Using heavy equipment and utility vehicles for earthmoving tasks such as grading and excavating does not usually generate hazardous levels of respirable crystalline silica dust.
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 heavy equipment or utility vehicles for earthmoving tasks such as grading and excavating soil are explained below.
Step 1: Use suitable engineering controls
Engineering control options:
- Apply water and/or dust suppressants as necessary to minimise dust emissions.
- Operate equipment within an enclosed cabin.
- When workers outside of the cab are engaged in the task, apply water and/or dust suppressants as necessary to minimise dust emissions.
Details of controls
Using water and/or dust suppressants can help to reduce exposure to dust when operating heavy equipment or utility vehicles for tasks such as grading and excavating. If the equipment operator is the only person there, the employer can choose to apply water and/or dust suppressants to minimise dust emissions or require the operator to stay within an enclosed cab. If there are other people there, water and/or dust suppressants must be used to minimise their exposure to airborne dust.
Wet methods for heavy equipment and utility vehicle operators include those which suppress dust emissions and are compatible with the task. These include:
- tank trucks with hoses and nozzles that spray water or other dust suppressants over large areas to wet materials disturbed during earthmoving, including haul roads and job sites in general
- a worker who sprays water or other types of dust suppressants to materials being moved.
- large atomized misting devices
- spray equipment attached to the vehicle
- adjust nozzles so water spray is directed at the work areas where dust suppression is required
- time the application of the water or other dust suppressants to ensure the materials are still damp when they are disturbed.
Water must be applied at flow rates sufficient to minimise the release of visible dust. Too much water can create mud slurry that can cause hazards. Too little water will not effectively control dust emissions.
When operators rely on enclosed cabs for protection against silica dust, the cab must:
- be well-sealed and well-ventilated using positive pressure
- have door jambs, window grooves, powerline entries and other joints that work properly and are tightly sealed
- have heating and air conditioning so operators can keep windows and doors closed
- have HEPA filters fitted to the intake and recirculation air intake
- be regularly maintained and cleaned to prevent settled dust from become airborne inside the enclosure.
Worker applying water/dust suppressant
When other workers are assisting, water or dust suppressants must 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.
RPE is not required while using heavy equipment for tasks such as grading and excavating.