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810 Hand and Power Tool Safety
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810 Hand and Power Tool Safety

Concrete Grinders and Cutters

Construction workers who perform concrete grinding and cutting may breathe dust that contains respirable crystalline silica (RCS).

Worker using a power grinder
Is this worker wearing eye and respiratory protection?

Construction workers who perform concrete grinding and cutting commonly breathe dust that contains respirable crystalline silica (RCS).

Grinding/polishing Dry grinding and polishing is the method most commonly used in the industry. A NIOSH study found that workers dry grinding concrete to smooth poured concrete surfaces were exposed to high levels of dust containing RCS, ranging from 35 to 55 times the NIOSH recommended exposure limit (REL). Wet polishing uses water to cool the diamond abrasives and eliminate grinding dust.

Concrete cutting is a process of controlled sawing, drilling and removing concrete.

Power grinder
There is a lot of exposure to hazardous dust during cutting?

Skilled operators use special saws to cut concrete and asphalt. As with grinding, dry cutting is most often used.

  • Careful selection of saw blades can help reduce exposure.
  • Diamond saw blades produce less dust and require less water which make them better than abrasive saw blades to cut.

The concrete saw should have a local exhaust ventilation (LEV) system, which can capture the majority of dust emitted during the cutting operation. When operating, the operator should always wear personal protective equipment (PPE).

A local exhaust ventilation (LEV) system can be used to reduce the exposure to silica dust. The LEV system consists of a grinder equipped with a ventilation shroud, a length of flexible hose, and a portable electric vacuum cleaner that acts as a fan and dust collector for the ventilation system. See illustration above.

Grinder Accident

An employee was using a grinder to grind a metal pin, when the pin became jammed and drawn into the space between the tool rest and the spinning grinding wheel. The employee's left index finger was also drawn into and against the abrasive wheel, and it was amputated. He was hospitalized. The distance between the tool rest and the abrasive wheel is not known. It is also not known whether the rest was secured in that position. At the time of the accident, the grinder's tongue guard was adjusted to a position 0.875 inches from the wheel. (Source: OSHA)

Knowledge Check Choose the best answer for the question.

5-4. What do construction workers who perform concrete grinding and cutting commonly breathe?

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