Containment and decontamination: what you should see
Containment keeps the fibres inside a boundary. Decontamination makes sure none of them leave with the people, the tools or the dust when that boundary comes down.
Containment is everything done to stop fibres leaving the work area: barriers, sealed sheeting, signage and, on the most serious jobs, an enclosure held at negative pressure. Decontamination (“decon” on a quote) is everything done to make sure fibres do not leave on people, on equipment or in the dust left behind.
They are the two halves of one idea. Material is being disturbed on purpose, so whatever it releases has to stay inside a boundary and be cleaned up before that boundary comes down.
This page explains what those two words mean and what they look like from the footpath. It is deliberately not a method. Setting up containment and running a decontamination are part of licensed removal work, and nothing below is written for a homeowner to copy.
What does asbestos containment actually mean?
Containment is a scale rather than a single thing, and the amount used should match how likely the material is to release fibres.
At the light end (a bonded sheet coming off an outdoor wall, say) containment can be an exclusion zone. Barricades and signs keep everybody except the removalist out, sheeting catches debris, and the waste is tightly controlled. The people being kept out are the family and the neighbours.
At the heavy end (friable material, the sort that crumbles under hand pressure) containment means a sealed enclosure. The space is lined and sealed, entry is through an airlock.
The enclosure also runs at negative pressure. Filters continuously extract air, so the inside sits at slightly lower pressure than the outside. Any leak then draws air inwards instead of pushing dust out. An enclosure is checked before work starts, not simply built and trusted.
The useful part for a homeowner is what the difference tells you. If a quote for friable work does not describe an enclosure, or what is on site is plastic taped across a doorway, that is not a small shortcut. It is the wrong category of work.
What does asbestos decontamination involve?
Three separate things get decontaminated, and it is worth naming them separately because the third is the one that gets skipped.
- People. On friable work, workers leave through a decontamination unit. A self-contained shower unit, usually on a trailer or truck in the driveway, with a dirty end, a shower and a clean end. The one-way order is the point: you cannot reach your own clothes without passing through the water.
- Equipment. Tools, the enclosure lining and anything else that met the material are either cleaned before they leave or bagged and disposed of as asbestos waste.
- The area. The final clean of the space itself: surfaces, ledges, the roof cavity if there is one, and the ground outside. This is done with wet methods and specialist vacuums fitted with HEPA filtration. A household vacuum cleaner is not a weaker version of that equipment: it is the opposite of it, because it returns the finest fraction straight into the room.
How much containment is proportionate?
| Bonded (non-friable) | Friable | |
|---|---|---|
| Typical material | Fibro sheet, eaves, fence sheeting, corrugated roofing | Loose-fill insulation, pipe lagging, badly damaged sheet |
| Containment | Exclusion zone, signage, sheeting to catch debris | Sealed enclosure, airlock, negative pressure |
| Worker decontamination | Proportionate to the job: wash facilities, disposable coveralls | Decontamination unit, one way through a shower |
| Air monitoring | Not always required | Mandatory, by an assessor independent of the removalist |
| Who may do the work | Licensing and homeowner limits are set by each state and territory | Class A licensed removalist, everywhere in Australia |
Why “decon” on a quote is worth more than it looks
When a household ends up with a contamination problem after a removal, the cause is usually not the removal. It is the clean-up. The sheets come off and the truck leaves, but material stays in the places nobody inspects: gutters and downpipes, garden beds, the soil under where the wall stood, the roof cavity, the ground behind the shed.
That is why does this include decontamination and a clearance inspection is a more useful question to ask a removalist than anything about the removal itself. Decontamination is what produces a site that can pass a clearance inspection, and the clearance is what lets people move back in.
What should a homeowner expect to see?
You are not inspecting the work (that is the assessor's job) but plenty is visible from outside the boundary. And it tells you which kind of job you are watching.
- Signs and physical barriers, up before the work starts rather than after.
- Material kept wet, and no dry sweeping at any point.
- A conspicuous absence of power tools that grind, sand or cut the material.
- Waste going straight into labelled heavy-duty bags or wrapped sheeting. Never a general skip or the household bin.
- On friable work: an enclosure, and a decontamination unit on site.
- At the end, the gutters, the ground and the roof cavity looked at, not only the wall that came off.
- Paperwork at the end, including the clearance where one applies.
What should worry you?
The reverse list is short. Each item is a reason to stop the job and ring the regulator in your state or territory: a broom, a household vacuum, a pressure washer, an angle grinder, no barrier between the work and where children or pets are, waste going into a domestic bin, or friable work with no enclosure. None of those is a matter of preference.
Where do the rules come from?
Asbestos work is regulated under the work health and safety laws of each state and territory, not by a single national rulebook. The model WHS Regulations are adopted separately in each jurisdiction. The detail varies between them, including what a homeowner may do on their own property and above what area a licence is required.
SafeWork NSW, WorkSafe Victoria and their counterparts in the other states and territories are the authority for their own patch. And a figure quoted in one should never be assumed to apply in another.
Two things do hold everywhere. Friable asbestos removal requires a Class A licence, with no homeowner exemption. And whether a material contains asbestos at all is settled by laboratory analysis of a sample. Not by its age, its appearance or a photograph. Accreditation, from a body such as NATA, is what gives you grounds to rely on the result you get back.
What is an asbestos decontamination unit?
A decontamination unit, often called a decon unit, is a self-contained shower unit that workers pass through when they leave a friable asbestos job. It usually sits on a trailer or truck in the driveway.
It has a dirty end, a shower and a clean end. The one-way order is the point: nobody can reach their own clothes without going through the water.
A decon unit is standard on friable, Class A work. For bonded material the arrangements are proportionate to the job rather than fixed, and each state or territory regulator sets the requirements. This page describes what you should see, not a method to copy.
Frequently asked questions
What is asbestos containment?
Everything done to stop fibres leaving the work area while material is being disturbed: barriers and signage at the light end, and at the heavy end a sealed enclosure held at negative pressure, so that any leak draws air inwards instead of pushing dust out.
What does asbestos decontamination involve?
Three things: the workers, who on friable work leave through a decontamination unit with a dirty end, a shower and a clean end; the equipment, cleaned or bagged as asbestos waste; and the area itself, cleaned with wet methods and HEPA-filtered vacuums rather than a household vacuum or a broom.
Is a decontamination unit always required?
It is standard on friable, Class A work. For bonded work the arrangements are proportionate to the job rather than fixed, and the requirements are set by the work health and safety regulator in each state and territory.
Can I set up containment and remove the material myself?
Friable asbestos is Class A licensed work everywhere in Australia, with no homeowner exemption. For bonded material, what a homeowner may do on their own property and above what area a licence is needed varies by state and territory, so check your own regulator. This site does not publish methods for either.
What usually goes wrong after a removal?
Incomplete clean-up rather than the removal itself: debris in gutters and downpipes, fragments in garden beds, dust left in the roof cavity, material in the soil. That is what decontamination and the clearance inspection exist to catch.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- SafeWork NSW. Asbestos. Hazards A, Z
- WorkSafe Victoria. Asbestos. Duties, licensing and safe removal