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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. |
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). |
The Technology
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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
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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
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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 |
NIOSH engineers conduct an engineering
performance test of asphalt paver engineering controls in Tippecanoe County,
Indiana. |
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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
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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
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Neither the Construction
Industry Institute 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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