Using crushing machines to reduce the size of large rocks, concrete, or construction rubble 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 crushing machines are explained below.
Step 1: Use suitable engineering controls
Engineering control options:
Use equipment which delivers water spray or mist for dust suppression at crusher and other dust generating points and either:
- a ventilated booth that provides fresh, climate-controlled air to the operator
- a remote-control station.
Details of controls
Using water sprays or mists for dust suppression at the points where dust is generated (e.g., hoppers, conveyers, sieves/sizing or vibrating components and discharge points) can control dust exposures when operating crushers. Additionally, a method to isolate the operator must be used. The crusher must be operated and maintained in accordance with the manufacturer’s instructions to minimise dust emissions.
Operator isolation for crushing machines includes using either an enclosed booth or a remote-control station. Operators using crushing machines with a ventilated booth can limit their silica exposure by staying inside the cab during crushing operations. The booth must:
- be well-sealed and well-ventilated using positive pressure
- have door jambs, window grooves, power-line entries and other joints that work properly and are tightly sealed
- have heating and air conditioning so operators can keep windows and doors closed
be regular maintained and cleaned to prevent settled dust from becoming airborne inside the enclosed booth.
Alternatively for operator isolation, a remote-control station located a sufficient distance upwind to limit exposure to silica containing dust can be used.
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.
When properly used, wet methods with either ventilated booths or remote-control stations can effectively limit exposure to airborne dust. The use of respiratory protection when using crushers at construction sites when the machines are equipped with water sprays along with either control booths or remote controls stations is not required.