Best Practices for the Reduction of Air Emissions From Construction ...

CHEMINFO
6.7 Demolition and Deconstruction
Unique work practices and technologies that can be
applied to reduce fugitive dust emissions from
demolition and deconstruction activities are outlined
below. There are many additional actions that can
also be employed, but those common to demolition
and construction activities are not repeated within
this section. Demolition firms are encouraged to
review Section 4 in order to identify additional
actions that can be employed to reduce fugitive dust
emissions from their operations.
6.7.1 Apply Deconstruction Techniques
Buildings that must be taken down should, to the
extent possible, be deconstructed rather than
demolished so that materials can be reused in other
buildings. Deconstruction generally results in lower
fugitive dust emissions compared to demolition.
6.7.2 Minimize Drop Heights for Debris
Material drop heights for building debris should be
minimized whenever possible. When debris is being
dropped from high levels, this material should be
dropped over several sequential stages instead of the
entire distance at once.
6.7.3 Enclose Chutes and Cover Bins
Chutes that are used to drop demolished materials to
the ground level should be enclosed, if feasible. In
addition, bins that are used to receive materials
should also be covered when not in use.
6.7.4 Use Fogging Systems
A fogging system can be used to direct fog into the
fugitive dust area. If fog droplets and airborne dust
mix, dust particles stick to the water droplets thereby
adding weight to the dust particles. The increased
mass of the dust particles causes them to fall out of
the air. Fogging systems can only be used in an area
that has a pocket or cover.
6.7.5 Barriers to Prevent Dispersion
Enclosures, curtains or shrouds can be utilized
during the demolition phase to confine dust
generation. Negative pressure dust collectors can be
used to collect the dust that has been confined by the
enclosures, etc. Enclosures, curtains or shrouds may
be impractical during demolition activities lasting a
few days or less.
Prior to blasting, buildings should be screened with
suitable debris screens and sheets.
6.7.6 Avoid Blasting When Feasible
Blasting with explosives has the potential to generate
large amounts of fugitive dust emissions in a very
short period of time. Blasting should be avoided and
other demolition and deconstruction methods used
wherever possible. It is noted that in some instances,
blasting is the safest manner in which to quickly
bring down a structure.
Blasting operations can significantly reduce the size
of the building and its component materials. The
generation of a large amount of fugitive dust in the
short term through blasting may reduce the potential
for prolonged periods of fugitive dust emissions that
would otherwise occur in ongoing size reduction
operations.
6.7.7 Vacuum Debris
Vacuums or similar cleaning devices should be used
to thoroughly clean blast debris from paved and other
surfaces following blasting operations. An industrial
vacuum should be used to clean debris prior to the
use of high pressure air to blow soil and debris.
6.7.8 Work Practices for Loading Debris
Loaders should tip debris into haulage trucks with a
minimum fall distance to minimize dust emissions
from tumbling debris. If possible, fine debris should
be placed into the truck bin first, followed by larger
debris on top. Alternatively, if possible, dry debris
should be placed into the truck bin first, followed by
wet debris on top. Debris loads should be balanced in
truck bins. Debris loads should not be compacted
using the impact of a loader bucket.
6.7.9 Avoid Prolonged Storage of Debris
Avoid prolonged storage of debris on site and its
exposure to wind.
Waste and refuse bins should be covered when they
are being removed from the construction site.
Best Practices for the Reduction of Air Emissions From Construction and Demolition Activities 26