How to Remove Dust, Fumes, and Contaminants from the Jobsite
Workers in industries such as construction, utilities, and agriculture use processes that can produce dust, particulates, fumes, or chemicals. For example, combustible dust exists as a potential explosive in grain elevators; workers replacing wastewater piping may encounter hydrogen sulfide; and welding necessarily produces dangerous fumes. Controlling dust, chemicals, fumes, and particulates at any job site may requires housekeeping, ventilation, filters, or dust collection systems; other control systems include separators (which remove materials that could ignite combustible dust) and specialized vacuum cleaners.
Companies may already have proper ventilation and containment systems in place; however, the control and removal of dust, vapors, fumes, and other contaminants begins with employee training. Good workplace housekeeping involves maintaining a regular schedule for using tools to keep work environments clean, as well as following best practices for controlling contaminants. In addition, hazard control involves the implementation of safe work practices, the strict use of personal protective equipment, and clear communication with workers about information included on Material Safety Data Sheets.
General ventilation systems control the humidity and temperature of an environment. The movement of air can serve to dilute accidental emissions, controlling contaminants that have a lower toxicity. However, a worksite ventilation system must be able to work continuously to protect against the ignition of dust and corrosion caused by gases.
In contrast to general ventilation systems, a local exhaust ventilation system must address two hazards of toxic contaminants. While preventing the concentration of dust, fumes, vapors, and gases, local exhaust ventilation systems must not draw the hazardous materials through the work area. Preventing the concentration of hazardous materials requires that local exhaust ventilation systems maintain the volume and velocity of exhaust air needed to gather contaminants from the source and move the materials away from workers. Filters and air cleaning devices prevent the discharge of contaminants to the outside environment — and from recirculating the toxic materials into the work area.
Different types of dust collectors can process large volumes of air while removing fine particulates. A dust collector provides the advantage of removing dust that could collect at a job site. Commonly used media filtration dust collectors trap dust from the incoming air stream in a fabric filter. Large central funnels called cyclone dust collectors attach to workplace ductwork and develop the suction needed to pull the dust into a cyclone dust collector. As the dust passes into a high-speed cyclone funnel, debris separates from clean air and collects in a container. Any remaining dust filters through a media filtration unit.
Wet scrubbers use a fine mist to remove dust, collecting particulates in clarification tank. Another type of dust collector, called an electrostatic precipitator, relies on electrostatic charges to remove dust from an incoming air stream. Dust passes through negative and positive electrodes, collecting on the positively-charged grounded electrodes; clean air then flows through another filter and into the workplace.