Asbestos Sample Testing And Its Procedures

Posted by Layla Flinn on January 12th, 2022

The rules and regulations of some countries state that if you have some work related to asbestos, then you must get it tested for safety purposes. As it is a very harmful mineral, it is required that asbestos sample testing be done before usage.

What Is Asbestos?

Asbestos is a mineral that occurs naturally in the earth. It was a substance that was extensively used to produce items that were required for construction sites and purposes. It was used until the late 80s and 90s, after which it was gradually phased out because of its toxicity. Many countries have banned this material, and in case there is a suspicion of the presence of asbestos. You must call up the authorities, and they will do the asbestos sample testing to find out if asbestos is present in it or not.

Asbestos Sample Testing

When there is any material that consists of asbestos, then the asbestos sample testing must be carried out. The process is carried out by gathering samples from the site and taking them to a laboratory. It can be done by taking single or multiple numbers of asbestos fibers and testing for the amount of asbestos present in it. After the test is carried out, the concerned people will also be able to detect and inform the type of asbestos found in the sample.

What Are The Different Stages Of Asbestos Testing?

Asbestos sample testing is done in laboratories in dust cabinets. The cabinets are complete with highly efficient particle air filters and negative pressures with which the tests are carried out. Most laboratories carry out the tests in two different stages.

Stage 1

Stereomicroscopy Stage

In the first stage of the asbestos sample testing, the samples are put through a stereo microscope that gives a three-dimensional view of the sample to be tested. The sample is put into the dust cabinet and opened there. In the cabinet, it is put on a disposable petri dish and examined with the eye.

The traces of asbestos fibres are judged by their physical properties and physical appearance.  If the characteristics are consistent with asbestos fibres, they decide on the next stage accordingly. And these properties are indicators of the selection of the refractive index liquid that will be used in the next stage.

Stage 2

Polarised Light Microscopy Stage

The refractive index liquid is used in the laboratory along with polarised light microscopy. The correct refractive index liquid is dropped on a slide outside the dust cabinet. They put the fibre for testing on the liquid and put a coverslip over the fiber in the dust cabinet.

Under the polarised light microscope, the technicians in the laboratory look for certain features like:

• Its morphology
• Pleochroism and colour
• Characteristics of extinction
• Elongation signs
• Dispersion staining

The technicians maintain the records of every stage for further procedures if required.

Testing Of Negative Samples

The initial stage may not confirm whether the sample is a fibre of asbestos or not. There is a possibility that the sample could not be identified, and in such a case, one has to go ahead with asbestos sample testing again. All the tests are done using probes or tweezers. So they will start by taking up random samples of fibre, and they will make two slide preparations. After further analysis by PLM, if they find no results, that sample may be negative.

Conclusion

Once the asbestos sample testing is done, the samples are put into double bags and stored. All the surfaces where the sample was kept are also cleaned. All the disposable items that were used in the test are taken to be as good as the sample of asbestos testing and are disposed of accordingly. But these samples are kept for six month, after which they are disposed of.