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Handheld grinders for tasks other than mortar removal

Using handheld grinders to smooth or cut the surfaces of concrete, masonry or other silica containing materials can generate respirable crystalline silica dust. When inhaled, the small particles of silica can irreversibly damage the lungs.

Exposure controls needed in accordance with Appendix 4 of the Managing respirable crystalline silica in construction and manufacturing of construction elements code of practice 2022 (PDF, 1.71 MB) when using handheld grinders for uses other than mortar removal are explained below.

Step 1: Use suitable engineering controls

Engineering control option (one of the following two controls must be used):

  • An integrated water delivery system that provide a continuous water feed to the grinding surface (outdoor use only).
  • A grinder equipped with a:
    • commercially available shroud
    • dust collector that:
      • provides at least an airflow of 25 cubic feet per minute per inch of blade (roughly 700 litres per 25mm of blade diameter)
      • is rated to either M-Class or H-Class
      • has a cyclonic pre-separator or filter cleaning mechanism.

Wet methods

Grinders equipped with an integrated water delivery system which feeds water to the grinding surface can be used to control dust when cutting, grinding or polishing materials containing crystalline silica outdoors. When used outdoors, water-fed grinders can control dust on uneven surfaces and near corners and edges more effectively than vacuum dust collection systems.

Clean up slurry produced before it dries and releases silica dust into the air.

Dust collection system

A dust collection system can also be used to control dust when using a handheld grinder. A person conducting a business or undertaking (PCBU) can comply by ensuing the dust collection system:

  • has a dust commercially available shroud on the tool designed to fit the grinder and wheel size
  • provides at least 25 cubic feet per minute (cfm) of airflow per inch of blade (roughly 700 litres per 25mm of wheel diameter) to capture dust at the point of grinding and removing mortar. For example, a five inch grinding wheel would require a rating of 125 cfm of air flow or more for effective capture
  • is equipped with a cyclonic pre-separator
  • is rated with a M-Class or H-Class as per AS/NZS60335.2.69.

Step 2: Select appropriate respiratory protective equipment (RPE)

The type of RPE you will need depends on:

  • what type of engineering controls you are using
  • how long the worker is going to do the task during the shift
  • where the work is being undertaken.

RPE is not required when wet cutting (outdoors only) but is required if using dust extraction. Half face reusable or disposable RPE has a minimum protection factor (MPF) of 10.

Engineering control used Time spent doing task during shift
Equal or less than 4 hours Greater than 4 hours
Wet cutting (Option 1) RPE not required RPE not required
Dust extraction (Option 2) Outdoors
RPE not required
RPE not required
Indoors / enclosed area
RPE not required
Indoors / enclosed area
P1 or P2 filtered RPE with a MPF 10 required

For tight fitting RPE, workers must be fit-tested to the specific make and model before using it. See section 7.6 of the Code (PDF, 1.71 MB) for more information on fit-testing and other requirements for using RPE.

A PCBU must provide health monitoring to a worker if their tasks require them to wear RPE 30 times or more in 12 months. See section 10 of the Code (PDF, 1.71 MB) for more information on health monitoring requirements.

Further information