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An evaluation of cab filtration and pressurization systems: two case studies.
Chekan GJ; Cecala AB; Colinet JF
Proceedings of the Environment, Safety & Health Forum and Expo. Alexandria, VA: National Stone, Sand, and Gravel Association, 2003 Sep; :114-129
Many equipment operators at stone, sand, and gravel operations are exposed to respirable silica dust and other harmful particulate. To protect workers from this health hazard, operators typically purchase equipment with enclosed cabs. As equipment ages, many of the original components on the cab enclosure deteriorate through normal operation in the harsh mine environment, reducing the integrity of the cab and its effectiveness for protecting the operator. In an effort to improve the protection provided by enclosed cabs, the National Institute for Occupational Safety and Health entered into two cooperative research efforts with companies that manufacture and install cab filtration and pressurization systems. The systems are affordable, can be adapted to most cabs, are installed on-site in several days, and are a practical solution for older cabs where excessive dust levels may be an issue. For these two studies, new systems were retrofitted onto a haul truck at an underground stone mine and a surface drill at a sand operation. These systems have three primary features. First, the outside air is cleaned with high-efficiency filters before it enters the cab. Second, for efficiency and operator comfort, the systems have heating and air conditioning features where a majority of the air inside the cab is recirculated, filtered, and combined with a smaller portion of outside makeup air. Third, the cab seals are upgraded to reduce air leakage and aid in achieving positive pressure within the cab to prevent dust penetration. In both case studies, a significant improvement in lowering respirable dust levels in the cab was achieved with the new systems. Comparing outside to inside cab respirable dust levels after the new units were installed, a 76% cab efficiency was achieved for the haul truck and 93% for the surface drill. This paper describes the specifications, installation, and the results from the dust sampling conducted before and after the systems were installed.
Respirable-dust; Dust-exposure; Silica-dusts; Stone-mines; Nonmetal-mining; Sand-and-gravel-mines; Health-hazards; Silicosis; Lung-disease; Lung-disorders; Pulmonary-disorders; Airborne-dusts; Limestone-mines; Dust-control
NIOSH Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Proceedings of the Environment, Safety & Health Forum and Expo
PA; IA; WA