usable materials and recycling as much of the remaining C&D debris as possible, the contractor
saved more than $800,000 by selling the salvaged material and reducing disposal fees.
Out of two buildings deconstructed at a demolition project at the closed Presidio Army
Compound in San Francisco, workers salvaged about 85% of the first building and approximately
40% of the second building. Material sorting was performed on site. Salvaged items included tim-
bers, dimensional lumber, flooring, windows, ceiling vent covers, iron work, plumbing fixtures, and
siding. Material sales took place at the deconstruction site, avoiding the significant cost of trans-
portation, while the remaining materials were taken to a warehouse and sold within 8 months. The