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Asphalt
Paver Engineering Control Systems
The Need
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At present,
there are approximately 300,000 asphalt paving workers who
are routinely exposed to asphalt fume. Presently, limited
data exists concerning the level of exposure and subsequent
health effects for paving workers. Some workers have
reported acute health effects including breathing
difficulty; burning of the eyes, nose, throat, and
skin; headaches; and nausea. Animal studies indicate that
asphalt fumes may be carcinogenic under certain conditions.
Asphalt paver engineering controls were implemented to
reduce workers' exposures to hot-mix asphalt fumes in
highway paving operations.
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Side-by-side
photograph of a paver undergoing a smoke-test challenge of
asphalt paver engineering controls
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This
is accompanied through the partnership including National
Institute for Occupational Safety and Health (NIOSH).
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The Technology
The
engineering control method developed for highway class
pavers includes ventilation systems, baffles, and enclosures
to capture the generated contaminant within the paver's
auger area and to exhaust it before it enters the workers'
working environment.The control systems capture up to 80
percent of fume emissions coming from the auger area, the
greatest source of fume emissions from paving machines.
The controls cover the auger area of the paver where fumes |
Ventilation
control system into paving machine
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are
generated. They then transport the fumes through a duct
system and exhaust them through a stack away from the
worker. This system significantly reduces worker's exposure
to asphalt fumes. |
The Benefits
Performance results
on first-generation prototypes ranged from 17-100% capture
efficiency. After incorporating design changes, the capture
efficiencies improved to a range of 80-100% by July 1997.
Five of the control systems were also evaluated during
actual paving environments. These tests revealed fume
reductions up to 80% from the pavers' auger area. |
Status
Initiated by the
National Asphalt Pavement Association (NAPA), the effort to
reduce workers' exposures to asphalt fumes involved 5
asphalt paver manufacturers who represented more than
80 % of the highway -class paver market. Through an
agreement withthe Department of Transpotation (DOT), NAPA
requested that the NIOSH assist the manufacturers with their
prototype designs and independently evaluate the performance
of each prototype. To reach the goal, manufacturers
suggested designs based on their knowledge of machine
structure and operating needs. NIOSH scientists provided
crucial engineering and industrial hygiene knowledge to
measure the
volume of fume |
NIOSH
engineers conduct an engineering performance test of
asphalt paver engineering controls in Tippecanoe County,
Indiana.
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captured by each prototype system, analyzed
results, and suggested design improvements. NIOSH
researchers developed and published a test protocol for
evaluating the asphalt paver under controlled conditions.
NIOSH used this protocol to evaluate the control systems of
each of the paver manufacturers and provided recommendations
to optimize the performance of each control system. The
diverse partners in the initiative signed a voluntary,
industrywide agreement with the Occupational Safety and
Health Administration (OSHA) to observe the guidelines and
to incorporate effective fume emission controls in all new
highway pavers. As of September 1998, over 700 of the first
generation of pavers built according to the guidelines have
rolled off the assembly line. |
Barriers
The engineering
control system for asphalt pavers is for highway-class
pavers, not for non-highway-class pavers, because the
research on engineering controls is based on prototype
controls applied to highway-class pavers. And current
research applies only to new equipment that has the
engineering control designs integrated into the basic paver
design. Manufacturers must develop kits for reducing worker
exposures without creating tripping hazards from duct work,
increased noise exposure from externally mounted exhaust
fans, or undue burdens on paver hydraulic or electrical
systems. |
Points of Contact
- Margaret Cervarich, National Asphalt
Pavement Association, <mbc@hotmix.org>
- Lomax, Margaret, Federal Highway
Administration, <Margaret.Lomax@fhwa.dot.gov>
References
- NIOSH - Reducing Exposure to Asphalt Fumes
<http://www.cdc.gov/niosh/innovatn.html>
- Engineering Control Guidelines for Hot Mix
Asphalt Pavers - NIOSH, U.S. Department of Health and Human Services.
1997
Disclaimer Statement
Neither
the Construction Safety Alliance nor Purdue University in
any way endorses this technology or represents that the
information presented can be relied upon without further
investigation. |
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