Asbestos air testing & four-stage clearance
Air testing measures whether asbestos fibres are present in the air, and a four-stage clearance is the formal check that an area is safe to go back into after removal. To mean anything, clearance must be independent, so it is carried out by a UKAS-accredited analyst, not by the firm that did the removal.
Air testing tells you whether asbestos fibres are in the air; a four-stage clearance is the formal process that confirms an area is genuinely clean and safe to reoccupy after asbestos work. Where bulk sampling tests a piece of material, air testing measures the air itself, drawing a known volume through a filter that an analyst examines for fibres.
This is the reassurance at the end of the job, or after a worrying disturbance: independent evidence that an area is safe, not just someone's word for it. It is one of four services in our surveys and testing range.
Why independence matters. A clearance only means something if it is carried out by someone with no stake in the result. A firm signing off its own removal work is marking its own homework. For that reason, four-stage clearances are carried out by an independent UKAS-accredited analyst, including on our own jobs — we never clear our own removals. That separation is what makes the certificate worth having.
Types of air testing
- Reassurance air testing— to confirm fibre levels are normal in an occupied space, for example after a disturbance or near recent work
- Clearance air testing— the air monitoring stage within a four-stage clearance after removal
- Background air testing— to establish fibre levels before work begins, as a baseline
What a four-stage clearance involves
Preliminary check
The analyst checks the paperwork and the site condition, confirming the work is complete and the area is ready to be assessed.
Visual inspection
A thorough visual inspection for any remaining debris or dust, the stage that most often catches a job that is not quite finished.
Air monitoring
Air is drawn through filters and examined for fibres, confirming levels are below the clearance limit.
Final assessment
After any enclosure is taken down, a final check and the clearance certificate confirming the area is safe to reoccupy.
The visual stage that stopped us issuing the certificate
After a garage roof removal in Woolwich, we arranged the 4-stage clearance through our independent UKAS-accredited analyst. Stage 1 is a thorough visual inspection of the enclosure before the analyst allows the air pumps to be set up. On this job, the analyst found a small fragment of asbestos-cement sheeting that had lodged in the gutter above the enclosure and dropped back in during dismantling. It was the size of a 50p piece. It was not visible from ground level. The air test would not have caught it.
We went back in, retrieved the fragment, re-cleaned the enclosure, and the analyst repeated the visual before proceeding to Stage 2. The air result came back clear. The certificate was issued the same afternoon. The homeowner asked why it had taken longer than expected. We explained what had been found and what we had done about it.
That is the point of the 4-stage process. The visual inspection is not a formality — it is the stage that catches what the air pumps cannot. An analyst who rushes it to get to the monitoring is not doing the job properly. Ours do not rush it, and we would not want them to.
How we handle air testing & clearance
This is the part of the job where trust is everything, so it is the part we are most careful to keep at arm's length. We arrange air testing and clearance through a UKAS-accredited analyst, and we keep that analyst independent of our removal work, because a certificate is only worth having if the person issuing it has nothing to gain.
- Independent, UKAS-accredited.
Testing and clearance are carried out by a UKAS-accredited analyst who is independent of the removal, the recognised standard for results you can rely on.
- We never clear our own work.
On our own removals, the clearance is done by someone other than us. No conflict of interest, no marking our own homework.
- The right test for the situation.
We will tell you plainly whether you need a reassurance test, a full four-stage clearance, or nothing at all, rather than selling a service you do not need.
If a material has been damaged or disturbed and you are anxious about the air, a reassurance test gives you a clear, independent answer. Keep people out of the area in the meantime and get in touch.
What affects the price
Air testing and clearance are priced to the job. The main factors:
Is air testing what you need?
Air testing answers whether fibres are in the air. To find out whether a material contains asbestos, you want testing and sampling; to assess a building, a management survey; and before building work, a refurbishment and demolition survey. See all options on the surveys and testing hub.
Air testing & clearance, answered
Why can't you clear your own removal work?
What is the difference between air testing and sampling?
When do I need a four-stage clearance?
What is a reassurance test?
What happens if a clearance fails?
Arrange air testing or a clearance
Tell us the situation — after removal, after a disturbance, or just to be sure — and we will arrange independent, UKAS-accredited air testing or a four-stage clearance, with a clear result you can rely on.