How long do clearance air test results take in Calgary?

Turnaround for clearance air results is set by the lab and the analytical method, so ask the consultant for their lab's turnaround in writing before the job is scheduled. The cost for clearance testing runs roughly $200 to $700 per area, depending on the number of samples taken and whether a written report is included.

A few things affect how quickly you get results. Phase contrast microscopy (PCM, NIOSH 7400) counts fibres in air but cannot distinguish asbestos from other fibres. Transmission electron microscopy (TEM, NIOSH 7402) positively identifies asbestos fibres. The Alberta Asbestos Abatement Manual describes both methods and notes that labs should participate in a proficiency testing program, though Alberta law does not require lab accreditation.

What the clearance standard actually is

The Alberta Asbestos Abatement Manual describes the air levels: during low-risk work, monitoring results should stay below 0.01 fibres per cubic centimetre in all phases; for moderate-risk work with a containment, final results must be less than 0.01 fibres per cubic centimetre with aggressive sampling; for high-risk enclosures, the containment stays under negative pressure until air tests confirm fibre levels are low enough to dismantle. These are the figures that drive how long the whole clearance process takes, not just the lab turnaround.

A few things worth asking before you accept a clearance result:

• Who collected the samples? Ask for a consultant independent of the abatement crew; the same company doing the removal and then signing off on the clearance is a conflict worth questioning.
• Which lab is processing the samples, and which method are they using?
• Does the quote include a written clearance letter, or just raw numbers? The City of Calgary's demolition permit guide requires a clearance letter stating all asbestos materials have been properly removed and the area is acceptable for demolition, so if a permit is involved you need that letter in writing.
• Is aggressive sampling included if a containment was used?

The 72-hour OHS notification that the contractor must file before work begins is separate from clearance; it does not add to lab turnaround time.

And if the material was disturbed before any of this was arranged: stop the work, leave the area, keep everyone including pets out, close the door, do not sweep or vacuum, and get it tested first.