Asbestos Air Monitoring in Perth: What Air Testing Measures

Most people ring us about a material. A sheet in the laundry, a textured ceiling, some eaves lining. That is a bulk sampling job.

Air monitoring is the other half of the picture, and it answers a genuinely different question. It does not tell you what your wall is made of. It tells you what is floating in the air you are breathing, at that place, at that time.

What air monitoring is

A small calibrated pump draws a known volume of air through a filter membrane over a set period. Anything airborne and small enough gets caught on that filter.

The filter then goes to an independent laboratory, where an analyst counts the respirable fibres on a measured portion of it under a phase contrast microscope. The count is converted back to a concentration, expressed as fibres per millilitre of air.

Air monitoring vs bulk testing

These get confused constantly, and choosing the wrong one wastes money. The short version is that bulk sampling identifies a material and air monitoring measures the atmosphere.

A clean air result does not mean your walls are asbestos free. It means the air was clean while the pump was running.

That distinction matters more than it sounds. Undisturbed bonded asbestos sheeting in good condition releases very little into the air, so a property can return a perfectly normal air result and still be full of asbestos containing material.

The four types of air monitoring

Australian practice splits air monitoring into four jobs. They use the same pumps and the same laboratory method, but they exist for different reasons.

Background monitoring

Taken before any work starts, to establish what the air is like normally. Without a baseline you cannot say whether a later reading was caused by the work or was there all along.

Control monitoring

Run outside the work area while removal is under way. It is not there to check the air inside the enclosure. It is there to confirm that the controls are holding and nothing is escaping to the rest of the building.

Clearance monitoring

Done after removal work is finished, as part of deciding whether an area is safe to reoccupy. For friable work it sits alongside a visual inspection, and both have to be satisfactory before a clearance certificate is issued.

Exposure monitoring

A pump worn on the person, with the sampling head clipped in the breathing zone near the collar. This measures what one worker actually breathed across a shift, rather than what the room average was.

How a monitoring visit runs

1. Step 01

   Scope the monitoring

   We work out which type you need, how many sampling positions, and where they go. Position choice is most of the job. A pump in the wrong spot produces a technically valid number that means nothing.

2. Step 02

   Calibrate and set up

   Each pump is calibrated to a known flow rate before sampling begins, and the filter cassette is fitted with the cowl facing down so it collects air rather than settled dust.

3. Step 03

   Run the sample

   The pump runs long enough to draw the volume of air the method requires. Short runs on a low volume push the detection limit up and make the result less useful.

4. Step 04

   Close out and check flow

   Flow rate is checked again at the end. If it has drifted the sample is flagged, because the volume of air is what turns a fibre count into a concentration.

5. Step 05

   Laboratory analysis

   Filters go to an independent laboratory under chain of custody and are counted under a phase contrast microscope. Field blanks go with them to catch contamination.

6. Step 06

   Written result

   You get a report with the concentration at each position, the sampling times and volumes, and a plain statement of what the numbers mean for the decision you are making.

Reading the results

Two numbers come up repeatedly in Australian guidance, and it helps to know which is which.

• 0.01 fibres per millilitre is the control level in the national code of practice for asbestos removal. Readings at or above it are the trigger to stop, investigate and fix the controls.
• 0.1 fibres per millilitre is the workplace exposure standard for asbestos, averaged over an eight hour working day.
• Results are often reported as 'less than' a figure, because the method has a detection limit and a clean filter cannot return a true zero.

Can it tell me if I was exposed?

This is the most common reason people search for air testing, and the honest answer is no.

Air monitoring measures a place, not a person, and only while the pump is running. If you drilled into a sheet last month, monitoring your lounge room today tells you nothing about that moment. The fibres released then have long since settled or dispersed.

There is also no test we can offer that reads a past exposure out of someone. If you are worried about your health after disturbing a material, that is a conversation for your GP, and it is worth having. What we can do is test the material so you know what you were dealing with.

When you actually need it

Air monitoring is genuinely necessary in a smaller set of situations than people expect. It earns its place when a material is being disturbed, or has been.

1. 1Friable asbestos removal work, where monitoring by an independent Licensed Asbestos Assessor is required rather than optional.
2. 2Clearance after removal, where a reading supports the decision to let people back into the area.
3. 3Occupied buildings next to removal work, such as a school, a strata block or a tenanted office, where neighbours need assurance the controls are holding.
4. 4After an uncontrolled disturbance, like a fire, storm damage or a trade cutting into something they should not have.
5. 5Disputes and due diligence, where an independent set of numbers settles an argument that opinions will not.

If none of those describe your situation and you simply want to know whether a material contains asbestos, you want bulk sampling instead. It is the cheaper and more direct answer, and we will tell you so rather than sell you monitoring you do not need.

Call (08) 6186 7484 and tell us what is happening at the property. We will tell you which test fits and give you a written quote before anything is booked.