The meaning of terms like ‘friable’ and requirements relating to reporting limits vary between jurisdictions and applications, depending on whether the legislation relates to testing driven by Occupational Health, Waste Classification and Disposal, Contaminated Site Assessment or other guidelines.
The Australian Standard method AS4964 is promulgated as the reference method for Asbestos testing in all jurisdictions, for both the intended application of asbestos identification and as the base method for Asbestos quantitation, most notably under the National Environment Protection (Assessment of Site Contamination) Amendment Measure 2013 (No. 1) (“the NEPM”). Although never intended as a quantitative method, under the NEPM, laboratories are routinely requested to apply AS4964 to quantitation of asbestos in soils.
In the NEPM, AF is defined by size (i.e. asbestos materials that pass through a 7x7mm sieve), whereas FA is defined by its degree of degradation or condition. In practice, these categories often overlap. In discussion of the definitions of FA and AF, the NEPM adds the following:
From a risk to human health perspective, FA and AF are considered to be equivalent to ‘friable’ asbestos in Safe Work Australia (2011), which is defined therein as ‘material that is in a powder form or that can be crumbled, pulverised or reduced to a powder by hand pressure when dry, and contains asbestos’ NEPM Schedule B1 p27-28
It has become evident that the purported equivalence of these terms under the NEPM as implied in Table 6 of the NEPM is not necessarily generally accepted, particularly outside the environmental sector. The exclusion of ‘free’ fibres, generally taken to mean the respirable (‘trace’) fibres which represent the greatest health risk, highlights this difference in definitions.
Under asbestos removal, waste classification and disposal and Occupational Health regulations, any reported detection of ‘friable’ asbestos implies the potential presence of respirable fibres. As a result, the use of this term can invoke rigorous dust controls and dramatically increase waste disposal and other costs for stakeholders. There is no explicit requirement in AS4964 to use the term ‘friable’ when describing asbestos found in samples for analysis. For homogenous samples, the laboratory is only required to describe the ‘entire sample, or sub-sample, or both’. The Standard does, however, suggest by example that the ‘form’ of asbestos fibres found should also be reported for non-homogenous samples.
Table 6: Equivalency of terms used in the NEPM, WA DoH (2009) and Work Health and Safety Legistation guidelines
(based on WA DoH 2009)
|Work Health and Safety terminology|
|Bonded asbestos-containing-material or 'bonded ACM' (referred to as ACM in WA DoH 2009)||Bonded asbestos/non-friable asbestos|
|Fibrous asbestos, FA||Non-bonded / friable asbestos|
|Asbestos fines, AF||Non-bonded / friable asbestos|
Clearly, accurate reporting of asbestos test results demands careful use of terminology to avoid unintended misinterpretations and increased costs for industries involved in asbestos related works.
Asbestos Analytes and Descriptions
AS4964-2004 Identification by AS4964 (NATA accredited)
|Asbestos Detected||Yes / No||0.1||g/kg|
|Sample weight (dry)||Weight||0.01||g|
|Asbestos (Trace)||Yes / No||5||Fibres|
* The ‘Description' reported under AS4964 is intended to give context to the form or condition of any asbestos found in the sample. The form is described in objective terms, with the term ‘friable’ only used when the asbestos is actually assessed by crushing as described by Safe Work Australia.
Asbestos Quantification under the ACS NEPM 2013 (non-NATA)
|Asbestos (Fines and Fibrous <7mm)||Dry Weight||0.0005||g|
|Fibrous Asbestos >7mm||Dry Weight||0.1||g|
|Asbestos (Fines and Fibrous FA+AF)||Percentage||0.001||% (w/w)|
|Asbestos Containing Material||Dry Weight||0.1||g|
|Asbestos Containing Material (as 15% Asbestos in ACM >7mm)||Percentage||0.01||% (w/w)|
|Weight Used for % Calculation||Soil Weight||0.0001||kg|
Results below the AS4964 Limit of Reporting
In some jurisdictions, there is an obligation on laboratories to report the presence of all asbestos found, even when estimated to be below the AS4964 Limit of Reporting (LOR). Consequently, when asbestos is found, but estimated to be below the AS4964 reporting limit, ALS will report a qualified No*. The “No*” will be accompanied in the report by an explanatory comment stating that “Asbestos was found at levels estimated to be below the reporting limit of 0.1g/Kg”. The asbestos type and description will also be reported.
For further information please contact your local ALS Client Services team.