Silica, a common mineral, can be found in construction materials such as sand, stone, concrete, and mortar. It is also often used in the manufacturing of glass, ceramics, pottery, bricks, and artificial stone or other landscaping materials.
Often referred to as quartz, silica poses little risk in its normal state. However for workers who may cut, grind, saw, drill, or otherwise modify materials that contain silica there is risk of exposure to respirable crystalline silica.
To better protect these workers OSHA has issued standards for the regulation and control of silica exposure in construction, general industry and maritime workplaces.
Employers are required to use engineering controls and work practices as the primary way to keep exposures at or below the permissible exposure limit (PEL). These engineering controls include wetting down work operations or using exhaust ventilation such as vacuums to keep silica-containing dust out of the air and out of workers lungs.
Central vacuum systems differ from traditional pneumatic conveying systems or dust collection systems. Pneumatic conveying systems have a defined source and destination while a central vacuum system varies in the number and location of the pick-up vacuum points. Most systems are designed for multiple users and thus they need to perform equally well when one or multiple users are using the system at one time.
A central system consists of a vacuum power unit with a collection container and it is usually installed at one location in the plant. In some applications, the power unit and container ore on wheels so the system can be moved. A network of tubes extends from the collection container, along the ceiling, to multiple workstations or pickup points. The central system usually has a larger blower running it.
Central vacuum systems for silica recovery utilize respirators, hoods, and specialized equipment such as a source capturing grinder to effectively collect and capture silica particles. Additional filters and/or HEPA filtration may be required to collect particles down to 0.3 microns. The addition of automated separators and bag collection further reduces operator exposure.
For facilities that already have centralized vacuum or dust collection systems in place there is potential to retrofit or upgrade existing equipment for OSHA compliance. A number of factors must be considered, and should be evaluated by an application engineer who is experienced in vacuum system design.
Hoffman & Lamson is with you every step of the way. Our experienced team of engineers can work with you to evaluate your conditions and existing system, provide recommendations on improvements, ensure proper installation and usage of new components, and make sure that your engineered vacuum system is not only compliant with OSHA's standards, but that it also creates a safer, healthier environment for your operators.
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