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Factory performance evaluations of engineering controls for asphalt paving equipment.

Authors
Mead-KR; Mickelsen-RL; Brumagin-TE
Source
Appl Occup Environ Hyg 1999 Aug; 14(8):565-573
NIOSHTIC No.
20025304
Abstract
This article describes a unique analytical tool to assist the development and implementation of engineering controls for the asphalt paving industry. Through an agreement with the U.S. Department of Transportation, the National Asphalt Pavement Association (NAPA) requested that the National Institute for Occupational Safety and Health (NIOSH) assist U.S. manufacturers of asphalt paving equipment with the development and evaluation of engineering controls. The intended function of the controls was to capture and remove asphalt emissions generated during the paving process. NIOSH engineers developed a protocol to evaluate prototype engineering controls using qualitative smoke and quantitative tracer gas methods. Video recordings documented each prototype's ability to capture theatrical smoke under "managed" indoor conditions. Sulfur hexafluoride (SF6), released as a tracer gas, enabled quantification of the capture efficiency and exhaust flow rate for each prototype. During indoor evaluations, individual prototypes' capture efficiencies averaged from 7 percent to 100 percent. Outdoor evaluations resulted in average capture efficiencies ranging from 81 percent down to 1 percent as wind gusts disrupted the ability of the controls to capture the SF6. The tracer gas testing protocol successfully revealed deficiencies in prototype designs which otherwise may have gone undetected. It also showed that the combination of a good enclosure and higher exhaust ventilation rate provided the highest capture efficiency. Some manufacturers used the stationary evaluation results to compare performances among multiple hood designs. All the manufacturers identified areas where their prototype designs were susceptible to cross-draft interferences. These stationary performance evaluations proved to be a valuable method to identify strengths and weaknesses in individual designs and subsequently optimize those designs prior to expensive analytical field studies.
Keywords
Engineering-controls; Engineering; Asphalt-industry; Asphalt-cements; Smoke-control; Smoke-inhalation; Control-technology; Road-surfacing; Road-construction
CODEN
AOEHE9
Publication Date
19990801
Document Type
Journal Article
Fiscal Year
1999
NTIS Accession No.
NTIS Price
Issue of Publication
8
ISSN
1047-322X
NIOSH Division
DPSE
Source Name
Applied Occupational and Environmental Hygiene
State
OH
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