Access to work area
Restrict access to work areas to authorized personnel only. Put signs when the area is at risk.
Water-injected hand cutting machines and tools
Two primary methods exist to control silica dust: using water injected machinery and local extraction and filtration systems.
Avoid using dry processing techniques whenever possible. All cutting, shaping, polishing and finishing of material should be done using water injected tools. Dust that is wet is less able to become or remain airborne. Water pumps, hoses and nozzles should be kept in excellent operating condition and cleaned regularly. When working with water it is essential to avoid electrical risks by using ground fault circuit interrupters (GFCIs) and watertight, sealable electrical connectors for electric tools and equipment. Employees operating in wet areas should also be required to wear rubber boots.
Local extraction and filtration systems
Use a reputable exhaust ventilation supplier. Only use qualified engineers to carry out the design and the installation.
The design should include the following items: a hood, an enclosure or other inlet to collect and contain contaminants, ducts to remove contaminants away from the source, a filter or any other air cleaning device, normally placed between the hood and fan, a fan or other device to move air to provide the air flow, and finally other ducts to discharge the clean air outside the workplace.
Apply local exhaust ventilation at the generation source to capture the dust.
Tightly close the dust source to help prevent it spreading.
Local exhaust ventilation should be connected to a suitable dust extraction unit (e.g. a bag filter or cyclone).
Workers should not to stand between the source of exposure and the local exhaust ventilation; otherwise, they will be directly in the path of the contaminated air flow. Please observe periodically the position of workers and train them.
Where possible, ensure that the work area is not close to doors, windows or walkways so as not to interfere with the local exhaust ventilation and to prevent dust from spreading.
Ensure that there is a clean air supply to replace the extracted air.
The ducts should be short and simple, avoid long sections of flexible ducts.
Discharge extracted air to a safe place away from doors, windows and air inlets.
General ventilation in factories
Because the hazardous dust is very fine and may stay in the air for days it is important to have adequate general ventilation.
Ensure that the building is properly ventilated, if necessary using forced ventilation. Ensure the ventilation system does not move settled dust and that contaminated air does not spread to clean areas.
Dust suppression sprays (fine mist of air and water) may be used to prevent the generation of airborne dust throughout indoor and outdoor traffic routes or conveyors.
Emissions from dust extraction systems in buildings must comply with local environmental legislation.
Periodic maintenance and supervision
Ensure equipment is maintained in good working condition as advised by the supplier’s recommendations manual.
Clean the equipment on a regular basis, at least one time at the end of the shift. Do not clean with a dry brush or using compressed air. Do not allow dust/waste deposits to dry out before they are cleaned up.
Ensure the local exhaust ventilation is maintained in good working condition in accordance with the supplier’s or the installer’s recommendations. Noisy or vibrating fans can indicate a problem.
Replace consumables (filters, etc) in accordance with the manufacturer’s recommendations.
Do not modify any part of the system. If you do so, check with the supplier to ensure that the system retains the CE mark or make inspection and risk assessment by and licensed expert.
You should receive instructions for use and a diagram of the installed systems. You must receive a commissioning report showing the airflows at all inlets, the air speed in the ducts and the pressure index in the cleaner or filter.
Please contact the supplier for information on the expected performance of the local exhaust ventilation. Keep this information to compare with future test results.
At least once a week, visually inspect the equipment for signs of damage. If they are constantly used, check them more frequently. If used rarely, check before each use.
Keep records of inspections for the period of time required by the country’s laws (recommended minimum five years).
Because the hazardous dust is very fine and can go easily to the air and so may stay there for days it is important to have a comprehensive housekeeping program.
Clean the equipment every day, at least one time before leaving for home.
Clean the workplace daily. Use walls and flooring surfaces that can easily be kept clean and that do not absorb or accumulate dust.
Clean floors and other surfaces on a regular basis. Clean also the entire warehouse structures and inlet roof.
Use wet or vacuum cleaning methods. Do not clean with a dry brush or using compressed air, it will boost the exposure to very high levels.
Clean up any spill immediately. Do not allow dust / debris deposits to dry out before they are cleaned up.
If vacuum cleaning systems are required for spill of large volumes of dust, they should be specially designed to avoid overloading and blocking.
When it is not possible to use wet or vacuum cleaning methods, and only dry cleaning with brushes can be carried out, ensure that workers wear appropriate personal protective equipment and that measures are taken to prevent crystalline silica dust from spreading outside the work area.
When necessary, to prevent dust from spreading between building levels, use solid floors and cover them with a wear-resistant material, colored to highlight dust contamination.
Control panels can be protected from dust by using a plastic barrier or similar membrane.
When using wet cleaning methods, provide an adequate number of correctly positioned water connection points.
Provide an adequate number of vacuum connection points when using a central vacuum cleaning system