In this article, written by our Lab Manager Livia Fioravanti, we look at the meaning of the limit of reporting.
Since March 2025, Chemsafety has adopted the standard ‘AS 5370:2024 – Sampling and qualitative identification of asbestos in bulk materials (ISO 22262-1:2012, MOD)’ that is applicable to the qualitative identification of asbestos in manufactured asbestos-containing products and other materials like soil, dust and minerals. The standard stipulates the limit of reporting shall be 0.01% w/w (weight of asbestos / weight of sample), meaning that if asbestos fibres are present in a percentage lower than 0.01% (w/w) we must report ‘No asbestos detected’.
With the right technique, sample treatment and depending on the sample matrix, the detection limit can be significantly lower than 0.01% (w/w), but the standard uses the reporting limit of 0.01%. Please note that the detection limit is different from the reporting limit.
As the standard describes qualitative identification (and not quantitative) using Polarized Light Microscopy, we can’t quantify the amount of asbestos present in a positive sample. To overcome this, the standard assumes that if asbestos fibres are detected in a commercial material, it indicates that the asbestos is present at a mass fraction exceeding 0.1% (that is above the reporting limits), for example:
- Stipple ceilings or popcorn ceilings applied before the mid-1980s commonly contain between 1% and 10% of asbestos.
- The backing material, normally present in vinyl flooring, may contain > 90% of asbestos.
Just for you to have an idea of proportionality, 0.01% w/w could be 1mg (see picture to the left for an asbestos bundle that weighs just over 1mg) of asbestos present in 10g of material analyzed.
Figure 1: Picture of an asbestos bundle (chrysotile) that weights 0.0012g (1.2mg)
Based on this, Chemsafety has the approach that if asbestos fibres are detected in commercial products (like cement, insulation board, plaster, putty, flooring, etc), the fraction mass is above 0.01% and the report will say that asbestos fibres was detected. For samples that are not commercial products, like dust material, if asbestos is observed we may use a visual estimate of the asbestos mass fraction in the sample and residual analysis (it will depend on the quantity of sample supplied). If relevant we may also add analysis observations on our report (e.g., asbestos fibres only found in ACM debris present in the dust material, etc).
You can use our analysis request form below when dropping off your samples for analysis, and if you have any questions please do not hesitate in contacting us.
