Air monitoring for respirable crystalline silica
The latest article in our series on Queensland’s new construction silica dust code of practice looks at the importance of air monitoring.
Air monitoring tests the air to find out how much of a harmful substance is in your workers’ breathing zone. This is important to find out if the dust controls in use are keeping the airborne concentration of respirable crystalline silica (RCS) below the legal workplace exposure standard (WES).
When must I conduct air monitoring?
Under Queensland’s work health and safety legislation, a person conducting a business or undertaking (PCBU) must conduct air monitoring for RCS if they are not certain whether or not the WES has been exceeded.
There are several ways a PCBU can be certain on reasonable grounds:
- By using all the recommended controls for the task as specified in Appendix 4, including RPE if required by the table.
- By using statistically valid exposure data for the task to demonstrate the higher order controls you are using minimise workers’ exposure to RCS below the WES, without the need for RPE.
- By using statistically valid exposure data for the task to demonstrate the combination of higher order controls and suitably rated RPE you are using minimise workers’ exposure to RCS below the WES.
If the PCBU is certain on reasonable grounds that the WES has not been exceeded, using Appendix 4 or statistically valid exposure data, they are not required to conduct air monitoring.
If the PCBU is not using Appendix 4 and does not have statistically valid exposure data to demonstrate the controls they are using protect workers from exposure to RCS at levels that exceed the WES, they can’t be reasonably certain and must conduct air monitoring.
Note that for fabrication of stone benchtops, including engineered and natural stone, the Managing respirable crystalline silica dust exposure in the stone benchtop industry code of practice 2019 outlines when air monitoring is required.
What is statistically valid exposure data?
Air monitoring produces exposure data, which is a measure of how much of the harmful substance (such as RCS) is in the air.
Statistically valid exposure data refers to data produced from air monitoring that meets the standards outlined in Section 9.3.1 of the new Code. These standards ensure that the air monitoring uses reliable sampling methods and is undertaken by a certified occupational hygienist.
A PCBU can use statistically valid exposure data to demonstrate how effective dust controls are at preventing RCS from getting into the breathing zone of workers.
How can I get statistically valid exposure data?
The statistically valid exposure data could come from a range of sources, including:
- the manufacturer of the control or tool used
- an industry association
- an occupational hygienist.
The duty is on the PCBU to be certain that the exposure data is statistically valid; and that it is relevant to the task, controls, and conditions. If they are not, then they can’t be certain on reasonable grounds that the controls used are effective.
If the PCBU is uncertain whether the existing exposure data is statistically valid, they should consult with a competent person (e.g., a certified occupational hygienist, or a recognised equivalent competency under an international certification scheme, e.g., certified industrial hygienist).
When consulting with a competent person, provide them with Section 9.3.1 of the Managing respirable crystalline silica dust exposure in construction and the manufacturing of construction elements code of practice 2022.
Who can do air monitoring?
Air monitoring should be undertaken by a person who has acquired the knowledge and skills to carry out the task, from training, qualification or experience. The table below outlines who is suitably competent to perform air monitoring tasks:
Task | Who is qualified |
|---|---|
Plan air monitoring at the workplace (including establishing similar exposure groups and develop a sampling plan) | Certified occupational hygienist, or a recognised equivalent competency under an international certification scheme (e.g., certified industrial hygienist). |
Conduct personal exposure monitoring at the workplace |
|
Interpreting the results of air monitoring, and drawing conclusions | Certified occupational hygienist, or a recognised equivalent competency under an international certification scheme (e.g., certified industrial hygienist). |
Visit the Australian Institute of Occupational Hygienists (AIOH) website to find a certified occupational hygienist.
Next steps
This eSafe series has so far looked at identifying silica dust risks and hazards, and choosing the right silica dust controls. In the next article in this series, we will explain when you need to provide health monitoring to your workers.
The new Code of practice commenced on 1 May 2023.