Analysis of suspect asbestos containing materials

The analysis of materials that possibly contain asbestos can be carried out by various methods, however the dispersion staining microscopic technique is considered to be a quick, reliable and cost-effective method that is used by the majority of laboratories that routinely carry out this type of work. This method should be in accordance with MDHS 77 (1994), which is published by the UK Health and Safety Executive and forms part of the series of the methods for the determination of hazardous substances, titled Asbestos in Bulk Materials -sampling and identification by polarised light microscopy (PLM). 

This method is generally applicable for the analysis of building materials that contain asbestos, however, if the material submitted for analysis comprises of a quantity of soil or fill type material, then careful screening will have to take place to remove all suspect ACMs from the soil. These suspect materials should be separated from the soil and washed if necessary prior to being analysed in accordance with MDHS 77 (1994) as detailed below. 

The determination of the type(s) of asbestos present within a bulk material must be performed within a specialised safety cabinet fitted with a high efficiency HEPA filter and may be summarised as follows  

The bulk material could be prepared to facilitate analysis by various methods which may include cleaning, grinding, crushing, solvent washing, acid washing, ultrasonic treatment etc. These tasks must obviously be carried out in a manner that ensures no fibres are lost from the sample or released into the atmosphere. 

The sample is initially examined under a zoom stereo microscope, individual fibres are carefully removed from the sample matrix and placed into an appropriate refractive index liquid to be examined. 

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III) Documentation showing that an analysis of suspected asbestos-containing material from the school is pending at an accredited laboratory. 

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