NATA Accredited Asbestos Testing and Analysis Services
Testing and analysis of asbestos is not just a case of putting a sample into a processor and having a result come out the other end. Have your samples tested by a skilled and experienced analyst to ensure that it is done correctly.
The asbestos testing process takes a number of different steps.
Finding the fibres
First the analyst has to find any fibres in the sample. For some products, like most asbestos cement sheets, rope seals and gaskets, this can be quite easy. For other products, such as vinyl, putty and bituminous materials, this can be a lot harder. The sample may need to be heated in a furnace or treated with acid to enable the analyst to separate the fibres from the matrix of the product. The analyst uses a stereo microscope to find the fibres and then extracts them from the sample.
Deciding what the fibres are most likely to be; organic, synthetic mineral fibre or asbestos
Once the fibres have been extracted, the analyst uses his/her knowledge and experience to make an initial assessment on what the fibres are most likely to be.
This is based on the physical appearance of the fibres for example:
- Are the fibres singular or bundled?
- Are they soft and flexible or straight and brittle?
- Are they flattened and ribbon-like?
Using the various characteristics the analyst will decide whether the fibre is most likely organic, Synthetic Mineral Fibre (SMF) or asbestos, and the likely type of asbestos.
This initial decision determines the next step in the process.
The fibres are viewed using a polarised light microscope
The next step involves mounting the fibres in a refractive index oil and viewing them under a polarised light microscope. There are a number of different refractive index oils. The one chosen is determined by the decision made previously on what the expected result is.
Using the polarised light microscope the various optical characteristics of the fibres are examined and compared to known characteristics of the fibre types. If the characteristics match then the identification is confirmed.
The analyst needs to be experienced to obtain the diagnosis
It might almost sound simple, but there are a lot of traps for an inexperienced analyst. Sometimes the wrong initial decision may be made. Occasionally Chrysotile asbestos, which is usually soft and flexible, may appear straight and springy and be mistaken at first glance for Amosite asbestos and mounted in the wrong refractive index oil. Because of this the optical characteristics under the polarised light microscope will not match. In this case you will need to get some more fibres from the sample and retry in the correct refractive index oil.
If asbestos fibres have been exposed to high temperatures their optical characteristics can change. The fibres may be stained, either deliberately for commercial reasons, or due to the location where they were used. For example, the optical characteristics of Chrysotile can be hidden by the staining that occurs due to the bitumen used in malthoid.
Other fibres may sometimes look like asbestos. Very fine spider-web can look similar to Chrysotile. So too can very fine organic fibres found on some plant roots.
Sometimes, no matter what you do you won’t get the correct dispersion staining colours when viewing the fibres under the polarised light microscope. It may be due to the way the asbestos has been treated or it could be because it is a type that the laboratory is not accredited to identify. In these cases you will get a diagnosis of “Unknown Mineral Fibre”
Need an asbestos sample tested and analysed?
Due to the complexities of analysing asbestos, you need to make sure your Asbestos Analysts are working for a NATA accredited laboratory, such as the Mairin Asbestos Laboratory. We have the experience and training to give you the correct results.