When grinding concrete, do you have a dust shroud on your grinder? If so, do you also have a high-efficiency particulate air (HEPA) vacuum or just a regular shop vacuum? When grinding, do you work in a fog of silica dust? (Photo 1). Not only are you exposing yourself, you are exposing the occupants of the home or business to silica dust as well.
Crystalline silica is a common mineral found in the earth’s crust. Materials like sand, stone, concrete, and mortar contain crystalline silica. It is also used to make products such as glass, pottery, ceramics, bricks and artificial stone.
If you haven’t been made aware, there is a new Occupational Safety and Health Administration (OSHA) regulation in place regarding silica dust. If you’re a small business, download the Small Entity Compliance Guide for the Respirable Crystalline Silica Standard for Construction (OSHA 3902-07R 2017) at www.osha.gov.
According to the OSHA website, if you have employees, you will be required to do the following:
- Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers, including procedures to restrict access to work areas where high exposures may occur.
- Designate a competent person to implement the written exposure control plan.
- Restrict housekeeping practices that expose workers to silica where feasible alternatives are available.
- Offer medical exams—including chest X-rays and lung function tests—every three years for workers who are required by the standard to wear a respirator for 30 or more days per year.
- Train workers on work operations that result in silica exposure and ways to limit exposure.
- Keep records of workers’ silica exposure and medical exams.
OSHA began enforcement of the respirable crystalline silica standard for construction on Sept. 23, 2017, while offering compliance assistance to employers making good faith efforts to comply during the first 30 days.
Overview from OSHA
Respirable crystalline silica, very small particles at least 100-times smaller than ordinary sand you might find on beaches and playgrounds, is created when cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and mortar. Activities such as abrasive blasting with sand; sawing brick or concrete; sanding or drilling into concrete walls; grinding mortar; manufacturing brick, concrete blocks, stone countertops, or ceramic products and cutting or crushing stone result in worker exposures to respirable crystalline silica dust. Industrial sand used in certain operations, such as foundry work and hydraulic fracturing (fracking), is also a source of respirable crystalline silica exposure. About 2.3 million people in the U.S. are exposed to silica at work.
Workers who inhale these very small crystalline silica particles are at increased risk of developing serious silica-related diseases, including:
- Silicosis, an incurable lung disease that can lead to disability and death;
- Lung cancer;
- Chronic obstructive pulmonary disease (COPD); and
- Kidney disease.
Requirements for Flooring Trades
So, what are the requirements for the flooring trades? If you’re going to be doing any type of grinding on concrete there are requirements. Hand grinding (Photo 2), crack chasing (Photo 3), walk behind (Photo 4). First, a HEPA vacuum is going to be a tool you’ll want to invest in (Photo 5) and then a cyclonic pre-separator (Photo 6). If applicable, an Assigned Protection Factor 10 (APF) ½ mask dust mask fit tested, will be what our industry requires for most applications that we are involved with, but make sure to follow OSHA requirements (Photo 7).
The majority of grinding involved for flooring requires dry grinding, as the use of a water delivery system can compromise many flooring products due to the addition of moisture to the concrete slab. There are some specialty tools that utilize extremely high, 30,000+ PSI water jets for profiling the concrete surface that dry in a very short time but these are typically used in large scale jobs (Photo 8).
If you use a demolition hammer, there are several manufacturers that now have dust extraction attachments that you can add to your demo hammers and with the proper vacuum, will reduce the amount of silica dust exposure to the operator and surrounding area and meet OSHA silica requirements. Photo 9 is a dust containment system called dust cuff pro from Boscotool.com.
For those of you who are conducting moisture testing using the ASTM F2170 in-situ rH test method, which requires drilling into a concrete slab, you are required to use a dust containment system that meets the requirements that OSHA has set forth. There is an SDS drill bit manufactured by Milwaukee, DeWalt and Bosch, that has dust extraction holes at the bit and a hollow shaft that allows the dust to be extracted (Photo 10). Makita also makes a dust extraction attachment for use with SDS drilling.
Proper silica dust containment will be required if you are conducting the ASTM F1869 calcium chloride test and doing a 20”x20” light grind of the concrete surface test areas.
Grinder operators’ silica exposures are among the highest in the construction industry. Using proper methods will reduce workers’ exposures to silica and protect them from exposure to lung disease. For more information on how to determine proper respiratory protection, visit OSHA’s web site at osha.gov.