Friable asbestos is removed inside sealed enclosures, where nobody outside can see what is happening. The only evidence that the controls worked is measurement. This page covers what gets measured, against which numbers, and what the resulting certificate actually says.
Three numbers, three different jobs
Conflating these is the most common technical error in public asbestos material, and it matters because acting on the wrong one either stops a job that should continue or continues a job that should stop.
A respirable fibre level measured in a person’s breathing zone, expressed as a time-weighted average over an eight-hour working day and measured over a minimum period of four hours. It describes what a worker breathed, not whether an area is clean.
Exceeded during Class A removal, this stops the work and triggers notification to the regulator. It is a control trigger measured at the enclosure and its surrounds, not an exposure measurement.
The level at or below which an area can be cleared for re-occupation, and the level work must return to before it can restart after a stoppage. In practice it is typically reported as below the analytical limit of detection.
Air monitoring during Class A work — reg 475
Part 8.8 of the model regulations is titled Asbestos removal requiring Class A licence and contains three provisions: reg 475 (air monitoring), reg 476 (action if the respirable fibre level is too high) and reg 477 (removing friable asbestos).
A PCBU who commissions asbestos removal work that requires a Class A licence must ensure that an independent licensed asbestos assessor undertakes air monitoring.
Queensland Code of Practice, How to safely remove asbestos 2021, on s 475
Note who carries the duty. It falls on the person who commissions the work — the client, the builder, the asset owner — not on the removalist. Engaging the assessor is not the removalist’s job, and a removalist who brings their own is precisely the arrangement the provision is designed to prevent.
Timing: control monitoring must be conducted immediately before and during Class A removal work. Reg 477 locks this together with the enclosure requirement — removal work must not commence until the independent assessor’s air monitoring has started, and the enclosure has passed its leak test.
A regulator statement we do not follow
SafeWork SA’s assessor guidance states that licensed assessors conduct air monitoring for Class A and Class B removal work. That does not match the model framework: Part 8.8 is titled Asbestos removal requiring Class A licence, and reg 475 sits inside it. Mandatory air monitoring by an independent licensed assessor applies to Class A work only. Monitoring during Class B work is permitted, and is sometimes a sensible thing to do, but it is not required by reg 475 and may be carried out by a competent person.
The action table — reg 476
Identical across the 2011 model Code, the 2018 model Code and the Queensland 2021 Code.
| Measured level | Required action |
|---|---|
| Below 0.01 fibres/mL | No new control measures are necessary. Continue with the existing control measures. |
| 0.01 up to and including 0.02 fibres/mL |
|
| More than 0.02 fibres/mL |
|
Two features of that table are worth dwelling on. The middle band is not a warning to be noted and filed — it requires an actual review, an actual investigation and actual implemented controls. And the recovery threshold after a stoppage is 0.01, not 0.02: coming back under the stop-work trigger is not enough to restart.
In Queensland the notification obligation is operationalised: licensed removalists must notify immediately on 1300 362 128 where fibre levels are recorded at more than 0.02 fibres/mL during Class A removal work.
The analytical method is the membrane filter method.
Removing friable asbestos — reg 477
For friable removal, a licensed removalist must ensure that:
- the asbestos removal area is enclosed to prevent the release of respirable asbestos fibres;
- negative pressure is used, provided the enclosure being used has been tested for leaks;
- the wet method of asbestos removal is used; and
- the removal work does not commence until the air monitoring is started by an independent licensed asbestos assessor, provided the enclosure has been tested for leaks.
The glove-bag exception
“If the glove bag method is used, you are not required to conduct air monitoring prior to the work commencing or to use negative pressure during the asbestos removal work.”
This is a narrow exception for small, contained items — typically lagging on a pipe run — where the bag itself is the enclosure. It disapplies two specific requirements: pre-start monitoring and negative pressure. It does not disapply the licence requirement, the control plan, the wet method, decontamination, waste handling, or clearance.
Notice how regs 475 and 477 interlock. The enclosure must be built and leak-tested, and the independent assessor’s monitoring must be running, before a single square metre of friable material is disturbed. Sequencing is part of the control, not administrative overhead.
Clearance — regs 473 and 474
A person commissioning licensed asbestos removal work must ensure that, once the licensed asbestos removal work has been completed, a clearance inspection is carried out and a clearance certificate is issued before the workplace can be re-occupied.
Model Code of Practice (2011), on regs 473–474
| Work type | Clearance must be issued by |
|---|---|
| Class A removal work | An independent licensed asbestos assessor |
| All other licensed removal work | An independent competent person |
The two limbs
A certificate cannot be issued unless both are satisfied.
1. The visual limb — always. The assessor or competent person must be satisfied that the asbestos removal area and the area immediately surrounding it are free from visible asbestos contamination.
2. The air monitoring limb — where monitoring is conducted. If air monitoring is also conducted, the results must show that any identified respirable asbestos fibre levels are below 0.01 fibres/mL.
For Class A work the second limb is never optional, because reg 475 makes the monitoring mandatory in the first place. For Class B work, where monitoring is not required, a clearance may rest on the visual limb alone.
Note the words “and the area immediately surrounding it”. A clearance is not a certificate about the inside of the enclosure. If material has been tracked out to a laydown area, a stairwell or a car park, that is within scope, and it is the single most common reason a clearance is refused on the first attempt.
The model Code provides a worked example of a clearance certificate at Appendix D in the 2018 edition, and at Appendix C in the 2011 edition.
We could not verify the statutory wording of reg 474, including whether it uses a “safe for normal use” formulation, and the Code does not state who must keep the certificate or for how long. We therefore do not publish a retention period for clearance certificates. In practice, keeping one with the asbestos register for the life of the asset is the sensible course.
Health monitoring
Part 8.5 of the model regulations, regs 435–444, sits alongside all of this and is frequently overlooked on shorter jobs.
A PCBU must ensure health monitoring is provided to a worker if they are carrying out licensed asbestos removal work, other ongoing asbestos removal work, or asbestos-related work, and are at risk of exposure to asbestos when carrying out the work.
| Timing | Before the worker commences licensed removal work; and at regular intervals — at least once every two years — after a worker commences asbestos-related work |
| Content | Consideration of the worker’s demographic, medical and occupational history, and a physical examination with emphasis on the respiratory system, including standardised respiratory function tests |
| Supervised by | A registered medical practitioner with relevant experience (reg 437) |
| Who pays | The PCBU must pay all expenses relating to health monitoring (reg 438) |
| Records | Kept as a confidential record for at least 40 years after the record is made (reg 444) |
Reports go to the worker (reg 441), to the regulator in defined circumstances (reg 442) and to other relevant PCBUs (reg 443). The forty-year retention period is a reminder of what this framework is ultimately about: the diseases in question have latency measured in decades, and the record has to outlive the job, the company and often the building.